@Article{IPB-206, author = {Wasternack, C. and Hause, B. and}, title = {{BFP1: One of 700 Arabidopsis F-box proteins mediates degradation of JA oxidases to promote plant immunity}}, year = {2024}, pages = {375-376}, journal = {Mol. Plant}, doi = {10.1016/j.molp.2024.02.008}, url = {https://doi.org/10.1016/j.molp.2024.02.008}, volume = {17}, } @Article{IPB-200, author = {Launhardt, L. and Uhlenberg, J. and Stellmach, H. and Schomburg, M. and Hause, B. and Heilmann, I. and Heilmann, M. and}, title = {{Association of the Arabidopsis oleoyl Δ12‐desaturase FAD2 with pre‐cis‐Golgi stacks at endoplasmic reticulum‐Golgi‐exit sites}}, year = {2024}, pages = {242-263}, journal = {Plant J.}, doi = {10.1111/tpj.16492}, url = {https://doi.org/10.1111/tpj.16492}, volume = {117}, abstract = {The unsaturation of phospholipids influences the function of membranes. In Arabidopsis thaliana, the oleoyl Δ12‐desaturase FAD2 converts oleic (18:1Δ9) to linoleic acid (18:2Δ9,12) and influences phospholipid unsaturation in different cellular membranes. Despite its importance, the precise localization of Arabidopsis FAD2 has not been unambiguously described. As FAD2 is thought to modify phospholipid‐associated fatty acids at the endoplasmic reticulum (ER), from where unsaturates are distributed to other cellular sites, we hypothesized that FAD2 locates to ER subdomains enabling trafficking of lipid intermediates through the secretory pathway. Fluorescent FAD2 fusions used to test this hypothesis were first assessed for functionality by heterologous expression in yeast (Saccharomyces cerevisiae), and in planta by Arabidopsis fad2 mutant rescue upon ectopic expression from an intrinsic FAD2 promoter fragment. Light sheet fluorescence, laser scanning confocal or spinning disc microscopy of roots, leaves, or mesophyll protoplasts showed the functional fluorescence‐tagged FAD2 variants in flattened donut‐shaped structures of ~0.5–1 μm diameter, in a pattern not resembling mere ER association. High‐resolution imaging of coexpressed organellar markers showed fluorescence‐tagged FAD2 in a ring‐shaped pattern surrounding ER‐proximal Golgi particles, colocalizing with pre‐cis‐Golgi markers. This localization required the unusual C‐terminal retention signal of FAD2, and deletion or substitutions in this protein region resulted in relaxed distribution and diffuse association with the ER. The distinct association of FAD2 with pre‐cis‐Golgi stacks in Arabidopsis root and leaf tissue is consistent with a contribution of FAD2 to membrane lipid homeostasis through the secretory pathway, as verified by an increased plasma membrane liquid phase order in the fad2 mutant.} } @Article{IPB-300, author = {Zeng, M. and Krajinski, F. and Dam, N. M. and Hause, B. and}, title = {{Jarin-1, an inhibitor of JA-Ile biosynthesis in Arabidopsis thaliana , acts differently in other plant species}}, year = {2023}, pages = {e2273515}, journal = {Plant Signaling \& Behavior}, doi = {10.1080/15592324.2023.2273515}, url = {https://doi.org/10.1080/15592324.2023.2273515}, volume = {18}, abstract = {Jasmonates (JAs), including jasmonic acid (JA) and its biologically active derivative JA-Ile, are lipid-derived plant signaling molecules. They govern plant responses to stresses, such as wounding and insect herbivory. Wounding elicits a rapid increase of JA and JA-Ile levels as well as the expression of JAR1, coding for the enzyme involved in JA-Ile biosynthesis. Endogenous increase and application of JAs, such as MeJA, a JA methylester, result in increased defense levels, often accompanied by diminished growth. A JA-Ile biosynthesis inhibitor, jarin-1, was shown to exclusively inhibit the JA-conjugating enzyme JAR1 in Arabidopsis thaliana. To investigate whether jarin-1 does function similarly in other plants, we tested this in Medicago truncatula, Solanum lycopersicum, and Brassica nigra seedlings in a root growth inhibition assay. Application of jarin-1 alleviated the inhibition of root growth after MeJA application in M. truncatula seedlings, proving that jarin-1 is biologically active in M. truncatula. Jarin-1 did not show, however, a similar effect in S. lycopersicum and B. nigra seedlings treated with MeJA. Even JA-Ile levels were not affected by application of jarin-1 in wounded leaf disks from S. lycopersicum. Based on these results, we conclude that the effect of jarin-1 is highly species-specific. Researchers intending to use jarin-1 for studying the function of JAR1 or JA-Ile in their model plants, must test its functionality before use.} } @Article{IPB-299, author = {Zeng, M. and Dam, N. M. and Hause, B. and}, title = {{MtEIN2 affects nitrate uptake and accumulation of photosynthetic pigments under phosphate and nitrate deficiency in Medicago truncatula}}, year = {2023}, pages = {e13899}, journal = {Physiol. Plant.}, doi = {10.1111/ppl.13899}, url = {https://doi.org/10.1111/ppl.13899}, volume = {175}, abstract = {Ethylene (ET) controls many facets of plant growth and development under abiotic and biotic stresses. MtEIN2, as a critical element of the ET signaling pathway, is essential in biotic interactions. However, the role of MtEIN2 in responding to abiotic stress, such as combined nutrient deficiency, is less known. To assess the role of ethylene signaling in nutrient uptake, we manipulated nitrate (NO3−) and phosphate (Pi) availability for wild-type (WT) and the ethylene-insensitive (MtEIN2-defective) mutant, sickle, in Medicago truncatula. We measured leaf biomass and photosynthetic pigments in WT and sickle to identify conditions leading to different responses in both genotypes. Under combined NO3− and Pi deficiency, sickle plants had higher chlorophyll and carotenoid contents than WT plants. Under these conditions, nitrate content and gene expression levels of nitrate transporters were higher in the sickle mutant than in the WT. This led to the conclusion that MtEIN2 is associated with nitrate uptake and the content of photosynthetic pigments under combined Pi and NO3−deficiency in M. truncatula. We conclude that ethylene perception plays a critical role in regulating the nutrient status of plants.} } @Article{IPB-261, author = {Ninck, S. and Halder, V. and Krahn, J. H. and Beisser, D. and Resch, S. and Dodds, I. and Scholtysik, R. and Bormann, J. and Sewald, L. and Gupta, M. D. and Heilmann, G. and Bhandari, D. D. and Morimoto, K. and Buscaill, P. and Hause, B. and van der Hoorn, R. A. L. and Kaschani, F. and Kaiser, M. and}, title = {{Chemoproteomics Reveals the Pan-HER Kinase Inhibitor Neratinib To Target an Arabidopsis Epoxide Hydrolase Related to Phytohormone Signaling}}, year = {2023}, pages = {1076-1088}, journal = {ACS Chem. Biol.}, doi = {10.1021/acschembio.2c00322}, url = {https://doi.org/10.1021/acschembio.2c00322}, volume = {18}, abstract = {Plant phytohormone pathways are regulated by an intricate network of signaling components and modulators, many of which still remain unknown. Here, we report a forward chemical genetics approach for the identification of functional SA agonists in Arabidopsis thaliana that revealed Neratinib (Ner), a covalent pan-HER kinase inhibitor drug in humans, as a modulator of SA signaling. Instead of a protein kinase, chemoproteomics unveiled that Ner covalently modifies a surface-exposed cysteine residue of Arabidopsis epoxide hydrolase isoform 7 (AtEH7), thereby triggering its allosteric inhibition. Physiologically, the Ner application induces jasmonate metabolism in an AtEH7-dependent manner as an early response. In addition, it modulates PATHOGENESIS RELATED 1 (PR1) expression as a hallmark of SA signaling activation as a later effect. AtEH7, however, is not the exclusive target for this physiological readout induced by Ner. Although the underlying molecular mechanisms of AtEH7-dependent modulation of jasmonate signaling and Ner-induced PR1-dependent activation of SA signaling and thus defense response regulation remain unknown, our present work illustrates the powerful combination of forward chemical genetics and chemical proteomics for identifying novel phytohormone signaling modulatory factors. It also suggests that marginally explored metabolic enzymes such as epoxide hydrolases may have further physiological roles in modulating signaling.} } @Article{IPB-253, author = {Manh, M. B. and Ost, C. and Peiter, E. and Hause, B. and Krupinska, K. and Humbeck, K. and}, title = {{WHIRLY1 acts upstream of ABA-related reprogramming of drought-induced gene expression in Barley and affects stress-related histone modifications}}, year = {2023}, pages = {6326}, journal = {Int. J. Mol. Sci.}, doi = {10.3390/ijms24076326}, url = {https://doi.org/10.3390/ijms24076326}, volume = {24}, abstract = {WHIRLY1, a small plant-specific ssDNA-binding protein, dually located in chloroplasts and the nucleus, is discussed to act as a retrograde signal transmitting a stress signal from the chloroplast to the nucleus and triggering there a stress-related gene expression. In this work, we investigated the function of WHIRLY1 in the drought stress response of barley, employing two overexpression lines (oeW1-2 and oeW1-15). The overexpression of WHIRLY1 delayed the drought-stress-related onset of senescence in primary leaves. Two abscisic acid (ABA)-dependent marker genes of drought stress, HvNCED1 and HvS40, whose expression in the wild type was induced during drought treatment, were not induced in overexpression lines. In addition, a drought-related increase in ABA concentration in the leaves was suppressed in WHIRLY1 overexpression lines. To analyze the impact of the gain-of-function of WHIRLY1 on the drought-related reprogramming of nuclear gene expression, RNAseq was performed comparing the wild type and an overexpression line. Cluster analyses revealed a set of genes highly up-regulated in response to drought in the wild type but not in the WHIRLY1 overexpression lines. Among these genes were many stress- and abscisic acid (ABA)-related ones. Another cluster comprised genes up-regulated in the oeW1 lines compared to the wild type. These were related to primary metabolism, chloroplast function and growth. Our results indicate that WHIRLY1 acts as a hub, balancing trade-off between stress-related and developmental pathways. To test whether the gain-of-function of WHIRLY1 affects the epigenetic control of stress-related gene expression, we analyzed drought-related histone modifications in different regions of the promoter and at the transcriptional start sites of HvNCED1 and HvS40. Interestingly, the level of euchromatic marks (H3K4me3 and H3K9ac) was clearly decreased in both genes in a WHIRLY1 overexpression line. Our results indicate that WHIRLY1, which is discussed to act as a retrograde signal, affects the ABA-related reprogramming of nuclear gene expression during drought via differential histone modifications.} } @Article{IPB-226, author = {Darwish, E. and Ghosh, R. and Bentzer, J. and Tsardakas Renhuldt, N. and Proux‐Wera, E. and Kamal, N. and Spannagl, M. and Hause, B. and Sirijovski, N. and Van Aken, O. and}, title = {{The dynamics of touch‐responsive gene expression in cereals}}, year = {2023}, pages = {282-302}, journal = {Plant J.}, doi = {10.1111/tpj.16269}, url = {https://doi.org/10.1111/tpj.16269}, volume = {116}, abstract = {Wind, rain, herbivores, obstacles, neighbouring plants, etc. provide important mechanical cues to steerplant growth and survival. Mechanostimulation to stimulate yield and stress resistance of crops is of signifi-cant research interest, yet a molecular understanding of transcriptional responses to touch is largely absentin cereals. To address this, we performed whole-genome transcriptomics following mechanostimulation ofwheat, barley, and the recent genome-sequenced oat. The largest transcriptome changes occurred 25 minafter touching, with most of the genes being upregulated. While most genes returned to basal expressionlevel by 1–2 h in oat, many genes retained high expression even 4 h post-treatment in barley and wheat.Functional categories such as transcription factors, kinases, phytohormones, and Ca2+regulation wereaffected. In addition, cell wall-related genes involved in (hemi)cellulose, lignin, suberin, and callose biosyn-thesis were touch-responsive, providing molecular insight into mechanically induced changes in cell wallcomposition. Furthermore, several cereal-specific transcriptomic footprints were identified that were notobserved in Arabidopsis. In oat and barley, we found evidence for systemic spreading of touch-induced sig-nalling. Finally, we provide evidence that both the jasmonic acid-dependent and the jasmonic acid-independent pathways underlie touch-signalling in cereals, providing a detailed framework and markergenes for further study of (a)biotic stress responses in cereals.} } @Article{IPB-213, author = {Ai, H. and Bellstaedt, J. and Bartusch, K. S. and Eschen‐Lippold, L. and Babben, S. and Balcke, G. U. and Tissier, A. and Hause, B. and Andersen, T. G. and Delker, C. and Quint, M. and}, title = {{Auxin‐dependent regulation of cell division rates governs root thermomorphogenesis}}, year = {2023}, pages = {e111926}, journal = {EMBO J.}, doi = {10.15252/embj.2022111926}, url = {https://doi.org/10.15252/embj.2022111926}, volume = {42}, abstract = {Roots are highly plastic organs enabling plants to adapt to a changing below-ground environment. In addition to abiotic factors like nutrients or mechanical resistance, plant roots also respond to temperature variation. Below the heat stress threshold, Arabidopsis thaliana seedlings react to elevated temperature by promoting primary root growth, possibly to reach deeper soil regions with potentially better water saturation. While above-ground thermomorphogenesis is enabled by thermo-sensitive cell elongation, it was unknown how temperature modulates root growth. We here show that roots are able to sense and respond to elevated temperature independently of shoot-derived signals. This response is mediated by a yet unknown root thermosensor that employs auxin as a messenger to relay temperature signals to the cell cycle. Growth promotion is achieved primarily by increasing cell division rates in the root apical meristem, depending on de novo local auxin biosynthesis and temperature-sensitive organization of the polar auxin transport system. Hence, the primary cellular target of elevated ambient temperature differs fundamentally between root and shoot tissues, while the messenger auxin remains the same.} } @Article{IPB-248, author = {Israeli, A. and Schubert, R. and Man, N. and Teboul, N. and Serrani Yarce, J. C. and Rosowski, E. E. and Wu, M.-F. and Levy, M. and Efroni, I. and Ljung, K. and Hause, B. and Reed, J. W. and Ori, N. and}, title = {{Modulating auxin response stabilizes tomato fruit set}}, year = {2023}, pages = {2336-2355}, journal = {Plant Physiol.}, doi = {10.1093/plphys/kiad205}, url = {https://doi.org/10.1093/plphys/kiad205}, volume = {192}, abstract = {Fruit formation depends on successful fertilization and is highly sensitive to weather fluctuations that affect pollination. Auxin promotes fruit initiation and growth following fertilization. Class A auxin response factors (Class A ARFs) repress transcription in the absence of auxin and activate transcription in its presence. Here, we explore how multiple members of the ARF family regulate fruit set and fruit growth in tomato (Solanum lycopersicum) and Arabidopsis thaliana, and test whether reduction of SlARF activity improves yield stability in fluctuating temperatures. We found that several tomato Slarf mutant combinations produced seedless parthenocarpic fruits, most notably mutants deficient in SlARF8A and SlARF8B genes. Arabidopsis Atarf8 mutants deficient in the orthologous gene had less complete parthenocarpy than did tomato Slarf8a Slarf8b mutants. Conversely, Atarf6 Atarf8 double mutants had reduced fruit growth after fertilization. AtARF6 and AtARF8 likely switch from repression to activation of fruit growth in response to a fertilization-induced auxin increase in gynoecia. Tomato plants with reduced SlARF8A and SlARF8B gene dosage had substantially higher yield than the wild type under controlled or ambient hot and cold growth conditions. In field trials, partial reduction in the SlARF8 dose increased yield under extreme temperature with minimal pleiotropic effects. The stable yield of the mutant plants resulted from a combination of early onset of fruit set, more fruit-bearing branches and more flowers setting fruits. Thus, ARF8 proteins mediate the control of fruit set, and relieving this control with Slarf8 mutations may be utilized in breeding to increase yield stability in tomato and other crops.} } @Article{IPB-405, author = {Zeng, M. and Hause, B. and van Dam, N. M. and Uthe, H. and Hoffmann, P. and Krajinski, F. and Martínez‐Medina, A. and}, title = {{The mycorrhizal symbiosis alters the plant defence strategy in a model legume plant}}, year = {2022}, pages = {3412-3428}, journal = {Plant Cell Environ.}, doi = {10.1111/pce.14421}, url = {https://doi.org/10.1111/pce.14421}, volume = {45}, abstract = {Arbuscular mycorrhizal (AM) symbiosis modulates plant‐herbivore interactions. Still, how it shapes the overall plant defence strategy and the mechanisms involved remain unclear. We investigated how AM symbiosis simultaneously modulates plant resistance and tolerance to a shoot herbivore, and explored the underlying mechanisms. Bioassays with Medicago truncatula plants were used to study the effect of the AM fungus Rhizophagus irregularis on plant resistance and tolerance to Spodoptera exigua herbivory. By performing molecular and chemical analyses, we assessed the impact of AM symbiosis on herbivore‐triggered phosphate (Pi)‐ and jasmonate (JA)‐related responses. Upon herbivory, AM symbiosis led to an increased leaf Pi content by boosting the mycorrhizal Pi‐uptake pathway. This enhanced both plant tolerance and herbivore performance. AM symbiosis counteracted the herbivore‐triggered JA burst, reducing plant resistance. To disentangle the role of the mycorrhizal Pi‐uptake pathway in the plant\'s response to herbivory, we used the mutant line ha1‐2, impaired in the H+‐ATPase gene HA1, which is essential for Pi‐uptake via the mycorrhizal pathway. We found that mycorrhiza‐triggered enhancement of herbivore performance was compromised in ha1‐2 plants. AM symbiosis thus affects the defence pattern of M. truncatula by altering resistance and tolerance simultaneously. We propose that the mycorrhizal Pi‐uptake pathway is involved in the modulation of the plant defence strategy.} } @Article{IPB-388, author = {Stellmach, H. and Hose, R. and Räde, A. and Marillonnet, S. and Hause, B. and}, title = {{A new set of Golden-Gate-Based organelle marker plasmids for colocalization studies in plants}}, year = {2022}, pages = {2620}, journal = {Plants}, doi = {10.3390/plants11192620}, url = {https://doi.org/10.3390/plants11192620}, volume = {11}, abstract = {In vivo localization of proteins using fluorescence-based approaches by fusion of the protein of interest (POI) to a fluorescent protein is a cost- and time-effective tool to gain insights into its physiological function in a plant cell. Determining the proper localization, however, requires the co-expression of defined organelle markers (OM). Several marker sets are available but, so far, the procedure requires successful co-transformation of POI and OM into the same cell and/or several cloning steps. We developed a set of vectors containing markers for basic cell organelles that enables the insertion of the gene of interest (GOI) by a single cloning step using the Golden Gate cloning approach and resulting in POI–GFP fusions. The set includes markers for plasma membrane, tonoplast, nucleus, endoplasmic reticulum, Golgi apparatus, peroxisomes, plastids, and mitochondria, all labelled with mCherry. Most of them were derived from well-established marker sets, but those localized in plasma membrane and tonoplast were improved by using different proteins. The final vectors are usable for localization studies in isolated protoplasts and for transient transformation of leaves of Nicotiana benthamiana. Their functionality is demonstrated using two enzymes involved in biosynthesis of jasmonic acid and located in either plastids or peroxisomes.} } @Article{IPB-305, author = {Asfaw, K. G. and Liu, Q. and Eghbalian, R. and Purper, S. and Akaberi, S. and Dhakarey, R. and Münch, S. W. and Wehl, I. and Bräse, S. and Eiche, E. and Hause, B. and Bogeski, I. and Schepers, U. and Riemann, M. and Nick, P. and}, title = {{The jasmonate biosynthesis Gene OsOPR7 can mitigate salinity induced mitochondrial oxidative stress}}, year = {2022}, pages = {111156}, journal = {Plant Sci.}, doi = {10.1016/j.plantsci.2021.111156}, url = {https://doi.org/10.1016/j.plantsci.2021.111156}, volume = {316}, abstract = {Salinity poses a serious threat to global agriculture and human food security. A better understanding of plant adaptation to salt stress is, therefore, mandatory. In the non-photosynthetic cells of the root, salinity perturbs oxidative balance in mitochondria, leading to cell death. In parallel, plastids accumulate the jasmonate precursor cis (+)12-Oxo-Phyto-Dienoic Acid (OPDA) that is then translocated to peroxisomes and has been identified as promoting factor for salt-induced cell death as well. In the current study, we probed for a potential interaction between these three organelles that are primarily dealing with oxidative metabolism. We made use of two tools: (i) Rice OPDA Reductase 7 (OsOPR7), an enzyme localised in peroxisomes converting OPDA into the precursors of the stress hormone JA-Ile. (ii) A Trojan Peptoid, Plant PeptoQ, which can specifically target to mitochondria and scavenge excessive superoxide accumulating in response to salt stress. We show that overexpression of OsOPR7 as GFP fusion in tobacco (Nicotiana tabacum L. cv. Bright Yellow 2, BY-2) cells, as well as a pretreatment with Plant PeptoQ can mitigate salt stress with respect to numerous aspects including proliferation, expansion, ionic balance, redox homeostasis, and mortality. This mitigation correlates with a more robust oxidative balance, evident from a higher activity of superoxide dismutase (SOD), lower levels of superoxide and lipid peroxidation damage, and a conspicuous and specific upregulation of mitochondrial SOD transcripts. Although both, Plant PeptoQ and ectopic OsOPR7, were acting in parallel and mostly additive, there are two specific differences: (i) OsOPR7 is strictly localised to the peroxisomes, while Plant PeptoQ found in mitochondria. (ii) Plant PeptoQ activates transcripts of NAC, a factor involved in retrograde signalling from mitochondria to the nucleus, while these transcripts are suppressed significantly in the cells overexpressing OsOPR7. The fact that overexpression of a peroxisomal enzyme shifting the jasmonate pathway from the cell-death signal OPDA towards JA-Ile, a hormone linked with salt adaptation, is accompanied by more robust redox homeostasis in a different organelle, the mitochondrion, indicates that cross-talk between peroxisome and mitochondrion is a crucial factor for efficient adaptation to salt stress.} } @Article{IPB-303, author = {Abuslima, E. and Kanbar, A. and Raorane, M. L. and Eiche, E. and Junker, B. H. and Hause, B. and Riemann, M. and Nick, P. and}, title = {{Gain time to adapt: How sorghum acquires tolerance to salinity}}, year = {2022}, pages = {1008172}, journal = {Front. Plant Sci.}, doi = {10.3389/fpls.2022.1008172}, url = {https://doi.org/10.3389/fpls.2022.1008172}, volume = {13}, abstract = {Salinity is a global environmental threat to agricultural production and food security around the world. To delineate salt-induced damage from adaption events we analysed a pair of sorghum genotypes which are contrasting in their response to salt stress with respect to physiological, cellular, metabolomic, and transcriptional responses. We find that the salt-tolerant genotype Della can delay the transfer of sodium from the root to the shoot, more swiftly deploy accumulation of proline and antioxidants in the leaves and transfer more sucrose to the root as compared to its susceptible counterpart Razinieh. Instead Razinieh shows metabolic indicators for a higher extent photorespiration under salt stress. Following sodium accumulation by a fluorescent dye in the different regions of the root, we find that Della can sequester sodium in the vacuoles of the distal elongation zone. The timing of the adaptive responses in Della leaves indicates a rapid systemic signal from the roots that is travelling faster than sodium itself. We arrive at a model where resistance and susceptibility are mainly a matter of temporal patterns in signalling.} } @Article{IPB-383, author = {Ruberti, C. and Feitosa-Araujo, E. and Xu, Z. and Wagner, S. and Grenzi, M. and Darwish, E. and Lichtenauer, S. and Fuchs, P. and Parmagnani, A. S. and Balcerowicz, D. and Schoenaers, S. and de la Torre, C. and Mekkaoui, K. and Nunes-Nesi, A. and Wirtz, M. and Vissenberg, K. and Van Aken, O. and Hause, B. and Costa, A. and Schwarzländer, M. and}, title = {{MCU proteins dominate in vivo mitochondrial Ca2+ uptake in Arabidopsis roots}}, year = {2022}, pages = {4428-4452}, journal = {Plant Cell}, doi = {10.1093/plcell/koac242}, url = {https://doi.org/10.1093/plcell/koac242}, volume = {34}, abstract = {Abstract Ca2+ signaling is central to plant development and acclimation. While Ca2+-responsive proteins have been investigated intensely in plants, only a few Ca2+-permeable channels have been identified, and our understanding of how intracellular Ca2+ fluxes is facilitated remains limited. Arabidopsis thaliana homologs of the mammalian channel-forming mitochondrial calcium uniporter (MCU) protein showed Ca2+ transport activity in vitro. Yet, the evolutionary complexity of MCU proteins, as well as reports about alternative systems and unperturbed mitochondrial Ca2+ uptake in knockout lines of MCU genes, leave critical questions about the in vivo functions of the MCU protein family in plants unanswered. Here, we demonstrate that MCU proteins mediate mitochondrial Ca2+ transport in planta and that this mechanism is the major route for fast Ca2+ uptake. Guided by the subcellular localization, expression, and conservation of MCU proteins, we generated an mcu triple knockout line. Using Ca2+ imaging in living root tips and the stimulation of Ca2+ transients of different amplitudes, we demonstrated that mitochondrial Ca2+ uptake became limiting in the triple mutant. The drastic cell physiological phenotype of impaired subcellular Ca2+ transport coincided with deregulated jasmonic acid-related signaling and thigmomorphogenesis. Our findings establish MCUs as a major mitochondrial Ca2+ entry route in planta and link mitochondrial Ca2+ transport with phytohormone signaling.} } @Article{IPB-364, author = {Mittelberger, C. and Hause, B. and Janik, K. and}, title = {{The ‘Candidatus Phytoplasma mali’ effector protein SAP11CaPm interacts with MdTCP16, a class II CYC/TB1 transcription factor that is highly expressed during phytoplasma infection}}, year = {2022}, pages = {e0272467}, journal = {PLOS ONE}, doi = {10.1371/journal.pone.0272467}, url = {https://doi.org/10.1371/journal.pone.0272467}, volume = {17}, abstract = {’Candidatus Phytoplasma mali’, is a bacterial pathogen associated with the so-called apple proliferation disease in Malus × domestica. The pathogen manipulates its host with a set of effector proteins, among them SAP11CaPm, which shares similarity to SAP11AYWB from ’Candidatus Phytoplasma asteris’. SAP11AYWB interacts and destabilizes the class II CIN transcription factors of Arabidopsis thaliana, namely AtTCP4 and AtTCP13 as well as the class II CYC/TB1 transcription factor AtTCP18, also known as BRANCHED1 being an important factor for shoot branching. It has been shown that SAP11CaPm interacts with the Malus × domestica orthologues of AtTCP4 (MdTCP25) and AtTCP13 (MdTCP24), but an interaction with MdTCP16, the orthologue of AtTCP18, has never been proven. The aim of this study was to investigate this potential interaction and close a knowledge gap regarding the function of SAP11CaPm. A Yeast two-hybrid test and Bimolecular Fluorescence Complementation in planta revealed that SAP11CaPm interacts with MdTCP16. MdTCP16 is known to play a role in the control of the seasonal growth of perennial plants and an increase of MdTCP16 gene expression has been detected in apple leaves in autumn. In addition to this, MdTCP16 is highly expressed during phytoplasma infection. Binding of MdTCP16 by SAP11CaPm might lead to the induction of shoot proliferation and early bud break, both of which are characteristic symptoms of apple proliferation disease.} } @Article{IPB-321, author = {El Amerany, F. and Rhazi, M. and Balcke, G. and Wahbi, S. and Meddich, A. and Taourirte, M. and Hause, B. and}, title = {{The effect of chitosan on plant physiology, wound response, and fruit quality of tomato}}, year = {2022}, pages = {5006}, journal = {Polymers}, doi = {10.3390/polym14225006}, url = {https://doi.org/10.3390/polym14225006}, volume = {14}, abstract = {In agriculture, chitosan has become popular as a metabolic enhancer; however, no deep information has been obtained yet regarding its mechanisms on vegetative tissues. This work was conducted to test the impact of chitosan applied at different plant growth stages on plant development, physiology, and response to wounding as well as fruit shape and composition. Five concentrations of chitosan were tested on tomato. The most effective chitosan doses that increased leaf number, leaf area, plant biomass, and stomatal conductance were 0.75 and 1 mg mL−1. Chitosan (1 mg mL−1) applied as foliar spray increased the levels of jasmonoyl–isoleucine and abscisic acid in wounded roots. The application of this dose at vegetative and flowering stages increased chlorophyll fluorescence (Fv/Fm) values, whereas application at the fruit maturation stage reduced the Fv/Fm values. This decline was positively correlated with fruit shape and negatively correlated with the pH and the content of soluble sugars, lycopene, total flavonoids, and nitrogen in fruits. Moreover, the levels of primary metabolites derived from glycolysis, such as inositol phosphate, lactic acid, and ascorbic acid, increased in response to treatment of plants with 1 mg mL−1- chitosan. Thus, chitosan application affects various plant processes by influencing stomata aperture, cell division and expansion, fruit maturation, mineral assimilation, and defense responses.} } @Article{IPB-344, author = {Jäckel, L. and Schnabel, A. and Stellmach, H. and Klauß, U. and Matschi, S. and Hause, G. and Vogt, T. and}, title = {{The terminal enzymatic step in piperine biosynthesis is co‐localized with the product piperine in specialized cells of black pepper (Piper nigrum L.)}}, year = {2022}, pages = {731–747}, journal = {Plant J.}, doi = {10.1111/tpj.15847}, url = {https://doi.org/10.1111/tpj.15847}, volume = {111}, abstract = {Piperine (1-piperoyl piperidine) is responsible for the pungent perception of dried black pepper (Pipernigrum) fruits and essentially contributes to the aromatic properties of this spice in combination with ablend of terpenoids. The final step in piperine biosynthesis involves piperine synthase (PS), which catalyzesthe reaction of piperoyl CoA and piperidine to the biologically active and pungent amide. Nevertheless, experimental data on the cellular localization of piperine and the complete biosynthetic pathway are missing. Not only co-localization of enzymes and products, but also potential transport of piperamides to thesink organs is a possible alternative. This work, which includes purification of the native enzyme, immunolocalization, laser microdissection, fluorescence microscopy, and electron microscopy combinedwith liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), providesexperimental evidence that piperine and PS are co-localized in specialized cells of the black pepper fruit peri-sperm. PS accumulates during early stages of fruit development and its level declines before the fruits arefully mature. The product piperine is co-localized to PS and can be monitored at the cellular level by itsstrong bluish fluorescence. Rising piperine levels during fruit maturation are consistent with the increasingnumbers of fluorescent cells within the perisperm. Signal intensities of individual laser-dissected cells whenmonitored by LC-ESI-MS/MS indicate molar concentrations of this alkaloid. Significant levels of piperineand additional piperamides were also detected in cells distributed in the cortex of black pepper roots. Insummary, the data provide comprehensive experimental evidence of and insights into cell-specific biosyn-thesis and storage of piperidine alkaloids, specific and characteristic for the Piperaceae. By a combination offluorescence microscopy and LC-MS/MS analysis we localized the major piperidine alkaloids to specific cellsof the fruit perisperm and the root cortex. Immunolocalization of native piperine and piperamide synthasesshows that enzymes are co-localized with high concentrations of products in these idioblasts.} } @Article{IPB-477, author = {Mielke, S. and Zimmer, M. and Meena, M. K. and Dreos, R. and Stellmach, H. and Hause, B. and Voiniciuc, C. and Gasperini, D. and}, title = {{Jasmonate biosynthesis arising from altered cell walls is prompted by turgor-driven mechanical compression}}, year = {2021}, pages = {eabf0356}, journal = {Sci. Adv.}, doi = {10.1126/sciadv.abf0356}, url = {https://advances.sciencemag.org/content/7/7/eabf0356}, volume = {7}, abstract = {Despite the vital roles of jasmonoyl-isoleucine (JA-Ile) in governing plant growth and environmental acclimation, it remains unclear what intracellular processes lead to its induction. Here, we provide compelling genetic evidence that mechanical and osmotic regulation of turgor pressure represents a key elicitor of JA-Ile biosynthesis. After identifying cell wall mutant alleles in KORRIGAN1 (KOR1) with elevated JA-Ile in seedling roots, we found that ectopic JA-Ile resulted from cell nonautonomous signals deriving from enlarged cortex cells compressing inner tissues and stimulating JA-Ile production. Restoring cortex cell size by cell type–specific KOR1 complementation, by isolating a genetic kor1 suppressor, and by lowering turgor pressure with hyperosmotic treatments abolished JA-Ile signaling. Conversely, hypoosmotic treatment activated JA-Ile signaling in wild-type plants. Furthermore, constitutive JA-Ile levels guided mutant roots toward greater water availability. Collectively, these findings enhance our understanding on JA-Ile biosynthesis initiation and reveal a previously undescribed role of JA-Ile in orchestrating environmental resilience.} } @Article{IPB-424, author = {Bittner, A. and Hause, B. and Baier, M. and}, title = {{Cold-priming causes oxylipin dampening during the early cold and light response of Arabidopsis thaliana}}, year = {2021}, pages = {7163-7179}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erab314}, url = {https://doi.org/10.1093/jxb/erab314}, volume = {72}, abstract = {Abstract The comparison of transcriptome time-courses of the first 2 h of the cold or highlight response of 24 h cold primed and naive Arabidopsis thaliana showed that priming quickly modifies gene expression in a trigger-specific manner. It dampened up- as well as down-regulation of genes in the cold and in the light. 1/3 of the priming-regulated genes were jasmonate sensitive, including the full set of genes required for oxylipin biosynthesis. qPCR-based analysis in wildtype plants and mutants demonstrated that OPDA (12-oxo phytenoic acid) biosynthesis relative to the jasmonic acid (JA) availability controls dampening of the genes for oxylipin biosynthetic enzymes: Gene regulation in oxylipin biosynthesis mutants more strongly depended on the biosynthesis of the JA precursor OPDA than on its conversion to JA. Additionally, priming-dependent dampening during triggering was more linked to OPDA than to JA level regulation and spray application of OPDA prior to triggering counteracted gene dampening. In contrast to cold-priming induced dampening of ZAT10, priming regulation of the oxylipin hub was insensitive to priming-induced accumulation of thylakoid ascorbate peroxidase and mediated by modulation of the oxylipin sensitivity of genes for OPDA biosynthesis.} } @Article{IPB-541, author = {El Amerany, F. and Meddich, A. and Wahbi, S. and Porzel, A. and Taourirte, M. and Rhazi, M. and Hause, B. and}, title = {{Foliar Application of Chitosan Increases Tomato Growth and Influences Mycorrhization and Expression of Endochitinase-Encoding Genes}}, year = {2020}, pages = {535}, journal = {Int. J. Mol. Sci.}, doi = {10.3390/ijms21020535}, volume = {21}, abstract = {Nowadays, applying bio-organic fertilizer (e.g., chitosan, Ch) or integrating beneficial microorganisms (e.g., arbuscular mycorrhizal fungi, AMF) are among the successful strategies to promote plant growth. Here, the effect of two application modes of Ch (foliar spray or root treatment) and Ch-derived nanoparticles (NPs) on tomato plants colonized with the AMF Rhizophagus irregularis were analyzed, thereby focusing on plant biomass, flowering and mycorrhization. An increase of shoot biomass and flower number was observed in arbuscular mycorrhizal (AM) plants sprayed with Ch. The interaction with AMF, however, was reduced as shown by decreased mycorrhization rates and AM-specific gene expression. To get insights into Ch effect on mycorrhization, levels of sugars, jasmonates, abscisic acid, and the expression of two chitinase-encoding genes were determined in mycorrhizal roots. Ch had no effect on sugar and phytohormone levels, but the reduced mycorrhization was correlated with down- and upregulated expression of Chi3 and Chi9, respectively. In contrast, application of NPs to leaves and Ch applied to the soil did not show any effect, neither on mycorrhization rate nor on growth of mycorrhizal plants. Concluding, Ch application to leaves enhanced plant growth and flowering and reduced interaction with AMF, whereas root treatment did not affect these parameters.} } @Article{IPB-528, author = {Asfaw, K. G. and Liu, Q. and Xu, X. and Manz, C. and Purper, S. and Eghbalian, R. and Münch, S. W. and Wehl, I. and Bräse, S. and Eiche, E. and Hause, B. and Bogeski, I. and Schepers, U. and Riemann, M. and Nick, P. and}, title = {{A mitochondria-targeted coenzyme Q peptoid induces superoxide dismutase and alleviates salinity stress in plant cells}}, year = {2020}, pages = {11563}, journal = {Sci. Rep.}, doi = {10.1038/s41598-020-68491-4}, volume = {10}, abstract = {Salinity is a serious challenge to global agriculture and threatens human food security. Plant cells can respond to salt stress either by activation of adaptive responses, or by programmed cell death. The mechanisms deciding the respective response are far from understood, but seem to depend on the degree, to which mitochondria can maintain oxidative homeostasis. Using plant PeptoQ, a Trojan Peptoid, as vehicle, it is possible to transport a coenzyme Q10 (CoQ10) derivative into plant mitochondria. We show that salinity stress in tobacco BY-2 cells (Nicotiana tabacum L. cv Bright Yellow-2) can be mitigated by pretreatment with plant PeptoQ with respect to numerous aspects including proliferation, expansion, redox homeostasis, and programmed cell death. We tested the salinity response for transcripts from nine salt-stress related-genes representing different adaptive responses. While most did not show any significant response, the salt response of the transcription factor NtNAC, probably involved in mitochondrial retrograde signaling, was significantly modulated by the plant PeptoQ. Most strikingly, transcripts for the mitochondrial, Mn-dependent Superoxide Dismutase were rapidly and drastically upregulated in presence of the peptoid, and this response was disappearing in presence of salt. The same pattern, albeit at lower amplitude, was seen for the sodium exporter SOS1. The findings are discussed by a model, where plant PeptoQ modulates retrograde signalling to the nucleus leading to a strong expression of mitochondrial SOD, what renders mitochondria more resilient to perturbations of oxidative balance, such that cells escape salt induced cell death and remain viable.} } @Article{IPB-602, author = {Tang, G. and Ma, J. and Hause, B. and Nick, P. and Riemann, M. and}, title = {{Jasmonate is required for the response to osmotic stress in rice}}, year = {2020}, pages = {104047}, journal = {Environ. Exp. Bot.}, doi = {10.1016/j.envexpbot.2020.104047}, volume = {175}, abstract = {Plants have the ability to alleviate the harmful effects caused by abiotic and biotic stress. Phytohormones play a very important role in the acclimation to these stresses. To study the role of jasmonate in the acclimation to osmotic stress, an ALLENE OXIDE CYCLASE (AOC) mutant of rice (cpm2), disrupted in the biosynthesis of jasmonic acid (JA), and its wild type (WT) background were employed to investigate their responses to osmotic stress caused by treatment with polyethylene glycol (PEG) 6000. WT showed tolerance to osmotic stress, correlated with a fast transient increase of JA and JA-isoleucine (JA-Ile) in the shoots prior to an increase in abscisic acid (ABA), followed by a second increase in jasmonates when exposing to osmotic stress during 24 h. In roots, the pattern of hormonal increase was similar, but the response appeared to be faster, and remained transient, also with respect to low levels of jasmonates upon continuing osmotic stress. The mutant, which was containing extremely low levels of jasmonates, was hypersensitive to the stress. However, ABA accumulated in both, shoots and roots of cpm2, to similar (but not equal) levels as those seen in the WT, demonstrating that the biosynthesis or catabolism of ABA in response to osmotic stress is at least partially independent of JA, but can be modulated by JA. Our results suggest that jasmonates operate in parallel, presumably synergistically, to ABA, and are indispensable for osmotic stress tolerance in rice.} } @Article{IPB-587, author = {Schubert, R. and Werner, S. and Cirka, H. and Rödel, P. and Tandron Moya, Y. and Mock, H.-P. and Hutter, I. and Kunze, G. and Hause, B. and}, title = {{Effects of Arbuscular Mycorrhization on fruit quality in industrialized tomato production}}, year = {2020}, pages = {7029}, journal = {Int. J. Mol. Sci.}, doi = {10.3390/ijms21197029}, url = {https://doi.org/10.3390/ijms21197029}, volume = {21}, abstract = {Industrialized tomato production faces a decrease in flavors and nutritional value due to conventional breeding. Moreover, tomato production heavily relies on nitrogen and phosphate fertilization. Phosphate uptake and improvement of fruit quality by arbuscular mycorrhizal (AM) fungi are well-studied. We addressed the question of whether commercially used tomato cultivars grown in a hydroponic system can be mycorrhizal, leading to improved fruit quality. Tomato plants inoculated with Rhizophagus irregularis were grown under different phosphate concentrations and in substrates used in industrial tomato production. Changes in fruit gene expression and metabolite levels were checked by RNAseq and metabolite determination, respectively. The tests revealed that reduction of phosphate to 80% and use of mixed substrate allow AM establishment without affecting yield. By comparing green fruits from non-mycorrhizal and mycorrhizal plants, differentially expressed genes (DEGs) were found to possibly be involved in processes regulating fruit maturation and nutrition. Red fruits from mycorrhizal plants showed a trend of higher BRIX values and increased levels of carotenoids in comparison to those from non-mycorrhizal plants. Free amino acids exhibited up to four times higher levels in red fruits due to AM, showing the potential of mycorrhization to increase the nutritional value of tomatoes in industrialized production.} } @Article{IPB-560, author = {Kusstatscher, P. and Wicaksono, W. A. and Bergna, A. and Cernava, T. and Bergau, N. and Tissier, A. and Hause, B. and Berg, G. and}, title = {{Trichomes form genotype-specific microbial hotspots in the phyllosphere of tomato}}, year = {2020}, pages = {17}, journal = {Environ. Microbiome}, doi = {10.1186/s40793-020-00364-9}, url = {https://doi.org/10.1186/s40793-020-00364-9}, volume = {15}, abstract = {Background: The plant phyllosphere is a well-studied habitat characterized by low nutrient availability and high community dynamics. In contrast, plant trichomes, known for their production of a large number of metabolites, are a yet unexplored habitat for microbes. We analyzed the phyllosphere as well as trichomes of two tomato genotypes (Solanum lycopersicum LA4024, S. habrochaites LA1777) by targeting bacterial 16S rRNA gene fragments. Results: Leaves, leaves without trichomes, and trichomes alone harbored similar abundances of bacteria (108–109 16S rRNA gene copy numbers per gram of sample). In contrast, bacterial diversity was found significantly increased in trichome samples (Shannon index: 4.4 vs. 2.5). Moreover, the community composition was significantly different when assessed with beta diversity analysis and corresponding statistical tests. At the bacterial class level, Alphaproteobacteria (23.6%) were significantly increased, whereas Bacilli (8.6%) were decreased in trichomes. The bacterial family Sphingomonadacea (8.4%) was identified as the most prominent, trichome-specific feature; Burkholderiaceae and Actinobacteriaceae showed similar patterns. Moreover, Sphingomonas was identified as a central element in the core microbiome of trichome samples, while distinct low-abundant bacterial families including Hymenobacteraceae and Alicyclobacillaceae were exclusively found in trichome samples. Niche preferences were statistically significant for both genotypes and genotype-specific enrichments were further observed. Conclusion: Our results provide first evidence of a highly specific trichome microbiome in tomato and show the importance of micro-niches for the structure of bacterial communities on leaves. These findings provide further clues for breeding, plant pathology and protection as well as so far unexplored natural pathogen defense strategies. } } @INBOOK{IPB-17, author = {Hause, B. and Requena, N. and}, title = {{Arbuscular Mycorrhizal Fungi}}, year = {2020}, pages = {185-196}, chapter = {{Detection of Arbuscular Mycorrhizal Fungal Gene Expression by In Situ Hybridization}}, journal = {Methods Mol. Biol.}, editor = {Ferrol, N. \& Lanfranco, L., eds.}, doi = {10.1007/978-1-0716-0603-2_14}, volume = {2146}, abstract = {The complexity of the obligate symbiotic interaction of arbuscular mycorrhizal (AM) fungi and their host roots requires sophisticated molecular methods. In particular, to capture the dynamic of the interaction, cell-specific methods for gene expression analysis are required. In situ hybridization is a technique that allows to determine the location of transcript accumulation within tissues, being of special interest for these fungi that cannot be genetically modified. The method requires proper fixation and embedding methods as well as specific probes for the hybridization allowing detection of specific transcripts. In this chapter, we present a method to prepare roots, which have established a symbiosis with an arbuscular mycorrhizal fungus for the detection of fungal transcripts. This includes chemical fixation, subsequent embedding in a suitable medium, sectioning and pretreatment of sections, the hybridization procedure itself, as well as the immunological detection of RNA-RNA hybrids.} } @Article{IPB-716, author = {Ronzan, M. and Piacentini, D. and Fattorini, L. and Federica, D. R. and Caboni, E. and Eiche, E. and Ziegler, J. and Hause, B. and Riemann, M. and Betti, C. and Altamura, M. M. and Falasca, G. and}, title = {{Auxin-jasmonate crosstalk in Oryza sativa L. root system formation after cadmium and/or arsenic exposure}}, year = {2019}, pages = {59-69}, journal = {Environ. Exp. Bot.}, doi = {10.1016/j.envexpbot.2019.05.013}, volume = {165}, abstract = {Soil pollutants may affect root growth through interactions among phytohormones like auxin and jasmonates. Rice is frequently grown in paddy fields contaminated by cadmium and arsenic, but the effects of these pollutants on jasmonates/auxin crosstalk during adventitious and lateral roots formation are widely unknown. Therefore, seedlings of Oryza sativa cv. Nihonmasari and of the jasmonate-biosynthetic mutant coleoptile photomorphogenesis2 were exposed to cadmium and/or arsenic, and/or jasmonic acid methyl ester, and then analysed through morphological, histochemical, biochemical and molecular approaches.In both genotypes, arsenic and cadmium accumulated in roots more than shoots. In the roots, arsenic levels were more than twice higher than cadmium levels, either when arsenic was applied alone, or combined with cadmium. Pollutants reduced lateral root density in the wild -type in every treatment condition, but jasmonic acid methyl ester increased it when combined with each pollutant. Interestingly, exposure to cadmium and/or arsenic did not change lateral root density in the mutant. The transcript levels of OsASA2 and OsYUCCA2, auxin biosynthetic genes, increased in the wild-type and mutant roots when pollutants and jasmonic acid methyl ester were applied alone. Auxin (indole-3-acetic acid) levels transiently increased in the roots with cadmium and/or arsenic in the wild-type more than in the mutant. Arsenic and cadmium, when applied alone, induced fluctuations in bioactive jasmonate contents in wild-type roots, but not in the mutant. Auxin distribution was evaluated in roots of OsDR5::GUS seedlings exposed or not to jasmonic acid methyl ester added or not with cadmium and/or arsenic. The DR5::GUS signal in lateral roots was reduced by arsenic, cadmium, and jasmonic acid methyl ester. Lipid peroxidation, evaluated as malondialdehyde levels, was higher in the mutant than in the wild-type, and increased particularly in As presence, in both genotypes.Altogether, the results show that an auxin/jasmonate interaction affects rice root system development in the presence of cadmium and/or arsenic, even if exogenous jasmonic acid methyl ester only slightly mitigates pollutants toxicity.} } @Article{IPB-694, author = {Mittelberger, C. and Stellmach, H. and Hause, B. and Kerschbamer, C. and Schlink, K. and Letschka, T. and Janik, K. and}, title = {{A Novel Effector Protein of Apple Proliferation Phytoplasma Disrupts Cell Integrity of Nicotiana spp. Protoplasts}}, year = {2019}, pages = {4613}, journal = {Int. J. Mol. Sci.}, doi = {10.3390/ijms20184613}, volume = {20}, abstract = {Effector proteins play an important role in the virulence of plant pathogens such as phytoplasma, which are the causative agents of hundreds of different plant diseases. The plant hosts comprise economically relevant crops such as apples (Malus × domestica), which can be infected by ‘Candidatus Phytoplasma mali’ (P. mali), a highly genetically dynamic plant pathogen. As the result of the genetic and functional analyses in this study, a new putative P. mali effector protein was revealed. The so-called “Protein in Malus Expressed 2” (PME2), which is expressed in apples during P. mali infection but not in the insect vector, shows regional genetic differences. In a heterologous expression assay using Nicotiana benthamiana and Nicotiana occidentalis mesophyll protoplasts, translocation of both PME2 variants in the cell nucleus was observed. Overexpression of the effector protein affected cell integrity in Nicotiana spp. protoplasts, indicating a potential role of this protein in pathogenic virulence. Interestingly, the two genetic variants of PME2 differ regarding their potential to manipulate cell integrity. However, the exact function of PME2 during disease manifestation and symptom development remains to be further elucidated. Aside from the first description of the function of a novel effector of P. mali, the results of this study underline the necessity for a more comprehensive description and understanding of the genetic diversity of P. mali as an indispensable basis for a functional understanding of apple proliferation disease.} } @Article{IPB-665, author = {Hause, B. and}, title = {{Elevated CO2‐induced improvement of mycorrhization – which players lie in‐between?}}, year = {2019}, pages = {5-7}, journal = {New Phytol.}, doi = {10.1111/nph.16023}, volume = {224}, abstract = {This article is a Commentary on Zhou et al. 224: 106–116.} } @Article{IPB-739, author = {Wasternack, C. and Hause, B. and Abel, S. and}, title = {{Benno Parthier (1932–2019)}}, year = {2019}, pages = {519-520}, journal = {Plant Mol. Biol.}, doi = {10.1007/s11103-019-00927-6}, volume = {101}, } @Article{IPB-725, author = {Schulze, A. and Zimmer, M. and Mielke, S. and Stellmach, H. and Melnyk, C. W. and Hause, B. and Gasperini, D. and}, title = {{Wound-Induced Shoot-to-Root Relocation of JA-Ile Precursors Coordinates Arabidopsis Growth}}, year = {2019}, pages = {1383-1394}, journal = {Mol. Plant}, doi = {10.1016/j.molp.2019.05.013}, volume = {12}, abstract = {Multicellular organisms rely on the movement of signaling molecules across cells, tissues, and organs to communicate among distal sites. In plants, localized leaf damage activates jasmonic acid (JA)-dependent transcriptional reprogramming in both harmed and unharmed tissues. Although it has been indicated that JA species can translocate from damaged into distal sites, the identity of the mobile compound(s), the tissues through which they translocate, and the effect of their relocation remain unknown. Here, we found that following shoot wounding, the relocation of endogenous jasmonates through the phloem is essential to initiate JA signaling and stunt growth in unharmed roots of Arabidopsis thaliana. By employing grafting experiments and hormone profiling, we uncovered that the hormone precursor cis-12-oxo-phytodienoic acid (OPDA) and its derivatives, but not the bioactive JA-Ile conjugate, translocate from wounded shoots into undamaged roots. Upon root relocation, the mobile precursors cooperatively regulated JA responses through their conversion into JA-Ile and JA signaling activation. Collectively, our findings demonstrate the existence of long-distance translocation of endogenous OPDA and its derivatives, which serve as mobile molecules to coordinate shoot-to-root responses, and highlight the importance of a controlled redistribution of hormone precursors among organs during plant stress acclimation.} } @Article{IPB-724, author = {Schubert, R. and Dobritzsch, S. and Gruber, C. and Hause, G. and Athmer, B. and Schreiber, T. and Marillonnet, S. and Okabe, Y. and Ezura, H. and Acosta, I. F. and Tarkowská, D. and Hause, B. and}, title = {{Tomato MYB21 Acts in Ovules to Mediate Jasmonate-Regulated Fertility}}, year = {2019}, pages = {1043-1062}, journal = {Plant Cell}, doi = {10.1105/tpc.18.00978}, volume = {31}, abstract = {The function of the plant hormone jasmonic acid (JA) in the development of tomato (Solanum lycopersicum) flowers was analyzed with a mutant defective in JA perception (jasmonate-insensitive1-1, jai1-1). In contrast with Arabidopsis (Arabidopsis thaliana) JA-insensitive plants, which are male sterile, the tomato jai1-1 mutant is female sterile, with major defects in female development. To identify putative JA-dependent regulatory components, we performed transcriptomics on ovules from flowers at three developmental stages from wild type and jai1-1 mutants. One of the strongly downregulated genes in jai1-1 encodes the MYB transcription factor SlMYB21. Its Arabidopsis ortholog plays a crucial role in JA-regulated stamen development. SlMYB21 was shown here to exhibit transcription factor activity in yeast, to interact with SlJAZ9 in yeast and in planta, and to complement Arabidopsis myb21-5. To analyze SlMYB21 function, we generated clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR associated protein 9 (Cas9) mutants and identified a mutant by Targeting Induced Local Lesions in Genomes (TILLING). These mutants showed female sterility, corroborating a function of MYB21 in tomato ovule development. Transcriptomics analysis of wild type, jai1-1, and myb21-2 carpels revealed processes that might be controlled by SlMYB21. The data suggest positive regulation of JA biosynthesis by SlMYB21, but negative regulation of auxin and gibberellins. The results demonstrate that SlMYB21 mediates at least partially the action of JA and might control the flower-to-fruit transition.} } @Article{IPB-723, author = {Schubert, R. and Grunewald, S. and von Sivers, L. and Hause, B. and}, title = {{Effects of Jasmonate on Ethylene Function during the Development of Tomato Stamens}}, year = {2019}, pages = {277}, journal = {Plants}, doi = {10.3390/plants8080277}, volume = {8}, abstract = {The phenotype of the tomato mutant jasmonate-insensitive1-1 (jai1-1) mutated in the JA-Ile co-receptor COI1 demonstrates JA function in flower development, since it is female-sterile. In addition, jai1-1 exhibits a premature anther dehydration and pollen release, being in contrast to a delayed anther dehiscence in the JA-insensitive Arabidopsis mutant coi1-1. The double mutant jai1-1 Never ripe (jai1-1 Nr), which is in addition insensitive to ethylene (ET), showed a rescue of the jai1-1 phenotype regarding pollen release. This suggests that JA inhibits a premature rise in ET to prevent premature stamen desiccation. To elucidate the interplay of JA and ET in more detail, stamen development in jai1-1 Nr was compared to wild type, jai1-1 and Nr regarding water content, pollen vitality, hormone levels, and accumulation of phenylpropanoids and transcripts encoding known JA- and ET-regulated genes. For the latter, RT-qPCR based on nanofluidic arrays was employed. The data showed that additional prominent phenotypic features of jai1-1, such as diminished water content and pollen vitality, and accumulation of phenylpropanoids were at least partially rescued by the ET-insensitivity. Hormone levels and accumulation of transcripts were not affected. The data revealed that strictly JA-regulated processes cannot be rescued by ET-insensitivity, thereby emphasizing a rather minor role of ET in JA-regulated stamen development.} } @Article{IPB-746, author = {Yadav, H. and Dreher, D. and Athmer, B. and Porzel, A. and Gavrin, A. and Baldermann, S. and Tissier, A. and Hause, B. and}, title = {{Medicago TERPENE SYNTHASE 10 Is Involved in Defense Against an Oomycete Root Pathogen}}, year = {2019}, pages = {1598-1613}, journal = {Plant Physiol.}, doi = {10.1104/pp.19.00278}, volume = {180}, abstract = {In nature, plants interact with numerous beneficial or pathogenic soil-borne microorganisms. Plants have developed various defense strategies to expel pathogenic microbes, some of which function soon after pathogen infection. We used Medicago truncatula and its oomycete pathogen Aphanomyces euteiches to elucidate early responses of the infected root. A. euteiches causes root rot disease in legumes and is a limiting factor in legume production. Transcript profiling of seedlings and adult plant roots inoculated with A. euteiches zoospores for 2 h revealed specific upregulation of a gene encoding a putative sesquiterpene synthase (M. truncatula TERPENE SYNTHASE 10 [MtTPS10]) in both developmental stages. MtTPS10 was specifically expressed in roots upon oomycete infection. Heterologous expression of MtTPS10 in yeast led to production of a blend of sesquiterpenes and sesquiterpene alcohols, with NMR identifying a major peak corresponding to himalachol. Moreover, plants carrying a tobacco (Nicotiana tabacum) retrotransposon Tnt1 insertion in MtTPS10 lacked the emission of sesquiterpenes upon A. euteiches infection, supporting the assumption that the identified gene encodes a multiproduct sesquiterpene synthase. Mttps10 plants and plants with reduced MtTPS10 transcript levels created by expression of an MtTPS10-artificial microRNA in roots were more susceptible to A. euteiches infection than were the corresponding wild-type plants and roots transformed with the empty vector, respectively. Sesquiterpenes produced by expression of MtTPS10 in yeast also inhibited mycelial growth and A. euteiches zoospore germination. These data suggest that sesquiterpene production in roots by MtTPS10 plays a previously unrecognized role in the defense response of M. truncatula against A. euteiches.} } @Article{IPB-743, author = {Wasternack, C. and Hause, B. and}, title = {{The missing link in jasmonic acid biosynthesis}}, year = {2019}, pages = {776-777}, journal = {Nat. Plants}, doi = {10.1038/s41477-019-0492-y}, volume = {5}, abstract = {Jasmonic acid biosynthesis starts in chloroplasts and is finalized in peroxisomes. The required export of a crucial intermediate out of the chloroplast is now shown to be mediated by a protein from the outer envelope called JASSY.} } @Article{IPB-645, author = {Dreher, D. and Baldermann, S. and Schreiner, M. and Hause, B. and}, title = {{An arbuscular mycorrhizal fungus and a root pathogen induce different volatiles emitted by Medicago truncatula roots}}, year = {2019}, pages = {85-90}, journal = {J. Adv. Res.}, doi = {10.1016/j.jare.2019.03.002}, volume = {19}, abstract = {Plants are in permanent contact with various microorganisms and are always impacted by them. To better understand the first steps of a plant’s recognition of soil-borne microorganisms, the early release of volatile organic compounds (VOCs) emitted from roots of Medicago truncatula in response to the symbiont Rhizophagus irregularis or the pathogenic oomycete Aphanomyces euteiches was analysed. More than 90 compounds were released from roots as detected by an untargeted gas chromatography-mass spectrometry approach. Principal component analyses clearly distinguished untreated roots from roots treated with either R. irregularis or A. euteiches. Several VOCs were found to be emitted specifically in response to each of the microorganisms. Limonene was specifically emitted from wild-type roots after contact with R. irregularis spores but not from roots of the mycorrhiza-deficient mutant does not make infections3. The application of limonene to mycorrhizal roots, however, did not affect the mycorrhization rate. Inoculation of roots with A. euteiches zoospores resulted in the specific emission of several sesquiterpenes, such as nerolidol, viridiflorol and nerolidol-epoxyacetate but application of nerolidol to zoospores of A. euteiches did not affect their vitality. Therefore, plants discriminate between different microorganisms at early stages of their interaction and respond differently to the level of root-emitted volatiles.} } @INBOOK{IPB-27, author = {Janik, K. and Stellmach, H. and Mittelberger, C. and Hause, B. and}, title = {{Phytoplasmas}}, year = {2019}, pages = {321-331}, chapter = {{Characterization of Phytoplasmal Effector Protein Interaction with Proteinaceous Plant Host Targets Using Bimolecular Fluorescence Complementation (BiFC)}}, journal = {Methods Mol. Biol.}, editor = {Musetti, R. \& Pagliari, L., eds.}, doi = {10.1007/978-1-4939-8837-2_24}, volume = {1875}, abstract = {Elucidating the molecular mechanisms underlying plant disease development has become an important aspect of phytoplasma research in the last years. Especially unraveling the function of phytoplasma effector proteins has gained interesting insights into phytoplasma-host interaction at the molecular level. Here, we describe how to analyze and visualize the interaction of a phytoplasma effector with its proteinaceous host partner using bimolecular fluorescence complementation (BiFC) in Nicotiana benthamiana mesophyll protoplasts. The protocol comprises a description of how to isolate protoplasts from leaves and how to transform these protoplasts with BiFC expression vectors containing the phytoplasma effector and the host interaction partner, respectively. If an interaction occurs, a fluorescent YFP-complex is reconstituted in the protoplast, which can be visualized using fluorescence microscopy.} } @INBOOK{IPB-24, author = {Hause, B. and Yadav, H. and}, title = {{The Model Legume Medicago truncatula}}, year = {2019}, pages = {1179-1184}, chapter = {{Creation of composite plants – transformation of Medicago truncatula roots}}, editor = {de Bruijn, F., ed.}, doi = {10.1002/9781119409144.ch152}, abstract = {Medicago truncatula, owing to its small diploid genome (∼500 Mbp), short life cycle, and high natural diversity makes it a good model plant and has opened the door of opportunities for scientists interested in studying legume biology. But over the years, challenges are also being faced for genetic manipulation of this plant. Many genetic manipulation protocols have been published involving Agrobacterium tumefaciens, a pathogen causing tumor disease in plants. These protocols apart from being difficult to achieve, are also time consuming. Nowadays, an easy, less time consuming and highly reproducible Agrobacterium rhizogenes based method is in use by many research groups. This method generates composite plants having transformed roots on a wild‐type shoot. Here, stable transformed lines that can be propagated over time are not achieved by this method, but for root‐development or root–microbe interaction studies this method has proven to be a useful tool for the community. In addition, transformed roots can be propagated by root organ cultures (ROCs), wherein transformed roots are propagated on sucrose containing media without any shoot part. Occasionally, even stable transgenic plants can be regenerated from transgenic roots. In this chapter, developments and improvements of various transformation protocols are discussed. The suitability of composite plants is highlighted by a study on mycorrhization of transformed and non‐transformed roots, which did not show differences in the mycorrhization rate and developmental stages of the arbuscular mycorrhizal (AM) fungus inside the roots as well as in transcript accumulation and metabolite levels of roots. Finally, applications of the A. rhizogenes based transformation method are discussed.} } @Article{IPB-773, author = {Ferlian, O. and Biere, A. and Bonfante, P. and Buscot, F. and Eisenhauer, N. and Fernandez, I. and Hause, B. and Herrmann, S. and Krajinski-Barth, F. and Meier, I. C. and Pozo, M. J. and Rasmann, S. and Rillig, M. C. and Tarkka, M. T. and van Dam, N. M. and Wagg, C. and Martinez-Medina, A. and}, title = {{Growing Research Networks on Mycorrhizae for Mutual Benefits}}, year = {2018}, pages = {975-984}, journal = {Trends Plant Sci.}, doi = {10.1016/j.tplants.2018.08.008}, volume = {23}, abstract = {Research on mycorrhizal interactions has traditionally developed into separate disciplines addressing different organizational levels. This separation has led to an incomplete understanding of mycorrhizal functioning. Integration of mycorrhiza research at different scales is needed to understand the mechanisms underlying the context dependency of mycorrhizal associations, and to use mycorrhizae for solving environmental issues. Here, we provide a road map for the integration of mycorrhiza research into a unique framework that spans genes to ecosystems. Using two key topics, we identify parallels in mycorrhiza research at different organizational levels. Based on two current projects, we show how scientific integration creates synergies, and discuss future directions. Only by overcoming disciplinary boundaries, we will achieve a more comprehensive understanding of the functioning of mycorrhizal associations.} } @Article{IPB-771, author = {Fattorini, L. and Hause, B. and Gutierrez, L. and Veloccia, A. and Della Rovere, F. and Piacentini, D. and Falasca, G. and Altamura, M. M. and}, title = {{Jasmonate promotes auxin-induced adventitious rooting in dark-grown Arabidopsis thaliana seedlings and stem thin cell layers by a cross-talk with ethylene signalling and a modulation of xylogenesis}}, year = {2018}, pages = {182}, journal = {BMC Plant Biol.}, doi = {10.1186/s12870-018-1392-4}, volume = {18}, abstract = {BackgroundAdventitious roots (ARs) are often necessary for plant survival, and essential for successful micropropagation. In Arabidopsis thaliana dark-grown seedlings AR-formation occurs from the hypocotyl and is enhanced by application of indole-3-butyric acid (IBA) combined with kinetin (Kin). The same IBA \+ Kin-treatment induces AR-formation in thin cell layers (TCLs). Auxin is the main inducer of AR-formation and xylogenesis in numerous species and experimental systems. Xylogenesis is competitive to AR-formation in Arabidopsis hypocotyls and TCLs. Jasmonates (JAs) negatively affect AR-formation in de-etiolated Arabidopsis seedlings, but positively affect both AR-formation and xylogenesis in tobacco dark-grown IBA \+ Kin TCLs. In Arabidopsis the interplay between JAs and auxin in AR-formation vs xylogenesis needs investigation. In de-etiolated Arabidopsis seedlings, the Auxin Response Factors ARF6 and ARF8 positively regulate AR-formation and ARF17 negatively affects the process, but their role in xylogenesis is unknown. The cross-talk between auxin and ethylene (ET) is also important for AR-formation and xylogenesis, occurring through EIN3/EIL1 signalling pathway. EIN3/EIL1 is the direct link for JA and ET-signalling. The research investigated JA role on AR-formation and xylogenesis in Arabidopsis dark-grown seedlings and TCLs, and the relationship with ET and auxin. The JA-donor methyl-jasmonate (MeJA), and/or the ET precursor 1-aminocyclopropane-1-carboxylic acid were applied, and the response of mutants in JA-synthesis and -signalling, and ET-signalling investigated. Endogenous levels of auxin, JA and JA-related compounds, and ARF6, ARF8 and ARF17 expression were monitored.ResultsMeJA, at 0.01 μM, enhances AR-formation, when combined with IBA \+ Kin, and the response of the early-JA-biosynthesis mutant dde2–2 and the JA-signalling mutant coi1–16 confirmed this result. JA levels early change during TCL-culture, and JA/JA-Ile is immunolocalized in AR-tips and xylogenic cells. The high AR-response of the late JA-biosynthesis mutant opr3 suggests a positive action also of 12-oxophytodienoic acid on AR-formation. The crosstalk between JA and ET-signalling by EIN3/EIL1 is critical for AR-formation, and involves a competitive modulation of xylogenesis. Xylogenesis is enhanced by a MeJA concentration repressing AR-formation, and is positively related to ARF17 expression.ConclusionsThe JA concentration-dependent role on AR-formation and xylogenesis, and the interaction with ET opens the way to applications in the micropropagation of recalcitrant species.} } @Article{IPB-763, author = {Dhakarey, R. and Raorane, M. L. and Treumann, A. and Peethambaran, P. K. and Schendel, R. R. and Sahi, V. P. and Hause, B. and Bunzel, M. and Henry, A. and Kohli, A. and Riemann, M. and}, title = {{Corrigendum: Physiological and Proteomic Analysis of the Rice Mutant cpm2 Suggests a Negative Regulatory Role of Jasmonic Acid in Drought Tolerance}}, year = {2018}, pages = {465}, journal = {Front. Plant Sci.}, doi = {10.3389/fpls.2018.00465}, volume = {9}, } @Article{IPB-749, author = {Akaberi, S. and Wang, H. and Claudel, P. and Riemann, M. and Hause, B. and Hugueney, P. and Nick, P. and}, title = {{Grapevine fatty acid hydroperoxide lyase generates actin-disrupting volatiles and promotes defence-related cell death}}, year = {2018}, pages = {2883-2896}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/ery133}, volume = {69}, abstract = {Fatty acid hydroperoxides can generate short-chained volatile aldehydes that may participate in plant defence. A grapevine hydroperoxide lyase (VvHPL1) clustering to the CYP74B class was functionally characterized with respect to a role in defence. In grapevine leaves, transcripts of this gene accumulated rapidly to high abundance in response to wounding. Cellular functions of VvHPL1 were investigated upon heterologous expression in tobacco BY-2 cells. A C-terminal green fluorescent protein (GFP) fusion of VvHPL1 was located in plastids. The overexpression lines were found to respond to salinity stress or the bacterial elicitor harpin by increasing cell death. This signal-dependent mortality response was mitigated either by addition of exogenous jasmonic acid or by treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases. By feeding different substrates to recombinantly expressed enzyme, VvHPL1 could also be functionally classified as true 13-HPL. The cognate products generated by this 13-HPL were cis-3-hexenal and trans-2-hexenal. Using a GFP-tagged actin marker line, one of these isomeric products, cis-3-hexenal, was found specifically to elicit a rapid disintegration of actin filaments. This response was not only observed in the heterologous system (tobacco BY-2), but also in a grapevine cell strain expressing this marker, as well as in leaf discs from an actin marker grape used as a homologous system. These results are discussed in the context of a role for VvHPL1 in a lipoxygenase-dependent signalling pathway triggering cell death-related defence that bifurcates from jasmonate-dependent basal immunity.} } @Article{IPB-843, author = {Wasternack, C. and Hause, B. and}, title = {{A Bypass in Jasmonate Biosynthesis – the OPR3-independent Formation}}, year = {2018}, pages = {276-279}, journal = {Trends Plant Sci.}, doi = {10.1016/j.tplants.2018.02.011}, volume = {23}, abstract = {For the first time in 25 years, a new pathway for biosynthesis of jasmonic acid (JA) has been identified. JA production takes place via 12-oxo-phytodienoic acid (OPDA) including reduction by OPDA reductases (OPRs). A loss-of-function allele, opr3-3, revealed an OPR3-independent pathway converting OPDA to JA.} } @Article{IPB-835, author = {van Aubel, G. and Serderidis, S. and Ivens, J. and Clinkemaillie, A. and Legrève, A. and Hause, B. and Van Cutsem, P. and}, title = {{Oligosaccharides successfully thwart hijacking of the salicylic acid pathway by Phytophthora infestans in potato leaves}}, year = {2018}, pages = {1901-1911}, journal = {Plant Pathol.}, doi = {10.1111/ppa.12908}, volume = {67}, abstract = {Potato growing is severely threatened by the late blight agent Phytophthora infestans, which is usually controlled by massive amounts of fungicides. While variety resistance is often bypassed by the pathogen, the plant innate immunity opens the way to new biological plant protection tools e.g. the COS‐OGA elicitor. This oligosaccharide composition mimics the interaction between plants and fungal pathogens as it combines chitosan oligomers (COS) with pectin‐derived oligogalacturonides (OGA).Two different COS‐OGA elicitors were evaluated against potato late blight: FytoSave® mainly efficient against powdery mildews and FytoSol, a new composition still under development. Next to the evaluation of their protective effect, a comparative study of plant defense induction was performed focusing on the effect of repeated sprayings as well as on the stimulation of salicylic acid (SA), jasmonic acid and ethylene‐related pathways during the biotrophic and the necrotrophic growth stages of the pathogen.The FytoSave® elicitor strongly increased the SA content but failed to induce a sufficient protection against late blight while FytoSol maintained or even decreased the free SA content in presence of P. infestans and was completely efficient. Surprisingly, the necrotrophic development of P. infestans occurred along with a strong leaf accumulation of free SA and SA‐related transcripts. It may represent an attempt by P. infestans to divert plant defenses for its own benefit. Preventive sprayings with FytoSol but not FytoSave® completely impeded this hijacking. FytoSol seemed to keep the SA pathway under control, thereby preventing its diversion by P. infestans.} } @Article{IPB-780, author = {Gelová, Z. and ten Hoopen, P. and Novák, O. and Motyka, V. and Pernisová, M. and Dabravolski, S. and Didi, V. and Tillack, I. and Oklešťková, J. and Strnad, M. and Hause, B. and Haruštiaková, D. and Conrad, U. and Janda, L. and Hejátko, J. and}, title = {{Antibody-mediated modulation of cytokinins in tobacco: organ-specific changes in cytokinin homeostasis}}, year = {2018}, pages = {441-454}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erx426}, volume = {69}, abstract = {Cytokinins comprise a group of phytohormones with an organ-specific mode of action. Although the mechanisms controlling the complex networks of cytokinin metabolism are partially known, the role of individual cytokinin types in the maintenance of cytokinin homeostasis remains unclear. Utilizing the overproduction of single-chain Fv antibodies selected for their ability to bind trans-zeatin riboside and targeted to the endoplasmic reticulum, we post-synthetically modulated cytokinin ribosides, the proposed transport forms of cytokinins. We observed asymmetric activity of cytokinin biosynthetic genes and cytokinin distribution in wild-type tobacco seedlings with higher cytokinin abundance in the root than in the shoot. Antibody-mediated modulation of cytokinin ribosides further enhanced the relative cytokinin abundance in the roots and induced cytokinin-related phenotypes in an organ-specific manner. The activity of cytokinin oxidase/dehydrogenase in the roots was strongly up-regulated in response to antibody-mediated formation of the cytokinin pool in the endoplasmic reticulum. However, we only detected a slight decrease in the root cytokinin levels. In contrast, a significant decrease of cytokinins occurred in the shoot. We suggest the roots as the main site of cytokinin biosynthesis in tobacco seedlings. Conversely, cytokinin levels in the shoot seem to depend largely on long-range transport of cytokinin} } @Article{IPB-888, author = {Janik, K. and Mithöfer, A. and Raffeiner, M. and Stellmach, H. and Hause, B. and Schlink, K. and}, title = {{An effector of apple proliferation phytoplasma targets TCP transcription factors—a generalized virulence strategy of phytoplasma?}}, year = {2017}, pages = {435-442}, journal = {Mol. Plant Pathol.}, doi = {10.1111/mpp.12409}, volume = {18}, abstract = {The plant pathogen Candidatus Phytoplasma mali (P. mali) is the causative agent of apple proliferation, a disease of increasing importance in apple‐growing areas within Europe. Despite its economic importance, little is known about the molecular mechanisms of disease manifestation within apple trees. In this study, we identified two TCP (TEOSINTE BRANCHED/CYCLOIDEA/PROLIFERATING CELL FACTOR) transcription factors of Malus x domestica as binding partners of the P. mali SAP11‐like effector ATP\_00189. Phytohormone analyses revealed an effect of P. mali infection on jasmonates, salicylic acid and abscisic acid levels, showing that P. mali affects phytohormonal levels in apple trees, which is in line with the functions of the effector assumed from its binding to TCP transcription factors. To our knowledge, this is the first characterization of the molecular targets of a P. mali effector and thus provides the basis to better understand symptom development and disease progress during apple proliferation. As SAP11 homologues are found in several Phytoplasma species infecting a broad range of different plants, SAP11‐like proteins seem to be key players in phytoplasmal infection.} } @Article{IPB-867, author = {Dreher, D. and Yadav, H. and Zander, S. and Hause, B. and}, title = {{Is there genetic variation in mycorrhization of Medicago truncatula?}}, year = {2017}, pages = {e3713}, journal = {PeerJ}, doi = {10.7717/peerj.3713}, volume = {5}, abstract = {Differences in the plant’s response among ecotypes or accessions are often used to identify molecular markers for the respective process. In order to analyze genetic diversity of Medicago truncatula in respect to interaction with the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis, mycorrhizal colonization was evaluated in 32 lines of the nested core collection representing the genetic diversity of the SARDI collection. All studied lines and the reference line Jemalong A17 were inoculated with R. irregularis and the mycorrhization rate was determined at three time points after inoculation. There were, however, no reliable and consistent differences in mycorrhization rates among all lines. To circumvent possible overlay of potential differences by use of the highly effective inoculum, native sandy soil was used in an independent experiment. Here, significant differences in mycorrhization rates among few of the lines were detectable, but the overall high variability in the mycorrhization rate hindered clear conclusions. To narrow down the number of lines to be tested in more detail, root system architecture (RSA) of in vitro-grown seedlings of all lines under two different phosphate (Pi) supply condition was determined in terms of primary root length and number of lateral roots. Under high Pi supply (100 µM), only minor differences were observed, whereas in response to Pi-limitation (3 µM) several lines exhibited a drastically changed number of lateral roots. Five lines showing the highest alterations or deviations in RSA were selected and inoculated with R. irregularis using two different Pi-fertilization regimes with either 13 mM or 3 mM Pi. Mycorrhization rate of these lines was checked in detail by molecular markers, such as transcript levels of RiTubulin and MtPT4. Under high phosphate supply, the ecotypes L000368 and L000555 exhibited slightly increased fungal colonization and more functional arbuscules, respectively. To address the question, whether capability for mycorrhizal colonization might be correlated to general invasion by microorganisms, selected lines were checked for infection by the root rot causing pathogen, Aphanoymces euteiches. The mycorrhizal colonization phenotype, however, did not correlate with the resistance phenotype upon infection with two strains of A. euteiches as L000368 showed partial resistance and L000555 exhibited high susceptibility as determined by quantification of A. euteiches rRNA within infected roots. Although there is genetic diversity in respect to pathogen infection, genetic diversity in mycorrhizal colonization of M. truncatula is rather low and it will be rather difficult to use it as a trait to access genetic markers.} } @Article{IPB-865, author = {Dhakarey, R. and Raorane, M. L. and Treumann, A. and Peethambaran, P. K. and Schendel, R. R. and Sahi, V. P. and Hause, B. and Bunzel, M. and Henry, A. and Kohli, A. and Riemann, M. and}, title = {{Physiological and Proteomic Analysis of the Rice Mutant cpm2 Suggests a Negative Regulatory Role of Jasmonic Acid in Drought Tolerance}}, year = {2017}, pages = {1903}, journal = {Front. Plant Sci.}, doi = {10.3389/fpls.2017.01903}, volume = {8}, abstract = {It is widely known that numerous adaptive responses of drought-stressed plants are stimulated by chemical messengers known as phytohormones. Jasmonic acid (JA) is one such phytohormone. But there are very few reports revealing its direct implication in drought related responses or its cross-talk with other phytohormones. In this study, we compared the morpho-physiological traits and the root proteome of a wild type (WT) rice plant with its JA biosynthesis mutant coleoptile photomorphogenesis 2 (cpm2), disrupted in the allene oxide cyclase (AOC) gene, for insights into the role of JA under drought. The mutant had higher stomatal conductance, higher water use efficiency and higher shoot ABA levels under severe drought as compared to the WT. Notably, roots of cpm2 were better developed compared to the WT under both, control and drought stress conditions. Root proteome was analyzed using the Tandem Mass Tag strategy to better understand this difference at the molecular level. Expectedly, AOC was unique but notably highly abundant under drought in the WT. Identification of other differentially abundant proteins (DAPs) suggested increased energy metabolism (i.e., increased mobilization of resources) and reactive oxygen species scavenging in cpm2 under drought. Additionally, various proteins involved in secondary metabolism, cell growth and cell wall synthesis were also more abundant in cpm2 roots. Proteome-guided transcript, metabolite, and histological analyses provided further insights into the favorable adaptations and responses, most likely orchestrated by the lack of JA, in the cpm2 roots. Our results in cpm2 are discussed in the light of JA crosstalk to other phytohormones. These results together pave the path for understanding the precise role of JA during drought stress in rice.} } @Article{IPB-1056, author = {Wasternack, C. and Hause, B. and}, title = {{OPDA-Ile – a new JA-Ile-independent signal?}}, year = {2016}, pages = {e1253646}, journal = {Plant Signal Behav.}, doi = {10.1080/15592324.2016.1253646}, volume = {11}, abstract = {Expression takes place for most of the jasmonic acid (JA)-induced genes in a COI1-dependent manner via perception of its conjugate JA-Ile in the SCFCOI1-JAZ co-receptor complex. There are, however, numerous genes and processes, which are preferentially induced COI1-independently by the precursor of JA, 12-oxo-phytodienoic acid (OPDA). After recent identification of the Ile-conjugate of OPDA, OPDA-Ile, biological activity of this compound could be unequivocally proven in terms of gene expression. Any interference of OPDA, JA, or JA-Ile in OPDA-Ile-induced gene expression could be excluded by using different genetic background. The data suggest individual signaling properties of OPDA-Ile. Future studies for analysis of an SCFCOI1-JAZ co-receptor-independent route of signaling are proposed.} } @Article{IPB-1004, author = {Klopotek, Y. and Franken, P. and Klaering, H.-P. and Fischer, K. and Hause, B. and Hajirezaei, M.-R. and Druege, U. and}, title = {{A higher sink competitiveness of the rooting zone and invertases are involved in dark stimulation of adventitious root formation in Petunia hybrida cuttings}}, year = {2016}, pages = {10-22}, journal = {Plant Sci.}, doi = {10.1016/j.plantsci.2015.11.001}, volume = {243}, abstract = {The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during the subsequent light period, but promoted dry matter partitioning to the roots. Under darkness, higher activities of cytosolic and vacuolar invertases were maintained in both tissues when compared to cuttings under light. This was partially associated with higher RNA levels of respective genes. However, activity of cell wall invertases and transcript levels of one cell wall invertase isogene increased specifically in the stem base during the first two days after cutting excision under both light and darkness. During five days after excision, RNA accumulation of four invertase genes indicated preferential expression in the stem base compared to the apex. Darkness shifted the balance of expression of one cytosolic and two vacuolar invertase genes towards the stem base. The results indicate that dark exposure before planting enhances the carbon sink competitiveness of the rooting zone and that expression and activity of invertases contribute to the shift in carbon allocation.} } @Article{IPB-995, author = {Hazman, M. and Hause, B. and Eiche, E. and Riemann, M. and Nick, P. and}, title = {{Different forms of osmotic stress evoke qualitatively different responses in rice}}, year = {2016}, pages = {45-56}, journal = {J. Plant Physiol.}, doi = {10.1016/j.jplph.2016.05.027}, volume = {202}, abstract = {Drought, salinity and alkalinity are distinct forms of osmotic stress with serious impacts on rice productivity. We investigated, for a salt-sensitive rice cultivar, the response to osmotically equivalent doses of these stresses. Drought, experimentally mimicked by mannitol (single factor: osmotic stress), salinity (two factors: osmotic stress and ion toxicity), and alkalinity (three factors: osmotic stress, ion toxicity, and depletion of nutrients and protons) produced different profiles of adaptive and damage responses, both locally (in the root) as well as systemically (in the shoot). The combination of several stress factors was not necessarily additive, and we even observed cases of mitigation, when two (salinity), or three stressors (alkalinity) were compared to the single stressor (drought). The response to combinations of individual stress factors is therefore not a mere addition of the partial stress responses, but rather represents a new quality of response. We interpret this finding in a model, where the output to signaling molecules is not determined by their abundance per se, but qualitatively depends on their adequate integration into an adaptive signaling network. This output generates a systemic signal that will determine the quality of the shoot response to local concentrations of ions.} } @Article{IPB-961, author = {Arnold, M. D. and Gruber, C. and Floková, K. and Miersch, O. and Strnad, M. and Novák, O. and Wasternack, C. and Hause, B. and}, title = {{The Recently Identified Isoleucine Conjugate of cis-12-Oxo-Phytodienoic Acid Is Partially Active in cis-12-Oxo-Phytodienoic Acid-Specific Gene Expression of Arabidopsis thaliana}}, year = {2016}, pages = {e0162829}, journal = {PLOS ONE}, doi = {10.1371/journal.pone.0162829}, volume = {11}, abstract = {Oxylipins of the jasmonate family are active as signals in plant responses to biotic and abiotic stresses as well as in development. Jasmonic acid (JA), its precursor cis-12-oxo-phytodienoic acid (OPDA) and the isoleucine conjugate of JA (JA-Ile) are the most prominent members. OPDA and JA-Ile have individual signalling properties in several processes and differ in their pattern of gene expression. JA-Ile, but not OPDA, is perceived by the SCFCOI1-JAZ co-receptor complex. There are, however, numerous processes and genes specifically induced by OPDA. The recently identified OPDA-Ile suggests that OPDA specific responses might be mediated upon formation of OPDA-Ile. Here, we tested OPDA-Ile-induced gene expression in wild type and JA-deficient, JA-insensitive and JA-Ile-deficient mutant background. Tests on putative conversion of OPDA-Ile during treatments revealed only negligible conversion. Expression of two OPDA-inducible genes, GRX480 and ZAT10, by OPDA-Ile could be detected in a JA-independent manner in Arabidopsis seedlings but less in flowering plants. The data suggest a bioactivity in planta of OPDA-Ile.} } @Article{IPB-1028, author = {Pedranzani, H. and Rodríguez-Rivera, M. and Gutiérrez, M. and Porcel, R. and Hause, B. and Ruiz-Lozano, J. M. and}, title = {{Arbuscular mycorrhizal symbiosis regulates physiology and performance of Digitaria eriantha plants subjected to abiotic stresses by modulating antioxidant and jasmonate levels}}, year = {2016}, pages = {141-152}, journal = {Mycorrhiza}, doi = {10.1007/s00572-015-0653-4}, volume = {26}, abstract = {This study evaluates antioxidant responses and jasmonate regulation in Digitaria eriantha cv. Sudafricana plants inoculated (AM) and non-inoculated (non-AM) with Rhizophagus irregularis and subjected to drought, cold, or salinity. Stomatal conductance, photosynthetic efficiency, biomass production, hydrogen peroxide accumulation, lipid peroxidation, antioxidants enzymes activities, and jasmonate levels were determined. Stomatal conductance and photosynthetic efficiency decreased in AM and non-AM plants under all stress conditions. However, AM plants subjected to drought, salinity, or non-stress conditions showed significantly higher stomatal conductance values. AM plants subjected to drought or non-stress conditions increased their shoot/root biomass ratios, whereas salinity and cold caused a decrease in these ratios. Hydrogen peroxide accumulation, which was high in non-AM plant roots under all treatments, increased significantly in non-AM plant shoots under cold stress and in AM plants under non-stress and drought conditions. Lipid peroxidation increased in the roots of all plants under drought conditions. In shoots, although lipid peroxidation decreased in AM plants under non-stress and cold conditions, it increased under drought and salinity. AM plants consistently showed high catalase (CAT) and ascorbate peroxidase (APX) activity under all treatments. By contrast, the glutathione reductase (GR) and superoxide dismutase (SOD) activity of AM roots was lower than that of non-AM plants and increased in shoots. The endogenous levels of cis-12-oxophytodienoc acid (OPDA), jasmonic acid (JA), and 12-OH-JA showed a significant increase in AM plants as compared to non-AM plants. 11-OH-JA content only increased in AM plants subjected to drought. Results show that D. eriantha is sensitive to drought, salinity, and cold stresses and that inoculation with AM fungi regulates its physiology and performance under such conditions, with antioxidants and jasmonates being involved in this process.} } @Article{IPB-1021, author = {Otto, M. and Naumann, C. and Brandt, W. and Wasternack, C. and Hause, B. and}, title = {{Activity Regulation by Heteromerization of Arabidopsis Allene Oxide Cyclase Family Members}}, year = {2016}, pages = {3}, journal = {Plants}, doi = {10.3390/plants5010003}, volume = {5}, abstract = {Jasmonates (JAs) are lipid-derived signals in plant stress responses and development. A crucial step in JA biosynthesis is catalyzed by allene oxide cyclase (AOC). Four genes encoding functional AOCs (AOC1, AOC2, AOC3 and AOC4) have been characterized for Arabidopsis thaliana in terms of organ- and tissue-specific expression, mutant phenotypes, promoter activities and initial in vivo protein interaction studies suggesting functional redundancy and diversification, including first hints at enzyme activity control by protein-protein interaction. Here, these analyses were extended by detailed analysis of recombinant proteins produced in Escherichia coli. Treatment of purified AOC2 with SDS at different temperatures, chemical cross-linking experiments and protein structure analysis by molecular modelling approaches were performed. Several salt bridges between monomers and a hydrophobic core within the AOC2 trimer were identified and functionally proven by site-directed mutagenesis. The data obtained showed that AOC2 acts as a trimer. Finally, AOC activity was determined in heteromers formed by pairwise combinations of the four AOC isoforms. The highest activities were found for heteromers containing AOC4 \+ AOC1 and AOC4 \+ AOC2, respectively. All data are in line with an enzyme activity control of all four AOCs by heteromerization, thereby supporting a putative fine-tuning in JA formation by various regulatory principles.} } @Article{IPB-1083, author = {Dobritzsch, S. and Weyhe, M. and Schubert, R. and Dindas, J. and Hause, G. and Kopka, J. and Hause, B. and}, title = {{Dissection of jasmonate functions in tomato stamen development by transcriptome and metabolome analyses}}, year = {2015}, pages = {28}, journal = {BMC Biol.}, doi = {10.1186/s12915-015-0135-3}, volume = {13}, abstract = {BackgroundJasmonates are well known plant signaling components required for stress responses and development. A prominent feature of jasmonate biosynthesis or signaling mutants is the loss of fertility. In contrast to the male sterile phenotype of Arabidopsis mutants, the tomato mutant jai1-1 exhibits female sterility with additional severe effects on stamen and pollen development. Its senescence phenotype suggests a function of jasmonates in regulation of processes known to be mediated by ethylene. To test the hypothesis that ethylene involved in tomato stamen development is regulated by jasmonates, a temporal profiling of hormone content, transcriptome and metabolome of tomato stamens was performed using wild type and jai1-1.ResultsWild type stamens showed a transient increase of jasmonates that is absent in jai1-1. Comparative transcriptome analyses revealed a diminished expression of genes involved in pollen nutrition at early developmental stages of jai1-1 stamens, but an enhanced expression of ethylene-related genes at late developmental stages. This finding coincides with an early increase of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) in jai1-1 and a premature pollen release from stamens, a phenotype similarly visible in an ethylene overproducing mutant. Application of jasmonates to flowers of transgenic plants affected in jasmonate biosynthesis diminished expression of ethylene-related genes, whereas the double mutant jai1-1 NeverRipe (ethylene insensitive) showed a complementation of jai1-1 phenotype in terms of dehiscence and pollen release.ConclusionsOur data suggest an essential role of jasmonates in the temporal inhibition of ethylene production to prevent premature desiccation of stamens and to ensure proper timing in flower development.} } @Article{IPB-1119, author = {Lischweski, S. and Muchow, A. and Guthörl, D. and Hause, B. and}, title = {{Jasmonates act positively in adventitious root formation in petunia cuttings}}, year = {2015}, pages = {229}, journal = {BMC Plant Biol.}, doi = {10.1186/s12870-015-0615-1}, volume = {15}, abstract = {BackgroundPetunia is a model to study the process of adventitious root (AR) formation on leafy cuttings. Excision of cuttings leads to a transient increase in jasmonates, which is regarded as an early, transient and critical event for rooting. Here, the role of jasmonates in AR formation on petunia cuttings has been studied by a reverse genetic approach.ResultsTo reduce the endogenous levels of jasmonates, transgenic plants were generated expressing a Petunia hybrida ALLENE OXIDE CYCLASE (PhAOC)-RNAi construct. The transgenic plants exhibited strongly reduced PhAOC transcript and protein levels as well as diminished accumulation of cis-12-oxo-phytodienoic acid, jasmonic acid and jasmonoyl-isoleucine after wounding in comparison to wild type and empty vector expressing plants. Reduced levels of endogenous jasmonates resulted in formation of lower numbers of ARs. However, this effect was not accompanied by altered levels of auxin and aminocyclopropane carboxylate (ACC, precursor of ethylene) or by impaired auxin and ethylene-induced gene expression. Neither activity of cell-wall invertases nor accumulation of soluble sugars was altered by jasmonate deficiency.ConclusionsDiminished numbers of AR in JA-deficient cuttings suggest that jasmonates act as positive regulators of AR formation in petunia wild type. However, wound-induced rise in jasmonate levels in petunia wild type cuttings seems not to be causal for increased auxin and ethylene levels and for sink establishment.} } @Article{IPB-1103, author = {Hazman, M. and Hause, B. and Eiche, E. and Nick, P. and Riemann, M. and}, title = {{Increased tolerance to salt stress in OPDA-deficient rice ALLENE OXIDE CYCLASE mutants is linked to an increased ROS-scavenging activity}}, year = {2015}, pages = {3339-3352}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erv142}, volume = {66}, abstract = {Salinity stress represents a global constraint for rice, the most important staple food worldwide. Therefore the role of the central stress signal jasmonate for the salt response was analysed in rice comparing the responses to salt stress for two jasmonic acid (JA) biosynthesis rice mutants (cpm2 and hebiba) impaired in the function of ALLENE OXIDE CYCLASE (AOC) and their wild type. The aoc mutants were less sensitive to salt stress. Interestingly, both mutants accumulated smaller amounts of Na\+ ions in their leaves, and showed better scavenging of reactive oxygen species (ROS) under salt stress. Leaves of the wild type and JA mutants accumulated similar levels of abscisic acid (ABA) under stress conditions, and the levels of JA and its amino acid conjugate, JA–isoleucine (JA-Ile), showed only subtle alterations in the wild type. In contrast, the wild type responded to salt stress by strong induction of the JA precursor 12-oxophytodienoic acid (OPDA), which was not observed in the mutants. Transcript levels of representative salinity-induced genes were induced less in the JA mutants. The absence of 12-OPDA in the mutants correlated not only with a generally increased ROS-scavenging activity, but also with the higher activity of specific enzymes in the antioxidative pathway, such as glutathione S-transferase, and fewer symptoms of damage as, for example, indicated by lower levels of malondialdehyde. The data are interpreted in a model where the absence of OPDA enhanced the antioxidative power in mutant leaves.} } @Article{IPB-1124, author = {Matschi, S. and Hake, K. and Herde, M. and Hause, B. and Romeis, T. and}, title = {{The Calcium-Dependent Protein Kinase CPK28 Regulates Development by Inducing Growth Phase-Specific, Spatially Restricted Alterations in Jasmonic Acid Levels Independent of Defense Responses in Arabidopsis}}, year = {2015}, pages = {591-606}, journal = {Plant Cell}, doi = {10.1105/tpc.15.00024}, volume = {27}, abstract = {Phytohormones play an important role in development and stress adaptations in plants, and several interacting hormonal pathways have been suggested to accomplish fine-tuning of stress responses at the expense of growth. This work describes the role played by the CALCIUM-DEPENDENT PROTEIN KINASE CPK28 in balancing phytohormone-mediated development in Arabidopsis thaliana, specifically during generative growth. cpk28 mutants exhibit growth reduction solely as adult plants, coinciding with altered balance of the phytohormones jasmonic acid (JA) and gibberellic acid (GA). JA-dependent gene expression and the levels of several JA metabolites were elevated in a growth phase-dependent manner in cpk28, and accumulation of JA metabolites was confined locally to the central rosette tissue. No elevated resistance toward herbivores or necrotrophic pathogens was detected for cpk28 plants, either on the whole-plant level or specifically within the tissue displaying elevated JA levels. Abolishment of JA biosynthesis or JA signaling led to a full reversion of the cpk28 growth phenotype, while modification of GA signaling did not. Our data identify CPK28 as a growth phase-dependent key negative regulator of distinct processes: While in seedlings, CPK28 regulates reactive oxygen species-mediated defense signaling; in adult plants, CPK28 confers developmental processes by the tissue-specific balance of JA and GA without affecting JA-mediated defense responses.} } @INBOOK{IPB-59, author = {Hause, B. and Hause, G. and}, title = {{Ecological Biochemistry: Environmental and Interspecies Interactions}}, year = {2015}, pages = {366-382}, chapter = {{Microscope Techniques and Single Cell Analysis}}, editor = {Krauss, G.-J. \& Nies, D. H., eds.}, doi = {10.1002/9783527686063.ch19}, abstract = {For centuries, progress in biological research has been connected to the development of tools and equipment that allow new insights into the living matter. The invention of and improvements in optical systems were very important because exceeding the limits of the optical resolution of the human eye delivered new insights into tissues, cells, and subcellular compartments on the one hand and cellular processes on the other. Even the very first light microscopes, developed at the beginning of the seventeenth century, enabled the discovery of “Cells as little boxes” by Robert Hooke, and of bacteria by Antoni van Leeuwenhoek. Since then, many aspects of microscopes have been improved and new illumination, staining, and detection methods have been developed in order to increase the optical resolution. In this chapter, we describe the principles and possibilities of the use of microscopes in biology, as well as specific methods of preparing biological materials in order to obtain optimum microscopic images with an appropriate scientific message. Further, emphasis is given on staining techniques used for biological materials including transgenic approaches that use the wide variance of fluorescent proteins.} } @Article{IPB-1196, author = {Druege, U. and Franken, P. and Lischewski, S. and Ahkami, A. H. and Zerche, S. and Hause, B. and Hajirezaei, M. R. and}, title = {{Transcriptomic analysis reveals ethylene as stimulator and auxin as regulator of adventitious root formation in petunia cuttings}}, year = {2014}, pages = {494}, journal = {Front. Plant Sci.}, doi = {10.3389/fpls.2014.00494}, volume = {5}, abstract = {Adventitious root (AR) formation in the stem base (SB) of cuttings is the basis for propagation of many plant species and petunia is used as model to study this developmental process. Following AR formation from 2 to 192 hours post-excision (hpe) of cuttings, transcriptome analysis by microarray revealed a change of the character of the rooting zone from SB to root identity. The greatest shift in the number of differentially expressed genes was observed between 24 and 72 hpe, when the categories storage, mineral nutrient acquisition, anti-oxidative and secondary metabolism, and biotic stimuli showed a notable high number of induced genes. Analyses of phytohormone-related genes disclosed multifaceted changes of the auxin transport system, auxin conjugation and the auxin signal perception machinery indicating a reduction in auxin sensitivity and phase-specific responses of particular auxin-regulated genes. Genes involved in ethylene biosynthesis and action showed a more uniform pattern as a high number of respective genes were generally induced during the whole process of AR formation. The important role of ethylene for stimulating AR formation was demonstrated by the application of inhibitors of ethylene biosynthesis and perception as well as of the precursor aminocyclopropane-1-carboxylic acid, all changing the number and length of AR. A model is proposed showing the putative role of polar auxin transport and resulting auxin accumulation in initiation of subsequent changes in auxin homeostasis and signal perception with a particular role of Aux/IAA expression. These changes might in turn guide the entrance into the different phases of AR formation. Ethylene biosynthesis, which is stimulated by wounding and does probably also respond to other stresses and auxin, acts as important stimulator of AR formation probably via the expression of ethylene responsive transcription factor genes, whereas the timing of different phases seems to be controlled by auxin.} } @Article{IPB-1194, author = {Dey, S. and Wenig, M. and Langen, G. and Sharma, S. and Kugler, K. G. and Knappe, C. and Hause, B. and Bichlmeier, M. and Babaeizad, V. and Imani, J. and Janzik, I. and Stempfl, T. and Hückelhoven, R. and Kogel, K.-H. and Mayer, K. F. X. and Vlot, A. C. and}, title = {{Bacteria-Triggered Systemic Immunity in Barley Is Associated with WRKY and ETHYLENE RESPONSIVE FACTORs But Not with Salicylic Acid}}, year = {2014}, pages = {2133-2151}, journal = {Plant Physiol.}, doi = {10.1104/pp.114.249276}, volume = {166}, abstract = {Leaf-to-leaf systemic immune signaling known as systemic acquired resistance is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to systemic acquired resistance in Arabidopsis (Arabidopsis thaliana), systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid. Instead, we documented a moderate local but not systemic induction of abscisic acid after infection of leaves with Psj. In contrast to salicylic acid or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or abscisic acid triggered systemic immunity to Xtc. RNA sequencing analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest, and quantitative reverse transcription-polymerase chain reaction associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR (ERF)-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors, possibly facilitating transcriptional reprogramming to potentiate immunity.} } @Article{IPB-1186, author = {Bucher, M. and Hause, B. and Krajinski, F. and Küster, H. and}, title = {{Through the doors of perception to function in arbuscular mycorrhizal symbioses}}, year = {2014}, pages = {833-840}, journal = {New Phytol.}, doi = {10.1111/nph.12862}, volume = {204}, abstract = {The formation of an arbuscular mycorrhizal (AM) symbiosis is initiated by the bidirectional exchange of diffusible molecules. While strigolactone hormones, secreted from plant roots, stimulate hyphal branching and fungal metabolism, fungal short‐chain chitin oligomers as well as sulfated and nonsulfated lipochitooligosaccharides (s/nsMyc‐LCOs) elicit pre‐symbiosis responses in the host. Fungal LCO signals are structurally related to rhizobial Nod‐factor LCOs. Genome‐wide expression studies demonstrated that defined sets of genes were induced by Nod‐, sMyc‐ and nsMyc‐LCOs, indicating LCO‐specific perception in the pre‐symbiosis phase. During hyphopodium formation and the subsequent root colonization, cross‐talk between plant roots and AM fungi also involves phytohormones. Notably, gibberellins control arbuscule formation via DELLA proteins, which themselves serve as positive regulators of arbuscule formation. The establishment of arbuscules is accompanied by a substantial transcriptional and post‐transcriptional reprogramming of host roots, ultimately defining the unique protein composition of arbuscule‐containing cells. Based on cellular expression profiles, key checkpoints of AM development as well as candidate genes encoding transcriptional regulators and regulatory microRNAs were identified. Detailed functional analyses of promoters specified short motifs sufficient for cell‐autonomous gene regulation in cells harboring arbuscules, and suggested simultaneous, multi‐level regulation of the mycorrhizal phosphate uptake pathway by integrating AM symbiosis and phosphate starvation response signaling.} } @Article{IPB-1181, author = {Bosch, M. and Wright, L. P. and Gershenzon, J. and Wasternack, C. and Hause, B. and Schaller, A. and Stintzi, A. and}, title = {{Jasmonic Acid and Its Precursor 12-Oxophytodienoic Acid Control Different Aspects of Constitutive and Induced Herbivore Defenses in Tomato}}, year = {2014}, pages = {396-410}, journal = {Plant Physiol.}, doi = {10.1104/pp.114.237388}, volume = {166}, abstract = {The jasmonate family of growth regulators includes the isoleucine (Ile) conjugate of jasmonic acid (JA-Ile) and its biosynthetic precursor 12-oxophytodienoic acid (OPDA) as signaling molecules. To assess the relative contribution of JA/JA-Ile and OPDA to insect resistance in tomato (Solanum lycopersicum), we silenced the expression of OPDA reductase3 (OPR3) by RNA interference (RNAi). Consistent with a block in the biosynthetic pathway downstream of OPDA, OPR3-RNAi plants contained wild-type levels of OPDA but failed to accumulate JA or JA-Ile after wounding. JA/JA-Ile deficiency in OPR3-RNAi plants resulted in reduced trichome formation and impaired monoterpene and sesquiterpene production. The loss of these JA/JA-Ile -dependent defense traits rendered them more attractive to the specialist herbivore Manduca sexta with respect to feeding and oviposition. Oviposition preference resulted from reduced levels of repellant monoterpenes and sesquiterpenes. Feeding preference, on the other hand, was caused by increased production of cis-3-hexenal acting as a feeding stimulant for M. sexta larvae in OPR3-RNAi plants. Despite impaired constitutive defenses and increased palatability of OPR3-RNAi leaves, larval development was indistinguishable on OPR3-RNAi and wild-type plants, and was much delayed compared with development on the jasmonic acid-insensitive1 (jai1) mutant. Apparently, signaling through JAI1, the tomato ortholog of the ubiquitin ligase CORONATINE INSENSITIVE1 in Arabidopsis (Arabidopsis thaliana), is required for defense, whereas the conversion of OPDA to JA/JA-Ile is not. Comparing the signaling activities of OPDA and JA/JA-Ile, we found that OPDA can substitute for JA/JA-Ile in the local induction of defense gene expression, but the production of JA/JA-Ile is required for a systemic response.} } @Article{IPB-1220, author = {Krajinski, F. and Courty, P.-E. and Sieh, D. and Franken, P. and Zhang, H. and Bucher, M. and Gerlach, N. and Kryvoruchko, I. and Zoeller, D. and Udvardi, M. and Hause, B. and}, title = {{The H\+-ATPase HA1 of Medicago truncatula Is Essential for Phosphate Transport and Plant Growth during Arbuscular Mycorrhizal Symbiosis}}, year = {2014}, pages = {1808-1817}, journal = {Plant Cell}, doi = {10.1105/tpc.113.120436}, volume = {26}, abstract = {A key feature of arbuscular mycorrhizal symbiosis is improved phosphorus nutrition of the host plant via the mycorrhizal pathway, i.e., the fungal uptake of Pi from the soil and its release from arbuscules within root cells. Efficient transport of Pi from the fungus to plant cells is thought to require a proton gradient across the periarbuscular membrane (PAM) that separates fungal arbuscules from the host cell cytoplasm. Previous studies showed that the H\+-ATPase gene HA1 is expressed specifically in arbuscule-containing root cells of Medicago truncatula. We isolated a ha1-2 mutant of M. truncatula and found it to be impaired in the development of arbuscules but not in root colonization by Rhizophagus irregularis hyphae. Artificial microRNA silencing of HA1 recapitulated this phenotype, resulting in small and truncated arbuscules. Unlike the wild type, the ha1-2 mutant failed to show a positive growth response to mycorrhizal colonization under Pi-limiting conditions. Uptake experiments confirmed that ha1-2 mutants are unable to take up phosphate via the mycorrhizal pathway. Increased pH in the apoplast of abnormal arbuscule-containing cells of the ha1-2 mutant compared with the wild type suggests that HA1 is crucial for building a proton gradient across the PAM and therefore is indispensible for the transfer of Pi from the fungus to the plant.} } @Article{IPB-1217, author = {Hilou, A. and Zhang, H. and Franken, P. and Hause, B. and}, title = {{Do jasmonates play a role in arbuscular mycorrhiza-induced local bioprotection of Medicago truncatula against root rot disease caused by Aphanomyces euteiches?}}, year = {2014}, pages = {45-54}, journal = {Mycorrhiza}, doi = {10.1007/s00572-013-0513-z}, volume = {24}, abstract = {Bioprotective effects of mycorrhization with two different arbuscular mycorrhizal (AM) fungi, Funneliformis mosseae and Rhizophagus irregularis, against Aphanomyces euteiches, the causal agent of root rot in legumes, were studied in Medicago truncatula using phenotypic and molecular markers. Previous inoculation with an AM-fungus reduced disease symptoms as well as the amount of pathogen within roots, as determined by the levels of A. euteiches rRNA or transcripts of the gene sterol C24 reductase. Inoculation with R. irregularis was as efficient as that with F. mosseae. To study whether jasmonates play a regulatory role in bioprotection of M. truncatula by the AM fungi, composite plants harboring transgenic roots were used to modulate the expression level of the gene encoding M. truncatula allene oxide cyclase 1, a key enzyme in jasmonic acid biosynthesis. Neither an increase nor a reduction in allene oxide cyclase levels resulted in altered bioprotection by the AM fungi against root infection by A. euteiches. These data suggest that jasmonates do not play a major role in the local bioprotective effect of AM fungi against the pathogen A. euteiches in M. truncatula roots.} } @Article{IPB-1270, author = {Weier, D. and Thiel, J. and Kohl, S. and Tarkowská, D. and Strnad, M. and Schaarschmidt, S. and Weschke, W. and Weber, H. and Hause, B. and}, title = {{Gibberellin-to-abscisic acid balances govern development and differentiation of the nucellar projection of barley grains}}, year = {2014}, pages = {5291-5304}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/eru289}, volume = {65}, abstract = {In cereal grains, the maternal nucellar projection (NP) constitutes the link to the filial organs, forming a transfer path for assimilates and signals towards the endosperm. At transition to the storage phase, the NP of barley (Hordeum vulgare) undergoes dynamic and regulated differentiation forming a characteristic pattern of proliferating, elongating, and disintegrating cells. Immunolocalization revealed that abscisic acid (ABA) is abundant in early non-elongated but not in differentiated NP cells. In the maternally affected shrunken-endosperm mutant seg8, NP cells did not elongate and ABA remained abundant. The amounts of the bioactive forms of gibberellins (GAs) as well as their biosynthetic precursors were strongly and transiently increased in wild-type caryopses during the transition and early storage phases. In seg8, this increase was delayed and less pronounced together with deregulated gene expression of specific ABA and GA biosynthetic genes. We concluded that differentiation of the barley NP is driven by a distinct and specific shift from lower to higher GA:ABA ratios and that the spatial–temporal change of GA:ABA balances is required to form the differentiation gradient, which is a prerequisite for ordered transfer processes through the NP. Deregulated ABA:GA balances in seg8 impair the differentiation of the NP and potentially compromise transfer of signals and assimilates, resulting in aberrant endosperm growth. These results highlight the impact of hormonal balances on the proper release of assimilates from maternal to filial organs and provide new insights into maternal effects on endosperm differentiation and growth of barley grains.} } @Article{IPB-1268, author = {Wasternack, C. and Hause, B. and}, title = {{Blütenduft, Abwehr, Entwicklung: Jasmonsäure - ein universelles Pflanzenhormon}}, year = {2014}, pages = {164-171}, journal = {Biologie in unserer Zeit}, doi = {10.1002/biuz.201410535}, volume = {44}, abstract = {Pflanzen müssen gegen vielfältige biotische und abiotische Umwelteinflusse eine Abwehr aufbauen. Aber gleichzeitig müssen sie wachsen und sich vermehren. Jasmonate sind neben anderen Hormonen ein zentrales Signal bei der Etablierung von Abwehrmechanismen, aber auch Signal von Entwicklungsprozessen wie Blüten‐ und Trichombildung, sowie der Hemmung von Wachstum. Biosynthese und essentielle Komponenten der Signaltransduktion von JA und seinem biologisch aktiven Konjugat JA‐Ile sind gut untersucht. Der Rezeptor ist ein Proteinkomplex, der “JA‐Ile‐Wahrnehmung” mit proteasomalem Abbau von Repressorproteinen verbindet. Dadurch können positiv agierende Transkriptionsfaktoren wirksam werden und vielfältige Genexpressionsänderungen auslösen. Dies betrifft die Bildung von Abwehrproteinen, Enzymen der JA‐Biosynthese und Sekundärstoffbildung, und Proteinen von Signalketten und Entwicklungsprozessen. Die Kenntnisse zur JA‐Ile‐Wirkung werden in Landwirtschaft und Biotechnologie genutzt.} } @Article{IPB-1239, author = {Phan, H. T. and Hause, B. and Hause, G. and Arcalis, E. and Stoger, E. and Maresch, D. and Altmann, F. and Joensuu, J. and Conrad, U. and}, title = {{Influence of Elastin-Like Polypeptide and Hydrophobin on Recombinant Hemagglutinin Accumulations in Transgenic Tobacco Plants}}, year = {2014}, pages = {e99347}, journal = {PLOS ONE}, doi = {10.1371/journal.pone.0099347}, volume = {9}, abstract = {Fusion protein strategies are useful tools to enhance expression and to support the development of purification technologies. The capacity of fusion protein strategies to enhance expression was explored in tobacco leaves and seeds. C-terminal fusion of elastin-like polypeptides (ELP) to influenza hemagglutinin under the control of either the constitutive CaMV 35S or the seed-specific USP promoter resulted in increased accumulation in both leaves and seeds compared to the unfused hemagglutinin. The addition of a hydrophobin to the C-terminal end of hemagglutinin did not significantly increase the expression level. We show here that, depending on the target protein, both hydrophobin fusion and ELPylation combined with endoplasmic reticulum (ER) targeting induced protein bodies in leaves as well as in seeds. The N-glycosylation pattern indicated that KDEL sequence-mediated retention of leaf-derived hemagglutinins and hemagglutinin-hydrophobin fusions were not completely retained in the ER. In contrast, hemagglutinin-ELP from leaves contained only the oligomannose form, suggesting complete ER retention. In seeds, ER retention seems to be nearly complete for all three constructs. An easy and scalable purification method for ELPylated proteins using membrane-based inverse transition cycling could be applied to both leaf- and seed-expressed hemagglutinins.} } @Article{IPB-1230, author = {Meesters, C. and Mönig, T. and Oeljeklaus, J. and Krahn, D. and Westfall, C. S. and Hause, B. and Jez, J. M. and Kaiser, M. and Kombrink, E. and}, title = {{A chemical inhibitor of jasmonate signaling targets JAR1 in Arabidopsis thaliana}}, year = {2014}, pages = {830-836}, journal = {Nat. Chem. Biol.}, doi = {10.1038/nchembio.1591}, volume = {10}, abstract = {Jasmonates are lipid-derived plant hormones that regulate plant defenses and numerous developmental processes. Although the biosynthesis and molecular function of the most active form of the hormone, (\+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), have been unraveled, it remains poorly understood how the diversity of bioactive jasmonates regulates such a multitude of plant responses. Bioactive analogs have been used as chemical tools to interrogate the diverse and dynamic processes of jasmonate action. By contrast, small molecules impairing jasmonate functions are currently unknown. Here, we report on jarin-1 as what is to our knowledge the first small-molecule inhibitor of jasmonate responses that was identified in a chemical screen using Arabidopsis thaliana. Jarin-1 impairs the activity of JA-Ile synthetase, thereby preventing the synthesis of the active hormone, JA-Ile, whereas closely related enzymes are not affected. Thus, jarin-1 may serve as a useful chemical tool in search for missing regulatory components and further dissection of the complex jasmonate signaling networks.} } @Article{IPB-1313, author = {Ischebeck, T. and Werner, S. and Krishnamoorthy, P. and Lerche, J. and Meijon, M. and Stenzel, I. and Löfke, C. and Wiessner, T. and Im, Y. J. and Perera, I. Y. and Iven, T. and Feussner, I. and Busch, W. and Boss, W. F. and Teichmann, T. and Hause, B. and Persson, S. and Heilmann, I. and}, title = {{Phosphatidylinositol 4,5-Bisphosphate Influences PIN Polarization by Controlling Clathrin-Mediated Membrane Trafficking in Arabidopsis}}, year = {2013}, pages = {4894-4911}, journal = {Plant Cell}, doi = {10.1105/tpc.113.116582}, volume = {25}, abstract = {The functions of the minor phospholipid phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] during vegetative plant growth remain obscure. Here, we targeted two related phosphatidylinositol 4-phosphate 5-kinases (PI4P 5-kinases) PIP5K1 and PIP5K2, which are expressed ubiquitously in Arabidopsis thaliana. A pip5k1 pip5k2 double mutant with reduced PtdIns(4,5)P2 levels showed dwarf stature and phenotypes suggesting defects in auxin distribution. The roots of the pip5k1 pip5k2 double mutant had normal auxin levels but reduced auxin transport and altered distribution. Fluorescence-tagged auxin efflux carriers PIN-FORMED (PIN1)–green fluorescent protein (GFP) and PIN2-GFP displayed abnormal, partially apolar distribution. Furthermore, fewer brefeldin A–induced endosomal bodies decorated by PIN1-GFP or PIN2-GFP formed in pip5k1 pip5k2 mutants. Inducible overexpressor lines for PIP5K1 or PIP5K2 also exhibited phenotypes indicating misregulation of auxin-dependent processes, and immunolocalization showed reduced membrane association of PIN1 and PIN2. PIN cycling and polarization require clathrin-mediated endocytosis and labeled clathrin light chain also displayed altered localization patterns in the pip5k1 pip5k2 double mutant, consistent with a role for PtdIns(4,5)P2 in the regulation of clathrin-mediated endocytosis. Further biochemical tests on subcellular fractions enriched for clathrin-coated vesicles (CCVs) indicated that pip5k1 and pip5k2 mutants have reduced CCV-associated PI4P 5-kinase activity. Together, the data indicate an important role for PtdIns(4,5)P2 in the control of clathrin dynamics and in auxin distribution in Arabidopsis.} } @Article{IPB-1353, author = {Wasternack, C. and Hause, B. and}, title = {{Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in Annals of Botany}}, year = {2013}, pages = {1021-1058}, journal = {Ann. Bot.}, doi = {10.1093/aob/mct067}, volume = {111}, abstract = {BackgroundJasmonates are important regulators in plant responses to biotic and abiotic stresses as well as in development. Synthesized from lipid-constituents, the initially formed jasmonic acid is converted to different metabolites including the conjugate with isoleucine. Important new components of jasmonate signalling including its receptor were identified, providing deeper insight into the role of jasmonate signalling pathways in stress responses and development.ScopeThe present review is an update of the review on jasmonates published in this journal in 2007. New data of the last five years are described with emphasis on metabolites of jasmonates, on jasmonate perception and signalling, on cross-talk to other plant hormones and on jasmonate signalling in response to herbivores and pathogens, in symbiotic interactions, in flower development, in root growth and in light perception.ConclusionsThe last few years have seen breakthroughs in the identification of JASMONATE ZIM DOMAIN (JAZ) proteins and their interactors such as transcription factors and co-repressors, and the crystallization of the jasmonate receptor as well as of the enzyme conjugating jasmonate to amino acids. Now, the complex nature of networks of jasmonate signalling in stress responses and development including hormone cross-talk can be addressed.} } @Article{IPB-1352, author = {Wasternack, C. and Forner, S. and Strnad, M. and Hause, B. and}, title = {{Jasmonates in flower and seed development}}, year = {2013}, pages = {79-85}, journal = {Biochimie}, doi = {10.1016/j.biochi.2012.06.005}, volume = {95}, abstract = {Jasmonates are ubiquitously occurring lipid-derived signaling compounds active in plant development and plant responses to biotic and abiotic stresses. Upon environmental stimuli jasmonates are formed and accumulate transiently. During flower and seed development, jasmonic acid (JA) and a remarkable number of different metabolites accumulate organ- and tissue specifically. The accumulation is accompanied with expression of jasmonate-inducible genes. Among these genes there are defense genes and developmentally regulated genes. The profile of jasmonate compounds in flowers and seeds covers active signaling molecules such as JA, its precursor 12-oxophytodienoic acid (OPDA) and amino acid conjugates such as JA-Ile, but also inactive signaling molecules occur such as 12-hydroxy-JA and its sulfated derivative. These latter compounds can occur at several orders of magnitude higher level than JA. Metabolic conversion of JA and JA-Ile to hydroxylated compounds seems to inactivate JA signaling, but also specific functions of jasmonates in flower and seed development were detected. In tomato OPDA is involved in embryo development. Occurrence of jasmonates, expression of JA-inducible genes and JA-dependent processes in flower and seed development will be discussed.} } @Article{IPB-1336, author = {Schaarschmidt, S. and Gresshoff, P. M. and Hause, B. and}, title = {{Analyzing the soybean transcriptome during autoregulation of mycorrhization identifies the transcription factors GmNF-YA1a/b as positive regulators of arbuscular mycorrhization}}, year = {2013}, pages = {R62}, journal = {Genome Biol.}, doi = {10.1186/gb-2013-14-6-r62}, volume = {14}, abstract = {BackgroundSimilarly to the legume-rhizobia symbiosis, the arbuscular mycorrhiza interaction is controlled by autoregulation representing a feedback inhibition involving the CLAVATA1-like receptor kinase NARK in shoots. However, little is known about signals and targets down-stream of NARK. To find NARK-related transcriptional changes in mycorrhizal soybean (Glycine max) plants, we analyzed wild-type and two nark mutant lines interacting with the arbuscular mycorrhiza fungus Rhizophagus irregularis.ResultsAffymetrix GeneChip analysis of non-inoculated and partially inoculated plants in a split-root system identified genes with potential regulation by arbuscular mycorrhiza or NARK. Most transcriptional changes occur locally during arbuscular mycorrhiza symbiosis and independently of NARK. RT-qPCR analysis verified nine genes as NARK-dependently regulated. Most of them have lower expression in roots or shoots of wild type compared to nark mutants, including genes encoding the receptor kinase GmSIK1, proteins with putative function as ornithine acetyl transferase, and a DEAD box RNA helicase. A predicted annexin named GmAnnx1a is differentially regulated by NARK and arbuscular mycorrhiza in distinct plant organs. Two putative CCAAT-binding transcription factor genes named GmNF-YA1a and GmNF-YA1b are down-regulated NARK-dependently in non-infected roots of mycorrhizal wild-type plants and functional gene analysis confirmed a positive role for these genes in the development of an arbuscular mycorrhiza symbiosis.ConclusionsOur results indicate GmNF-YA1a/b as positive regulators in arbuscular mycorrhiza establishment, whose expression is down-regulated by NARK in the autoregulated root tissue thereby diminishing subsequent infections. Genes regulated independently of arbuscular mycorrhization by NARK support an additional function of NARK in symbioses-independent mechanisms.} } @Article{IPB-1326, author = {Nahar, K. and Kyndt, T. and Hause, B. and Höfte, M. and Gheysen, G. and}, title = {{Brassinosteroids Suppress Rice Defense Against Root-Knot Nematodes Through Antagonism With the Jasmonate Pathway}}, year = {2013}, pages = {106-115}, journal = {Mol. Plant Microbe Interact.}, doi = {10.1094/MPMI-05-12-0108-FI}, volume = {26}, abstract = {The importance of phytohormone balance is increasingly recognized as central to the outcome of plant–pathogen interactions. Next to their well-known developmental role, brassinosteroids (BR) were recently found to be involved in plant innate immunity. In this study, we examined the role of BR in rice (Oryza sativa) innate immunity during infection with the root-knot nematode Meloidogyne graminicola, and we studied the inter-relationship with the jasmonate (JA) pathway. Exogenous epibrassinolide (BL) supply at low concentrations induced susceptibility in the roots whereas high concentrations of BL enforced systemic defense against this nematode. Upon high exogenous BL supply on the shoot, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) confirmed a strong feedback inhibitory effect, leading to reduced BR biosynthesis in the root. Moreover, we demonstrate that the immune suppressive effect of BR is at least partly due to negative cross-talk with the JA pathway. Mutants in the BR biosynthesis or signaling pathway accumulate slightly higher levels of the immediate JA-precursor 12-oxo-phytodienoic acid, and qRT-PCR data showed that the BR and JA pathway are mutually antagonistic in rice roots. Collectively, these results suggest that the balance between the BR and JA pathway is an effective regulator of the outcome of the rice–M. graminicola interaction.} } @INBOOK{IPB-85, author = {Wasternack, C. and Hause, B. and}, title = {{Festkolloquium der Leopoldina anlässlich des 80. Geburtstages von Herrn Altpräsidenten Benno Parthier}}, year = {2013}, pages = {29-38}, chapter = {{Benno Parthier und die Jasmonatforschung in Halle}}, journal = {Nova Acta Leopoldina}, editor = {Hacker, J., ed.}, url = {https://www.leopoldina.org/publikationen/detailansicht/publication/festkolloquium-der-leopoldina-anlaesslich-des-80-geburtstages-von-herrn-altpraesidenten-benno-parthie/}, volume = {Supplementum Nr. 28}, } @INBOOK{IPB-79, author = {Hause, B. and Mielke, K. and Forner, S. and}, title = {{Jasmonate Signaling}}, year = {2013}, pages = {135-144}, chapter = {{Cell-Specific Detection of Jasmonates by Means of an Immunocytological Approach}}, journal = {Methods Mol. Biol.}, editor = {Goossens, A. \& Pauwels, L., eds.}, doi = {10.1007/978-1-62703-414-2_11}, volume = {1011}, abstract = {To determine the location of specific molecules within tissues or cells, immunological techniques are frequently used. However, immunolocalization of small molecules, such as jasmonic acid (JA) and its bioactive amino acid conjugate, JA-isoleucine, requires proper fixation and embedding methods as well as specific antibodies. In this chapter, we present a method to prepare plant tissues for the detection of jasmonates, including the chemical fixation to immobilize JA within the tissue, the subsequent embedding in a suitable medium, and the immunolabeling procedure itself.} } @Article{IPB-1448, author = {Wasternack, C. and Goetz, S. and Hellwege, A. and Forner, S. and Strnad, M. and Hause, B. and}, title = {{Another JA/COI1-independent role of OPDA detected in tomato embryo development}}, year = {2012}, pages = {1349-1353}, journal = {Plant Signal Behav.}, doi = {10.4161/psb.21551}, volume = {7}, abstract = {Jasmonates (JAs) are ubiquitously occurring signaling compounds in plants formed in response to biotic and abiotic stress as well as in development. (\+)-7-iso-jasmonoyl isoleucine, the bioactive JA, is involved in most JA-dependent processes mediated by the F-box protein COI1 in a proteasome-dependent manner. However, there is an increasing number of examples, where the precursor of JA biosynthesis, cis-(\+)-12-oxophytodienoic acid (OPDA) is active in a JA/COI1-independent manner. Here, we discuss those OPDA-dependent processes, thereby giving emphasis on tomato embryo development. Recent data on seed coat-generated OPDA and its role in embryo development is discussed based on biochemical and genetic evidences.} } @Article{IPB-1444, author = {Vadassery, J. and Reichelt, M. and Hause, B. and Gershenzon, J. and Boland, W. and Mithöfer, A. and}, title = {{CML42-Mediated Calcium Signaling Coordinates Responses to Spodoptera Herbivory and Abiotic Stresses in Arabidopsis}}, year = {2012}, pages = {1159-1175}, journal = {Plant Physiol.}, doi = {10.1104/pp.112.198150}, volume = {159}, abstract = {In the interaction between Arabidopsis (Arabidopsis thaliana) and the generalist herbivorous insect Spodoptera littoralis, little is known about early events in defense signaling and their link to downstream phytohormone pathways. S. littoralis oral secretions induced both Ca2\+ and phytohormone elevation in Arabidopsis. Plant gene expression induced by oral secretions revealed up-regulation of a gene encoding a calmodulin-like protein, CML42. Functional analysis of cml42 plants revealed more resistance to herbivory than in the wild type, because caterpillars gain less weight on the mutant, indicating that CML42 negatively regulates plant defense; cml42 also showed increased aliphatic glucosinolate content and hyperactivated transcript accumulation of the jasmonic acid (JA)-responsive genes VSP2 and Thi2.1 upon herbivory, which might contribute to increased resistance. CML42 up-regulation is negatively regulated by the jasmonate receptor Coronatine Insensitive1 (COI1), as loss of functional COI1 resulted in prolonged CML42 activation. CML42 thus acts as a negative regulator of plant defense by decreasing COI1-mediated JA sensitivity and the expression of JA-responsive genes and is independent of herbivory-induced JA biosynthesis. JA-induced Ca2\+ elevation and root growth inhibition were more sensitive in cml42, also indicating higher JA perception. Our results indicate that CML42 acts as a crucial signaling component connecting Ca2\+ and JA signaling. CML42 is localized to cytosol and nucleus. CML42 is also involved in abiotic stress responses, as kaempferol glycosides were down-regulated in cml42, and impaired in ultraviolet B resistance. Under drought stress, the level of abscisic acid accumulation was higher in cml42 plants. Thus, CML42 might serve as a Ca2\+ sensor having multiple functions in insect herbivory defense and abiotic stress responses.} } @Article{IPB-1438, author = {Stenzel, I. and Otto, M. and Delker, C. and Kirmse, N. and Schmidt, D. and Miersch, O. and Hause, B. and Wasternack, C. and}, title = {{ALLENE OXIDE CYCLASE (AOC) gene family members of Arabidopsis thaliana: tissue- and organ-specific promoter activities and in vivo heteromerization}}, year = {2012}, pages = {6125-6138}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/ers261}, volume = {63}, abstract = {Jasmonates are important signals in plant stress responses and plant development. An essential step in the biosynthesis of jasmonic acid (JA) is catalysed by ALLENE OXIDE CYCLASE (AOC) which establishes the naturally occurring enantiomeric structure of jasmonates. In Arabidopsis thaliana, four genes encode four functional AOC polypeptides (AOC1, AOC2, AOC3, and AOC4) raising the question of functional redundancy or diversification. Analysis of transcript accumulation revealed an organ-specific expression pattern, whereas detailed inspection of transgenic lines expressing the GUS reporter gene under the control of individual AOC promoters showed partially redundant promoter activities during development: (i) In fully developed leaves, promoter activities of AOC1, AOC2, and AOC3 appeared throughout all leaf tissue, but AOC4 promoter activity was vascular bundle-specific; (ii) only AOC3 and AOC4 showed promoter activities in roots; and (iii) partially specific promoter activities were found for AOC1 and AOC4 in flower development. In situ hybridization of flower stalks confirmed the GUS activity data. Characterization of single and double AOC loss-of-function mutants further corroborates the hypothesis of functional redundancies among individual AOCs due to a lack of phenotypes indicative of JA deficiency (e.g. male sterility). To elucidate whether redundant AOC expression might contribute to regulation on AOC activity level, protein interaction studies using bimolecular fluorescence complementation (BiFC) were performed and showed that all AOCs can interact among each other. The data suggest a putative regulatory mechanism of temporal and spatial fine-tuning in JA formation by differential expression and via possible heteromerization of the four AOCs.} } @Article{IPB-1413, author = {Landgraf, R. and Schaarschmidt, S. and Hause, B. and}, title = {{Repeated leaf wounding alters the colonization of Medicago truncatula roots by beneficial and pathogenic microorganisms}}, year = {2012}, pages = {1344-1357}, journal = {Plant Cell Environ.}, doi = {10.1111/j.1365-3040.2012.02495.x}, volume = {35}, abstract = {In nature, plants are subject to various stresses that are often accompanied by wounding of the aboveground tissues. As wounding affects plants locally and systemically, we investigated the impact of leaf wounding on interactions of Medicago truncatula with root‐colonizing microorganisms, such as the arbuscular mycorrhizal (AM) fungus Glomus intraradices, the pathogenic oomycete Aphanomyces euteiches and the nitrogen‐fixing bacterium Sinorhizobium meliloti. To obtain a long‐lasting wound response, repeated wounding was performed and resulted in locally and systemically increased jasmonic acid (JA) levels accompanied by the expression of jasmonate‐induced genes, among them the genes encoding allene oxide cyclase 1 (MtAOC1) and a putative cell wall‐bound invertase (cwINV). After repeated wounding, colonization with the AM fungus was increased, suggesting a role of jasmonates as positive regulators of mycorrhization, whereas the interaction with the rhizobacterium was not affected. In contrast, wounded plants appeared to be less susceptible to pathogens which might be caused by JA‐induced defence mechanisms. The effects of wounding on mycorrhization and pathogen infection could be partially mimicked by foliar application of JA. In addition to JA itself, the positive effect on mycorrhization might be mediated by systemically induced cwINV, which was previously shown to exhibit a regulatory function on interaction with AM fungi.} } @Article{IPB-1401, author = {Goetz, S. and Hellwege, A. and Stenzel, I. and Kutter, C. and Hauptmann, V. and Forner, S. and McCaig, B. and Hause, G. and Miersch, O. and Wasternack, C. and Hause, B. and}, title = {{Role of cis-12-Oxo-Phytodienoic Acid in Tomato Embryo Development}}, year = {2012}, pages = {1715-1727}, journal = {Plant Physiol.}, doi = {10.1104/pp.111.192658}, volume = {158}, abstract = {Oxylipins including jasmonates are signaling compounds in plant growth, development, and responses to biotic and abiotic stresses. In Arabidopsis (Arabidopsis thaliana) most mutants affected in jasmonic acid (JA) biosynthesis and signaling are male sterile, whereas the JA-insensitive tomato (Solanum lycopersicum) mutant jai1 is female sterile. The diminished seed formation in jai1 together with the ovule-specific accumulation of the JA biosynthesis enzyme allene oxide cyclase (AOC), which correlates with elevated levels of JAs, suggest a role of oxylipins in tomato flower/seed development. Here, we show that 35S::SlAOC-RNAi lines with strongly reduced AOC in ovules exhibited reduced seed set similarly to the jai1 plants. Investigation of embryo development of wild-type tomato plants showed preferential occurrence of AOC promoter activity and AOC protein accumulation in the developing seed coat and the embryo, whereas 12-oxo-phytodienoic acid (OPDA) was the dominant oxylipin occurring nearly exclusively in the seed coat tissues. The OPDA- and JA-deficient mutant spr2 was delayed in embryo development and showed an increased programmed cell death in the developing seed coat and endosperm. In contrast, the mutant acx1a, which accumulates preferentially OPDA and residual amount of JA, developed embryos similar to the wild type, suggesting a role of OPDA in embryo development. Activity of the residual amount of JA in the acx1a mutant is highly improbable since the known reproductive phenotype of the JA-insensitive mutant jai1 could be rescued by wound-induced formation of OPDA. These data suggest a role of OPDA or an OPDA-related compound for proper embryo development possibly by regulating carbohydrate supply and detoxification.} } @Article{IPB-1400, author = {Gaupels, F. and Sarioglu, H. and Beckmann, M. and Hause, B. and Spannagl, M. and Draper, J. and Lindermayr, C. and Durner, J. and}, title = {{Deciphering Systemic Wound Responses of the Pumpkin Extrafascicular Phloem by Metabolomics and Stable Isotope-Coded Protein Labeling}}, year = {2012}, pages = {2285-2299}, journal = {Plant Physiol.}, doi = {10.1104/pp.112.205336}, volume = {160}, abstract = {In cucurbits, phloem latex exudes from cut sieve tubes of the extrafascicular phloem (EFP), serving in defense against herbivores. We analyzed inducible defense mechanisms in the EFP of pumpkin (Cucurbita maxima) after leaf damage. As an early systemic response, wounding elicited transient accumulation of jasmonates and a decrease in exudation probably due to partial sieve tube occlusion by callose. The energy status of the EFP was enhanced as indicated by increased levels of ATP, phosphate, and intermediates of the citric acid cycle. Gas chromatography coupled to mass spectrometry also revealed that sucrose transport, gluconeogenesis/glycolysis, and amino acid metabolism were up-regulated after wounding. Combining ProteoMiner technology for the enrichment of low-abundance proteins with stable isotope-coded protein labeling, we identified 51 wound-regulated phloem proteins. Two Sucrose-Nonfermenting1-related protein kinases and a 32-kD 14-3-3 protein are candidate central regulators of stress metabolism in the EFP. Other proteins, such as the Silverleaf Whitefly-Induced Protein1, Mitogen Activated Protein Kinase6, and Heat Shock Protein81, have known defensive functions. Isotope-coded protein labeling and western-blot analyses indicated that Cyclophilin18 is a reliable marker for stress responses of the EFP. As a hint toward the induction of redox signaling, we have observed delayed oxidation-triggered polymerization of the major Phloem Protein1 (PP1) and PP2, which correlated with a decline in carbonylation of PP2. In sum, wounding triggered transient sieve tube occlusion, enhanced energy metabolism, and accumulation of defense-related proteins in the pumpkin EFP. The systemic wound response was mediated by jasmonate and redox signaling.} } @Article{IPB-1370, author = {Balcke, G. U. and Handrick, V. and Bergau, N. and Fichtner, M. and Henning, A. and Stellmach, H. and Tissier, A. and Hause, B. and Frolov, A. and}, title = {{An UPLC-MS/MS method for highly sensitive high-throughput analysis of phytohormones in plant tissues}}, year = {2012}, pages = {47}, journal = {Plant Meth.}, doi = {10.1186/1746-4811-8-47}, volume = {8}, abstract = {BackgroundPhytohormones are the key metabolites participating in the regulation of multiple functions of plant organism. Among them, jasmonates, as well as abscisic and salicylic acids are responsible for triggering and modulating plant reactions targeted against pathogens and herbivores, as well as resistance to abiotic stress (drought, UV-irradiation and mechanical wounding). These factors induce dramatic changes in phytohormone biosynthesis and transport leading to rapid local and systemic stress responses. Understanding of underlying mechanisms is of principle interest for scientists working in various areas of plant biology. However, highly sensitive, precise and high-throughput methods for quantification of these phytohormones in small samples of plant tissues are still missing.ResultsHere we present an LC-MS/MS method for fast and highly sensitive determination of jasmonates, abscisic and salicylic acids. A single-step sample preparation procedure based on mixed-mode solid phase extraction was efficiently combined with essential improvements in mobile phase composition yielding higher efficiency of chromatographic separation and MS-sensitivity. This strategy resulted in dramatic increase in overall sensitivity, allowing successful determination of phytohormones in small (less than 50 mg of fresh weight) tissue samples. The method was completely validated in terms of analyte recovery, sensitivity, linearity and precision. Additionally, it was cross-validated with a well-established GC-MS-based procedure and its applicability to a variety of plant species and organs was verified.ConclusionThe method can be applied for the analyses of target phytohormones in small tissue samples obtained from any plant species and/or plant part relying on any commercially available (even less sensitive) tandem mass spectrometry instrumentation.} } @Article{IPB-1486, author = {Helber, N. and Wippel, K. and Sauer, N. and Schaarschmidt, S. and Hause, B. and Requena, N. and}, title = {{A Versatile Monosaccharide Transporter That Operates in the Arbuscular Mycorrhizal Fungus Glomus sp Is Crucial for the Symbiotic Relationship with Plants}}, year = {2011}, pages = {3812-3823}, journal = {Plant Cell}, doi = {10.1105/tpc.111.089813}, volume = {23}, abstract = {For more than 400 million years, plants have maintained a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi. This evolutionary success can be traced to the role of these fungi in providing plants with mineral nutrients, particularly phosphate. In return, photosynthates are given to the fungus, which support its obligate biotrophic lifestyle. Although the mechanisms involved in phosphate transfer have been extensively studied, less is known about the reciprocal transfer of carbon. Here, we present the high-affinity Monosaccharide Transporter2 (MST2) from Glomus sp with a broad substrate spectrum that functions at several symbiotic root locations. Plant cell wall sugars can efficiently outcompete the Glc uptake capacity of MST2, suggesting they can serve as alternative carbon sources. MST2 expression closely correlates with that of the mycorrhiza-specific PhosphateTransporter4 (PT4). Furthermore, reduction of MST2 expression using host-induced gene silencing resulted in impaired mycorrhiza formation, malformed arbuscules, and reduced PT4 expression. These findings highlight the symbiotic role of MST2 and support the hypothesis that the exchange of carbon for phosphate is tightly linked. Unexpectedly, we found that the external mycelium of AM fungi is able to take up sugars in a proton-dependent manner. These results imply that the sugar uptake system operating in this symbiosis is more complex than previously anticipated.} } @Article{IPB-1477, author = {Escalante-Pérez, M. and Krol, E. and Stange, A. and Geiger, D. and Al-Rasheid, K. A. S. and Hause, B. and Neher, E. and Hedrich, R. and}, title = {{A special pair of phytohormones controls excitability, slow closure, and external stomach formation in the Venus flytrap}}, year = {2011}, pages = {15492-15497}, journal = {Proc. Natl. Acad. Sci. U.S.A.}, doi = {10.1073/pnas.1112535108}, volume = {108}, abstract = {Venus flytrap\'s leaves can catch an insect in a fraction of a second. Since the time of Charles Darwin, scientists have struggled to understand the sensory biology and biomechanics of this plant, Dionaea muscipula. Here we show that insect-capture of Dionaea traps is modulated by the phytohormone abscisic acid (ABA) and jasmonates. Water-stressed Dionaea, as well as those exposed to the drought-stress hormone ABA, are less sensitive to mechanical stimulation. In contrast, application of 12-oxo-phytodienoic acid (OPDA), a precursor of the phytohormone jasmonic acid (JA), the methyl ester of JA (Me-JA), and coronatine (COR), the molecular mimic of the isoleucine conjugate of JA (JA-Ile), triggers secretion of digestive enzymes without any preceding mechanical stimulus. Such secretion is accompanied by slow trap closure. Under physiological conditions, insect-capture is associated with Ca2\+ signaling and a rise in OPDA, Apparently, jasmonates bypass hapto-electric processes associated with trap closure. However, ABA does not affect OPDA-dependent gland activity. Therefore, signals for trap movement and secretion seem to involve separate pathways. Jasmonates are systemically active because application to a single trap induces secretion and slow closure not only in the given trap but also in all others. Furthermore, formerly touch-insensitive trap sectors are converted into mechanosensitive ones. These findings demonstrate that prey-catching Dionaea combines plant-specific signaling pathways, involving OPDA and ABA with a rapidly acting trigger, which uses ion channels, action potentials, and Ca2\+ signals.} } @Article{IPB-1498, author = {Mielke, K. and Forner, S. and Kramell, R. and Conrad, U. and Hause, B. and}, title = {{Cell-specific visualization of jasmonates in wounded tomato and Arabidopsis leaves using jasmonate-specific antibodies}}, year = {2011}, pages = {1069-1080}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2010.03638.x}, volume = {190}, abstract = {Jasmonates are well‐characterized signals in the development of plants and their response to abiotic and biotic stresses, such as touch and wounding by herbivores. A gap in our knowledge on jasmonate‐induced processes, however, is the cellular localization of jasmonates.Here, a novel antibody‐based approach was developed to visualize jasmonates in cross‐sections of plant material. Antibodies raised in rabbits against BSA‐coupled jasmonic acid (JA) are specific for JA, its methyl ester and isoleucine conjugate. They do not bind to 12‐oxophytodienoic acid, 12‐hydoxy‐JA or coronatine. These antibodies were used in combination with newly established fixation and embedding methods.Jasmonates were rapidly and uniformly distributed within all cells near the site of damage of a mechanically wounded tomato (Solanum lycopersicum) leaf. Leaf tissue distally located to the wound site exhibited identical distribution, but had a lower signal intensity. The occurrence of jasmonates in all cell types of a wounded leaf was accompanied by transcript accumulation of early JA‐induced genes visualized by in situ hybridization.With these new antibodies, a powerful tool is available to detect cell‐specifically the occurrence of jasmonates in any jasmonate‐dependent stress response or developmental process of plants.} } @Article{IPB-1523, author = {Zdyb, A. and Demchenko, K. and Heumann, J. and Mrosk, C. and Grzeganek, P. and Göbel, C. and Feussner, I. and Pawlowski, K. and Hause, B. and}, title = {{Jasmonate biosynthesis in legume and actinorhizal nodules}}, year = {2011}, pages = {568-579}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2010.03504.x}, volume = {189}, abstract = {Jasmonic acid (JA) is a plant signalling compound that has been implicated in the regulation of mutualistic symbioses. In order to understand the spatial distribution of JA biosynthetic capacity in nodules of two actinorhizal species, Casaurina glauca and Datisca glomerata, and one legume, Medicago truncatula, we determined the localization of allene oxide cyclase (AOC) which catalyses a committed step in JA biosynthesis. In all nodule types analysed, AOC was detected exclusively in uninfected cells.The levels of JA were compared in the roots and nodules of the three plant species. The nodules and noninoculated roots of the two actinorhizal species, and the root systems of M. truncatula, noninoculated or nodulated with wild‐type Sinorhizobium meliloti or with mutants unable to fix nitrogen, did not show significant differences in JA levels. However, JA levels in all plant organs examined increased significantly on mechanical disturbance.To study whether JA played a regulatory role in the nodules of M. truncatula, composite plants containing roots expressing an MtAOC1‐sense or MtAOC1‐RNAi construct were inoculated with S. meliloti. Neither an increase nor reduction in AOC levels resulted in altered nodule formation.These data suggest that jasmonates are not involved in the development and function of root nodules.} } @Article{IPB-1589, author = {Weichert, N. and Saalbach, I. and Weichert, H. and Kohl, S. and Erban, A. and Kopka, J. and Hause, B. and Varshney, A. and Sreenivasulu, N. and Strickert, M. and Kumlehn, J. and Weschke, W. and Weber, H. and}, title = {{Increasing Sucrose Uptake Capacity of Wheat Grains Stimulates Storage Protein Synthesis}}, year = {2010}, pages = {698-710}, journal = {Plant Physiol.}, doi = {10.1104/pp.109.150854}, volume = {152}, abstract = {Increasing grain sink strength by improving assimilate uptake capacity could be a promising approach toward getting higher yield. The barley (Hordeum vulgare) sucrose transporter HvSUT1 (SUT) was expressed under control of the endosperm-specific Hordein B1 promoter (HO). Compared with the wild type, transgenic HOSUT grains take up more sucrose (Suc) in vitro, showing that the transgene is functional. Grain Suc levels are not altered, indicating that Suc fluxes are influenced rather than steady-state levels. HOSUT grains have increased percentages of total nitrogen and prolamins, which is reflected in increased levels of phenylalanine, tyrosine, tryptophan, isoleucine, and leucine at late grain development. Transcript profiling indicates specific stimulation of prolamin gene expression at the onset of storage phase. Changes in gene expression and metabolite levels related to carbon metabolism and amino acid biosynthesis suggest deregulated carbon-nitrogen balance, which together indicate carbon sufficiency and relative depletion of nitrogen. Genes, deregulated together with prolamin genes, might represent candidates, which respond positively to assimilate supply and are related to sugar-starch metabolism, cytokinin and brassinosteroid functions, cell proliferation, and sugar/abscisic acid signaling. Genes showing inverse expression patterns represent potential negative regulators. It is concluded that HvSUT1 overexpression increases grain protein content but also deregulates the metabolic status of wheat (Triticum aestivum) grains, accompanied by up-regulated gene expression of positive and negative regulators related to sugar signaling and assimilate supply. In HOSUT grains, alternating stimulation of positive and negative regulators causes oscillatory patterns of gene expression and highlights the capacity and great flexibility to adjust wheat grain storage metabolism in response to metabolic alterations.} } @Article{IPB-1579, author = {Teutschbein, J. and Gross, W. and Nimtz, M. and Milkowski, C. and Hause, B. and Strack, D. and}, title = {{Identification and Localization of a Lipase-like Acyltransferase in Phenylpropanoid Metabolism of Tomato (Solanum lycopersicum)}}, year = {2010}, pages = {38374-38381}, journal = {J. Biol. Chem.}, doi = {10.1074/jbc.M110.171637}, volume = {285}, abstract = {We have isolated an enzyme classified as chlorogenate: glucarate caffeoyltransferase (CGT) from seedlings of tomato (Solanum lycopersicum) that catalyzes the formation of caffeoylglucarate and caffeoylgalactarate using chlorogenate (5-O-caffeoylquinate) as acyl donor. Peptide sequences obtained by trypsin digestion and spectrometric sequencing were used to isolate the SlCGT cDNA encoding a protein of 380 amino acids with a putative targeting signal of 24 amino acids indicating an entry of the SlCGT into the secretory pathway. Immunogold electron microscopy revealed the localization of the enzyme in the apoplastic space of tomato leaves. Southern blot analysis of genomic cDNA suggests that SlCGT is encoded by a single-copy gene. The SlCGT cDNA was functionally expressed in Nicotiana benthamiana leaves and proved to confer chlorogenate-dependent caffeoyltransferase activity in the presence of glucarate. Sequence comparison of the deduced amino acid sequence identified the protein unexpectedly as a GDSL lipase-like protein, representing a new member of the SGNH protein superfamily. Lipases of this family employ a catalytic triad of Ser-Asp-His with Ser as nucleophile of the GDSL motif. Site-directed mutagenesis of each residue of the assumed respective SlCGT catalytic triad, however, indicated that the catalytic triad of the GDSL lipase is not essential for SlCGT enzymatic activity. SlCGT is therefore the first example of a GDSL lipase-like protein that lost hydrolytic activity and has acquired a completely new function in plant metabolism, functioning in secondary metabolism as acyltransferase in synthesis of hydroxycinnamate esters by employing amino acid residues different from the lipase catalytic triad.} } @Article{IPB-1578, author = {Stumpe, M. and Göbel, C. and Faltin, B. and Beike, A. K. and Hause, B. and Himmelsbach, K. and Bode, J. and Kramell, R. and Wasternack, C. and Frank, W. and Reski, R. and Feussner, I. and}, title = {{The moss Physcomitrella patens contains cyclopentenones but no jasmonates: mutations in allene oxide cyclase lead to reduced fertility and altered sporophyte morphology}}, year = {2010}, pages = {740-749}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2010.03406.x}, volume = {188}, abstract = {Two cDNAs encoding allene oxide cyclases (PpAOC1, PpAOC2), key enzymes in the formation of jasmonic acid (JA) and its precursor (9S,13S)‐12‐oxo‐phytodienoic acid (cis‐(\+)‐OPDA), were isolated from the moss Physcomitrella patens.Recombinant PpAOC1 and PpAOC2 show substrate specificity against the allene oxide derived from 13‐hydroperoxy linolenic acid (13‐HPOTE); PpAOC2 also shows substrate specificity against the allene oxide derived from 12‐hydroperoxy arachidonic acid (12‐HPETE).In protonema and gametophores the occurrence of cis‐(\+)‐OPDA, but neither JA nor the isoleucine conjugate of JA nor that of cis‐(\+)‐OPDA was detected.Targeted knockout mutants for PpAOC1 and for PpAOC2 were generated, while double mutants could not be obtained. The ΔPpAOC1 and ΔPpAOC2 mutants showed reduced fertility, aberrant sporophyte morphology and interrupted sporogenesis.} } @Article{IPB-1567, author = {Paetzold, H. and Garms, S. and Bartram, S. and Wieczorek, J. and Urós-Gracia, E.-M. and Rodríguez-Concepción, M. and Boland, W. and Strack, D. and Hause, B. and Walter, M. H. and}, title = {{The Isogene 1-Deoxy-D-Xylulose 5-Phosphate Synthase 2 Controls Isoprenoid Profiles, Precursor Pathway Allocation, and Density of Tomato Trichomes}}, year = {2010}, pages = {904-916}, journal = {Mol. Plant}, doi = {10.1093/mp/ssq032}, volume = {3}, abstract = {Plant isoprenoids are formed from precursors synthesized by the mevalonate (MVA) pathway in the cytosol or by the methyl-D-erythritol 4-phosphate (MEP) pathway in plastids. Although some exchange of precursors occurs, cytosolic sesquiterpenes are assumed to derive mainly from MVA, while plastidial monoterpenes are produced preferentially from MEP precursors. Additional complexity arises in the first step of the MEP pathway, which is typically catalyzed by two divergent 1-deoxy-D-xylulose 5-phosphate synthase isoforms (DXS1, DXS2). In tomato (Solanum lycopersicum), the SlDXS1 gene is ubiquitously expressed with highest levels during fruit ripening, whereas SlDXS2 transcripts are abundant in only few tissues, including young leaves, petals, and isolated trichomes. Specific down-regulation of SlDXS2 expression was performed by RNA interference in transgenic plants to investigate feedback mechanisms. SlDXS2 down-regulation led to a decrease in the monoterpene β-phellandrene and an increase in two sesquiterpenes in trichomes. Moreover, incorporation of MVA-derived precursors into residual monoterpenes and into sesquiterpenes was elevated as determined by comparison of 13C to 12C natural isotope ratios. A compensatory up-regulation of SlDXS1 was not observed. Down-regulated lines also exhibited increased trichome density and showed less damage by leaf-feeding Spodoptera littoralis caterpillars. The results reveal novel, non-redundant roles of DXS2 in modulating isoprenoid metabolism and a pronounced plasticity in isoprenoid precursor allocation.} } @Article{IPB-1532, author = {Breuillin, F. and Schramm, J. and Hajirezaei, M. and Ahkami, A. and Favre, P. and Druege, U. and Hause, B. and Bucher, M. and Kretzschmar, T. and Bossolini, E. and Kuhlemeier, C. and Martinoia, E. and Franken, P. and Scholz, U. and Reinhardt, D. and}, title = {{Phosphate systemically inhibits development of arbuscular mycorrhiza in Petunia hybrida and represses genes involved in mycorrhizal functioning}}, year = {2010}, pages = {1002-1017}, journal = {Plant J.}, doi = {10.1111/j.1365-313X.2010.04385.x}, volume = {64}, abstract = {Most terrestrial plants form arbuscular mycorrhiza (AM), mutualistic associations with soil fungi of the order Glomeromycota. The obligate biotrophic fungi trade mineral nutrients, mainly phosphate (Pi), for carbohydrates from the plants. Under conditions of high exogenous phosphate supply, when the plant can meet its own P requirements without the fungus, AM are suppressed, an effect which could be interpreted as an active strategy of the plant to limit carbohydrate consumption of the fungus by inhibiting its proliferation in the roots. However, the mechanisms involved in fungal inhibition are poorly understood. Here, we employ a transcriptomic approach to get insight into potential shifts in metabolic activity and symbiotic signalling, and in the defence status of plants exposed to high Pi levels. We show that in mycorrhizal roots of petunia, a similar set of symbiosis‐related genes is expressed as in mycorrhizal roots of Medicago, Lotus and rice. Pi acts systemically to repress symbiotic gene expression and AM colonization in the root. In established mycorrhizal roots, Pi repressed symbiotic gene expression rapidly, whereas the inhibition of colonization followed with a lag of more than a week. Taken together, these results suggest that Pi acts by repressing essential symbiotic genes, in particular genes encoding enzymes of carotenoid and strigolactone biosynthesis, and symbiosis‐associated phosphate transporters. The role of these effects in the suppression of symbiosis under high Pi conditions is discussed.} } @Article{IPB-1562, author = {Mallona, I. and Lischewski, S. and Weiss, J. and Hause, B. and Egea-Cortines, M. and}, title = {{Validation of reference genes for quantitative real-time PCR during leaf and flower development in Petunia hybrida}}, year = {2010}, pages = {4}, journal = {BMC Plant Biol.}, doi = {10.1186/1471-2229-10-4}, volume = {10}, abstract = {BackgroundIdentification of genes with invariant levels of gene expression is a prerequisite for validating transcriptomic changes accompanying development. Ideally expression of these genes should be independent of the morphogenetic process or environmental condition tested as well as the methods used for RNA purification and analysis.ResultsIn an effort to identify endogenous genes meeting these criteria nine reference genes (RG) were tested in two Petunia lines (Mitchell and V30). Growth conditions differed in Mitchell and V30, and different methods were used for RNA isolation and analysis. Four different software tools were employed to analyze the data. We merged the four outputs by means of a non-weighted unsupervised rank aggregation method. The genes identified as optimal for transcriptomic analysis of Mitchell and V30 were EF1α in Mitchell and CYP in V30, whereas the least suitable gene was GAPDH in both lines.ConclusionsThe least adequate gene turned out to be GAPDH indicating that it should be rejected as reference gene in Petunia. The absence of correspondence of the best-suited genes suggests that assessing reference gene stability is needed when performing normalization of data from transcriptomic analysis of flower and leaf development.} } @Article{IPB-1559, author = {Leitner, M. and Kaiser, R. and Hause, B. and Boland, W. and Mithöfer, A. and}, title = {{Does mycorrhization influence herbivore-induced volatile emission in Medicago truncatula?}}, year = {2010}, pages = {89-101}, journal = {Mycorrhiza}, doi = {10.1007/s00572-009-0264-z}, volume = {20}, abstract = {Symbiosis with mycorrhizal fungi substantially impacts secondary metabolism and defensive traits of colonised plants. In the present study, we investigated the influence of mycorrhization (Glomus intraradices) on inducible indirect defences against herbivores using the model legume Medicago truncatula. Volatile emission by mycorrhizal and non-mycorrhizal plants was measured in reaction to damage inflicted by Spodoptera spp. and compared to the basal levels of volatile emission by plants of two different cultivars. Emitted volatiles were recorded using closed-loop stripping and gas chromatography/mass spectrometry. The documented volatile patterns were evaluated using multidimensional scaling to visualise patterns and stepwise linear discriminant analysis to distinguish volatile blends of plants with distinct physiological status and genetic background. Volatile blends emitted by different cultivars of M. truncatula prove to be clearly distinct, whereas mycorrhization only slightly influenced herbivore-induced volatile emissions. Still, the observed differences were sufficient to create classification rules to distinguish mycorrhizal and non-mycorrhizal plants by the volatiles emitted. Moreover, the effect of mycorrhization turned out to be opposed in the two cultivars examined. Root symbionts thus seem to alter indirect inducible defences of M. truncatula against insect herbivores. The impact of this effect strongly depends on the genetic background of the plant and, hence, in part explains the highly contradictory results on tripartite interactions gathered to date.} } @Article{IPB-1557, author = {Klopotek, Y. and Haensch, K.-T. and Hause, B. and Hajirezaei, M.-R. and Druege, U. and}, title = {{Dark exposure of petunia cuttings strongly improves adventitious root formation and enhances carbohydrate availability during rooting in the light}}, year = {2010}, pages = {547-554}, journal = {J. Plant Physiol.}, doi = {10.1016/j.jplph.2009.11.008}, volume = {167}, abstract = {The effect of temporary dark exposure on adventitious root formation (ARF) in Petunia×hybrida ‘Mitchell’ cuttings was investigated. Histological and metabolic changes in the cuttings during the dark treatment and subsequent rooting in the light were recorded. Excised cuttings were exposed to the dark for seven days at 10°C followed by a nine-day rooting period in perlite or were rooted immediately for 16 days in a climate chamber at 22/20°C (day/night) and a photosynthetic photon flux density (PPFD) of 100 μmol m−2 s−1. Dark exposure prior to rooting increased, accelerated and synchronized ARF. The rooting period was reduced from 16 days (non-treated cuttings) to 9 days (treated cuttings). Under optimum conditions, despite the reduced rooting period, dark-exposed cuttings produced a higher number and length of roots than non-treated cuttings. An increase in temperature to 20 °C during the dark treatment or extending the cold dark exposure to 14 days caused a similar enhancement of root development compared to non-treated cuttings. Root meristem formation had already started during the dark treatment and was enhanced during the subsequent rooting period. Levels of soluble sugars (glucose, fructose and sucrose) and starch in leaf and basal stem tissues significantly decreased during the seven days of dark exposure. This depletion was, however, compensated during rooting after 6 and 24h for soluble sugars in leaves and the basal stem, respectively, whereas the sucrose level in the basal stem was already increased at 6 h. The association of higher carbohydrate levels with improved rooting in previously dark-exposed versus non-treated cuttings indicates that increased post-darkness carbohydrate availability and allocation towards the stem base contribute to ARF under the influence of dark treatment and provide energy for cell growth subject to a rising sink intensity in the base of the cutting.} } @Article{IPB-1595, author = {Ahkami, A. H. and Lischewski, S. and Haensch, K.-T. and Porfirova, S. and Hofmann, J. and Rolletschek, H. and Melzer, M. and Franken, P. and Hause, B. and Druege, U. and Hajirezaei, M. R. and}, title = {{Molecular physiology of adventitious root formation in Petunia hybrida cuttings: involvement of wound response and primary metabolism}}, year = {2009}, pages = {613-625}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2008.02704.x}, volume = {181}, abstract = {Adventitious root formation (ARF) in the model plant Petunia hybrida cv. Mitchell has been analysed in terms of anatomy, gene expression, enzymatic activities and levels of metabolites. This study focuses on the involvement of wound response and primary metabolism.Microscopic techniques were complemented with targeted transcript, enzyme and metabolite profiling using real time polymerase chain reaction (PCR), Northern blot, enzymatic assays, chromatography and mass spectrometry.Three days after severance from the stock plants, first meristematic cells appeared which further developed into root primordia and finally adventitious roots. Excision of cuttings led to a fast and transient increase in the wound‐hormone jasmonic acid, followed by the expression of jasmonate‐regulated genes such as cell wall invertase. Analysis of soluble and insoluble carbohydrates showed a continuous accumulation during ARF. A broad metabolite profiling revealed a strong increase in organic acids and resynthesis of essential amino acids.Substantial changes in enzyme activities and metabolite levels indicate that specific enzymes and metabolites might play a crucial role during ARF. Three metabolic phases could be defined: (i) sink establishment phase characterized by apoplastic unloading of sucrose and being probably mediated by jasmonates; (ii) recovery phase; and (iii) maintenance phase, in which a symplastic unloading occurs.} } @Article{IPB-1627, author = {Hause, B. and Wasternack, C. and Strack, D. and}, title = {{Jasmonates in stress responses and development}}, year = {2009}, pages = {1483-1484}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2009.07.004}, volume = {70}, } @Article{IPB-1624, author = {Grunwald, U. and Guo, W. and Fischer, K. and Isayenkov, S. and Ludwig-Müller, J. and Hause, B. and Yan, X. and Küster, H. and Franken, P. and}, title = {{Overlapping expression patterns and differential transcript levels of phosphate transporter genes in arbuscular mycorrhizal, Pi-fertilised and phytohormone-treated Medicago truncatula roots}}, year = {2009}, pages = {1023-1034}, journal = {Planta}, doi = {10.1007/s00425-008-0877-z}, volume = {229}, abstract = {A microarray carrying 5,648 probes of Medicago truncatula root-expressed genes was screened in order to identify those that are specifically regulated by the arbuscular mycorrhizal (AM) fungus Gigaspora rosea, by Pi fertilisation or by the phytohormones abscisic acid and jasmonic acid. Amongst the identified genes, 21% showed a common induction and 31% a common repression between roots fertilised with Pi or inoculated with the AM fungus G. rosea, while there was no obvious overlap in the expression patterns between mycorrhizal and phytohormone-treated roots. Expression patterns were further studied by comparing the results with published data obtained from roots colonised by the AM fungi Glomus mosseae and Glomus intraradices, but only very few genes were identified as being commonly regulated by all three AM fungi. Analysis of Pi concentrations in plants colonised by either of the three AM fungi revealed that this could be due to the higher Pi levels in plants inoculated by G. rosea compared with the other two fungi, explaining that numerous genes are commonly regulated by the interaction with G. rosea and by phosphate. Differential gene expression in roots inoculated with the three AM fungi was further studied by expression analyses of six genes from the phosphate transporter gene family in M. truncatula. While MtPT4 was induced by all three fungi, the other five genes showed different degrees of repression mirroring the functional differences in phosphate nutrition by G. rosea, G. mosseae and G. intraradices.} } @Article{IPB-1650, author = {Schaarschmidt, S. and Hause, B. and Strack, D. and}, title = {{Wege zur Endomykorrhiza. Einladung ans Buffet}}, year = {2009}, pages = {102-113}, journal = {Biologie in unserer Zeit}, doi = {10.1002/biuz.200610385}, volume = {39}, abstract = {Die Lebensgemeinschaft mit Mykorrhizapilzen stellt Pflanzen mineralische Nährstoffe und Wasser zur Verfügung und gilt daher als evolutionäre Grundlage für die Entwicklung der Landpflanzen. Die heute weit verbreitete arbuskuläre Mykorrhiza (AM) ist insbesondere unter widrigen Bedingungen (Nährstoffmangel, Trocken‐, Salz‐ oder Schwermetallstress sowie Pathogenbefall) für die Pflanze von Nutzen. Der pilzliche AM‐Partner, der obligat auf die Interaktion angewiesen ist, wird im Gegenzug mit Kohlenhydraten versorgt. Der Artikel beschreibt den aktuellen Stand der Forschung bezüglich der Etablierung und Regulation der AM durch die Pflanze. Es werden die frühen Erkennungssignale und die nachfolgende Wegbereitung der Pflanze für den eindringenden Pilz, die Kohlenhydratversorgung des AM‐Pilzes, wie auch die Limitierung der pilzlichen Infektionen mittels Autoregulation und die Rolle der Phytohormone für eine funktionelle und ausgeglichene Symbiose behandelt.} } @Article{IPB-1641, author = {Mrosk, C. and Forner, S. and Hause, G. and Küster, H. and Kopka, J. and Hause, B. and}, title = {{Composite Medicago truncatula plants harbouring Agrobacterium rhizogenes-transformed roots reveal normal mycorrhization by Glomus intraradices}}, year = {2009}, pages = {3797-3807}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erp220}, volume = {60}, abstract = {Composite plants consisting of a wild-type shoot and a transgenic root are frequently used for functional genomics in legume research. Although transformation of roots using Agrobacterium rhizogenes leads to morphologically normal roots, the question arises as to whether such roots interact with arbuscular mycorrhizal (AM) fungi in the same way as wild-type roots. To address this question, roots transformed with a vector containing the fluorescence marker DsRed were used to analyse AM in terms of mycorrhization rate, morphology of fungal and plant subcellular structures, as well as transcript and secondary metabolite accumulations. Mycorrhization rate, appearance, and developmental stages of arbuscules were identical in both types of roots. Using Mt16kOLI1Plus microarrays, transcript profiling of mycorrhizal roots showed that 222 and 73 genes exhibited at least a 2-fold induction and less than half of the expression, respectively, most of them described as AM regulated in the same direction in wild-type roots. To verify this, typical AM marker genes were analysed by quantitative reverse transcription-PCR and revealed equal transcript accumulation in transgenic and wild-type roots. Regarding secondary metabolites, several isoflavonoids and apocarotenoids, all known to accumulate in mycorrhizal wild-type roots, have been found to be up-regulated in mycorrhizal in comparison with non-mycorrhizal transgenic roots. This set of data revealed a substantial similarity in mycorrhization of transgenic and wild-type roots of Medicago truncatula, validating the use of composite plants for studying AM-related effects.} } @Article{IPB-1629, author = {Hohnjec, N. and Lenz, F. and Fehlberg, V. and Vieweg, M. F. and Baier, M. C. and Hause, B. and Küster, H. and}, title = {{The Signal Peptide of the Medicago truncatula Modular Nodulin MtNOD25 Operates as an Address Label for the Specific Targeting of Proteins to Nitrogen-Fixing Symbiosomes}}, year = {2009}, pages = {63-72}, journal = {Mol. Plant Microbe Interact.}, doi = {10.1094/MPMI-22-1-0063}, volume = {22}, abstract = {The nodule-specific MtNOD25 gene of the model legume Medicago truncatula encodes a modular nodulin composed of different repetitive modules flanked by distinct N- and C-termini. Although similarities are low with respect to all repetitive modules, both the N-terminal signal peptide (SP) and the C-terminus are highly conserved in modular nodulins from different legumes. On the cellular level, MtNOD25 is only transcribed in the infected cells of root nodules, and this activation is mediated by a 299-bp minimal promoter containing an organ-specific element. By expressing mGFP6 translational fusions in transgenic nodules, we show that MtNOD25 proteins are exclusively translocated to the symbiosomes of infected cells. This specific targeting only requires an N-terminal MtNOD25 SP that is highly conserved across a family of legume-specific symbiosome proteins. Our finding sheds light on one possible mechanism for the delivery of host proteins to the symbiosomes of infected root nodule cells and, in addition, defines a short molecular address label of only 24 amino acids whose N-terminal presence is sufficient to translocate proteins across the peribacteroid membrane.} } @Article{IPB-1628, author = {Hause, B. and Schaarschmidt, S. and}, title = {{The role of jasmonates in mutualistic symbioses between plants and soil-born microorganisms}}, year = {2009}, pages = {1589-1599}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2009.07.003}, volume = {70}, abstract = {Many plants are able to develop mutualistic interactions with arbuscular mycorrhizal fungi and/or nitrogen-fixing bacteria. Whereas the former is widely distributed among most of the land plants, the latter is restricted to species of ten plant families, including the legumes. The establishment of both associations is based on mutual recognition and a high degree of coordination at the morphological and physiological level. This requires the activity of a number of signals, including jasmonates. Here, recent knowledge on the putative roles of jasmonates in both mutualistic symbioses will be reviewed. Firstly, the action of jasmonates will be discussed in terms of the initial signal exchange between symbionts and in the resulting plant signaling cascade common for nodulation and mycorrhization. Secondly, the putative role of jasmonates in the autoregulation of the endosymbioses will be outlined. Finally, aspects of function of jasmonates in the fully established symbioses will be presented. Various processes will be discussed that are possibly mediated by jasmonates, including the redox status of nodules and the carbohydrate partitioning of mycorrhizal roots.} } @Article{IPB-1667, author = {Zurbriggen, M. D. and Carrillo, N. and Tognetti, V. B. and Melzer, M. and Peisker, M. and Hause, B. and Hajirezaei, M.-R. and}, title = {{Chloroplast-generated reactive oxygen species play a major role in localized cell death during the non-host interaction between tobacco and Xanthomonas campestris pv. vesicatoria}}, year = {2009}, pages = {962-973}, journal = {Plant J.}, doi = {10.1111/j.1365-313X.2009.04010.x}, volume = {60}, abstract = {Attempted infection of plants by pathogens elicits a complex defensive response. In many non‐host and incompatible host interactions it includes the induction of defence‐associated genes and a form of localized cell death (LCD), purportedly designed to restrict pathogen advance, collectively known as the hypersensitive response (HR). It is preceded by an oxidative burst, generating reactive oxygen species (ROS) that are proposed to cue subsequent deployment of the HR, although neither the origin nor the precise role played by ROS in the execution of this response are completely understood. We used tobacco plants expressing cyanobacterial flavodoxin to address these questions. Flavodoxin is an electron shuttle present in prokaryotes and algae that, when expressed in chloroplasts, specifically prevents ROS formation in plastids during abiotic stress episodes. Infiltration of tobacco wild‐type leaves with high titres of Xanthomonas campestris pv. vesicatoria (Xcv ), a non‐host pathogen, resulted in ROS accumulation in chloroplasts, followed by the appearance of localized lesions typical of the HR. In contrast, chloroplast ROS build‐up and LCD were significantly reduced in Xcv ‐inoculated plants expressing plastid‐targeted flavodoxin. Metabolic routes normally inhibited by pathogens were protected in the transformants, whereas other aspects of the HR, including the induction of defence‐associated genes and synthesis of salicylic and jasmonic acid, proceeded as in inoculated wild‐type plants. Therefore, ROS generated in chloroplasts during this non‐host interaction are essential for the progress of LCD, but do not contribute to the induction of pathogenesis‐related genes or other signalling components of the response.} } @Article{IPB-1658, author = {Vandenborre, G. and Miersch, O. and Hause, B. and Smagghe, G. and Wasternack, C. and Van Damme, E. J. and}, title = {{Spodoptera littoralis-Induced Lectin Expression in Tobacco}}, year = {2009}, pages = {1142-1155}, journal = {Plant Cell Physiol.}, doi = {10.1093/pcp/pcp065}, volume = {50}, abstract = {The induced defense response in plants towards herbivores is mainly regulated by jasmonates and leads to the accumulation of so-called jasmonate-induced proteins. Recently, a jasmonate (JA) inducible lectin called Nicotiana tabacum agglutinin or NICTABA was discovered in tobacco (N. tabacum cv Samsun) leaves. Tobacco plants also accumulate the lectin after insect attack by caterpillars. To study the functional role of NICTABA, the accumulation of the JA precursor 12-oxophytodienoic acid (OPDA), JA as well as different JA metabolites were analyzed in tobacco leaves after herbivory by larvae of the cotton leafworm (Spodoptera littoralis) and correlated with NICTABA accumulation. It was shown that OPDA, JA as well as its methyl ester can trigger NICTABA accumulation. However, hydroxylation of JA and its subsequent sulfation and glucosylation results in inactive compounds that have lost the capacity to induce NICTABA gene expression. The expression profile of NICTABA after caterpillar feeding was recorded in local as well as in systemic leaves, and compared to the expression of several genes encoding defense proteins, and genes encoding a tobacco systemin and the allene oxide cyclase, an enzyme in JA biosynthesis. Furthermore, the accumulation of NICTABA was quanti-fied after S. littoralis herbivory and immunofluorescence microscopy was used to study the localization of NICTABA in the tobacco leaf.} } @Article{IPB-1660, author = {Wasternack, C. and Hause, B. and}, title = {{Emerging complexity: jasmonate-induced volatiles affect parasitoid choice}}, year = {2009}, pages = {2451-2453}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erp197}, volume = {60}, } @INBOOK{IPB-103, author = {Dorka, R. and Miersch, O. and Hause, B. and Weik, P. and Wasternack, C. and}, title = {{Die Mistel in der Tumortherapie 2. Aktueller Stand der Forschung und klinische Anwendung}}, year = {2009}, pages = {49-66}, chapter = {{Chronobiologische Phänomene und Jasmonatgehalt bei Viscum album L.}}, } @Article{IPB-1724, author = {Schaarschmidt, S. and Hause, B. and}, title = {{Apoplastic invertases: Multi-faced players in the arbuscular mycorrhization}}, year = {2008}, pages = {317-319}, journal = {Plant Signal Behav.}, doi = {10.4161/psb.3.5.5307}, volume = {3}, abstract = {The mutualistic interaction of plants with arbuscular mycorrhizal (AM) fungi is characterized by an exchange of nutrients. The plant provides sugars in the form of hexoses to the heterotrophic fungus in return for phosphate as well as nitrogen, water, and micronutrients. Plant sucrose-cleaving enzymes are predicted to play a crucial role in hexose mobilization as these enzymes appear to be absent in the fungal partner. Here, recent findings concerning the function of plant apoplastic invertases in the AM symbiosis are discussed. Plants with modulated enzyme activity in roots and leaves provide additional insight on the complexity of the regulation of the AM interaction by apoplastic invertases as mycorrhization could be reduced or stimulated depending on the level of invertase activity and its tissue-specific expression.} } @Article{IPB-1690, author = {Floß, D. S. and Hause, B. and Lange, P. R. and Küster, H. and Strack, D. and Walter, M. H. and}, title = {{Knock-down of the MEP pathway isogene 1-deoxy-d-xylulose 5-phosphate synthase 2 inhibits formation of arbuscular mycorrhiza-induced apocarotenoids, and abolishes normal expression of mycorrhiza-specific plant marker genes}}, year = {2008}, pages = {86-100}, journal = {Plant J.}, doi = {10.1111/j.1365-313X.2008.03575.x}, volume = {56}, abstract = {The first step of the plastidial methylerythritol phosphate (MEP) pathway is catalyzed by two isoforms of 1‐deoxy‐d‐ xylulose 5‐phosphate synthase (DXS1 and DXS2). In Medicago truncatula , MtDXS1 and MtDXS2 genes exhibit completely different expression patterns. Most prominently, colonization by arbuscular mycorrhizal (AM) fungi induces the accumulation of certain apocarotenoids (cyclohexenone and mycorradicin derivatives) correlated with the expression of MtDXS2 but not of MtDXS1. To prove a distinct function of DXS2, a selective RNAi approach on MtDXS2 expression was performed in transgenic hairy roots of M. truncatula. Repression of MtDXS2 consistently led to reduced transcript levels in mycorrhizal roots, and to a concomitant reduction of AM‐induced apocarotenoid accumulation. The transcript levels of MtDXS1 remained unaltered in RNAi plants, and no phenotypical changes in non‐AM plants were observed. Late stages of the AM symbiosis were adversely affected, but only upon strong repression with residual MtDXS2‐1 transcript levels remaining below approximately 10%. This condition resulted in a strong decrease in the transcript levels of MtPT4 , an AM‐specific plant phosphate transporter gene, and in a multitude of other AM‐induced plant marker genes, as shown by transcriptome analysis. This was accompanied by an increased proportion of degenerating and dead arbuscules at the expense of mature ones. The data reveal a requirement for DXS2‐dependent MEP pathway‐based isoprenoid products to sustain mycorrhizal functionality at later stages of the symbiosis. They further validate the concept of a distinct role for DXS2 in secondary metabolism, and offer a novel tool to selectively manipulate the levels of secondary isoprenoids by targeting their precursor supply.} } @Article{IPB-1689, author = {Fellenberg, C. and Milkowski, C. and Hause, B. and Lange, P.-R. and Böttcher, C. and Schmidt, J. and Vogt, T. and}, title = {{Tapetum-specific location of a cation-dependent O-methyltransferase in Arabidopsis thaliana}}, year = {2008}, pages = {132-145}, journal = {Plant J.}, doi = {10.1111/j.1365-313X.2008.03576.x}, volume = {56}, abstract = {Cation‐ and S ‐adenosyl‐l ‐methionine (AdoMet)‐dependent plant natural product methyltransferases are referred to as CCoAOMTs because of their preferred substrate, caffeoyl coenzyme A (CCoA). The enzymes are encoded by a small family of genes, some of which with a proven role in lignin monomer biosynthesis. In Arabidopsis thaliana individual members of this gene family are temporally and spatially regulated. The gene At1g67990 is specifically expressed in flower buds, and is not detected in any other organ, such as roots, leaves or stems. Several lines of evidence indicate that the At1g67990 transcript is located in the flower buds, whereas the corresponding CCoAOMT‐like protein, termed AtTSM1, is located exclusively in the tapetum of developing stamen. Flowers of At1g67990 RNAi‐suppressed plants are characterized by a distinct flower chemotype with severely reduced levels of the N  ′,N  ′′‐ bis‐(5‐hydroxyferuloyl)‐N  ′′′‐sinapoylspermidine compensated for by N1 ,N5 ,N10 ‐tris‐(5‐hydroxyferuloyl)spermidine derivative, which is characterized by the lack of a single methyl group in the sinapoyl moiety. This severe change is consistent with the observed product profile of AtTSM1 for aromatic phenylpropanoids. Heterologous expression of the recombinant protein shows the highest activity towards a series of caffeic acid esters, but 5‐hydroxyferuloyl spermidine conjugates are also accepted substrates. The in vitro substrate specificity and the in vivo RNAi‐mediated suppression data of the corresponding gene suggest a role of this cation‐dependent CCoAOMT‐like protein in the stamen/pollen development of A. thaliana .} } @Article{IPB-1741, author = {Tretner, C. and Huth, U. and Hause, B. and}, title = {{Mechanostimulation of Medicago truncatula leads to enhanced levels of jasmonic acid}}, year = {2008}, pages = {2847-2856}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/ern145}, volume = {59}, abstract = {Wounding of plants leads to endogenous rise of jasmonic acid (JA) accompanied with the expression of a distinct set of genes. Among them are those coding for the allene oxide cyclase (AOC) that catalyses a regulatory step in JA biosynthesis, and for 1-deoxy-D-xylulose 5-phosphate synthase 2 (DXS2), an enzyme involved in isoprenoid biosynthesis. To address the question how roots and shoots of Medicago truncatula respond to mechanostimulation and wounding, M. truncatula plants were analysed in respect to JA levels as well as MtAOC1 and MtDXS2-1 transcript accumulation. Harvest-caused mechanostimulation resulted in a strong, but transient increase in JA level in roots and shoots followed by a transient increase in MtAOC1 transcript accumulation. Additional wounding of either shoots or roots led to further increased JA and MtAOC1 transcript levels in shoots, but not in roots. In situ hybridization revealed a cell-specific transcript accumulation of MtAOC1 after mechanostimulation in companion cells of the vascular tissue of the stem. AOC protein, however, was found to occur constitutively in vascular bundles. Further, transcript accumulation of MtDXS2-1 was similar to that of MtAOC1 in shoots, but its transcript levels were not enhanced in roots. Repeated touching of shoots increased MtAOC1 transcript levels and led to significantly shorter shoots and increased biomass. In conclusion, M. truncatula plants respond very sensitively to mechanostimulation with enhanced JA levels and altered transcript accumulation, which might contribute to the altered phenotype after repeated touching of plants.} } @Article{IPB-1734, author = {Stenzel, I. and Ischebeck, T. and König, S. and Hołubowska, A. and Sporysz, M. and Hause, B. and Heilmann, I. and}, title = {{The Type B Phosphatidylinositol-4-Phosphate 5-Kinase 3 Is Essential for Root Hair Formation in Arabidopsis thaliana}}, year = {2008}, pages = {124-141}, journal = {Plant Cell}, doi = {10.1105/tpc.107.052852}, volume = {20}, abstract = {Root hairs are extensions of root epidermal cells and a model system for directional tip growth of plant cells. A previously uncharacterized Arabidopsis thaliana phosphatidylinositol-4-phosphate 5-kinase gene (PIP5K3) was identified and found to be expressed in the root cortex, epidermal cells, and root hairs. Recombinant PIP5K3 protein was catalytically active and converted phosphatidylinositol-4-phosphate to phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2]. Arabidopsis mutant plants homozygous for T-DNA–disrupted PIP5K3 alleles were compromised in root hair formation, a phenotype complemented by expression of wild-type PIP5K3 cDNA under the control of a 1500-bp PIP5K3 promoter fragment. Root hair–specific PIP5K3 overexpression resulted in root hair deformation and loss of cell polarity with increasing accumulation of PIP5K3 transcript. Using reestablishment of root hair formation in T-DNA mutants as a bioassay for physiological functionality of engineered PIP5K3 variants, catalytic activity was found to be essential for physiological function, indicating that PtdIns(4,5)P2 formation is required for root hair development. An N-terminal domain containing membrane occupation and recognition nexus repeats, which is not required for catalytic activity, was found to be essential for the establishment of root hair growth. Fluorescence-tagged PIP5K3 localized to the periphery of the apical region of root hair cells, possibly associating with the plasma membrane and/or exocytotic vesicles. Transient heterologous expression of full-length PIP5K3 in tobacco (Nicotiana tabacum) pollen tubes increased plasma membrane association of a PtdIns(4,5)P2-specific reporter in these tip-growing cells. The data demonstrate that root hair development requires PIP5K3-dependent PtdIns(4,5)P2 production in the apical region of root hair cells.} } @Article{IPB-1733, author = {Stenzel, I. and Hause, B. and Proels, R. and Miersch, O. and Oka, M. and Roitsch, T. and Wasternack, C. and}, title = {{The AOC promoter of tomato is regulated by developmental and environmental stimuli}}, year = {2008}, pages = {1859-1869}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2008.03.007}, volume = {69}, abstract = {The allene oxide cyclase (AOC) catalyzes the formation of cis-(\+)-12-oxophytodienoic acid, an intermediate in jasmonate biosynthesis and is encoded by a single copy gene in tomato. The full length AOC promoter isolated by genome walk contains 3600 bp. Transgenic tomato lines carrying a 1000 bp promoter fragment and the full length promoter, respectively, in front of the β-glucuronidase (GUS)-encoding uidA gene and several tobacco lines carrying the full length tomato AOC promoter before GUS were used to record organ- and tissue-specific promoter activities during development and in response to various stimuli. High promoter activities corresponding to immunocytochemically detected occurrence of the AOC protein were found in seeds and young seedlings and were confined to the root tip, hypocotyl and cotyledons of 3-d-old seedlings. In 10-d-old seedlings promoter activity appeared preferentially in the elongation zone. Fully developed tomato leaves were free of AOC promoter activity, but showed high activity upon wounding locally and systemically or upon treatment with JA, systemin or glucose. Tomato flowers showed high AOC promoter activities in ovules, sepals, anthers and pollen. Most of the promoter activity patterns found in tomato with the 1000 bp promoter fragment were also detected with the full length tomato AOC promoter in tobacco during development or in response to various stimuli. The data support a spatial and temporal regulation of JA biosynthesis during development and in response to environmental stimuli.} } @Article{IPB-1726, author = {Schliemann, W. and Kolbe, B. and Schmidt, J. and Nimtz, M. and Wray, V. and}, title = {{Accumulation of apocarotenoids in mycorrhizal roots of leek (Allium porrum)}}, year = {2008}, pages = {1680-1688}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2008.02.015}, volume = {69}, abstract = {Colonization of the roots of leek (Allium porrum L.) by the arbuscular mycorrhizal fungus Glomus intraradices induced the formation of apocarotenoids, whose accumulation has been studied over a period of 25 weeks. Whereas the increase in the levels of the dominating cyclohexenone derivatives resembles the enhancement of root length colonization, the content of mycorradicin derivatives remains relatively low throughout. Structural analysis of the cyclohexenone derivatives by mass spectrometry and NMR spectroscopy showed that they are mono- and diglycosides of 13-hydroxyblumenol C and blumenol C acylated with 3-hydroxy-3-methyl-glutaric and/or malonic acid. Along with the isolation of three known compounds five others are shown to be hitherto unknown members of the fast-growing family of mycorrhiza-induced cyclohexenone conjugates.} } @Article{IPB-1823, author = {ten Hoopen, P. and Hunger, A. and Muller, A. and Hause, B. and Kramell, R. and Wasternack, C. and Rosahl, S. and Conrad, U. and}, title = {{Immunomodulation of jasmonate to manipulate the wound response}}, year = {2007}, pages = {2525-2535}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erm122}, volume = {58}, abstract = {Jasmonates are signals in plant stress responses and development. The exact mode of their action is still controversial. To modulate jasmonate levels intracellularly as well as compartment-specifically, transgenic Nicotiana tabacum plants expressing single-chain antibodies selected against the naturally occurring (3R,7R)-enantiomer of jasmonic acid (JA) were created in the cytosol and the endoplasmic reticulum. Consequently, the expression of anti-JA antibodies in planta caused JA-deficient phenotypes such as insensitivity of germinating transgenic seedlings towards methyl jasmonate and the loss of wound-induced gene expression. Results presented here suggest an essential role for cytosolic JA in the wound response of tobacco plants. The findings support the view that substrate availability takes part in regulating JA biosynthesis upon wounding. Moreover, high JA levels observed in immunomodulated plants in response to wounding suggest that tobacco plants are able to perceive a reduced level of physiologically active JA and attempt to compensate for this by increased JA accumulation.} } @Article{IPB-1813, author = {Schaarschmidt, S. and González, M.-C. and Roitsch, T. and Strack, D. and Sonnewald, U. and Hause, B. and}, title = {{Regulation of Arbuscular Mycorrhization by Carbon. The Symbiotic Interaction Cannot Be Improved by Increased Carbon Availability Accomplished by Root-Specifically Enhanced Invertase Activity}}, year = {2007}, pages = {1827-1840}, journal = {Plant Physiol.}, doi = {10.1104/pp.107.096446}, volume = {143}, abstract = {The mutualistic interaction in arbuscular mycorrhiza (AM) is characterized by an exchange of mineral nutrients and carbon. The major benefit of AM, which is the supply of phosphate to the plant, and the stimulation of mycorrhization by low phosphate fertilization has been well studied. However, less is known about the regulatory function of carbon availability on AM formation. Here the effect of enhanced levels of hexoses in the root, the main form of carbohydrate used by the fungus, on AM formation was analyzed. Modulation of the root carbohydrate status was performed by expressing genes encoding a yeast (Saccharomyces cerevisiae)-derived invertase, which was directed to different subcellular locations. Using tobacco (Nicotiana tabacum) alc∷cwINV plants, the yeast invertase was induced in the whole root system or in root parts. Despite increased hexose levels in these roots, we did not detect any effect on the colonization with Glomus intraradices analyzed by assessment of fungal structures and the level of fungus-specific palmitvaccenic acid, indicative for the fungal carbon supply, or the plant phosphate content. Roots of Medicago truncatula, transformed to express genes encoding an apoplast-, cytosol-, or vacuolar-located yeast-derived invertase, had increased hexose-to-sucrose ratios compared to β-glucuronidase-transformed roots. However, transformations with the invertase genes did not affect mycorrhization. These data suggest the carbohydrate supply in AM cannot be improved by root-specifically increased hexose levels, implying that under normal conditions sufficient carbon is available in mycorrhizal roots. In contrast, tobacco rolC∷ppa plants with defective phloem loading and tobacco pyk10∷InvInh plants with decreased acid invertase activity in roots exhibited a diminished mycorrhization.} } @Article{IPB-1812, author = {Schaarschmidt, S. and Kopka, J. and Ludwig-Müller, J. and Hause, B. and}, title = {{Regulation of arbuscular mycorrhization by apoplastic invertases: enhanced invertase activity in the leaf apoplast affects the symbiotic interaction}}, year = {2007}, pages = {390-405}, journal = {Plant J.}, doi = {10.1111/j.1365-313X.2007.03150.x}, volume = {51}, abstract = {The effect of constitutive invertase overexpression on the arbuscular mycorrhiza (AM) is shown. The analysis of the enhanced potential for sucrose cleavage was performed with a heterozygous line of Nicotiana tabacum 35S::cwINV expressing a chimeric gene encoding apoplast‐located yeast‐derived invertase with the CaMV35S promoter. Despite the 35S promoter, roots of the transgenic plants showed no or only minor effects on invertase activity whereas the activity in leaves was increased at different levels. Plants with strongly elevated leaf invertase activity, which exhibited a strong accumulation of hexoses in source leaves, showed pronounced phenotypical effects like stunted growth and chlorosis, and an undersupply of the root with carbon. Moreover, transcripts of PR (pathogenesis related) genes accumulated in the leaves. In these plants, mycorrhization was reduced. Surprisingly, plants with slightly increased leaf invertase activity showed a stimulation of mycorrhization, particularly 3 weeks after inoculation. Compared with wild‐type, a higher degree of mycorrhization accompanied by a higher density of all fungal structures and a higher level of Glomus intraradices ‐specific rRNA was detected. Those transgenic plants showed no accumulation of hexoses in the source leaves, minor phenotypical effects and no increased PR gene transcript accumulation. The roots had even lower levels of phenolic compounds (chlorogenic acid and scopolin), amines (such as tyramine, dopamine, octopamine and nicotine) and some amino acids (including 5‐amino‐valeric acid and 4‐amino‐butyric acid), as well as an increased abscisic acid content compared with wild‐type. Minor metabolic changes were found in the leaves of these plants. The changes in metabolism and defense status of the plant and their putative role in the formation of an AM symbiosis are discussed.} } @Article{IPB-1825, author = {Textor, S. and de Kraker, J.-W. and Hause, B. and Gershenzon, J. and Tokuhisa, J. G. and}, title = {{MAM3 Catalyzes the Formation of All Aliphatic Glucosinolate Chain Lengths in Arabidopsis}}, year = {2007}, pages = {60-71}, journal = {Plant Physiol.}, doi = {10.1104/pp.106.091579}, volume = {144}, abstract = {Chain elongated, methionine (Met)-derived glucosinolates are a major class of secondary metabolites in Arabidopsis (Arabidopsis thaliana). The key enzymatic step in determining the length of the chain is the condensation of acetyl-coenzyme A with a series of ω-methylthio-2-oxoalkanoic acids, catalyzed by methylthioalkylmalate (MAM) synthases. The existence of two MAM synthases has been previously reported in the Arabidopsis ecotype Columbia: MAM1 and MAM3 (formerly known as MAM-L). Here, we describe the biochemical properties of the MAM3 enzyme, which is able to catalyze all six condensation reactions of Met chain elongation that occur in Arabidopsis. Underlining its broad substrate specificity, MAM3 also accepts a range of non-Met-derived 2-oxoacids, e.g. converting pyruvate to citramalate and 2-oxoisovalerate to isopropylmalate, a step in leucine biosynthesis. To investigate its role in vivo, we identified plant lines with mutations in MAM3 that resulted in a complete lack or greatly reduced levels of long-chain glucosinolates. This phenotype could be complemented by reintroduction of a MAM3 expression construct. Analysis of MAM3 mutants demonstrated that MAM3 catalyzes the formation of all glucosinolate chain lengths in vivo as well as in vitro, making this enzyme the major generator of glucosinolate chain length diversity in the plant. The localization of MAM3 in the chloroplast suggests that this organelle is the site of Met chain elongation.} } @Article{IPB-1788, author = {Hause, B. and Mrosk, C. and Isayenkov, S. and Strack, D. and}, title = {{Jasmonates in arbuscular mycorrhizal interactions}}, year = {2007}, pages = {101-110}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2006.09.025}, volume = {68}, abstract = {The mutualistic interaction between plants and arbuscular mycorrhizal (AM) fungi is believed to be regulated from the plant side among other signals by the action of phytohormones. Evidences for this are based mainly on application experiments and determination of phytohormone levels in AM roots by comparison to non-mycorrhizal roots. In case of jasmonates, additional proof is given by reverse genetic approaches, which led to first insights into their putative role in the establishment and functioning of the symbiosis. This review summarizes the current data about phytohormone action in AM roots and the role of jasmonates in particular.} } @Article{IPB-1785, author = {Guranowski, A. and Miersch, O. and Staswick, P. E. and Suza, W. and Wasternack, C. and}, title = {{Substrate specificity and products of side-reactions catalyzed by jasmonate:amino acid synthetase (JAR1)}}, year = {2007}, pages = {815-820}, journal = {FEBS Lett.}, doi = {10.1016/j.febslet.2007.01.049}, volume = {581}, abstract = {Jasmonate:amino acid synthetase (JAR1) is involved in the function of jasmonic acid (JA) as a plant hormone. It catalyzes the synthesis of several JA‐amido conjugates, the most important of which appears to be JA‐Ile. Structurally, JAR1 is a member of the firefly luciferase superfamily that comprises enzymes that adenylate various organic acids. This study analyzed the substrate specificity of recombinant JAR1 and determined whether it catalyzes the synthesis of mono‐ and dinucleoside polyphosphates, which are side‐reaction products of many enzymes forming acyl ∼ adenylates. Among different oxylipins tested as mixed stereoisomers for substrate activity with JAR1, the highest rate of conversion to Ile‐conjugates was observed for (±)‐JA and 9,10‐dihydro‐JA, while the rate of conjugation with 12‐hydroxy‐JA and OPC‐4 (3‐oxo‐2‐(2Z ‐pentenyl)cyclopentane‐1‐butyric acid) was only about 1–2% that for (±)‐JA. Of the two stereoisomers of JA, (−)‐JA and (\+)‐JA, rate of synthesis of the former was about 100‐fold faster than for (\+)‐JA. Finally, we have demonstrated that (1) in the presence of ATP, Mg2\+, (−)‐JA and tripolyphosphate the ligase produces adenosine 5′‐tetraphosphate (p4A); (2) addition of isoleucine to that mixture halts the p4A synthesis; (3) the enzyme produces neither diadenosine triphosphate (Ap3A) nor diadenosine tetraphosphate (Ap4A) and (4) Ap4A cannot substitute ATP as a source of adenylate in the complete reaction that yields JA‐Ile.} } @Article{IPB-1783, author = {Gremillon, L. and Kiessling, J. and Hause, B. and Decker, E. L. and Reski, R. and Sarnighausen, E. and}, title = {{Filamentous temperature-sensitive Z (FtsZ) isoforms specifically interact in the chloroplasts and in the cytosol of Physcomitrella patens}}, year = {2007}, pages = {299-310}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2007.02169.x}, volume = {176}, abstract = {Plant filamentous temperature‐sensitive Z (FtsZ) proteins have been reported to be involved in biological processes related to plastids. However, the precise functions of distinct isoforms are still elusive. Here, the intracellular localization of the FtsZ1‐1 isoform in a moss, Physcomitrella patens , was examined. Furthermore, the in vivo interaction behaviour of four distinct FtsZ isoforms was investigated.Localization studies of green fluorescent protein (GFP)‐tagged FtsZ1‐1 and fluorescence resonance energy transfer (FRET) analyses employing all dual combinations of four FtsZ isoforms were performed in transient protoplast transformation assays.FtsZ1‐1 is localized to network structures inside the chloroplasts and exerts influence on plastid division. Interactions between FtsZ isoforms occur in distinct ordered structures in the chloroplasts as well as in the cytosol.The results expand the view of the involvement of Physcomitrella FtsZ proteins in chloroplast and cell division. It is concluded that duplication and diversification of ftsZ genes during plant evolution were the main prerequisites for the successful remodelling and integration of the prokaryotic FtsZ‐dependent division mechanism into the cellular machineries of distinct complex processes in plants.} } @Article{IPB-1776, author = {Fester, T. and Lohse, S. and Halfmann, K. and}, title = {{“Chromoplast” development in arbuscular mycorrhizal roots}}, year = {2007}, pages = {92-100}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2006.09.034}, volume = {68}, abstract = {The accumulation of apocarotenoids in arbuscular mycorrhizal (AM) roots suggests a dramatic reorganization of the plastids responsible for the biosynthesis of these compounds. This review describes the cytological and biochemical characterization of this phenomenon. The results presented suggest that plastids are key organelles for the establishment of the symbiotic interface of the AM symbiosis. In addition, a complex interplay of various plant cell components during the different functional phases of this interface is suggested. Arbuscule degradation appears to be of particular interest, as it correlates with the formation of the most extensive plastid structures and with apocarotenoid accumulation.} } @Article{IPB-1775, author = {Fester, T. and Hause, B. and}, title = {{Drought and symbiosis – why is abscisic acid necessary for arbuscular mycorrhiza?}}, year = {2007}, pages = {383-386}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2007.02171.x}, volume = {175}, } @Article{IPB-1768, author = {Deepak, S. and Shailasree, S. and Kini, R. K. and Hause, B. and Shetty, S. H. and Mithöfer, A. and}, title = {{Role of hydroxyproline-rich glycoproteins in resistance of pearl millet against downy mildew pathogen Sclerospora graminicola}}, year = {2007}, pages = {323-333}, journal = {Planta}, doi = {10.1007/s00425-007-0484-4}, volume = {226}, abstract = {Hydroxyproline-rich glycoproteins (HRGPs) are important plant cell wall components involved in plant defense response to pathogen attack. In the present study, a resistant pearl millet (Pennisetum glaucum) cultivar, IP18292, was compared with a susceptible cultivar, 7042S, to investigate the contribution of HRGPs in the successful defense against the phytopathogenic oomycete S. graminicola. Northern hybridization using MeHRGP cDNA, a heterologous probe from cassava, indicated steady accumulation of HRGP transcripts, from 2 h.p.i. onwards with a maximum at 6 h.p.i., in the resistant cultivar. This is followed by HRGPs accumulation at about 8 h.p.i. as revealed by Western-blot analysis. Immunocytochemical localization by tissue printing and confocal immunofluorescence microscopy indicated cell walls of parenchymatic cells and the vascular tissue of coleoptile as sites of HRGP deposition. In vitro studies in the presence of horseradish peroxidase and H2O2 showed cross-linking of pearl millet HRGPs, which occurred parallel to isodityrosine accumulation. Inducible high isodityrosine content was also observed in vivo in the resistant cultivar. Here, H2O2 was found to accumulate as twin burst at 1 and 6 h.p.i., whereas in the susceptible cultivar only an early single peak was detectable. Moreover, the amount of hydroxyproline in HRGPs was about twice as high in the resistant as in the susceptible cultivar. These results suggest that cell wall strengthening in S. graminicola-infected resistant pearl millet is brought about by a combination of polypeptide cross-linking of isodityrosine as well as by the high content of hydroxyproline in HRGPs, and H2O2, in contrast to the susceptible plant.} } @Article{IPB-1766, author = {Cenzano, A. and Abdala, G. and Hause, B. and}, title = {{Cytochemical immuno-localization of allene oxide cyclase, a jasmonic acid biosynthetic enzyme, in developing potato stolons}}, year = {2007}, pages = {1449-1456}, journal = {J. Plant Physiol.}, doi = {10.1016/j.jplph.2006.10.007}, volume = {164}, abstract = {The involvement of jasmonates in the tuber development has been proved by the presence of many of these compounds in potato stolons, modification of their levels during the transition of the stolon into tuber, and induction of cell expansion upon exogenous jasmonates treatment. However, to date there is only little evidence of the presence of the jasmonic acid-biosynthetic enzymes in stolons or young tubers. As allene oxide cyclase represents the major control point for jasmonic acid biosynthesis, we studied the occurrence of allene oxide cyclase by immunological approaches in the early stages of tuber formation. In developing stolons, allene oxide cyclase as well as lipoxygenase were clearly detectable, but their levels did not change during development. Jasmonic acid treatment for 24 h, however, increased lipoxygenase and allene oxide cyclase protein levels in both developmental stages analyzed. In longitudinal sections of stolons of stages 1 and 2, allene oxide cyclase and lipoxygenase occurred in the apex and along the stolon axis. Allene oxide cyclase was clearly detectable in epidermal, cortical and pith parenchymatic cells, showing the highest levels in vascular tissues surrounding cells. Lipoxygenase was mainly located in the parenchymatic cortex cells. The occurrence of allene oxide cyclase in stolons together with the previous identification of jasmonates from developing stolons reveals that these organs are capable to synthesize and metabolize jasmonates.} } @Article{IPB-1764, author = {Burow, M. and Rice, M. and Hause, B. and Gershenzon, J. and Wittstock, U. and}, title = {{Cell- and tissue-specific localization and regulation of the epithiospecifier protein in Arabidopsis thaliana}}, year = {2007}, pages = {173-185}, journal = {Plant Mol. Biol.}, doi = {10.1007/s11103-007-9143-1}, volume = {64}, abstract = {The glucosinolate-myrosinase system found in plants of the order Brassicales is one of the best studied plant defense systems. Hydrolysis of the physiologically inert glucosinolates by hydrolytic enzymes called myrosinases, which only occurs upon tissue disruption, leads to the formation of biologically active compounds. The chemical nature of the hydrolysis products depends on the presence or absence of supplementary proteins, such as epithiospecifier proteins (ESPs). ESPs promote the formation of epithionitriles and simple nitriles at the expense of the corresponding isothiocyanates which are formed through spontaneous rearrangement of the aglucone core structure. While isothiocyanates are toxic to a wide range of organisms, including insects, the ecological significance of nitrile formation and thus the role of ESP in plant-insect interactions is unclear. Here, we identified ESP-expressing cells in various organs and several developmental stages of different Arabidopsis thaliana ecotypes by immunolocalization. In the ecotype Landsberg erecta, ESP was found to be consistently present in the epidermal cells of all aerial parts except the anthers and in S-cells of the stem below the inflorescence. Analyses of ESP expression by quantitative real-time PCR, Western blotting, and ESP activity assays suggest that plants control the outcome of glucosinolate hydrolysis by regulation of ESP at both the transcriptional and the post-transcriptional levels. The localization of ESP in the epidermal cell layers of leaves, stems and reproductive organs supports the hypothesis that this protein has a specific function in defense against herbivores and pathogens.} } @INBOOK{IPB-118, author = {Wasternack, C. and Hause, B. and Stenzel, I. and Goetz, S. and Feussner, I. and Miersch, O. and}, title = {{Proceeding of the 17th Int. Symp. on Plant Lipids}}, year = {2007}, pages = {107-111}, chapter = {{Jasmonate signaling in tomato – The input of tissue-specific occurrence of allene oxide cyclase and JA metabolites}}, editor = {Benning C., Ollrogge, J.}, } @Article{IPB-1897, author = {Sharma, V. K. and Monostori, T. and Göbel, C. and Hänsch, R. and Bittner, F. and Wasternack, C. and Feussner, I. and Mendel, R. R. and Hause, B. and Schulze, J. and}, title = {{Transgenic barley plants overexpressing a 13-lipoxygenase to modify oxylipin signature}}, year = {2006}, pages = {264-276}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2005.11.009}, volume = {67}, abstract = {Three chimeric gene constructs were designed comprising the full length cDNA of a lipoxygenase (LOX) from barley (LOX2:Hv:1) including its chloroplast targeting sequence (cTP) under control of either (1) CaMV35S- or (2) polyubiquitin-1-promoter, whereas the third plasmid contains 35S promoter and the cDNA without cTP. Transgenic barley plants overexpressing LOX2:Hv:1 were generated by biolistics of scutella from immature embryos. Transformation frequency for 35S::LOX with or without cTP was in a range known for barley particle bombardment, whereas for Ubi::cTP-LOX no transgenic plants were detected. In general, a high number of green plantlets selected on bialaphos became yellow and finally died either in vitro or after potting. All transgenic plants obtained were phenotypically indistinguishable from wild type plants and all of them set seeds. The corresponding protein (LOX-100) in transgenic T0 and T1 plants accumulated constitutively to similar levels as in the jasmonic acid methyl ester (JAME)-treated wild type plants. Moreover, LOX-100 was clearly detectable immunocytochemically within the chloroplasts of untreated T0 plants containing the LOX-100-cDNA with the chloroplast target sequence. In contrast, an exclusive localization of LOX-100 in the cytoplasm was detectable when the target sequence was removed. In comparison to sorbitol-treated wild type leaves, analysis of oxylipin profiles in T2 progenies showed higher levels of jasmonic acid (JA) for those lines that displayed elevated levels of LOX-100 in the chloroplasts and for those lines that harboured LOX-100 in the cytoplasm, respectively. The studies demonstrate for the first time the constitutive overexpression of a cDNA coding for a 13-LOX in a monocotyledonous species and indicate a link between the occurrence of LOX-100 and senescence.} } @Article{IPB-1893, author = {Schliemann, W. and Schmidt, J. and Nimtz, M. and Wray, V. and Fester, T. and Strack, D. and}, title = {{Erratum to “Accumulation of apocarotenoids in mycorrhizal roots of Ornithogalum umbellatum” [Phytochem. 67 (2006) 1196–1205]}}, year = {2006}, pages = {2090}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2006.07.018}, volume = {67}, } @Article{IPB-1892, author = {Schliemann, W. and Schmidt, J. and Nimtz, M. and Wray, V. and Fester, T. and Strack, D. and}, title = {{Accumulation of apocarotenoids in mycorrhizal roots of Ornithogalum umbellatum}}, year = {2006}, pages = {1196-1205}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2006.05.005}, volume = {67}, abstract = {Colonization of roots of Ornithogalum umbellatum by the arbuscular mycorrhizal fungus Glomus intraradices induced the accumulation of different types of apocarotenoids. In addition to the mycorrhiza-specific occurrence of cyclohexenone derivatives and the “yellow pigment” described earlier, free mycorradicin and numerous mycorradicin derivatives were detected in a complex apocarotenoid mixture for the first time. From the accumulation pattern of the mycorradicin derivatives their possible integration into the continuously accumulating “yellow pigment” is suggested. Structure analyses of the cyclohexenone derivatives by MS and NMR revealed that they are mono-, di- and branched triglycosides of blumenol C, 13-hydroxyblumenol C, and 13-nor-5-carboxy-blumenol C, some of which contain terminal rhamnose as sugar moiety.} } @Article{IPB-1891, author = {Schaarschmidt, S. and Roitsch, T. and Hause, B. and}, title = {{Arbuscular mycorrhiza induces gene expression of the apoplastic invertase LIN6 in tomato (Lycopersicon esculentum) roots}}, year = {2006}, pages = {4015-4023}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/erl172}, volume = {57}, abstract = {Extracellular invertases are suggested to play a crucial role in the arbuscular mycorrhiza (AM) symbiosis to fulfil the increased sink function of the mycorrhizal root and the supply of the obligate biotrophic AM fungus with hexoses. In tomato (Lycopersicon esculentum), LIN6 represents an apoplastic invertase which is described as a key enzyme in establishing and maintaining sink metabolism. In this study, transcript levels of LIN6 were analysed in tomato roots colonized with the AM fungus Glomus intraradices. Using real-time RT–PCR, a nearly 3-fold increase in LIN6 mRNA levels was detected at late stages of mycorrhization (11 weeks after inoculation). A 1.8-fold induction could already be achieved at earlier stages (5 weeks after inoculation) using higher inoculum concentrations, whereas wounding of non-mycorrhizal roots resulted in up to 12-fold enhanced LIN6 transcripts. As revealed by in situ hybridization, the expression of LIN6 upon mycorrhization was specifically restricted to colonized cells and to the central cylinder. Such a strongly localized pattern due to mycorrhizal cells and to the central core could also be shown for promoter activity using transgenic Nicotiana tabacum plants expressing the gene coding for β-glucuronidase under the control of the LIN6 promoter. The moderate induction of LIN6 expression in mycorrhizal tomato roots compared with stress-stimulated induction suggested a fine-tuning in the activation of sink metabolism in the mutualistic interaction, avoiding stress-induced defence reactions.} } @Article{IPB-1880, author = {Lohse, S. and Hause, B. and Hause, G. and Fester, T. and}, title = {{FtsZ Characterization and Immunolocalization in the Two Phases of Plastid Reorganization in Arbuscular Mycorrhizal Roots of Medicago truncatula}}, year = {2006}, pages = {1124-1134}, journal = {Plant Cell Physiol.}, doi = {10.1093/pcp/pcj083}, volume = {47}, abstract = {We have analyzed plastid proliferation in root cortical cells of Medicago truncatula colonized by arbuscular mycorrhizal (AM) fungi by concomitantly labeling fungal structures, root plastids, a protein involved in plastid division (FtsZ1) and a protein involved in the biosynthesis of AM-specific apocarotenoids. Antibodies directed against FtsZ1 have been generated after heterologous expression of the respective gene from M. truncatula and characterization of the gene product. Analysis of enzymatic activity and assembly experiments showed similar properties of this protein when compared with the bacterial proteins. Immunocytological experiments allowed two phases of fungal and plastid development to be clearly differentiated and plastid division to be monitored during these phases. In the early phase of arbuscule development, lens-shaped plastids, intermingled with the arbuscular branches, divide frequently. Arbuscule degradation, in contrast, is characterized by large, tubular plastids, decorated by a considerable number of FtsZ division rings.} } @Article{IPB-1876, author = {Kaiser, H. and Richter, U. and Keiner, R. and Brabant, A. and Hause, B. and Dräger, B. and}, title = {{Immunolocalisation of two tropinone reductases in potato (Solanum tuberosum L.) root, stolon, and tuber sprouts}}, year = {2006}, pages = {127-137}, journal = {Planta}, doi = {10.1007/s00425-006-0335-8}, volume = {225}, abstract = {Tropinone reductases (TRs) are essential enzymes in the tropane alkaloid biosynthesis, providing either tropine for hyoscyamine and scopolamine formation or providing pseudotropine for calystegines. Two cDNAs coding for TRs were isolated from potato (Solanum tuberosum L.) tuber sprouts and expressed in E. coli. One reductase formed pseudotropine, the other formed tropine and showed kinetic properties typical for tropine-forming tropinone reductases (TRI) involved in hyoscyamine formation. Hyoscyamine and tropine are not found in S. tuberosum plants. Potatoes contain calystegines as the only products of the tropane alkaloid pathway. Polyclonal antibodies raised against both enzymes were purified to exclude cross reactions and were used for Western-blot analysis and immunolocalisation. The TRI (EC 1.1.1.206) was detected in protein extracts of tuber tissues, but mostly in levels too low to be localised in individual cells. The function of this enzyme in potato that does not form hyoscyamine is not clear. The pseudotropine-forming tropinone reductase (EC 1.1.1.236) was detected in potato roots, stolons, and tuber sprouts. Cortex cells of root and stolon contained the protein; additional strong immuno-labelling was located in phloem parenchyma. In tuber spouts, however, the protein was detected in companion cells.} } @Article{IPB-1874, author = {Isayenkova, J. and Wray, V. and Nimtz, M. and Strack, D. and Vogt, T. and}, title = {{Cloning and functional characterisation of two regioselective flavonoid glucosyltransferases from Beta vulgaris}}, year = {2006}, pages = {1598-1612}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2006.06.026}, volume = {67}, abstract = {Two full-length cDNAs encoding flavonoid-specific glucosyltransferases, UGT73A4 and UGT71F1, were isolated from a cDNA library of Beta vulgaris (Amaranthaceae) cell suspension cultures. They displayed high identity to position-specific betanidin and flavonoid glucosyltransferases from Dorotheanthus bellidiformis (Aizoaceae) and to enzymes with similar substrate specificities from various plant families. The open reading frame of the sequences encode proteins of 476 (UGT73A4) and 492 (UGT71F1) amino acids with calculated molecular masses of 54.07 kDa and 54.39 kDa, and isoelectric points of 5.8 and 5.6, respectively. Both enzymes were functionally expressed in Escherichia coli as His- and GST-tagged proteins, respectively. They exhibited a broad substrate specificity, but a distinct regioselectivity, glucosylating a variety of flavonols, flavones, flavanones, and coumarins. UGT73A4 showed a preference for the 4′- and 7-OH position in the flavonoids, whereas UGT71F1 preferentially glucosylated the 3- or the 7-OH position. Glucosylation of betanidin, the aglycone of the major betacyanin, betanin, in B. vulgaris was also observed to a low extent by both enzymes. Several O-glycosylated vitexin derivatives isolated from leaves of young B. vulgaris plants and rutin obtained from B. vulgaris tissue culture are discussed as potential endogenous products of UGT73A4 and UGT71F1. The results are analyzed with regard to evolution and specificity of plant natural product glucosyltransferases.} } @Article{IPB-1912, author = {Wasternack, C. and Stenzel, I. and Hause, B. and Hause, G. and Kutter, C. and Maucher, H. and Neumerkel, J. and Feussner, I. and Miersch, O. and}, title = {{The wound response in tomato – Role of jasmonic acid}}, year = {2006}, pages = {297-306}, journal = {J. Plant Physiol.}, doi = {10.1016/j.jplph.2005.10.014}, volume = {163}, abstract = {Plants respond to mechanical wounding or herbivore attack with a complex scenario of sequential, antagonistic or synergistic action of different signals leading to defense gene expression. Tomato plants were used as a model system since the peptide systemin and the lipid-derived jasmonic acid (JA) were recognized as essential signals in wound-induced gene expression. In this review recent data are discussed with emphasis on wound-signaling in tomato. The following aspects are covered: (i) systemin signaling, (ii) JA biosynthesis and action, (iii) orchestration of various signals such as JA, H2O2, NO, and salicylate, (iv) local and systemic response, and (v) amplification in wound signaling. The common occurrence of JA biosynthesis and systemin generation in the vascular bundles suggest JA as the systemic signal. Grafting experiments with JA-deficient, JA-insensitive and systemin-insensitive mutants strongly support this assumption.} } @Article{IPB-1902, author = {Strack, D. and Fester, T. and}, title = {{Isoprenoid metabolism and plastid reorganization in arbuscular mycorrhizal roots}}, year = {2006}, pages = {22-34}, journal = {New Phytol.}, doi = {10.1111/j.1469-8137.2006.01837.x}, volume = {172}, abstract = {Plant root‐colonizing arbuscular mycorrhizal (AM) fungi activate the methylerythritol phosphate pathway, carotenoid biosynthesis and oxidative carotenoid cleavage in roots, leading to C13 and C14 apocarotenoids, that is, cyclohexenone and mycorradicin derivatives. Mycorradicin causes the characteristic yellow coloration of many AM roots accumulating within a complex mixture of unknown components. The accumulating C13 cyclohexenones exhibit various ring substitutions and different glycosyl moieties. Transcript levels of the first two enzymes of the MEP pathway, 1‐deoxy‐d ‐xylulose 5‐phosphate synthase and 1‐deoxy‐d ‐xylulose 5‐phosphate reductoisomerase, and of the carotenoid pathway, phytoene desaturase and ζ‐carotene desaturase, along with a carotenoid‐cleaving dioxygenase, are markedly increased in AM roots. This correlates with proliferation and reorganization of root plastids. These results allow at this point only speculation about the significance of apocarotenoid accumulation: participation in the production of signaling molecules and control of fungal colonization or protection against soil‐borne pathogens; protection of root cells against oxidative damage of membranes by reactive oxygen species; and promotion of the symbiotic interactions between plant roots and AM fungi.} } @Article{IPB-1859, author = {Frenzel, A. and Tiller, N. and Hause, B. and Krajinski, F. and}, title = {{The conserved arbuscular mycorrhiza-specific transcription of the secretory lectin MtLec5 is mediated by a short upstream sequence containing specific protein binding sites}}, year = {2006}, pages = {792-800}, journal = {Planta}, doi = {10.1007/s00425-006-0262-8}, volume = {224}, abstract = {In Medicago truncatula a family of mycorrhiza-specific expressed lectins has been identified recently, but the function and regulation of these lectins during the arbuscular mycorrhiza symbiosis are still unknown. In order to characterize a first member of this protein family, MtLec5 was analyzed concerning its localization and regulation. Confocal laser scanning microscopy showed that MtLec5 is a secretory protein indicating a role as a vegetative storage protein, which is specifically expressed in mycorrhizal root systems. To study the molecular mechanisms leading to the mycorrhiza-specific transcription, deletion studies of pMtLec5 were done using reporter gene fusions. Potential cis-acting elements could be narrowed down to a 150 bp fragment that was located approximately at −300/−150 according to the transcription start, suggesting the binding of positive regulators to this area. Similar expression pattern of the reporter gene was found after transforming roots of the non-legume Nicotiana tabacum with the heterologous promoter–reporter fusions. This indicated that the observed mycorrhiza-specific transcriptional induction is not legume-specific. Electrophoretic mobility shift assays showed that several factors which were exclusively present in mycorrhizal roots bind within the 150 bp promoter area. This strengthens the hypothesis of positive regulators mediating the AM-specific gene expression.} } @Article{IPB-1854, author = {Delker, C. and Stenzel, I. and Hause, B. and Miersch, O. and Feussner, I. and Wasternack, C. and}, title = {{Jasmonate Biosynthesis in Arabidopsis thaliana - Enzymes, Products, Regulation}}, year = {2006}, pages = {297-306}, journal = {Plant Biol.}, doi = {10.1055/s-2006-923935}, volume = {8}, abstract = {Among the plant hormones jasmonic acid and related derivatives are known to mediate stress responses and several developmental processes. Biosynthesis, regulation, and metabolism of jasmonic acid in Arabidopsis thaliana are reviewed, including properties of mutants of jasmonate biosynthesis. The individual signalling properties of several jasmonates are described.} } @INBOOK{IPB-121, author = {Hause, B. and Frugier, F. and Crespi, M. and}, title = {{Medicago truncatula Handbook}}, year = {2006}, chapter = {{Immunolocalization}}, url = {https://www.noble.org/medicago-handbook/}, abstract = {This chapter presents an overview about the immunocytochemical techniques using in the model legume Medicago truncatula. After a short introduction into the basics of immunocytochemistry, detailed protocols that can be used to perform immunolabelling on light, confocal and electron microscopical level are listed. These protocols are successfully applied in the author’s laboratories to obtain information about the localization of various proteins in a range of tissues from Medicago truncatula. Depending on facilities to perform sectioning and the microscopical equipment, modifications might be required to suit individual demands. Therefore, please use these protocols as a starting point and adjust them after consulting experienced personnel at your local facilities.} } @Article{IPB-1953, author = {Isayenkov, S. and Mrosk, C. and Stenzel, I. and Strack, D. and Hause, B. and}, title = {{Suppression of Allene Oxide Cyclase in Hairy Roots of Medicago truncatula Reduces Jasmonate Levels and the Degree of Mycorrhization with Glomus intraradices}}, year = {2005}, pages = {1401-1410}, journal = {Plant Physiol.}, doi = {10.1104/pp.105.069054}, volume = {139}, abstract = {During the symbiotic interaction between Medicago truncatula and the arbuscular mycorrhizal (AM) fungus Glomus intraradices, an endogenous increase in jasmonic acid (JA) occurs. Two full-length cDNAs coding for the JA-biosynthetic enzyme allene oxide cyclase (AOC) from M. truncatula, designated as MtAOC1 and MtAOC2, were cloned and characterized. The AOC protein was localized in plastids and found to occur constitutively in all vascular tissues of M. truncatula. In leaves and roots, MtAOCs are expressed upon JA application. Enhanced expression was also observed during mycorrhization with G. intraradices. A partial suppression of MtAOC expression was achieved in roots following transformation with Agrobacterium rhizogenes harboring the MtAOC1 cDNA in the antisense direction under control of the cauliflower mosaic virus 35S promoter. In comparison to samples transformed with 35S∷uidA, roots with suppressed MtAOC1 expression exhibited lower JA levels and a remarkable delay in the process of colonization with G. intraradices. Both the mycorrhization rate, quantified by fungal rRNA, and the arbuscule formation, analyzed by the expression level of the AM-specific gene MtPT4, were affected. Staining of fungal material in roots with suppressed MtAOC1 revealed a decreased number of arbuscules, but these did not exhibit an altered structure. Our results indicate a crucial role for JA in the establishment of AM symbiosis.} } @Article{IPB-1948, author = {Hause, B. and Fester, T. and}, title = {{Molecular and cell biology of arbuscular mycorrhizal symbiosis}}, year = {2005}, pages = {184-196}, journal = {Planta}, doi = {10.1007/s00425-004-1436-x}, volume = {221}, abstract = {The roots of most extant plants are able to become engaged in an interaction with a small group of fungi of the fungal order Glomales (Glomeromycota). This interaction—arbuscular mycorrhizal (AM) symbiosis—is the evolutionary precursor of most other mutualistic root-microbe associations. The molecular analysis of this interaction can elucidate basic principles regarding such associations. This review summarizes our present knowledge about cellular and molecular aspects of AM. Emphasis is placed on morphological changes in colonized cells, transfer of nutrients between both interacting partners, and plant defence responses. Similarities to and differences from other associations of plant and microorganisms are highlighted regarding defence reactions and signal perception.} } @Article{IPB-1947, author = {Hause, G. and Lischewski, S. and Wessjohann, L. A. and Hause, B. and}, title = {{Epothilone D affects cell cycle and microtubular pattern in plant cells}}, year = {2005}, pages = {2131-2137}, journal = {J. Exp. Bot.}, doi = {10.1093/jxb/eri211}, volume = {56}, abstract = {Epothilones, macrocyclic lactones from culture filtrates of the myxobacterium Sorangium cellulosum, are known as taxol-like microtubular drugs in human medicine. To date, nothing is known about the effect of epothilones on microtubules (MTs) in plant cells and/or on the plant cell cycle. As shown in this report, the treatment of tomato cell suspension cultures with epothilone D produced a continuous increase in the mitotic index. Dose–response curves revealed that epothilone D alters the mitotic index at concentrations as low as 1.5 μM. Mitotic arrest was already visible after only 2 h of treatment, and 55% of the cells were arrested after 24 h. As shown by immunocytological methods, abnormal spindles are formed during metaphase, which leads to a random distribution of chromosomes in the whole cell and prevents the formation of a metaphase plate. The process of chromosome decondensation does not seem to be affected, because micronuclei form at the same place with the distributed chromosomes. This suggests that epothilone D influences the stability of plant MTs mainly during metaphase of the mitotic cycle. In metaphase, the effects of epothilone D seem to be irreversible, because cells with an abnormal spindle could not be recovered after removal of the drug.} } @Article{IPB-1941, author = {Fester, T. and Wray, V. and Nimtz, M. and Strack, D. and}, title = {{Is stimulation of carotenoid biosynthesis in arbuscular mycorrhizal roots a general phenomenon?}}, year = {2005}, pages = {1781-1786}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2005.05.009}, volume = {66}, abstract = {The identification and quantification of cyclohexenone glycoside derivatives from the model legume Lotus japonicus revealed far higher levels than expected according to the stoichiometric relation to another, already determined carotenoid cleavage product, i.e., mycorradicin. Mycorradicin is responsible for the yellow coloration of many arbuscular mycorrhizal (AM) roots and is usually esterified in a complex way to other compounds. After liberation from such complexes it has been detected in AM roots of many, but not of all plants examined. The non-stoichiometric occurrence of this compound compared with other carotenoid cleavage products suggested that carotenoid biosynthesis might be activated upon mycorrhization even in plant species without detectable levels of mycorradicin. This assumption has been supported by inhibition of a key enzyme of carotenoid biosynthesis (phytoene desaturase) and quantification of the accumulating enzymic substrate (phytoene). Our observations suggest that the activation of carotenoid biosynthesis in AM roots is a general phenomenon and that quantification of mycorradicin is not always a good indicator for this activation.} } @Article{IPB-1940, author = {Fester, T. and Hause, G. and}, title = {{Accumulation of reactive oxygen species in arbuscular mycorrhizal roots}}, year = {2005}, pages = {373-379}, journal = {Mycorrhiza}, doi = {10.1007/s00572-005-0363-4}, volume = {15}, abstract = {We investigated the accumulation of reactive oxygen species (ROS) in arbuscular mycorrhizal (AM) roots from Medicago truncatula, Zea mays and Nicotiana tabacum using three independent staining techniques. Colonized root cortical cells and the symbiotic fungal partner were observed to be involved in the production of ROS. Extraradical hyphae and spores from Glomus intraradices accumulated small levels of ROS within their cell wall and produced ROS within the cytoplasm in response to stress. Within AM roots, we observed a certain correlation of arbuscular senescence and H2O2 accumulation after staining by diaminobenzidine (DAB) and a more general accumulation of ROS close to fungal structures when using dihydrorhodamine 123 (DHR 123) for staining. According to electron microscopical analysis of AM roots from Z. mays after staining by CeCl3, intracellular accumulation of H2O2 was observed in the plant cytoplasm close to intact and collapsing fungal structures, whereas intercellular H2O2 was located on the surface of fungal hyphae. These characteristics of ROS accumulation in AM roots suggest similarities to ROS accumulation during the senescence of legume root nodules.} } @Article{IPB-1983, author = {Stumpe, M. and Carsjens, J.-G. and Stenzel, I. and Göbel, C. and Lang, I. and Pawlowski, K. and Hause, B. and Feussner, I. and}, title = {{Lipid metabolism in arbuscular mycorrhizal roots of Medicago truncatula}}, year = {2005}, pages = {781-791}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2005.01.020}, volume = {66}, abstract = {The peroxidation of polyunsaturated fatty acids, common to all eukaryotes, is mostly catalyzed by members of the lipoxygenase enzyme family of non-heme iron containing dioxygenases. Lipoxygenase products can be metabolized further in the oxylipin pathway by several groups of CYP74 enzymes. One prominent oxylipin is jasmonic acid (JA), a product of the 13-allene oxide synthase branch of the pathway and known as signaling substance that plays a role in vegetative and propagative plant development as well as in plant responses to wounding and pathogen attack. In barley roots, JA level increases upon colonization by arbuscular mycorrhizal fungi. Apart from this first result regarding JA, no information is available on the relevance of lipidperoxide metabolism in arbuscular mycorrhizal symbiosis. Thus we analyzed fatty acid and lipidperoxide patterns in roots of Medicago truncatula during mycorrhizal colonization. Levels of fungus-specific fatty acids as well as palmitic acid (16:0) and oleic acid (18:1 n − 9) were increased in mycorrhizal roots. Thus the degree of arbuscular mycorrhizal colonization of roots can be estimated via analysis of fungal specific esterified fatty acids. Otherwise, no significant changes were found in the profiles of esterified and free fatty acids. The 9- and 13-LOX products of linoleic and α-linolenic acid were present in all root samples, but did not show significant differences between mycorrhizal and non-mycorrhizal roots, except JA which showed elevated levels in mycorrhizal roots. In both types of roots levels of 13-LOX products were higher than those of 9-LOX products. In addition, three cDNAs encoding CYP74 enzymes, two 9/13-hydroperoxide lyases and a 13-allene oxide synthase, were isolated and characterized. The transcript accumulation of these three genes, however, was not increased in mycorrhizal roots of M. truncatula.} } @Article{IPB-1982, author = {Sharma, V. K. and Monostori, T. and Hause, B. and Maucher, H. and Göbel, C. and Hornung, E. and Hänsch, R. and Bittner, F. and Wasternack, C. and Feussner, I. and Mendel, R. R. and Schulze, J. and}, title = {{Genetic transformation of barley to modify expression of a 13-lipoxygenase}}, year = {2005}, pages = {33-34}, journal = {Acta Biol. Szeged.}, url = {http://abs.bibl.u-szeged.hu/index.php/abs/article/view/2409}, volume = {49}, abstract = {Immature scutella of barley were transformed with cDNA coding for a 13-lipoxygenase of barley (LOX-100) via particle bombardment. Regenerated plants were tested by PAT-assay, Western-analysis and PCR-screening. Immunocytochemical assay of T0 plants showed expression of the LOX cDNA both in the chloroplasts and in the cytosol, depending on the presence of the chloroplast signal peptide sequences in the cDNA. A few transgenic plants containing higher amounts of LOX-derived products have been found. These are the candidates for further analysis concerning pathogen resistance.} } @Article{IPB-1963, author = {Lohse, S. and Schliemann, W. and Ammer, C. and Kopka, J. and Strack, D. and Fester, T. and}, title = {{Organization and Metabolism of Plastids and Mitochondria in Arbuscular Mycorrhizal Roots of Medicago truncatula}}, year = {2005}, pages = {329-340}, journal = {Plant Physiol.}, doi = {10.1104/pp.105.061457}, volume = {139}, abstract = {Colonization of root cortical cells by arbuscular mycorrhizal fungi leads to marked cytological changes of plastids and mitochondria. Plastids in particular are forming tubular extensions partially connecting individual organelles in a network-like way. These cytological changes correspond to an increased need for plastid and mitochondrial products during establishment and functioning of the symbiosis. The analysis of metabolite and transcript levels in mycorrhizal and nonmycorrhizal roots from Medicago truncatula revealed concomitant changes regarding a number of metabolic pathways. Our results indicate the activation of the mitochondrial tricarboxylic acid cycle and of plastid biosynthetic pathways producing fatty acids, amino acids, and apocarotenoids. These observations provide a general overview of structural and metabolic changes of plastids and mitochondria during colonization of root cortical cells by arbuscular mycorrhizal fungi.} } @Article{IPB-2040, author = {Schaarschmidt, S. and Qu, N. and Strack, D. and Sonnewald, U. and Hause, B. and}, title = {{Local Induction of the alc Gene Switch in Transgenic Tobacco Plants by Acetaldehyde}}, year = {2004}, pages = {1566-1577}, journal = {Plant Cell Physiol.}, doi = {10.1093/pcp/pch177}, volume = {45}, abstract = {The alc promoter system, derived from the filamentous fungi Aspergillus nidulans, allows chemically regulated gene expression in plants and thereby the study of gene function as well as metabolic and developmental processes. In addition to ethanol, this system can be activated by acetaldehyde, described as the physiological inducer in A. nidulans. Here, we show that in contrast to ethanol, acetaldehyde allows tissue-specific activation of the alc promoter in transgenic tobacco plants. Soil drenching with aqueous acetaldehyde solutions at a concentration of 0.05% (v/v) resulted in the rapid and temporary induction of the alc gene expression system exclusively in roots. In addition, the split root system allows activation to be restricted to the treated part of the root. The temporary activation of the alc system by soil drenching with acetaldehyde could be prolonged over several weeks by subsequent applications at intervals of 7 d. This effect was demonstrated for the root-specific induction of a yeast-derived apoplast-located invertase under the control of the alcohol-inducible promoter system. In leaves, which exhibit a lower responsiveness to acetaldehyde than roots, the alc system was induced in the directly treated tissue only. Thus, acetaldehyde can be used as a local inducer of the alc gene expression system in tobacco plants.} } @Article{IPB-2031, author = {Miersch, O. and Weichert, H. and Stenzel, I. and Hause, B. and Maucher, H. and Feussner, I. and Wasternack, C. and}, title = {{Constitutive overexpression of allene oxide cyclase in tomato (Lycopersicon esculentum cv. Lukullus) elevates levels of some jasmonates and octadecanoids in flower organs but not in leaves}}, year = {2004}, pages = {847-856}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2004.01.016}, volume = {65}, abstract = {The allene oxide cyclase (AOC), an enzyme in jasmonate biosynthesis, occurs in vascular bundles and ovules of tomato flowers which exhibit a tissue-specific oxylipin signature (Plant J. 24, 113-126, 2000). Constitutive overexpression of the AOC did not led to altered levels of jasmonates in leaves, but these levels increased upon wounding or other stresses suggesting regulation of jasmonate biosynthesis by substrate availability (Plant J. 33, 577-589, 2003). Here, we show dramatic changes in levels of jasmonic acid (JA), of 12-oxo-phytodienoic acid (OPDA), their methyl esters (JAME, OPDAME), and of dinor-OPDA in most flower organs upon constitutive overexpression of AOC. Beside a dominant occurrence of OPDAME and JA in most flower organs, the ratio among the various compounds was altered differentially in the organs of transgenic flowers, e.g. OPDAME increased up to 53-fold in stamen, and JA increased about 51-fold in buds and 7.5-fold in sepals. The increase in jasmonates and octadecanoids was accompanied by decreased levels of free lipid hydro(per)oxy compounds. Except for 16:2, the AOC overexpression led to a significant increase in free but not esterified polyunsaturated fatty acids in all flower organs. The data suggest different regulation of JA biosynthesis in leaves and flowers of tomato.Constitutive overexpression of the AOC increases in all flower organs levels of some jasmonates and octadecanoids, alters the ratios among the compounds, decreases levels of free lipid hydro(per)oxy compounds and increases levels of free but not of esterified polyunsaturated fatty acids.} } @Article{IPB-2029, author = {Maucher, H. and Stenzel, I. and Miersch, O. and Stein, N. and Prasad, M. and Zierold, U. and Schweizer, P. and Dorer, C. and Hause, B. and Wasternack, C. and}, title = {{The allene oxide cyclase of barley (Hordeum vulgare L.)—cloning and organ-specific expression}}, year = {2004}, pages = {801-811}, journal = {Phytochemistry}, doi = {10.1016/j.phytochem.2004.01.009}, volume = {65}, abstract = {The naturally occurring enantiomer of the various octadecanoids and jasmonates is established in a biosynthetic step catalyzed by the allene oxide cyclase (AOC). The AOC converts an allene oxide formed by an allene oxide synthase (AOS). Here, we show cloning and characterization of cDNAs encoding the AOC and a third AOS, respectively, in addition to the two AOSs previously published (Plant J. 21, 199–213, 2000). The ORF of the AOC-cDNA of 717 bp codes for a protein of 238 amino acid residues carrying a putative chloroplast target sequence. Overexpression without chloroplast target sequence revealed AOC activity. The AOC was found to be a single copy gene which mapped on chromosome 6H. AOC mRNA accumulation appeared in leaf segments upon treatment with various jasmonates, octadecanoids and ABA or during stress such as treatment with sorbitol or glucose solutions. Infection with powdery mildew activated AOC expression in susceptible and resistant lines of barley which correlated with PR1b expression. Among different tissues of barley seedlings, the scutellar node and leaf base accumulated AOC mRNA preferentially which correlated with accumulation of mRNAs for other biosynthetic enzymes (lipoxygenases, AOSs). AOC mRNA accumulation appeared also abundantly in parts of the root containing the tip and correlated with elevated levels of jasmonates. The data suggest a link of AOC expression and JA formation and support role of JA in stress responses and development of barley.Barley plants contain one allene oxide cyclase and three allene oxide synthases which are up-regulated during seedling development accompanied by elevated levels of jasmonate.} } @Article{IPB-2021, author = {Isayenkov, S. and Fester, T. and Hause, B. and}, title = {{Rapid determination of fungal colonization and arbuscule formation in roots of Medicago truncatula using real-time (RT) PCR}}, year = {2004}, pages = {1379-1383}, journal = {J. Plant Physiol.}, doi = {10.1016/j.jplph.2004.04.012}, volume = {161}, abstract = {The quantifications of root colonization and symbiotic activity in the arbuscular mycorrhizal (AM) association of Medicago truncatula and Glomus intraradices were performed by quantitative polymerase chain reaction (real-time PCR). A strong correlation between fungal colonization of the root system and the amounts of fungal rDNA and rRNA were shown. In contrast, the transcript levels of the AM-specific phosphate transporter 4 from M. truncatula (MtPT4) correlate with arbuscule formation rather than with fungal colonization. These results suggest (i) that real-time PCR assay is a rapid, useful, and accurate method for the determination of arbuscular mycorrhizal features, (ii) that the amount of fungal rDNA or rRNA is a good parameter to estimate fungal colonization, and (iii) that it is necessary to evaluate the amount of other transcripts—like the MtPT4 transcript—to obtain additional information about the symbiotic state of the colonized root system.} } @Article{IPB-2016, author = {Hans, J. and Hause, B. and Strack, D. and Walter, M. H. and}, title = {{Cloning, Characterization, and Immunolocalization of a Mycorrhiza-Inducible 1-Deoxy-D-Xylulose 5-Phosphate Reductoisomerase in Arbuscule-Containing Cells of Maize}}, year = {2004}, pages = {614-624}, journal = {Plant Physiol.}, doi = {10.1104/pp.103.032342}, volume = {134}, abstract = {Colonization of plant roots by symbiotic arbuscular mycorrhizal fungi frequently leads to the accumulation of several apocarotenoids. The corresponding carotenoid precursors originate from the plastidial 2-C-methyl-d-erythritol 4-phosphate pathway. We have cloned and characterized 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), catalyzing the first committed step of the pathway, from maize (Zea mays). Functional identification was accomplished by heterologous expression of sequences coding for the mature protein in Escherichia coli. DXR is up-regulated in maize roots during mycorrhization as shown at transcript and protein levels, but is also abundant in leaves and young seedlings. Inspection of sequenced genomes and expressed sequence tag (EST) databases argue for a single-copy DXR gene. Immunolocalization studies in mycorrhizal roots using affinity-purified antibodies revealed a DXR localization in plastids around the main symbiotic structures, the arbuscules. DXR protein accumulation is tightly correlated with arbuscule development. The highest level of DXR protein is reached around maturity and initial senescence of these structures. We further demonstrate the formation of a DXR-containing plastidial network around arbuscules, which is highly interconnected in the mature, functional state of the arbuscules. Our findings imply a functional role of a still unknown nature for the apocarotenoids or their respective carotenoid precursors in the arbuscular life cycle.} } @Article{IPB-2004, author = {Bücking, H. and Förster, H. and Stenzel, I. and Miersch, O. and Hause, B. and}, title = {{Applied jasmonates accumulate extracellularly in tomato, but intracellularly in barley}}, year = {2004}, pages = {45-50}, journal = {FEBS Lett.}, doi = {10.1016/S0014-5793(04)00178-4}, volume = {562}, abstract = {Jasmonic acid (JA) and its derivatives are well‐characterized signaling molecules in plant defense and development, but the site of their localization within plant tissue is entirely unknown. To address the question whether applied JA accumulates extracellularly or intracellularly, leaves of tomato and barley were fed with 14C‐labeled JA and the label was localized in cryofixed and lyophilized leaf tissues by microautoradiography. In tomato the radioactivity was detectable within the apoplast, but no label was found within the mesophyll cells. By contrast, in barley leaf tissues, radioactivity was detected within the mesophyll cells suggesting a cellular uptake of exogenously applied JA. JA, applied to leaves of both plants as in the labeling experiments, led in all leaf cells to the expression of JA‐inducible genes indicating that the perception is completed by JA signal transduction.} } @INBOOK{IPB-135, author = {Fester, T. and}, title = {{Wurzelinduzierte Bodenvorgänge}}, year = {2004}, pages = {39-42}, chapter = {{Plastiden bei der arbuskulären Mykorrhizasymbiose}}, doi = {10.1007/978-3-322-80084-8_5}, abstract = {In arbuscular mycorrhizal symbioses, root cortical cell plastids catalyze central processes regarding the transported metabolites on the one hand and molecular building blocks for symbiotic structures on the other. These metabolic tasks correlate with a strong proliferation and structural changes of the organelles. Future work will address the molecular factors responsible for these metabolic and structural changes.} } @Article{IPB-2124, author = {Wang, W. and Hause, B. and Peumans, W. J. and Smagghe, G. and Mackie, A. and Fraser, R. and Van Damme, E. J. M. and}, title = {{The Tn Antigen-Specific Lectin from Ground Ivy Is an Insecticidal Protein with an Unusual Physiology}}, year = {2003}, pages = {1322-1334}, journal = {Plant Physiol.}, doi = {10.1104/pp.103.023853}, volume = {132}, abstract = {Leaves of ground ivy (Glechoma hederacea) contain a lectin (called Gleheda) that is structurally and evolutionary related to the classical legume lectins. Screening of a population of wild plants revealed that Gleheda accounts for more than one-third of the total leaf protein in some clones, whereas it cannot be detected in other clones growing in the same environment. Gleheda is predominantly expressed in the leaves where it accumulates during early leaf maturation. The lectin is not uniformly distributed over the leaves but exhibits a unique localization pattern characterized by an almost exclusive confinement to a single layer of palisade parenchyma cells. Insect feeding trials demonstrated that Gleheda is a potent insecticidal protein for larvae of the Colorado potato beetle (Leptinotarsa decemlineata). Because Gleheda is not cytotoxic, it is suggested that the insecticidal activity is linked to the carbohydrate-binding specificity of the lectin, which as could be demonstrated by agglutination assays with different types of polyagglutinable human erythrocytes is specifically directed against the Tn antigen structure (N-acetylgalactosamine O-linked to serine or threonine residues of proteins).} } @Article{IPB-2123, author = {Varet, A. and Hause, B. and Hause, G. and Scheel, D. and Lee, J. and}, title = {{The Arabidopsis NHL3 Gene Encodes a Plasma Membrane Protein and Its Overexpression Correlates with Increased Resistance to Pseudomonas syringae pv. tomato DC3000}}, year = {2003}, pages = {2023-2033}, journal = {Plant Physiol.}, doi = {10.1104/pp.103.020438}, volume = {132}, abstract = {The Arabidopsis genome contains a family of NDR1/HIN1-like (NHL) genes that show homology to the nonrace-specific disease resistance (NDR1) and the tobacco (Nicotiana tabacum) harpin-induced (HIN1) genes. NHL3 is a pathogen-responsive member of this NHL gene family that is potentially involved in defense. In independent transgenic NHL3-overexpressing plant lines, a clear correlation between increased resistance to virulent Pseudomonas syringae pv. tomato DC3000 and enhanced NHL3 transcript levels was seen. These transgenic plants did not show enhanced pathogenesis-related gene expression or reactive oxygen species accumulation. Biochemical and localization experiments were performed to assist elucidation of how NHL3 may confer enhanced disease resistance. Gene constructs expressing amino-terminal c-myc-tagged or carboxyl-terminal hemagglutinin epitope (HA)-tagged NHL3 demonstrated membrane localization in transiently transformed tobacco leaves. Stable Arabidopsis transformants containing the NHL3-HA construct corroborated the findings observed in tobacco. The detected immunoreactive proteins were 10 kD larger than the calculated size and could be partially accounted for by the glycosylation state. However, the expected size was not attained with deglycosylation, suggesting possibly additional posttranslational modification. Detergent treatment, but not chemicals used to strip membrane-associated proteins, could displace the immunoreactive signal from microsomal fractions, showing that NHL3 is tightly membrane associated. Furthermore, immunofluorescence and immunogold labeling, coupled with two-phase partitioning techniques, revealed plasma membrane localization of NHL3-HA. This subcellular localization of NHL3 positions it at an initial contact site to pathogens and may be important in facilitating interception of pathogen-derived signals.} } @Article{IPB-2119, author = {Strack, D. and Fester, T. and Hause, B. and Schliemann, W. and Walter, M. H. and}, title = {{Arbuscular Mycorrhiza: Biological, Chemical, and Molecular Aspects}}, year = {2003}, pages = {1955-1979}, journal = {J. Chem. Ecol.}, doi = {10.1023/A:1025695032113}, volume = {29}, abstract = {Mycorrhizas are the most important mutualistic symbioses on earth. The most prevalent type are the arbuscular mycorrhizas (AMs) that develop between roots of most terrestrial plants and fungal species of the Zygomycota. The AM fungi are able to grow into the root cortex forming intercellular hyphae from which highly branched structures, arbuscules, originate within cortex cells. The arbuscules are responsible for nutrient exchange between the host and the symbiont, transporting carbohydrates from the plant to the fungus and mineral nutrients, especially phosphate, and water from the fungus to the plant. Plants adapt their phosphate uptake to the interaction with the AM fungus by synthesis of specific phosphate transporters. Colonization of root cells induces dramatic changes in the cytoplasmic organization: vacuole fragmentation, transformation of the plasma membrane to a periarbuscular membrane covering the arbuscule, increase of the cytoplasm volume and numbers of cell organelles, as well as movement of the nucleus into a central position. The plastids form a dense network covering the symbiotic interface. In some of these changes, microtubules are most likely involved. With regard to the molecular crosstalk between the two organisms, a number of phytohormones (cytokinins, abscisic acid, jasmonate) as well as various secondary metabolites have been examined: (i) Jasmonates occur at elevated level, which is accompanied by cell-specific expression of genes involved in jasmonate biosynthesis that might be linked to strong carbohydrate sink function of AM roots and induced defense reactions; (ii) apocarotenoids (derivatives of mycorradicin and glycosylated cyclohexenones) accumulate in most mycorrhizal roots examined so far. Their biosynthesis via the nonmevalonate methylerythritol phosphate (MEP) pathway has been studied resulting in new insights into AM-specific gene expression and biosynthesis of secondary isoprenoids.} } @Article{IPB-2118, author = {Stenzel, I. and Hause, B. and Miersch, O. and Kurz, T. and Maucher, H. and Weichert, H. and Ziegler, J. and Feussner, I. and Wasternack, C. and}, title = {{Jasmonate biosynthesis and the allene oxide cyclase family of Arabidopsis thaliana}}, year = {2003}, pages = {895-911}, journal = {Plant Mol. Biol.}, doi = {10.1023/A:1023049319723}, volume = {51}, abstract = {In biosynthesis of octadecanoids and jasmonate (JA), the naturally occurring enantiomer is established in a step catalysed by the gene cloned recently from tomato as a single-copy gene (Ziegler et al., 2000). Based on sequence homology, four full-length cDNAs were isolated from Arabidopsis thaliana ecotype Columbia coding for proteins with AOC activity. The expression of AOCgenes was transiently and differentially up-regulated upon wounding both locally and systemically and was induced by JA treatment. In contrast, AOC protein appeared at constitutively high basal levels and was slightly increased by the treatments. Immunohistochemical analyses revealed abundant occurrence of AOC protein as well as of the preceding enzymes in octadecanoid biosynthesis, lipoxygenase (LOX) and allene oxide synthase (AOS), in fully developed tissues, but much less so in 7-day old leaf tissues. Metabolic profiling data of free and esterified polyunsaturated fatty acids and lipid peroxidation products including JA and octadecanoids in wild-type leaves and the jasmonate-deficient mutant OPDA reductase 3 (opr3) revealed preferential activity of the AOS branch within the LOX pathway. 13-LOX products occurred predominantly as esterified derivatives, and all 13-hydroperoxy derivatives were below the detection limits. There was a constitutive high level of free 12-oxo-phytodienoic acid (OPDA) in untreated wild-type and opr3 leaves, but an undetectable expression of AOC. Upon wounding opr3 leaves exhibited only low expression of AOC, wounded wild-type leaves, however, accumulated JA and AOC mRNA. These and further data suggest regulation of JA biosynthesis by OPDA compartmentalization and a positive feedback by JA during leaf development.} } @Article{IPB-2116, author = {Stenzel, I. and Hause, B. and Maucher, H. and Pitzschke, A. and Miersch, O. and Ziegler, J. and Ryan, C. A. and Wasternack, C. and}, title = {{Allene oxide cyclase dependence of the wound response and vascular bundle-specific generation of jasmonates in tomato - amplification in wound signalling}}, year = {2003}, pages = {577-589}, journal = {Plant J.}, doi = {10.1046/j.1365-313X.2003.01647.x}, volume = {33}, abstract = {The allene oxide cyclase (AOC)‐catalyzed step in jasmonate (JA) biosynthesis is important in the wound response of tomato. As shown by treatments with systemin and its inactive analog, and by analysis of 35S::prosysteminsense and 35S::prosysteminantisense plants, the AOC seems to be activated by systemin (and JA) leading to elevated formation of JA. Data are presented on the local wound response following activation of AOC and generation of JA, both in vascular bundles. The tissue‐specific occurrence of AOC protein and generation of JA is kept upon wounding or other stresses, but is compromised in 35S::AOCsense plants, whereas 35S::AOCantisense plants exhibited residual AOC expression, a less than 10% rise in JA, and no detectable expression of wound response genes. The (i) activation of systemin‐dependent AOC and JA biosynthesis occurring only upon substrate generation, (ii) the tissue‐specific occurrence of AOC in vascular bundles, where the prosystemin gene is expressed, and (iii) the tissue‐specific generation of JA suggest an amplification in the wound response of tomato leaves allowing local and rapid defense responses.} } @Article{IPB-2104, author = {Proels, R. K. and Hause, B. and Berger, S. and Roitsch, T. and}, title = {{Novel mode of hormone induction of tandem tomato invertase genes in floral tissues}}, year = {2003}, pages = {191-201}, journal = {Plant Mol. Biol.}, doi = {10.1023/A:1023973705403}, volume = {52}, abstract = {The genomic organization of two extracellular invertase genes from tomato (Lin5 and Lin7), which are linked in a direct tandem repeat, and their tissue-specific and hormone-inducible expression are shown. Transient expression analysis ofLin5 promoter sequences fused to the β-glucuronidase (GUS) reporter gene (uidA) demonstrates a specific expression of Lin5during tomato fruit development. A Lin5 promoter fragment was fused to the truncated nos promoter to analyse hormone induction via GUS reporter gene activity in transiently transformed tobacco leaves. A specific up-regulation of GUS activity conferred by this Lin5 promoter fragment in response to gibberellic acid (GA), auxin and abscisic acid (ABA) treatment was observed, indicating a critical role of the regulation of Lin5 by phytohormones in tomato flower and fruit development. In situ hybridization analysis of Lin7 shows a high tissue-specific expression in tapetum and pollen. These results support an important role for Lin5 and Lin7 extracellular invertases in the development of reproductive organs in tomato and contribute to unravel the underlying regulatory mechanisms.} } @Article{IPB-2101, author = {Opitz, S. and Schnitzler, J.-P. and Hause, B. and Schneider, B. and}, title = {{Histochemical analysis of phenylphenalenone-related compounds in Xiphidium caeruleum (Haemodoraceae)}}, year = {2003}, pages = {881-889}, journal = {Planta}, doi = {10.1007/s00425-002-0941-z}, volume = {216}, abstract = {Phenylphenalenones represent a typical group of secondary metabolites of the Haemodoraceae. Some of these phenolic compounds show organ-specific distribution within the plant. However, detailed information on cellular localisation is still lacking. To this end, confocal laser-scanning microscopy, microspectral photometry and high-performance liquid chromatography were used to study the tissue localisation of phenylphenalenone-type compounds in Xiphidium caeruleum Aubl. From the autofluorescence potential of these compounds, specific distribution of allophanylglucosides and non-glucosidic compounds of the phenylphenalenone-type in distinct cells of the roots (apical meristem, cortex, cap, epidermis) and the shoot system was revealed. Fluorescence enhancement using \"Naturstoff reagent A\" (NA) indicated the occurrence of NA-positive natural products in the vacuoles of leaf epidermal cells. The present results provide new insights into the possible functions of phenylphenalenone-related compounds in the context of their localisation. Additionally, the advantages and limitations of the techniques are discussed.} } @Article{IPB-2096, author = {Monostori, T. and Schulze, J. and Sharma, V. K. and Maucher, H. and Wasternack, C. and Hause, B. and}, title = {{Novel plasmid vectors for homologous transformation of barley (Hordeum vulgare L.) with JIP23 cDNA in sense and antisense orientation}}, year = {2003}, pages = {17-24}, journal = {Cereal Res. Commun.}, doi = {10.1007/BF03543245}, volume = {31}, abstract = {The most abundant jasmonate-induced protein (JIP) in barley leaves is a 23 kDa protein (JIP23). Its function, however, is unknown. In order to analyze its function by homologous transformation, new plasmid vectors have been constructed. They carry the cDNA coding for JIP23 in sense or antisense orientation under the control of the Ubi-1-promoter as well as the pat resistance gene under the control of the 35S promoter. Barley mesophyll protoplasts were transiently transformed with the sense constructs. PAT activity and immunological detection of JIP23 could be achieved in transformed protoplasts but not in untransformed protoplasts indicating that the construct was active. Thus, these new vectors are suitable for stable transformation of barley. Carrying a multiple cloning site (MCS), these vectors can be used now in a wide range of transformation of barley.} } @Article{IPB-2088, author = {Krajinski, F. and Hause, B. and Gianinazzi-Pearson, V. and Franken, P. and}, title = {{Mtha1, a Plasma Membrane H\+-ATPase Gene from Medicago truncatula, Shows Arbuscule-Specific Induced Expression in Mycorrhizal Tissue}}, year = {2003}, pages = {754-761}, journal = {Plant Biol.}, doi = {10.1055/s-2002-37407}, volume = {4}, abstract = {Transport processes between plant and fungal cells are key elements in arbuscular mycorrhiza (AM), where H\+‐ATPases are considered to be involved in active uptake of nutrients from the symbiotic interface. Genes encoding H\+‐ATPases were identified in the genome of Medicago truncatula and three cDNA fragments of the H\+‐ATPase gene family (Mtha 1 ‐ 3) were obtained by RT‐PCR using RNA from M. truncatula mycorrhizal roots as template. While Mtha 2 and Mtha 3 appeared to be constitutively expressed in roots and unaffected by AM development, transcripts of Mtha 1 could only be detected in AM tissues and not in controls. Further analyses by RT‐PCR revealed that Mtha 1 transcripts are not detectable in shoots and phosphate availability did not affect RNA accumulation of the gene. Localization of transcripts by in situ hybridization on AM tissues showed that Mtha 1 RNA accumulates only in cells containing fungal arbuscules. This is the first report of arbuscule‐specific induced expression of a plant H\+‐ATPase gene in mycorrhizal tissues.} } @Article{IPB-2083, author = {Hause, B. and Stenzel, I. and Miersch, O. and Wasternack, C. and}, title = {{Occurrence of the allene oxide cyclase in different organs and tissues of Arabidopsis thaliana}}, year = {2003}, pages = {971-980}, journal = {Phytochemistry}, doi = {10.1016/S0031-9422(03)00447-3}, volume = {64}, abstract = {Occurrence of an essential enzyme in jasmonate (JA) biosynthesis, the allene oxide cyclase, (AOC) was analyzed in different developmental stages and various organs of Arabidopsis thaliana plants by immuno blot analysis and immunocytological approaches. Levels of AOC and of the two preceding enzymes in JA biosynthesis increased during seedling development accompanied by increased levels of JA and 12-oxophytodienoic acid levels after 4 and 8 weeks. Most tissues including all vascular bundles and that of flower buds contain AOC protein. Flowers shortly before opening, however, contain AOC protein preferentially in ovules, stigma cells and vascular bundles, whereas in anthers and pollen AOC could not be detected. The putative roles of AOC and JA in development are discussed.The allene oxide cyclase (AOC) is an important enzyme in jasmonate biosynthesis. Levels and occurrence of AOC in different organs and tissues are altered during development of Arabidopsis thaliana.} } @Article{IPB-2082, author = {Hause, B. and Hause, G. and Kutter, C. and Miersch, O. and Wasternack, C. and}, title = {{Enzymes of Jasmonate Biosynthesis Occur in Tomato Sieve Elements}}, year = {2003}, pages = {643-648}, journal = {Plant Cell Physiol.}, doi = {10.1093/pcp/pcg072}, volume = {44}, abstract = {The allene oxide cyclase (AOC) is a plastid-located enzyme in the biosynthesis of the signaling compound jasmonic acid (JA). In tomato, AOC occurs specifically in ovules and vascular bundles [Hause et al. (2000)PlantJ. 24; 113]. Immunocytological analysis of longitudinal sections of petioles and flower stalks revealed the occurrence of AOC in companion cells (CC) and sieve elements (SE). Electron microscopic analysis led to the conclusion that the AOC-containing structures of SE are plastids. AOC was not detected in SE of 35S::AOCantisense plants. The enzymes preceding AOC in JA biosynthesis, the allene oxide synthase (AOS) and the lipoxygenase, were also detected in SE. In situ hybridization showed that the SE are free of AOC-mRNA suggesting AOC protein traffic from CC to SE via plasmodesmata. A control by in situ hybridization of AOS mRNA coding for a protein with a size above the exclusion limit of plasmodesmata indicated mRNA in CC and SE. The data suggest that SE carry the capacity to form 12-oxo-phytodienoic acid, the unique precursor of JA. Together with preferential generation of JA in vascular bundles [Stenzel et al. (2003)Plant J. 33: 577], the data support a role of JA in systemic wound signaling.} } @Article{IPB-2075, author = {Doll, J. and Hause, B. and Demchenko, K. and Pawlowski, K. and Krajinski, F. and}, title = {{A Member of the Germin-Like Protein Family is a Highly Conserved Mycorrhiza-Specific Induced Gene}}, year = {2003}, pages = {1208-1214}, journal = {Plant Cell Physiol.}, doi = {10.1093/pcp/pcg153}, volume = {44}, abstract = {A Medicago truncatula cDNA encoding a germin-like protein (GLP) was isolated from a suppression subtractive hybridization cDNA library enriched for arbuscular mycorrhiza (AM)-induced genes. The MtGLP1 amino acid sequence shows some striking differences to previously described plant GLP sequences and might therefore represent a new subgroup of this multigene family. The MtGlp1 mRNA was strongly induced in roots and root cultures colonized by the AM fungus Glomus intraradices. Whereas MtGlp1 is strongly induced in AM, no transcripts of the gene were detected in non-infected roots or in roots after infection with the oomycete root pathogen Aphanomyces euteiches or with Rhizobia. Increased phosphate levels during fertilization also could not stimulate MtGlp1 transcription. Hence, MtGlp1 induction seems to be an AM-specific phenomenon. In situ hybridization showed that MtGlp1 is localized in arbuscule containing cells. A putative orthologue of this AM-specific GLP gene could be localized in a second legume Lotus japonicus, indicating that the regulation of a member of the GLP family belongs to a conserved mechanism in AM regulation in different plant species.} } @INBOOK{IPB-147, author = {Stumpe, M. and Stenzel, I. and Weichert, H. and Hause, B. and Feussner, I. and}, title = {{Advanced Research on Plant Lipids}}, year = {2003}, pages = {287-290}, chapter = {{The Lipoxygenase Pathway in Mycorrhizal Roots of Medicago Truncatula}}, doi = {10.1007/978-94-017-0159-4_67}, abstract = {Mycorrhizas are by far the most frequent occurring beneficial symbiotic interactions between plants and fungi. Species in \>80% of extant plant families are capable of establishing an arbuscular mycorrhiza (AM). In relation to the development of the symbiosis the first molecular modifications are those associated with plant defense responses, which seem to be locally suppressed to levels compatible with symbiotic interaction (Gianinazzi-Pearson, 1996). AM symbiosis can, however, reduce root disease caused by several soil-borne pathogens. The mechanisms underlying this protective effect are still not well understood. In plants, products of the enzyme lipoxygenase (LOX) and the corresponding downstream enzymes, collectively named LOX pathway (Fig. 1B), are involved in wound healing, pest resistance, and signaling, or they have antimicrobial and antifungal activity (Feussner and Wasternack, 2002). The central reaction in this pathway is catalyzed by LOXs leading to formation of either 9- or 13-hydroperoxy octadeca(di/trien)oic acids (9/13-HPO(D/T); Brash, 1999). Thus LOXs may be divided into 9- and 13-LOXs (Fig. 1A). Seven different reaction branches within this pathway can use these hydroperoxy polyenoic fatty acids (PUFAs) leading to (i) keto PUFAs by a LOX; (ii) epoxy hydroxy-fatty acids by an epoxy alcohol synthase (EAS); (iii) octadecanoids and jasmonates via allene oxide synthase (AOS); (iv) leaf aldehydes and leaf alcohols via fatty acid hydroperoxide lyase (HPL); (v) hydroxy PUFAs (reductase); (vi) divinyl ether PUFAs via divinyl ether synthase (DES); and (vii) epoxy- or dihydrodiolPUFAs via peroxygenase (PDX; Feussner and Wasternack, 2002). AOS, HPL and DES belong to one subfamily of P450-containing enzymes, the CYP74 family (Feussner and Wasternack, 2002). Here, the involvement of this CYP74 enzyme family in mycorrhizal roots of M. truncatula during early stages of AM symbiosis formation was analyzed.} } @INBOOK{IPB-145, author = {Stenzel, I. and Hause, B. and Feussner, I. and Wasternack, C. and}, title = {{Advanced Research on Plant Lipids}}, year = {2003}, pages = {267-270}, chapter = {{Transcriptional Activation of Jasmonate Biosynthesis Enzymes is not Reflected at Protein Level}}, doi = {10.1007/978-94-017-0159-4_62}, abstract = {Jasmonic acid (JA) and its precursor 12-oxo phytodienoic acid (OPDA) are lipid-derived signals in plant stress responses and development (Wasternack and Hause, 2002). Within the wound-response pathway of tomato, a local response of expression of defense genes such as the proteinase inhibitor 2 gene (PIN2) is preceded by a rise in JA (Herde et al., 1996; Howe et al., 1996) and ethylene (O’Donnell et al., 1996). Mutants affected in JA biosynthesis such as defl (Howe et al., 1996) or spr-2 (Li et al., 2002) clearly indicated that JA biosynthesis is an ultimate part of wound signaling. It is less understood, however, how the rise in JA is regulated.} } @Article{IPB-2182, author = {Van Damme, E. J. M. and Hause, B. and Hu, J. and Barre, A. and Rougé, P. and Proost, P. and Peumans, W. J. and}, title = {{Two Distinct Jacalin-Related Lectins with a Different Specificity and Subcellular Location Are Major Vegetative Storage Proteins in the Bark of the Black Mulberry Tree}}, year = {2002}, pages = {757-769}, journal = {Plant Physiol.}, doi = {10.1104/pp.005892}, volume = {130}, abstract = {Using a combination of protein isolation/characterization and molecular cloning, we have demonstrated that the bark of the black mulberry tree (Morus nigra) accumulates large quantities of a galactose-specific (MornigaG) and a mannose (Man)-specific (MornigaM) jacalin-related lectin. MornigaG resembles jacalin with respect to its molecular structure, specificity, and co- and posttranslational processing indicating that it follows the secretory pathway and eventually accumulates in the vacuolar compartment. In contrast, MornigaM represents a novel type of highly active Man-specific jacalin-related lectin that is synthesized without signal peptide or other vacuolar targeting sequences, and accordingly, accumulates in the cytoplasm. The isolation and cloning, and immunocytochemical localization of MornigaG and MornigaM not only demonstrates that jacalin-related lectins act as vegetative storage proteins in bark, but also allows a detailed comparison of a vacuolar galactose-specific and a cytoplasmic Man-specific jacalin-related lectin from a single species. Moreover, the identification of MornigaM provides the first evidence, to our knowledge, that bark cells accumulate large quantities of a cytoplasmic storage protein. In addition, due to its high activity, abundance, and ease of preparation, MornigaM is of great potential value for practical applications as a tool and bioactive protein in biological and biomedical research.} } @Article{IPB-2158, author = {Hause, B. and Maier, W. and Miersch, O. and Kramell, R. and Strack, D. and}, title = {{Induction of Jasmonate Biosynthesis in Arbuscular Mycorrhizal Barley Roots}}, year = {2002}, pages = {1213-1220}, journal = {Plant Physiol.}, doi = {10.1104/pp.006007}, volume = {130}, abstract = {Colonization of barley (Hordeum vulgare cv Salome) roots by an arbuscular mycorrhizal fungus, Glomus intraradices Schenck \& Smith, leads to elevated levels of endogenous jasmonic acid (JA) and its amino acid conjugate JA-isoleucine, whereas the level of the JA precursor, oxophytodienoic acid, remains constant. The rise in jasmonates is accompanied by the expression of genes coding for an enzyme of JA biosynthesis (allene oxide synthase) and of a jasmonate-induced protein (JIP23). In situ hybridization and immunocytochemical analysis revealed that expression of these genes occurred cell specifically within arbuscule-containing root cortex cells. The concomitant gene expression indicates that jasmonates are generated and act within arbuscule-containing cells. By use of a near-synchronous mycorrhization, analysis of temporal expression patterns showed the occurrence of transcript accumulation 4 to 6 d after the appearance of the first arbuscules. This suggests that the endogenous rise in jasmonates might be related to the fully established symbiosis rather than to the recognition of interacting partners or to the onset of interaction. Because the plant supplies the fungus with carbohydrates, a model is proposed in which the induction of JA biosynthesis in colonized roots is linked to the stronger sink function of mycorrhizal roots compared with nonmycorrhizal roots.} } @Article{IPB-2157, author = {Hause, B. and Meyer, K. and Viitanen, P. and Chapple, C. and Strack, D. and}, title = {{Immunolocalization of 1-O-sinapoylglucose:malate sinapoyltransferase in Arabidopsis thaliana}}, year = {2002}, pages = {26-32}, journal = {Planta}, doi = {10.1007/s00425-001-0716-y}, volume = {215}, abstract = {The serine carboxypeptidase-like protein 1-O-sinapoylglucose:malate sinapoyltransferase (SMT) catalyzes the transfer of the sinapoyl moiety of 1-O-sinapoylglucose to malate in the formation of sinapoylmalate in some members of the Brassicaceae. Rabbit polyclonal monospecific antibodies were raised against the recombinant SMT produced in Escherichia coli from the corresponding Arabidopsis thaliana (L.) Heynh. cDNA. Immunoblot analysis of protein from different Arabidopsis tissues showed that the SMT is produced in all plant organs, except in the seeds and young seedlings. The enzyme was most abundant in older seedlings as well as in rosette leaves and the flowering stem of the plant. Minor amounts were found in the cauline leaves, flower buds and siliques. Traces were detected in the root and flowers. Arabidopsis and transgenic tobacco (Nicotiana tabacum L.) plants expressing the full-length Arabidopsis SMT containing an N-terminal signal peptide showed apparent molecular masses of the protein of 52–55 kDa. The difference of ca. 8 kDa compared to the recombinant protein produced in E. coli was shown to be due to post-translational N-glycosylation of SMT in plants. Immunofluorescent labeling of Arabidopsis leaf sections localized SMT to the central vacuoles of mesophyll and epidermal cells. Comparable leaf sections of an SMT deletion mutant showed no vacuolar immunofluorescent labeling. We conclude that Arabidopsis SMT is synthesized as a precursor protein that is targeted to the endoplasmic reticulum where the signal peptide is removed. The correct N-terminus of the recombinantly produced SMT protein lacking the signal peptide was confirmed by Edman degradation. The protein is probably glycosylated in the Golgi apparatus from where it is subsequently routed to the vacuole.} } @Article{IPB-2149, author = {Fester, T. and Schmidt, D. and Lohse, S. and Walter, M. H. and Giuliano, G. and Bramley, P. M. and Fraser, P. D. and Hause, B. and Strack, D. and}, title = {{Stimulation of carotenoid metabolism in arbuscular mycorrhizal roots}}, year = {2002}, pages = {148-154}, journal = {Planta}, doi = {10.1007/s00425-002-0917-z}, volume = {216}, abstract = {Development of arbuscular mycorrhizal roots is correlated with accumulation of various isoprenoids, i.e. acyclic C14 polyene \'mycorradicin\' and C13 cyclohexenone derivatives. We present data indicating a strong stimulation of carotenoid metabolism in such roots. Carotenoid profiling revealed mycorrhiza-specific accumulation of ζ-carotene in Zea mays and Medicago truncatula. Precursor accumulation after inhibition of phytoene desaturase (Pds) activity by norflurazon indicated an increased phytoene biosynthetic capacity in mycorrhizal roots of all species analyzed. Nicotiana tabacum plants transformed with a PDS promoter-GUS construct showed a cell-specific induction of PDS promoter activity in root cells containing arbuscules. Mycorradicin biosynthesis and, partially, mycorrhization were impaired in maize mutants deficient in carotenoid biosynthesis. These data indicate that (1) mycorradicin is probably synthesized via a C40 precursor carotenoid, (2) carotenoid biosynthesis is induced in mycorrhizal roots, (3) induction occurs, at least partially, at the transcriptional level, and (4) that this may play a functional role during mycorrhization.} } @Article{IPB-2148, author = {Fester, T. and Hause, B. and Schmidt, D. and Halfmann, K. and Schmidt, J. and Wray, V. and Hause, G. and Strack, D. and}, title = {{Occurrence and Localization of Apocarotenoids in Arbuscular Mycorrhizal Plant Roots}}, year = {2002}, pages = {256-265}, journal = {Plant Cell Physiol.}, doi = {10.1093/pcp/pcf029}, volume = {43}, abstract = {The core structure of the yellow pigment from arbuscular mycorrhizal (AM) maize roots contains the apocarotenoids mycorradicin (an acyclic C14 polyene) and blumenol C cellobioside (a C13 cyclohexenone diglucoside). The pigment seems to be a mixture of different esterification products of these apocarotenoids. It is insoluble in water and accumulates as hydrophobic droplets in the vacuoles of root cortical cells. Screening 58 species from 36 different plant families, we detected mycorradicin in mycorrhizal roots of all Liliopsida analyzed and of a considerable number of Rosopsida, but also species were found in which mycorradicin was undetectable in mycorrhizal roots. Kinetic experiments and microscopic analyses indicate that accumulation of the yellow pigment is correlated with the concomitant degradation of arbuscules and the extensive plastid network covering these haustorium-like fungal structures. The role of the apocarotenoids in mycorrhizal roots is still unknown. The potential C40 carotenoid precursors, however, are more likely to be of functional importance in the development and functioning of arbuscules.} } @Article{IPB-2147, author = {Fester, T. and Kiess, M. and Strack, D. and}, title = {{A mycorrhiza-responsive protein in wheat roots}}, year = {2002}, pages = {219-222}, journal = {Mycorrhiza}, doi = {10.1007/s00572-002-0173-x}, volume = {12}, abstract = {A small protein, designated Myk15, was found to be strongly induced in wheat (Triticum aestivum) roots colonized by the arbuscular mycorrhizal fungus Glomus intraradices. This protein, which is most abundant in root fractions characterized by strong mycorrhizal colonization, has been characterized using two-dimensional polyacrylamide gel electrophoresis and microsequencing. It has an apparent molecular mass of 15 kDa and an isoelectric point of 4.5. The N-terminal sequence has high similarity to a peptide sequence deduced from an expressed sequence tag (EST) clone derived from Medicago truncatula roots colonized by G. intraradices. This EST clone is predicted to code for a protein with a similar size and isoelectric point as Myk15. The N-terminus of the deduced M. truncatula protein contains a highly hydrophobic stretch of 24 amino acid residues preceding the region with high similarity to the Myk15 N-terminus. This hydrophobic stretch is predicted to form a transmembrane α-helix and may correspond to a cleavable targeting domain.} } @Article{IPB-2141, author = {Chen, Y. and Peumans, W. J. and Hause, B. and Bras, J. and Kumar, M. and Proost, P. and Barre, A. and Rougé, P. and Van Damme, E. J. M. and}, title = {{Jasmonate methyl ester induces the synthesis of a cytoplasmic/nuclear chitooligosaccharide‐binding lectin in tobacco leaves}}, year = {2002}, pages = {905-907}, journal = {FASEB J.}, doi = {10.1096/fj.01-0598fje}, volume = {16}, abstract = {In contrast to animal lectins, no evidence has indicated the occurrence of plant lectins, which recognize and bind “endogenous” receptors and accordingly are involved in recognition mechanisms within the organism itself. Here we show that the plant hormone jasmonic acid methyl ester (JAME) induces in leaves of Nicotiana tabacum (var. Samsun NN) the expression of a lectin that is absent from untreated plants. The lectin specifically binds to oligomers of N‐acetylglucosamine and is detected exclusively in the cytoplasm and the nucleus. Both the subcellular location and specificity indicate that the Nicotiana tabacum agglutinin (called Nictaba) may be involved in the regulation of gene expression in stressed plants through specific protein‐carbohydrate interactions with regulatory cytoplasmic/nuclear glycoproteins. Searches in the databases revealed that many flowering plants contain sequences encoding putative homologues of the tobacco lectin, which suggest that Nictaba is the prototype of a widespread or possibly ubiquitous family of lectins with a specific endogenous role.} } @Article{IPB-2131, author = {Bachmann, A. and Hause, B. and Maucher, H. and Garbe, E. and Vörös, K. and Weichert, H. and Wasternack, C. and Feussner, I. and}, title = {{Jasmonate-Induced Lipid Peroxidation in Barley Leaves Initiated by Distinct 13-LOX Forms of Chloroplasts}}, year = {2002}, pages = {1645-1657}, journal = {Biol. Chem.}, doi = {10.1515/BC.2002.185}, volume = {383}, abstract = {In addition to a previously characterized 13-lipoxygenase of 100 kDa encoded by LOX2:Hv:1 [Vörös et al., Eur. J. Biochem. 251 (1998), 36 44], two fulllength cDNAs (LOX2:Hv:2, LOX2:Hv:3) were isolated from barley leaves (Hordeum vulgare cv. Salome) and characterized. Both of them encode 13-lipoxygenases with putative target sequences for chloroplast import. Immunogold labeling revealed preferential, if not exclusive, localization of lipoxygenase proteins in the stroma. The ultrastructure of the chloroplast was dramatically altered following methyl jasmonate treatment, indicated by a loss of thylakoid membranes, decreased number of stacks and appearance of numerous osmiophilic globuli. The three 13-lipoxygenases are differentially expressed during treatment with jasmonate, salicylate, glucose or sorbitol. Metabolite profiling of free linolenic acid and free linoleic acid, the substrates of lipoxygenases, in water floated or jasmonatetreated leaves revealed preferential accumulation of linolenic acid. Remarkable amounts of free 9- as well as 13-hydroperoxy linolenic acid were found. In addition, metabolites of these hydroperoxides, such as the hydroxy derivatives and the respective aldehydes, appeared following methyl jasmonate treatment. These findings were substantiated by metabolite profiling of isolated chloroplasts, and subfractions including the envelope, the stroma and the thylakoids, indicating a preferential occurrence of lipoxygenasederived products in the stroma and in the envelope. These data revealed jasmonateinduced activation of the hydroperoxide lyase and reductase branch within the lipoxygenase pathway and suggest differential activity of the three 13-lipoxygenases under different stress conditions.} } @INBOOK{IPB-159, author = {Wasternack, C. and Hause, B. and}, year = {2002}, pages = {165-221}, chapter = {{Jasmonates and octadecanoids: Signals in plant stress responses and development}}, journal = {Prog. Nucleic Acid Res. Mol. Biol.}, doi = {10.1016/S0079-6603(02)72070-9}, volume = {72}, abstract = {Plants are sessile organisms. Consequently they have to adapt constantly to fluctuations in the environment. Some of these changes involve essential factors such as nutrients, light, and water. Plants have evolved independent systems to sense nutrients such as phosphate and nitrogen. However, many of the environmental factors may reach levels which represent stress for the plant. The fluctuations can range between moderate and unfavorable, and the factors can be of biotic or abiotic origin. Among the biotic factors influencing plant life are pathogens and herbivores. In case of bacteria and fungi, symbiotic interactions such as nitrogen-fixating nodules and mycorrhiza, respectively, may be established. In case of insects, a tritrophic interaction of herbivores, carnivores, and plants may occur mutualistically or parasitically. Among the numerous abiotic factors are low temperature, frost, heat, high light conditions, ultraviolet light, darkness, oxidation stress, hypoxia, wind, touch, nutrient imbalance, salt stress, osmotic adjustment, water deficit, and desiccation.In the last decade jasmonates were recognized as being signals in plant responses to most of these biotic and abiotic factors. Signaling via jasmonates was found to occur intracellularly, and systemically as well as interorganismically. Jasmonates are a group of ubiquitously occurring plant growth regulators originally found as the major constituents in the etheric oil of jasmine, and were first suggested to play a role in senescence due to a strong senescence-promoting effect. Subsequently, numerous developmental processes were described in which jasmonates exhibited hormone-like properties. Recent knowledge is reviewed here on jasmonates and their precursors, the octadecanoids. After discussing occurrence and biosynthesis, emphasis is placed upon the signal transduction pathways in plant stress responses in which jasmonates act a signal. Finally, examples are described on the role of jasmonates in developmental processes.} } @INBOOK{IPB-157, author = {Riemann, D. and Röntsch, J. and Hause, B. and Langner, J. and Kehlen, A. and}, title = {{Cellular Peptidases in Immune Functions and Diseases 2}}, year = {2002}, pages = {57-66}, chapter = {{Cell-Cell Contact Between Lymphocytes and Fibroblast-Like Synovioctyes Induces Lymphocytic Expression of Aminopeptidase n/cd13 and Results in Lymphocytic Activation}}, journal = {Adv. Exp. Med. Biol.}, doi = {10.1007/0-306-46826-3_6}, volume = {477}, } @Article{IPB-2231, author = {Strack, D. and Fester, T. and Hause, B. and Walter, M. H. and}, title = {{Die arbuskuläre Mykorrhiza: Eine unterirdische Lebensgemeinschaft}}, year = {2001}, pages = {286-295}, journal = {Biologie in unserer Zeit}, doi = {10.1002/1521-415X(200109)31:5<286::AID-BIUZ286>3.0.CO;2-G}, volume = {31}, abstract = {Pflanzen und bestimmte Pilze haben im Laufe ihrer Entwicklungsgeschichte „gelernt”︁, in einer engen Assoziation im Boden, der Mykorrhiza, eine äußerst erfolgreiche Symbiose miteinander einzugehen. Arbuskuläre Mykorrhizapilze helfen Pflanzen sich auf nährstoffarmen Böden ausreichend mit Wasser, Nährsalzen und Spurenelementen zu versorgen und fördern entscheidend Diversität und Produktivität von Pflanzengesellschaften. Darüber hinaus zeigen mykorrhizierte Pflanzen eine erhöhte Widerstandsfähigkeit gegen Pathogenbefall. Im Gegenzug „bezahlt”︁ die Pflanze den Pilz für diesen Gewinn mit Kohlenhydraten in Form einfacher Zucker (Glucose, Fructose). Durch manche Erfolge in der Erforschung der Mykorrhiza auf Metaboliten‐ und Genebene beginnen wir allmählich zu erahnen, wie komplex die molekularen Interaktionen dieser Symbiose sind. Es ist zu erwarten, dass das steigende Interesse an der Mykorrhizaforschung zu neuen Einsichten in die Strategien von Pflanzen und Pilzen in der Entwicklung mutualistisch‐symbiontischer Assoziationen führen wird.} } @Article{IPB-2220, author = {Lehmann, K. and Hause, B. and Altmann, D. and Köck, M. and}, title = {{Tomato Ribonuclease LX with the Functional Endoplasmic Reticulum Retention Motif HDEF Is Expressed during Programmed Cell Death Processes, Including Xylem Differentiation, Germination, and Senescence}}, year = {2001}, pages = {436-449}, journal = {Plant Physiol.}, doi = {10.1104/pp.010362}, volume = {127}, abstract = {We have studied the subcellular localization of the acid S-like ribonuclease (RNase) LX in tomato (Lycopersicon esculentum Mill.) cells using a combination of biochemical and immunological methods. It was found that the enzyme, unexpectedly excluded from highly purified vacuoles, accumulates in the endoplasmic reticulum. The evidence that RNase LX is a resident of the endoplasmic reticulum (ER) is supported by an independent approach showing that the C-terminal peptide HDEF of RNase LX acts as an alternative ER retention signal in plants. For functional testing, the cellular distribution of chimeric protein constructs based on a marker protein, Brazil nut (Bertholletia excelsa) 2S albumin, was analyzed immunochemically in transgenic tobacco (Nicotiana tabacum) plants. Here, we report that the peptide motif is necessary and sufficient to accumulate 2S albumin constructs of both vacuolar and extracellular final destinations in the ER. We have shown immunochemically that RNase LX is specifically expressed during endosperm mobilization and leaf and flower senescence. Using immunofluorescence, RNase LX protein was detected in immature tracheary elements, suggesting a function in xylem differentiation. These results support a physiological function of RNase LX in selective cell death processes that are also thought to involve programmed cell death. It is assumed that RNase LX accumulates in an ER-derived compartment and is released by membrane disruption into the cytoplasma of those cells that are intended to undergo autolysis. These processes are accompanied by degradation of cellular components supporting a metabolic recycling function of the intracellular RNase LX.} } @Article{IPB-2213, author = {Hao, Q. and Van Damme, E. J. M. and Hause, B. and Barre, A. and Chen, Y. and Rougé, P. and Peumans, W. J. and}, title = {{Iris Bulbs Express Type 1 and Type 2 Ribosome-Inactivating Proteins with Unusual Properties}}, year = {2001}, pages = {866-876}, journal = {Plant Physiol.}, doi = {10.1104/pp.125.2.866}, volume = {125}, abstract = {Two closely related lectins from bulbs of the Dutch iris (Iris hollandica var. Professor Blaauw) have been isolated and cloned. Both lectins, called Iris agglutinin b and Iris agglutinin r, possess N-glycosidase activity and share a high sequence similarity with previously described type 2 ribosome-inactivating proteins (RIP). However, these lectins show only 57% to 59% sequence identity to a previously characterized type 1 RIP from iris, called IRIP. The identification of the iris lectins as type 2 RIP provides unequivocal evidence for the simultaneous occurrence of type 1 and type 2 RIP in iris bulbs and allowed a detailed comparison of type 1 and type 2 RIP from a single plant, which provides further insight into the molecular evolution of RIP. Binding studies and docking experiments revealed that the lectins exhibit binding activity not only toward Gal/N-acetylgalactosamine, but also toward mannose, demonstrating for the first time that RIP-binding sites can accommodate mannose.} } @Article{IPB-2206, author = {Fester, T. and Strack, D. and Hause, B. and}, title = {{Reorganization of tobacco root plastids during arbuscule development}}, year = {2001}, pages = {864-868}, journal = {Planta}, doi = {10.1007/s004250100561}, volume = {213}, abstract = {In the present paper we analyzed plastid populations labeled by the green fluorescent protein in non-mycorrhizal and mycorrhizal roots of tobacco (Nicotiana tabacum L.). We show by confocal laser scanning microscopy (i) a dramatic increase in these plastids in mycorrhizal roots and (ii) the formation of dense plastid networks covering the symbiotic interface of the arbuscular mycorrhiza, the arbuscule. These cytological observations point to an important role of root cortical cell plastids in the functioning of arbuscular mycorrhizal symbiosis.} } @Article{IPB-2235, author = {Van Damme, E. J. M. and Hu, J. and Barre, A. and Hause, B. and Baggerman, G. and Rougé, P. and Peumans, W. J. and}, title = {{Purification, characterization, immunolocalization and structural analysis of the abundant cytoplasmic β-amylase from Calystegia sepium (hedge bindweed) rhizomes}}, year = {2001}, pages = {6263-6273}, journal = {Eur. J. Biochem.}, doi = {10.1046/j.0014-2956.2001.02584.x}, volume = {268}, abstract = {An abundant catalytically active β‐amylase (EC 3.2.1.2) was isolated from resting rhizomes of hedge bindweed (Calystegia sepium ). Biochemical analysis of the purified protein, molecular modeling, and cloning of the corresponding gene indicated that this enzyme resembles previously characterized plant β‐amylases with regard to its amino‐acid sequence, molecular structure and catalytic activities. Immunolocalization demonstrated that the β‐amylase is exclusively located in the cytoplasm. It is suggested that the hedge bindweed rhizome β‐amylase is a cytoplasmic vegetative storage protein.} } @Article{IPB-2260, author = {Lee, Y. K. and Hippe-Sanwald, S. and Jung, H. W. and Hong, J. K. and Hause, B. and Hwang, B. K. and}, title = {{In situ localization of chitinase mRNA and protein in compatible and incompatible interactions of pepper stems with Phytophthora capsici}}, year = {2000}, pages = {111-121}, journal = {Physiol. Mol. Plant Pathol.}, doi = {10.1006/pmpp.2000.0290}, volume = {57}, abstract = {The induction of chitinase (CAChi2) mRNA started as early as 6 h after inoculation and gradually increased in the incompatible interaction of pepper stems with Phytophthora capsici. In the compatible interaction, the induction of the chitinase transcripts was detected later than that in the incompatible interaction. The CAChi2 mRNA was usually localized in the vascular tissues and their expression was constricted in the phloem-related cells. These results showed that the spatial pattern of CAChi2 mRNA expression was similar in both compatible and incompatible interactions but the temporal patterns were different from each other. In addition, the early induction ofCAChi2 mRNA was quite distinct in the incompatible interaction. Immunogold labelling data showed specific labelling of chitinase on the cell wall of the oomycete in both compatible and incompatible interactions at 24 h after inoculation. In particular, numerous gold particles were deposited on the cell wall of P. capsici with a predominant accumulation over areas showing signs of degradation in the incompatible interaction. Chitinase labelling was also detected in the intercellular space and the host cytoplasm. However, healthy pepper stem tissue was nearly free of labelling.} } @Article{IPB-2251, author = {Hause, B. and Stenzel, I. and Miersch, O. and Maucher, H. and Kramell, R. and Ziegler, J. and Wasternack, C. and}, title = {{Tissue-specific oxylipin signature of tomato flowers: allene oxide cyclase is highly expressed in distinct flower organs and vascular bundles}}, year = {2000}, pages = {113-126}, journal = {Plant J.}, doi = {10.1046/j.1365-313x.2000.00861.x}, volume = {24}, abstract = {A crucial step in the biosynthesis of jasmonic acid (JA) is the formation of its correct stereoisomeric precursor, cis (\+)12‐oxophytodienoic acid (OPDA). This step is catalysed by allene oxide cyclase (AOC), which has been recently cloned from tomato . In stems, young leaves and young flowers, AOC mRNA accumulates to a low level , contrasting with a high accumulation in flower buds, flower stalks and roots. The high levels of AOC mRNA and AOC protein in distinct flower organs correlate with high AOC activity, and with elevated levels of JA, OPDA and JA isoleucine conjugate. These compounds accumulate in flowers to levels of about 20 nmol g−1 fresh weight, which is two orders of magnitude higher than in leaves. In pistils, the level of OPDA is much higher than that of JA, whereas in flower stalks, the level of JA exceeds that of OPDA. In other flower tissues, the ratios among JA, OPDA and JA isoleucine conjugate differ remarkably, suggesting a tissue‐specific oxylipin signature. Immunocytochemical analysis revealed the specific occurrence of the AOC protein in ovules, the transmission tissue of the style and in vascular bundles of receptacles, flower stalks, stems, petioles and roots. Based on the tissue‐specific AOC expression and formation of JA, OPDA and JA amino acid conjugates, a possible role for these compounds in flower development is discussed in terms of their effect on sink–source relationships and plant defence reactions. Furthermore, the AOC expression in vascular bundles might play a role in the systemin‐mediated wound response of tomato.} } @Article{IPB-2250, author = {Hause, B. and Weichert, H. and Höhne, M. and Kindl, H. and Feussner, I. and}, title = {{Expression of cucumber lipid-body lipoxygenase in transgenic tobacco: lipid-body lipoxygenase is correctly targeted to seed lipid bodies}}, year = {2000}, pages = {708-714}, journal = {Planta}, doi = {10.1007/s004250050671}, volume = {210}, abstract = {A particular isoform of lipoxygenase (LOX, EC 1.13.11.12) localized on lipid bodies has been shown by earlier investigations to play a role during seed germination in initiating the mobilization of triacylglycerols. On lipid bodies of germinating cucumber (Cucumis sativus L.) seedlings, the modification of linoleoyl moieties by this LOX precedes the hydrolysis of the ester bonds. We analyzed the expression and intracellular location of this particular LOX form in leaves and seeds of tobacco (Nicotiana tabacum L.) transformed with one construct coding for cucumber lipid-body LOX and one construct coding for cucumber LOX fused with a hemagglutinin epitope. In both tissues, the amount of lipid-body LOX was clearly detectable. Biochemical analysis revealed that in mature seeds the foreign LOX was targeted to lipid bodies, and the preferred location of the LOX on lipid bodies was verified by immunofluorescence microscopy. Cells of the endosperm and of the embryo exhibited fluorescence based on the immunodecoration of LOX protein whereas very weak fluorescent label was visible in seeds of untransformed control plants. Further cytochemical analysis of transformed plants showed that the LOX protein accumulated in the cytoplasm when green leaves lacking lipid bodies were analyzed. Increased LOX activity was shown in young leaves of transformed plants by an increase in the amounts of endogenous (2E)-hexenal and jasmonic acid.} } @Article{IPB-2240, author = {Binarová, P. and Cenklová, V. and Hause, B. and Kubátová, E. and Lysák, M. and Doležel, J. and Bögre, L. and Dráber, P. and}, title = {{Nuclear γ-Tubulin during Acentriolar Plant Mitosis}}, year = {2000}, pages = {433-442}, journal = {Plant Cell}, doi = {10.1105/tpc.12.3.433}, volume = {12}, abstract = {Neither the molecular mechanism by which plant microtubules nucleate in the cytoplasm nor the organization of plant mitotic spindles, which lack centrosomes, is well understood. Here, using immunolocalization and cell fractionation techniques, we provide evidence that γ-tubulin, a universal component of microtubule organizing centers, is present in both the cytoplasm and the nucleus of plant cells. The amount of γ-tubulin in nuclei increased during the G2 phase, when cells are synchronized or sorted for particular phases of the cell cycle. γ-Tubulin appeared on prekinetochores before preprophase arrest caused by inhibition of the cyclin-dependent kinase and before prekinetochore labeling of the mitosis-specific phosphoepitope MPM2. The association of nuclear γ-tubulin with chromatin displayed moderately strong affinity, as shown by its release after DNase treatment and by using extraction experiments. Subcellular compartmentalization of γ-tubulin might be an important factor in the organization of plant-specific microtubule arrays and acentriolar mitotic spindles.} } @Article{IPB-2264, author = {Maucher, H. and Hause, B. and Feussner, I. and Ziegler, J. and Wasternack, C. and}, title = {{Allene oxide synthases of barley (Hordeum vulgare cv. Salome): tissue specific regulation in seedling development}}, year = {2000}, pages = {199-213}, journal = {Plant J.}, doi = {10.1046/j.1365-313x.2000.00669.x}, volume = {21}, abstract = {Allene oxide synthase (AOS) is the first enzyme in the lipoxygenase (LOX) pathway which leads to formation of jasmonic acid (JA). Two full‐length cDNAs of AOS designated as AOS1 and AOS2, respectively, were isolated from barley (H. vulgare cv. Salome) leaves, which represent the first AOS clones from a monocotyledonous species. For AOS1, the open reading frame encompasses 1461 bp encoding a polypeptide of 487 amino acids with calculated molecular mass of 53.4 kDa and an isoelectric point of 9.3, whereas the corresponding data of AOS2 are 1443 bp, 480 amino acids, 52.7 kDa and 7.9. Southern blot analysis revealed at least two genes. Despite the lack of a putative chloroplast signal peptide in both sequences, the protein co‐purified with chloroplasts and was localized within chloroplasts by immunocytochemical analysis. The barley AOSs, expressed in bacteria as active enzymes, catalyze the dehydration of LOX‐derived 9‐ as well as 13‐hydroperoxides of polyenoic fatty acids to the unstable allene oxides. In leaves, AOS mRNA accumulated upon treatment with jasmonates, octadecanoids and metabolizable carbohydrates, but not upon floating on abscisic acid, NaCl, Na‐salicylate or infection with powdery mildew. In developing seedlings, AOS mRNA strongly accumulated in the scutellar nodule, but less in the leaf base. Both tissues exhibited elevated JA levels. In situ hybridizations revealed the preferential occurrence of AOS mRNA in parenchymatic cells surrounding the vascular bundles of the scutellar nodule and in the young convoluted leaves as well as within the first internode. The properties of both barley AOSs, their up‐regulation of their mRNAs and their tissue specific expression suggest a role during seedling development and jasmonate biosynthesis.} } @Article{IPB-2286, author = {Ziegler, J. and Stenzel, I. and Hause, B. and Maucher, H. and Hamberg, M. and Grimm, R. and Ganal, M. and Wasternack, C. and}, title = {{Molecular Cloning of Allene Oxide Cyclase}}, year = {2000}, pages = {19132-19138}, journal = {J. Biol. Chem.}, doi = {10.1074/jbc.M002133200}, volume = {275}, abstract = {Allene oxide cyclase (EC 5.3.99.6) catalyzes the stereospecific cyclization of an unstable allene oxide to (9S,13S)-12-oxo-(10,15Z)-phytodienoic acid, the ultimate precursor of jasmonic acid. This dimeric enzyme has previously been purified, and two almost identical N-terminal peptides were found, suggesting allene oxide cyclase to be a homodimeric protein. Furthermore, the native protein was N-terminally processed. Using degenerate primers, a polymerase chain reaction fragment could be generated from tomato, which was further used to isolate a full-length cDNA clone of 1 kilobase pair coding for a protein of 245 amino acids with a molecular mass of 26 kDa. Whereas expression of the whole coding region failed to detect allene oxide cyclase activity, a 5′-truncated protein showed high activity, suggesting that additional amino acids impair the enzymatic function. Steric analysis of the 12-oxophytodienoic acid formed by the recombinant enzyme revealed exclusive (\>99%) formation of the 9S,13Senantiomer. Exclusive formation of this enantiomer was also found in wounded tomato leaves. Southern analysis and genetic mapping revealed the existence of a single gene for allene oxide cyclase located on chromosome 2 of tomato. Inspection of the N terminus revealed the presence of a chloroplastic transit peptide, and the location of allene oxide cyclase protein in that compartment could be shown by immunohistochemical methods. Concomitant with the jasmonate levels, the accumulation of allene oxide cyclase mRNA was transiently induced after wounding of tomato leaves.} } @Article{IPB-2282, author = {Wasternack, C. and Hause, B. and}, title = {{Stressabwehr und Entwicklung: Jasmonate — chemische Signale in Pflanzen}}, year = {2000}, pages = {312-320}, journal = {Biologie in unserer Zeit}, doi = {10.1002/1521-415X(200011)30:6<312::AID-BIUZ312>3.0.CO;2-8}, volume = {30}, abstract = {Chemische Signale wurden bereits im 19.Jahrhundert als Regulatoren von Wachstum und Entwicklung der Pflanzen postuliert.In den letzten 70 Jahren wurde die Wirkungsweise der klassischen Pflanzenhormone wie der Auxine, Gibberelline, Cytokinine, Ethylen und Abscisinsäure aufgeklärt. Doch erst im letzten Jahrzehnt entdeckte man die Bedeutung der Brassinosteroide, der Peptidhormone und der Jasmonate.} } @Article{IPB-2281, author = {Walter, M. H. and Fester, T. and Strack, D. and}, title = {{Arbuscular mycorrhizal fungi induce the non-mevalonate methylerythritol phosphate pathway of isoprenoid biosynthesis correlated with accumulation of the \'yellow pigment\' and other apocarotenoids}}, year = {2000}, pages = {571-578}, journal = {Plant J.}, doi = {10.1046/j.1365-313x.2000.00708.x}, volume = {21}, abstract = {Plants and certain bacteria use a non‐mevalonate alternative route for the biosynthesis of many isoprenoids, including carotenoids. This route has been discovered only recently and has been designated the deoxyxylulose phosphate pathway or methylerythritol phosphate (MEP) pathway. We report here that colonisation of roots from wheat, maize, rice and barley by the arbuscular mycorrhizal fungal symbiont Glomus intraradices involves strong induction of transcript levels of two of the pivotal enzymes of the MEP pathway, 1‐deoxy‐D‐xylulose 5‐phosphate synthase (DXS) and 1‐deoxy‐D‐xylulose 5‐phosphate reductoisomerase (DXR). This induction is temporarily and spatially correlated with specific and concomitant accumulation of two classes of apocarotenoids, namely glycosylated C13 cyclohexenone derivatives and mycorradicin (C14) conjugates, the latter being a major component of the long‐known ‘yellow pigment’. A total of six cyclohexenone derivatives were characterised from mycorrhizal wheat and maize roots. Furthermore, the acyclic structure of mycorradicin described previously only from maize has been identified from mycorrhizal wheat roots after alkaline treatment of an ‘apocarotenoid complex’ of yellow root constituents. We propose a hypothetical scheme for biogenesis of both types of apocarotenoids from a common oxocarotenoid (xanthophyll) precursor. This is the first report demonstrating (i) that the plastidic MEP pathway is active in plant roots and (ii) that it can be induced by a fungus.} } @Article{IPB-2273, author = {Roitsch, T. and Ehneß, R. and Goetz, M. and Hause, B. and Hofmann, M. and Sinha, A. K. and}, title = {{Regulation and function of extracellular invertase from higher plants in relation to assimilate partitioning, stress responses and sugar signalling}}, year = {2000}, pages = {815-825}, journal = {Funct. Plant Biol.}, doi = {10.1071/PP00001}, volume = {27}, abstract = {Carbohydrates are synthesised in photosynthetically active source tissues and exported, in most species in the form of sucrose, to photosynthetically less active or inactive sink tissues. Sucrose hydrolysis at the site of utilisation contributes to phloem unloading. This phenomenon links sink metabolism with phloem transport to, and partitioning between, sinks. Invertases catalyse the irreversible hydrolysis of sucrose and thus are expected to contribute to carbohydrate partitioning. Different invertase isoenzymes may be distinguished based on their intracellular location, their isoelectric points and pH optima. Extracellular, cell-wall-bound invertase is uniquely positioned to supply carbohydrates to sink tissues via an apoplasmic pathway, and links the transport sugar sucrose to hexose transporters. A number of studies demonstrate an essential function of this invertase isoenzyme for phloem unloading, carbohydrate partitioning and growth of sink tissues. Extracellular invertases were shown to be specifically expressed under conditions that require a high carbohydrate supply to sink tissues. Further, their expression is upregulated by a number of stimuli that affect source–sink relations. Substrate and reaction products of invertases are not only nutri-ents, but also signal molecules. Like hormones and in combination with hormones and other stimuli, they can regu-late many aspects of plant development from gene expression to long-distance nutrient allocation. Based on studies in Chenopodium rubrum, tomato (Lycopersicon esculentum) and tobacco (Nicotiana tabacum), the regulation of extracellular invertase and its function in assimilate partitioning, defence reactions and sugar signal transduction pathways are discussed.} } @Article{IPB-2270, author = {Peumans, W. J. and Hause, B. and Van Damme, E. J. M. and}, title = {{The galactose-binding and mannose-binding jacalin-related lectins are located in different sub-cellular compartments}}, year = {2000}, pages = {186-192}, journal = {FEBS Lett.}, doi = {10.1016/S0014-5793(00)01801-9}, volume = {477}, abstract = {A galactose-specific and a mannose-specific lectin of the family of the jacalin-related lectins have been localized by immunofluorescence microscopy. The present localization studies provide for the first time unambiguous evidence for the cytoplasmic location of the mannose-specific jacalin-related lectin from rhizomes of Calystegia sepium, which definitely differs from the vacuolar location of the galactose-specific jacalin from Artocarpus integrifolia. These observations support the hypothesis that the galactose-specific jacalin-related lectins evolved from their mannose-specific homologues through the acquisition of vacuolar targeting sequences.} } @Article{IPB-2316, author = {Ortel, B. and Atzorn, R. and Hause, B. and Feussner, I. and Miersch, O. and Wasternack, C. and}, title = {{Jasmonate-induced gene expression of barley (Hordeum vulgare) leaves - the link between jasmonate and abscisic acid}}, year = {1999}, pages = {113-122}, journal = {Plant Growth Regul.}, doi = {10.1023/A:1006212017458}, volume = {29}, abstract = {In barley leaves a group of genes is expressed in response to treatment with jasmonates and abscisic acid (ABA) [21]. One of these genes coding for a jasmonate-induced protein of 23 kDa (JIP-23) was analyzed to find out the link between ABA and jasmonates by recording its expression upon modulating independently, the endogenous level of both of them. By use of inhibitors of JA synthesis and ABA degradation, and the ABA-deficient mutant Az34, as well as of cultivar-specific differences, it was shown that endogenous jasmonate increases are necessary and sufficient for expression of this gene. The endogenous rise of ABA did not induce synthesis of JIP-23, whereas exogenous ABA did not act via jasmonates. Different signalling pathways are suggested and discussed.} } @Article{IPB-2302, author = {Hause, B. and Hertel, S. C. and Klaus, D. and Wasternack, C. and}, title = {{Cultivar-Specific Expression of the Jasmonate-Induced Protein of 23 kDa (JIP-23) Occurs in Hordeum vulgare L. by Jasmonates but not During Seed Germination}}, year = {1999}, pages = {83-89}, journal = {Plant Biol.}, doi = {10.1111/j.1438-8677.1999.tb00712.x}, volume = {1}, abstract = {Treatment of barley leaf segments with jasmonic acid methyl ester (JM) leads to the accumulation of a set of newly formed abundant proteins. Among them, the most abun dant protein exhibits a molecular mass of 23 kDa (JIP‐23). Here, data are presented on the occurrence and expression of the lIP‐23 genes in different cultivars of Hordeum vulgare . Southern blot analysis of 80 cultivars revealed the occurrence of 2 to 4 genes coding for JIP‐23 in all cultivars. By means of Northern blot and immunoblot analysis it is shown that some cultivars lack the ex pression of jip‐23 upon treatment of primary leaves with JM as well as upon stress performed by incubation with 1 M sorbitol solution. During germination, however, all tested cultivars ex hibited developmental expression of jip‐23 . The results are dis cussed in terms of possible functions of JIP‐23 in barley.} } @Article{IPB-2301, author = {Hause, B. and Vörös, K. and Kogel, K.-H. and Besser, K. and Wasternack, C. and}, title = {{A Jasmonate-responsive Lipoxygenase of Barley Leaves is Induced by Plant Activators but not by Pathogens}}, year = {1999}, pages = {459-462}, journal = {J. Plant Physiol.}, doi = {10.1016/S0176-1617(99)80283-1}, volume = {154}, abstract = {Using the recently isolated eDNA clone LOX2 : Hv : 1 which codes for the most abundant jasmonateinducible lipoxygenase (LOX) in barley leaves (Vörös et al., 1998), we analysed the capability of different activators of systemic activated resistance (SAR) to induce the expression of that LOX. Upon treatment of barley leaves with salicylate, 2,6-dichloroisonicotinic acid and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester, all these compounds were able to induce the expression of the LOX2 : Hv : 1 gene, whereas upon infection with the powdery mildew fungus (Blumeria graminis f. sp. hordei) mRNA accumulation was not detectable in compatible or in incompatible interactions. The induction of the LOX2 : Hv : 1 protein by SAR activators and the expression of different sets of genes induced by jasmonate and salicylate, respectively, are discussed in relation to defense responses against pathogenic fungi.} } @Article{IPB-2358, author = {Ratajczak, R. and Feussner, I. and Hause, B. and Böhm, A. and Parthier, B. and Wasternack, C. and}, title = {{Alteration of V-type H\+-ATPase during methyljasmonate-induced senescence in barley (Hordeum vulgare L. cv. Salome)}}, year = {1998}, pages = {199-206}, journal = {J. Plant Physiol.}, doi = {10.1016/S0176-1617(98)80133-8}, volume = {152}, abstract = {In barley leaves, the application of (−)-jasmonic acid or its methyl ester (JAME) induces a senescencelike phenotype. This is accompanied by the synthesis of abundant proteins, so-called jasmonate-induced proteins (JlPs). Here, we show that modifications of vacuolar H\+-ATPase (V-ATPase) subunits are jasmo-nate inducible. Using immunofluorescence analysis, we demonstrate that V-ATPase of barley leaves is exclusively located at the tonoplast also upon JAME treatment. Total ATP-hydrolysis activity of microsomal fractions increased by a factor of 10 during 72 h of JAME-treatment, while Bafilomycin Ai-sensitive ATP-hydrolysis activity, which is usually referred to V-ATPase activity, increased by a factor of about 2 in tono-plast-enriched membrane fractions. Moreover, due to JAME treatment there was a pronounced increase in ATP-hydrolysis activity at pH 6.2. This activity was not affected by inhibitors of P-, F-, or V-ATPases. However, biochemical analysis of partially purified V-ATPase suggests, that this activity might be due at least in part to the V-ATPase. JAME-treatment seems to change biochemical properties of the V-ATPase, i.e. a shift of the pH optimum of activity to a more acidic pH and a decrease in Bafilomycin A1 sensitivity. This is accompanied by the appearance of several additional forms of V-ATPase subunits which might represent either different isoforms or post-translationally modified proteins. We suggest that these changes in properties of the V-ATPase, which is involved in house-keeping and stress responses, may be due to JAME-induced senescence to overcome concomitant changes of the vacuolar membrane.} } @Article{IPB-2340, author = {Churin, J. and Hause, B. and Feussner, I. and Maucher, H. P. and Feussner, K. and Börner, T. and Wasternack, C. and}, title = {{Cloning and expression of a new cDNA from monocotyledonous plants coding for a diadenosine 5′,5′′′-P1,P4-tetraphosphate hydrolase from barley (Hordeum vulgare)}}, year = {1998}, pages = {481-485}, journal = {FEBS Lett.}, doi = {10.1016/S0014-5793(98)00819-9}, volume = {431}, abstract = {From a cDNA library generated from mRNA of white leaf tissues of the ribosome‐deficient mutant ‘albostrians\' of barley (Hordeum vulgare cv. Haisa) a cDNA was isolated carrying 54.2% identity to a recently published cDNA which codes for the diadenosine‐5′,5′′′‐P1,P4‐tetraphosphate (Ap4A) hydrolase of Lupinus angustifolius (Maksel et al. (1998) Biochem. J. 329, 313–319), and 69% identity to four partial peptide sequences of Ap4A hydrolase of tomato. Overexpression in Escherichia coli revealed a protein of about 19 kDa, which exhibited Ap4A hydrolase activity and cross‐reactivity with an antibody raised against a purified tomato Ap4A hydrolase (Feussner et al. (1996) Z. Naturforsch. 51c, 477–486). Expression studies showed an mRNA accumulation in all organs of a barley seedling. Possible functions of Ap4A hydrolase in plants will be discussed.} } @Article{IPB-2336, author = {Binarová, P. and Hause, B. and Doležel, J. and Dráber, P. and}, title = {{Association of γ-tubulin with kinetochore/centromeric region of plant chromosomes}}, year = {1998}, pages = {751-757}, journal = {Plant J.}, doi = {10.1046/j.1365-313x.1998.00166.x}, volume = {14}, abstract = {Monoclonal antibodies raised against a phylogenetically conserved peptide from the C‐terminal domain of γ‐tubulin molecule were used for immunofluorescence detection of γ‐tubulin in acentriolar mitotic spindles of plant cells. The antibodies stained kinetochore fibres along their whole length, including the close vicinity of kinetochores. After microtubule disassembly by the antimicrotubular drugs amiprophos‐methyl, oryzalin and colchicine, γ‐tubulin was found on remnants of kinetochore fibres attached to chromosomes. In cells recovering from the amiprophos‐methyl treatment, γ‐tubulin was localized with the re‐growing kinetochore microtubule fibres nucleated or captured by kinetochore/centromeric regions. On isolated chromosomes, γ‐tubulin co‐localized with α‐tubulin in the kinetochore/centromeric region. The data presented suggest that in acentriolar higher plant cells γ‐tubulin might be directly or indirectly involved in modulation and/or stabilization of kinetochore–microtubule interactions.} } @Article{IPB-2370, author = {Wasternack, C. and Miersch, O. and Kramell, R. and Hause, B. and Ward, J. and Beale, M. and Boland, W. and Parthier, B. and Feussner, I. and}, title = {{Jasmonic acid: biosynthesis, signal transduction, gene expression}}, year = {1998}, pages = {139-146}, journal = {Fett/Lipid}, doi = {10.1002/(SICI)1521-4133(19985)100:4/5<139::AID-LIPI139>3.0.CO;2-5}, volume = {100}, abstract = {Jasmonic acid (JA) is an ubiquitously occurring plant growth regulator which functions as a signal of developmentally or environmentally regulated expression of various genes thereby contributing to the defense status of plants [1–5]. The formation of jasmonates in a lipid‐based signalling pathway via octadecanoids seems to be a common principle for many plant species to express wound‐ and stressinduced genes [4, 5].There are various octadecanoid‐derived signals [3]. Among them, jasmonic acid and its amino acid conjugates are most active in barley, supporting arguments that β‐oxidation is an essential step in lipid‐based JA mediated responses. Furthermore, among derivatives of 12‐oxophytodienoic acid (PDA) carrying varying length of the carboxylic acid side‐chain, only those with a straight number of carbon atoms are able to induce JA responsive genes in barley leaves after treatment with these compounds. Barley leaves stressed by treatment with sorbitol solutions exhibit mainly an endogenous rise of JA and JA amino acid conjugates suggesting that both of them are stress signals. Data on organ‐ and tissue‐specific JA‐responsive gene expression will be presented and discussed in terms of “JA as a master switch” among various lipid‐derived signals.} } @Article{IPB-2369, author = {Wasternack, C. and Ortel, B. and Miersch, O. and Kramell, R. and Beale, M. and Greulich, F. and Feussner, I. and Hause, B. and Krumm, T. and Boland, W. and Parthier, B. and}, title = {{Diversity in octadecanoid-induced gene expression of tomato}}, year = {1998}, pages = {345-352}, journal = {J. Plant Physiol.}, doi = {10.1016/S0176-1617(98)80149-1}, volume = {152}, abstract = {In tomato plants wounding leads to up-regulation of various plant defense genes via jasmonates (Ryan, 1992; Bergey et al., 1996). Using this model system of jasmonic acid (JA) signalling, we analyzed activity of octadecanoids to express JA-responsive genes. Leaf treatments were performed with naturally occurring octadecanoids and their molecular mimics such as coronatine or indanone conjugates. JA responses were recorded in terms of up- or down-regulation of various genes by analyzing transcript accumulation, and at least partially in vitro translation products and polypeptide pattern of leaf extracts. The data suggest: (i) 12-Oxo-phytodienoic acid and other intermediates of the octadecanoid pathway has to be ß-oxidized to give a JA response, (ii) Octadecanoids which can not be ß-oxidized are inactive, (iii) JA, its methyl ester (JM), and its amino acid conjugates are most active signals in tomato leaves leading to up regulation of mainly wound-inducible genes and down-regulation of mainly \<house-keeping\> genes, (iv) Some compounds carrying a JA/JM- or JA amino acid conjugate-like structure induce/repress only a subset of genes suggesting diversity of JA signalling.} } @Article{IPB-2397, author = {Lee, J. E. and Vogt, T. and Hause, B. and Löbler, M. and}, title = {{Methyl Jasmonate Induces an O-Methyltransferase in Barley}}, year = {1997}, pages = {851-862}, journal = {Plant Cell Physiol.}, doi = {10.1093/oxfordjournals.pcp.a029244}, volume = {38}, abstract = {We have previously described a truncated cDNA clone for a barley (Hordeum vulgare L. cv. Salome) jasmonate regulated gene, JRG5, which shows homology to caffeic acid O-methyltransferase (COMT). A cDNA encompassing the coding region was amplified by PCR and cloned for overexpression in E. coli. Western blot analyses indicate that the recombinant protein crossreacts with the antibodies directed against the tobacco class II OMT and only weakly with the antibodies for the tobacco class I OMT. An immunoreactive band in the protein extract of jasmo-nate-treated leaf segments suggests that JRG5 transcripts that accumulate after jasmonate treatment are also translated. Specific methylating activities on caffeic acid and catechol were obtained from the recombinant protein through renaturation of protein extracted from inclusion bodies or from bacteria grown and induced at low temperature. On Northern blots, the JRG5 transcripts were detected in the leaf sheath but not the leaf lamina, stem, root or inflorescence and accumulated in leaf segments after jasmonate application. Several hormone or stress treatments did not induce JRG5 mRNA accumulation. This includes sor-bitol stress which is known to lead to enhanced endogenous jasmonate levels and the implications for jasmonate signaling are discussed. Based on quantitative measurements and fluorescence microscopy, jasmonate-induced accumulation of ferulic acid and phenolic polymers in the cell wall were detected and the possibility of cell wall strengthening mediated through phenolic crosslinks is discussed} } @Article{IPB-2395, author = {Kramell, R. and Miersch, O. and Hause, B. and Ortel, B. and Parthier, B. and Wasternack, C. and}, title = {{Amino acid conjugates of jasmonic acid induce jasmonate-responsive gene expression in barley (Hordeum vulgare L.) leaves}}, year = {1997}, pages = {197-202}, journal = {FEBS Lett.}, doi = {10.1016/S0014-5793(97)01005-3}, volume = {414}, abstract = {Leaves of barley (Hordeum vulgare L. cv. Salome ) treated with jasmonic acid (JA), its methyl ester (JM), or its amino acid conjugates exhibit up‐regulation of specific genes and down‐regulation of house‐keeping genes. This transcriptional regulation exhibits several specificities. (i) The (−)‐enantiomers are more active, and conjugates are mainly active if they carry an l ‐amino acid moiety. (ii) The various JA‐responsive genes respond differentially to enantiomeric and chiralic forms. (iii) Both JA and its amino acid conjugates exhibiting no or negligible interconversion induce/repress genes.} } @Article{IPB-2390, author = {Hause, B. and Feussner, K. and Wasternack, C. and}, title = {{Nuclear Location of a Diadenosine 5′,5′”-P1,P4Tetraphosphate (Ap4A) Hydrolase in Tomato Cells Grown in Suspension Cultures}}, year = {1997}, pages = {452-457}, journal = {Bot. Acta}, doi = {10.1111/j.1438-8677.1997.tb00662.x}, volume = {110}, abstract = {Diadenosine 5′,5′”‐P1,P4‐tetraphosphate (Ap4A) cleaving enzymes are assumed to regulate intracellular levels of Ap4A, a compound known to affect cell proliferation and stress responses. From plants an Ap4A hydrolase was recently purified using tomato cells grown in suspension. It was partially sequenced and a peptide antibody was prepared (Feussner et al., 1996). Using this polyclonal monospecific antibody, an abundant nuclear location of Ap4A hydrolase in 4‐day‐old cells of atomato cell suspension culture is demonstrated here by means of immunocytochemical techniques using FITC (fluorescein‐5‐isothiocyanate) labeled secondary antibodies. The microscopic analysis of the occurrence of Ap4A hydrolase performed for different stages of the cell cycle visualized by parallel DAPI (4,6‐diamidino‐2‐phenylindole) staining revealed that the protein accumulates within nuclei of cells in the interphase, but is absent in the nucleus as well as cytoplasm during all stages of mitosis. This first intracellular localization of an Ap4A degrading enzyme within the nucleus and its pattern of appearance during the cell cycle is discussed in relation to the suggested role of Ap4A in triggering DNA synthesis and cell proliferation.} } @Article{IPB-2389, author = {Hause, B. and Kogel, K.-H. and Parthier, B. and Wasternack, C. and}, title = {{In barley leaf cells, jasmonates do not act as a signal during compatible or incompatible interactions with the powdery mildew fungus (Erysiphe graminis f. sp. hordei)}}, year = {1997}, pages = {127-132}, journal = {J. Plant Physiol.}, doi = {10.1016/S0176-1617(97)80191-5}, volume = {150}, abstract = {We have studied a possible function of jasmonates as mediators in the host-pathogen interaction of barley (Hordeum vulgare L.) with the powdery mildew fungus Egh (Erysiphe graminis f. sp. hordei). Previous findings from whole-leaf extracts demonstrated that (i) extracts from infected barley leaves did not contain enhanced levels of jasmonates, (ii) transcripts of jasmonate-inducible genes were not expressed upon infection, and (iii) exogenous application of jasmonates did not induce resistance to Egh (Kogel et al., 1995). Nevertheless, the question arises whether or not jasmonates are involved in the interaction of barley with the powdery mildew fungus at the local site of infection. Using an immunocytological approach the analysis of leaf cross-sections from a susceptible barley cultivar and its near-isogenic mlo5-resistant line revealed no accumulation of JIP-23, the most abundant jasmonate inducible protein, neither in epidermal cells attacked by the pathogen nor in adjacent mesophyll cells. As a positive control, cross-sections from methyl jasmonate-treated leaf segments showed a strong signal for JIP-23 accumulation. Because the presence of the jasmonate-inducible protein is highly indicative for an already low threshold level of endogenous jasmonate (Lehmann et al., 1995), the lack of JIP-23 accumulation at the sites of attempted fungal infection clearly demonstrates the absence of enhanced levels of jasmonates. This excludes even a local rise of jasmonate confined to those single cells penetrated (Mlo genotype) or attacked (mlo5 genotype) by the fungus.} } @Article{IPB-2387, author = {Görschen, E. and Dunaeva, M. and Hause, B. and Reeh, I. and Wasternack, C. and Parthier, B. and}, title = {{Expression of the ribosome-inactivating protein JIP60 from barley in transgenic tobacco leads to an abnormal phenotype and alterations on the level of translation}}, year = {1997}, pages = {470-478}, journal = {Planta}, doi = {10.1007/s004250050151}, volume = {202}, abstract = {In this paper we report the in-planta activity of the ribosome-inactivating protein JIP60, a 60-kDa jasmonate-induced protein from barley (Hordeum vulgare L.), in transgenic tobacco (Nicotiana tabacum L.) plants. All plants expressing the complete JIP60 cDNA under the control of the cauliflower mosaic virus (CaMV) 35S promoter exhibited conspicuous and similar phenotypic alterations, such as slower growth, shorter internodes, lanceolate leaves, reduced root development, and premature senescence of leaves. Microscopic inspection of developing leaves showed a loss of residual meristems and higher degree of vacuolation of mesophyll cells as compared to the wild type. When probed with an antiserum which was immunoreactive against both the N- and the C-terminal half of JIP60, a polypeptide with a molecular mass of about 30 kDa, most probably a processed JIP60 product, could be detected. Phenotypic alterations could be correlated with the differences in the detectable amount of the JIP60 mRNA and processed JIP60 protein. The protein biosynthesis of the transformants was characterized by an increased polysome/monosome ratio but a decreased in-vivo translation activity. These findings suggest that JIP60 perturbs the translation machinery in planta. An immunohistological analysis using the JIP60 antiserum indicated that the immunoreactive polypeptide(s) are located mainly in the nucleus of transgenic tobacco leaf cells and to a minor extent in the cytoplasm.} } @Article{IPB-2380, author = {Feussner, I. and Fritz, I. G. and Hause, B. and Ullrich, W. R. and Wasternack, C. and}, title = {{Induction of a new Lipoxygenase Form in Cucumber Leaves by Salicylic Acid or 2,6-Dichloroisonicotinic Acid}}, year = {1997}, pages = {101-108}, journal = {Bot. Acta}, doi = {10.1111/j.1438-8677.1997.tb00616.x}, volume = {110}, abstract = {Changes in lipoxygenase (LOX) protein pattern and/or activity were investigated in relation to acquired resistance of cucumber (Cucumis sativus L.) leaves against two powdery mildews, Sphaerotheca fuliginea (Schlecht) Salmon and Erysiphe cichoracearum DC et Merat. Acquired resistance was established by spraying leaves with salicylic acid (SA) or 2,6‐dichloroisonicotinic acid (INA) and estimated in whole plants by infested leaf area compared to control plants. SA was more effective than INA. According to Western blots, untreated cucumber leaves contained a 97 kDa LOX form, which remained unchanged for up to 48 h after pathogen inoculation. Upon treatment with SA alone for 24 h or with INA plus pathogen, an additional 95 kDa LOX form appeared which had an isoelectric point in the alkaline range. For the induction of this form, a threshold concentration of 1 mM SA was required, higher SA concentrations did not change LOX‐95 expression which remained similar between 24 h and 96 h but further increased upon mildew inoculation. Phloem exudates contained only the LOX‐97 form, in intercellular washing fluid no LOX was detected. dichloroisonicotinic localization revealed LOX protein in the cytosol of the mesophyll cells without differences between the forms.} } @Article{IPB-2432, author = {Leopold, J. and Hause, B. and Lehmann, J. and Graner, A. and Parthier, B. and Wasternack, C. and}, title = {{Isolation, characterization and expression of a cDNA coding for a jasmonate-inducible protein of 37 kDa in barley leaves}}, year = {1996}, pages = {675-684}, journal = {Plant Cell Environ.}, doi = {10.1111/j.1365-3040.1996.tb00402.x}, volume = {19}, abstract = {In barley leaves, there is a dramatic alteration of gene expression upon treatment with jasmonates leading to the accumulation of newly formed proteins, designated as jasmonate‐inducible proteins (JIPs). In the present study, a new jasmonate‐inducible cDNA, designated pHvJS37, has been isolated by differential screening of a γgt10 cDNA library constructed from mRNA of jasmonate‐treated barley leaf segments. The open reading frame (ORF) encodes a 39‐9 kDa polypeptide which cross‐reacts with antibodies raised against the in vivo JIP‐37. The hydropathic plot suggests that the protein is mainly hydrophilic, containing two hydrophilic domains near the C‐terminus. Database searches did not show any sequence homology of pHv.JS37 to known sequences. Southern analysis revealed at least two genes coding for JIP‐37 which map to the distal portion of the long arm of chromosome 3 and are closely related to genes coding for JIP‐23. The expression pattern of the JIP‐37 genes over time shows differential responses to jasmonate, abscisic acid (ABA), osmotic stress (such as sorbitol treatment) and desiccation stress. No expression was found under salt stress. From experiments using an inhibitor and intermediates of jasmonate synthesis such as α‐linolenic acid and 12‐oxophytodienoic acid, we hypothesize that there is a stress‐induced lipid‐based signalling pathway in which an endogenous rise of jasmonate switches on JIP‐37 gene expression. Using immunocytochemical techniques, JIP‐37 was found to be simultaneously located in the nucleus, the cytoplasm and the vacuoles.} } @Article{IPB-2426, author = {Hause, B. and Demus, U. and Teichmann, C. and Parthier, B. and Wasternack, C. and}, title = {{Developmental and Tissue-Specific Expression of JIP-23, a Jasmonate-Inducible Protein of Barley}}, year = {1996}, pages = {641-649}, journal = {Plant Cell Physiol.}, doi = {10.1093/oxfordjournals.pcp.a028993}, volume = {37}, abstract = {Developmental expression of a 23 kDa jasmonate-induced protein (JIP-23) of barley leaves (Hordeum vulgare cv. Salome) was studied by measuring the time-dependent accumulation of transcript and protein during germination. Tissue-specific expression of JIP-23 was analyzed immunocytochemically and by in situ hybridizations, respectively. During seed germination JIP-23 mRNA was found to accumulate transiently with a maximum at 32 h, whereas the protein was steadily detectable after the onset of expression. The occurrence of new isoforms of JIP-23 during germination in comparison to jasmonate-treated leaves suggests, that the JIP-23 gene family of barley is able to express different subsets of isoforms dependent on the developmental stage.JIP-23 and its transcript were found mainly in the scutellum, the scutellar nodule and in lower parts of the primary leaf of 6 days old seedlings. All these tissues exhibited high levels of endogenous jasmonates. In situ hybridization revealed specific accumulation of JIP-23 mRNA in companion cells of the phloem in the nodule plate of the scutellum. In accordance with that, JIP-23 was detected immunocytochemically in phloem cells of the root as well as of the scutellar nodule and in parenchymatic cells of the scutellum. The cell type-specific occurrence of JIP-23 was restricted to cells, which are known to be highly stressed osmotically by active solute transport. This observation suggests, that the expression of this protein might be a response to osmotic stress during development.} } @Article{IPB-2425, author = {Feussner, I. and Hause, B. and Nellen, A. and Wasternack, C. and Kindl, H. and}, title = {{Lipid-body lipoxygenase is expressed in cotyledons during germination prior to other lipoxygenase forms}}, year = {1996}, pages = {288-293}, journal = {Planta}, doi = {10.1007/BF00206255}, volume = {198}, abstract = {Lipid bodies are degraded during germination. Whereas some proteins, e.g. oleosins, are synthesized during the formation of lipid bodies of maturating seeds, a new set of proteins, including a specific form of lipoxygenase (LOX; EC 1.13.11.12), is detectable in lipid bodies during the stage of fat degradation in seed germination. In cotyledons of cucumber (Cucumis sativus L.) seedlings at day 4 of germination, the most conspicuous staining with anti-LOX antibodies was observed in the cytosol. At very early stages of germination, however, the LOX form present in large amounts and synthesized preferentially was the lipid-body LOX. This was demonstrated by immunocytochemical staining of cotyledons from 1-h and 24-h-old seedlings: the immunodecoration of sections of 24-h-old seedlings with anti-LOX antiserum showed label exclusively correlated with lipid bodies of around 3 μm in diameter. In accordance, the profile of LOX protein isolated from lipid bodies during various stages of germination showed a maximum at day 1. By measuring biosynthesis of the protein in vivo we demonstrated that the highest rates of synthesis of lipid-body LOX occurred at day 1 of germination. The early and selective appearance of a LOX form associated with lipid bodies at this stage of development is discussed.} } @Article{IPB-2448, author = {Feussner, I. and Hause, B. and Vörös, K. and Parthier, B. and Wasternack, C. and}, title = {{Jasmonate-induced lipoxygenase forms are localized in chloroplasts of barley leaves (Hordeum vulgare cv. Salome)}}, year = {1995}, pages = {949-957}, journal = {Plant J.}, doi = {10.1046/j.1365-313X.1995.07060949.x}, volume = {7}, abstract = {Barley leaves respond to application of (−)‐jasmonic acid (JA), or its methylester (JM) with the synthesis of abundant proteins, so‐called jasmonate induced proteins (JIPs). Here Western blot analysis is used to show a remarkable increase upon JM treatment of a 100 kDa lipoxygenase (LOX), and the appearance of two new LOX forms of 98 and 92 kDa. The temporal increase of LOX‐100 protein upon JM treatment was clearly distinguishable from the additionally detectable LOX forms. JM‐induced LOX forms in barley leaves were compared with those of Arabidopsis and soybean leaves. Both dicot species showed a similar increase of one LOX upon JM induction, whereas, leaves from soybean responded with additional synthesis of a newly formed LOX of 94 kDa.Using immunofluorescence analysis and isolation of intact chloroplasts, it is demonstrated that JM‐induced LOX forms of barley leaves are exclusively located in the chloroplasts of all chloroplast‐containing cells. Analogous experiments carried out with Arabidopsis and soybean revealed a similar plastidic location of JM‐induced LOX forms in Arabidopsis but a different situation for soybean. In untreated soybean leaves the LOX protein was mainly restricted to vacuoles of paraveinal mesophyll cells. Additionally, LOX forms could be detected in cytoplasm and nuclei of bundle sheath cells. Upon JM treatment cytosolic LOX was detectable in spongy mesophyll cells, too. The intracellular location of JM‐induced LOX is discussed in terms of stress‐related phenomena mediated by JM.} } @Article{IPB-2467, author = {Hause, B. and zur Nieden, U. and Lehmann, J. and Wasternack, C. and Parthier, B. and}, title = {{Intracellular Localization of Jasmonate-Induced Proteins in Barley Leaves}}, year = {1994}, pages = {333-341}, journal = {Bot. Acta}, doi = {10.1111/j.1438-8677.1994.tb00804.x}, volume = {107}, abstract = {The plant growth substance jasmonic acid and its methyl ester (JA‐Me) induce a set of proteins (jasmonate‐induced proteins, JIPs) when applied to leaf segments of barley (Hordeum vulgare L. cv. Salome). Most of these JIPs could be localized within different cell compartments by using a combination of biochemical and histochemical methods. Isolation and purification of various cell organelles of barley mesophyll cells, the separation of their proteins by one‐dimensional polyacrylamide gel electrophoresis and the identification of the major abundant JIPs by Western blot analysis, as well as the immuno‐gold labelling of JIPs in ultrathin sections were performed to localize JIPs intracellularly. JIP‐23 was found to be in vacuoles, peroxisomes, and in the granular parts of the nucleus as well as within the cytoplasm; JIP‐37 was detected in vacuoles and in the nucleoplasm; JIP‐66 is a cytosolic protein. Some less abundant JIPs were also localized within different cell compartments: JIP‐100 was found within the stromal fraction of chloroplasts; JIP‐70 is present in the peroxisome and the nucleus; JIP‐50 and JIP‐6 accumulate in vacuoles. The location of JIP‐66 and JIP‐6 confirms their possible physiological role deduced from molecular analysis of their cDNA.} }