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Publikationen - Molekulare Signalverarbeitung

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Publikation

Drost, H.-G.; Bellstädt, J.; Ó'Maoiléidigh, D. S.; Silva, A. T.; Gabel, A.; Weinholdt, C.; Ryan, P. T.; Dekkers, B. J. W.; Bentsink, L.; Hilhorst, H. W. M.; Ligterink, W.; Wellmer, F.; Grosse, I.; Quint, M.; Post-embryonic Hourglass Patterns Mark Ontogenetic Transitions in Plant Development Mol. Biol. Evol. 33, 1158-1163, (2016) DOI: 10.1093/molbev/msw039

The historic developmental hourglass concept depicts the convergence of animal embryos to a common form during the phylotypic period. Recently, it has been shown that a transcriptomic hourglass is associated with this morphological pattern, consistent with the idea of underlying selective constraints due to intense molecular interactions during body plan establishment. Although plants do not exhibit a morphological hourglass during embryogenesis, a transcriptomic hourglass has nevertheless been identified in the model plant Arabidopsis thaliana. Here, we investigated whether plant hourglass patterns are also found postembryonically. We found that the two main phase changes during the life cycle of Arabidopsis, from embryonic to vegetative and from vegetative to reproductive development, are associated with transcriptomic hourglass patterns. In contrast, flower development, a process dominated by organ formation, is not. This suggests that plant hourglass patterns are decoupled from organogenesis and body plan establishment. Instead, they may reflect general transitions through organizational checkpoints.
Publikation

Drost, H.-G.; Gabel, A.; Grosse, I.; Quint, M.; Evidence for Active Maintenance of Phylotranscriptomic Hourglass Patterns in Animal and Plant Embryogenesis Mol. Biol. Evol. 32, 1221-1231, (2015) DOI: 10.1093/molbev/msv012

The developmental hourglass model has been used to describe the morphological transitions of related species throughout embryogenesis. Recently, quantifiable approaches combining transcriptomic and evolutionary information provided novel evidence for the presence of a phylotranscriptomic hourglass pattern across kingdoms. As its biological function is unknown it remains speculative whether this pattern is functional or merely represents a nonfunctional evolutionary relic. The latter would seriously hamper future experimental approaches designed to test hypotheses regarding its function. Here, we address this question by generating transcriptome divergence index (TDI) profiles across embryogenesis of Danio rerio, Drosophila melanogaster, and Arabidopsis thaliana. To enable meaningful evaluation of the resulting patterns, we develop a statistical test that specifically assesses potential hourglass patterns. Based on this objective measure we find that two of these profiles follow a statistically significant hourglass pattern with the most conserved transcriptomes in the phylotypic periods. As the TDI considers only recent evolutionary signals, this indicates that the phylotranscriptomic hourglass pattern is not a rudiment but possibly actively maintained, implicating the existence of some linked biological function associated with embryogenesis in extant species.
Publikation

Wasternack, C.; Stenzel, I.; Hause, B.; Hause, G.; Kutter, C.; Maucher, H.; Neumerkel, J.; Feussner, I.; Miersch, O.; The wound response in tomato – Role of jasmonic acid J. Plant Physiol. 163, 297-306, (2006) DOI: 10.1016/j.jplph.2005.10.014

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.
Publikation

Hause, B.; Vörös, K.; Kogel, K.-H.; Besser, K.; Wasternack, C.; A Jasmonate-responsive Lipoxygenase of Barley Leaves is Induced by Plant Activators but not by Pathogens J. Plant Physiol. 154, 459-462, (1999) DOI: 10.1016/S0176-1617(99)80283-1

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.
Publikation

Wasternack, C.; Ortel, B.; Miersch, O.; Kramell, R.; Beale, M.; Greulich, F.; Feussner, I.; Hause, B.; Krumm, T.; Boland, W.; Parthier, B.; Diversity in octadecanoid-induced gene expression of tomato J. Plant Physiol. 152, 345-352, (1998) DOI: 10.1016/S0176-1617(98)80149-1

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.
Publikation

Ratajczak, R.; Feussner, I.; Hause, B.; Böhm, A.; Parthier, B.; Wasternack, C.; Alteration of V-type H+-ATPase during methyljasmonate-induced senescence in barley (Hordeum vulgare L. cv. Salome) J. Plant Physiol. 152, 199-206, (1998) DOI: 10.1016/S0176-1617(98)80133-8

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.
Publikation

Hause, B.; Feussner, K.; Wasternack, C.; Nuclear Location of a Diadenosine 5′,5′”-P1,P4Tetraphosphate (Ap4A) Hydrolase in Tomato Cells Grown in Suspension Cultures Bot. Acta 110, 452-457, (1997) DOI: 10.1111/j.1438-8677.1997.tb00662.x

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.
Publikation

Hause, B.; Kogel, K.-H.; Parthier, B.; Wasternack, C.; 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) J. Plant Physiol. 150, 127-132, (1997) DOI: 10.1016/S0176-1617(97)80191-5

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.
Publikation

Feussner, I.; Fritz, I. G.; Hause, B.; Ullrich, W. R.; Wasternack, C.; Induction of a new Lipoxygenase Form in Cucumber Leaves by Salicylic Acid or 2,6-Dichloroisonicotinic Acid Bot. Acta 110, 101-108, (1997) DOI: 10.1111/j.1438-8677.1997.tb00616.x

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.
Publikation

Wasternack, C.; Atzorn, R.; Peña-Cortés, H.; Parthier, B.; Alteration of Gene Expression by Jasmonate and ABA in Tobacco and Tomato J. Plant Physiol. 147, 503-510, (1996) DOI: 10.1016/S0176-1617(96)80038-1

The synthesis of jasmonate-induced proteins in leaves of tobacco (Nicotiana plumbaginifolia) and tomato (Lycopersicon esculentum) was studied in order to find a possible functional link in the actions of abscisic acid (ABA) and jasmonates. ABA-deficient mutants of tobacco (CKR1) and of tomato (sitiens, flacca), and their corresponding wild-types, were compared with respect to endogenous contents of jasmonates and ABA, and polypeptide and transcript patterns in water- or jasmonate-floated leaves, leaves stressed by floating on sorbitol, or by weak desiccation. Our results indicate that in tobacco the synthesis of proteins induced by jasmonate differed from those induced by ABA, whereas in tomato some jasmonate-induced proteins were also induced by ABA. The results provide further evidence that different signalling pathways exist for jasmonate/ABA-responsive gene expression in various plant species.
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