TY - JOUR ID - 213 TI - BFP1: One of 700 Arabidopsis F-box proteins mediates degradation of JA oxidases to promote plant immunity JO - Mol. Plant PY - 2024 SP - 375-376 AU - Wasternack, C. AU - Hause, B. AU - VL - 17 UR - https://doi.org/10.1016/j.molp.2024.02.008 DO - 10.1016/j.molp.2024.02.008 AB - A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 2510 TI - Synthetic and analytical routes to the L-amino acid conjugates of cis-OPDA and their identification and quantification in plants JO - ChemRxiv PY - 2023 SP - AU - Mik, V. AU - Poslíšil, T. AU - Brunoni, F. AU - Grúz, J. AU - Nožková, V. AU - Wasternack, C. AU - Miersch, O. AU - Strnad, M. AU - Floková, K. AU - Novák, O. AU - Široká, J. AU - VL - UR - https://doi.org/10.26434/chemrxiv-2023-qlzj4 DO - 10.26434/chemrxiv-2023-qlzj4 AB - Cis-(+)-12-oxophytodienoic acid (cis-(+)-OPDA) is a bioactive jasmonate, a precursor of jasmonic acid, which also displays signaling activity on its own. Modulation of cis-(+)-OPDA actions may be carried out via biotransformation leading to metabolites of various functions, similar to other phytohormones. This work introduces a methodology for the synthesis of racemic cis-OPDA conjugates with amino acids (OPDA-aa) and their deuterium-labeled analogs, which enables the identification and accurate quantification of these compounds in plants. We have developed a highly sensitive liquid chromatography-tandem mass spectrometry-based method for the reliable determination of seven OPDA-aa (OPDA-Alanine, OPDA-Aspartate, OPDA-Glutamate, OPDA-Glycine, OPDA-Isoleucine, OPDA-Phenylalanine, and OPDA-Valine) from minute amount of plant material. The extraction from 10 mg of fresh plant tissue by 10% aqueous methanol followed by single-step sample clean-up on hydrophilic–lipophilic balanced columns prior to final analysis was optimized. The method was validated in terms of accuracy and precision, and the method parameters such as process efficiency, recovery and matrix effects were evaluated. In mechanically wounded 30-day-old Arabidopsis thaliana leaves, five endogenous (+)-OPDA-aa were identified and their endogenous levels reached a maximum of pmol/g. The time-course accumulation revealed a peak 60 min after the wounding, roughly corresponding to the accumulation of cis-(+)-OPDA. Current synthetic and analytical methodologies support studies on cis-(+)-OPDA conjugation with amino acids and research into the biological significance of these metabolites in plants. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2509 TI - Conjugation ofcis-OPDA with amino acids is a conserved pathway affectingcis-OPDA homeostasis upon stress responses JO - PY - 2023 SP - AU - Brunoni, F. AU - Široká, J. AU - Mik, V. AU - Pospíšil, T. AU - Kralová, M. AU - Ament, A. AU - Pernisová, M. AU - Karady, M. AU - Htitich, M. AU - Ueda, M. AU - Floková, K. AU - Wasternack, C. AU - Strnad, M. AU - Novák, O. AU - VL - UR - https://doi.org/10.1101/2023.07.18.549545 DO - 10.1101/2023.07.18.549545 AB - Jasmonates (JAs) are a family of oxylipin phytohormones regulating plant development and growth and mediating ‘defense versus growth’ responses. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-OPDA) has been reported to act independently of the COI1-mediated JA signaling in several stress-induced and developmental processes. However, its means of perception and metabolism are only partially understood. Furthermore, cis-OPDA, but not JA, occurs in non-vascular plant species, such as bryophytes, exhibiting specific functions in defense and development. A few years ago, a low abundant isoleucine analog of the biologically active JA-Ile, OPDA-Ile, was detected in wounded leaves of flowering plants, opening up to the possibility that conjugation of cis-OPDA to amino acids might be a relevant mechanism for cis-OPDA regulation. Here, we extended the analysis of amino acid conjugates of cis-OPDA and identified naturally occurring OPDA-Val, OPDA-Phe, OPDA-Ala, OPDA-Glu, and OPDA-Asp in response to biotic and abiotic stress in Arabidopsis. The newly identified OPDA-amino acid conjugates show cis-OPDA-related plant responses in a JAR1-dependent manner. We also discovered that the synthesis and hydrolysis of cis-OPDA amino acid conjugates are regulated by members of the amidosynthetase GH3 and the amidohydrolase ILR1/ILL families. Finally, we found that the cis-OPDA conjugative pathway already functions in non-vascular plants and gymnosperms. Thus, one level of regulation by which plants modulate cis-OPDA homeostasis is the synthesis and hydrolysis of OPDA-amino acid conjugates, which temporarily store cis-OPDA in stress responses. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 264 TI - Synthetic and analytical routes to the L-amino acid conjugates of cis-OPDA and their identification and quantification in plants JO - Phytochemistry PY - 2023 SP - 113855 AU - Mik, V. AU - Pospíšil, T. AU - Brunoni, F. AU - Grúz, J. AU - Nožková, V. AU - Wasternack, C. AU - Miersch, O. AU - Strnad, M. AU - Floková, K. AU - Novák, O. AU - Široká, J. AU - VL - 215 UR - https://doi.org/10.1016/j.phytochem.2023.113855 DO - 10.1016/j.phytochem.2023.113855 AB - Cis-(+)-12-oxophytodienoic acid (cis-(+)-OPDA) is a bioactive jasmonate, a precursor of jasmonic acid, which also displays signaling activity on its own. Modulation of cis-(+)-OPDA actions may be carried out via biotransformation leading to metabolites of various functions. This work introduces a methodology for the synthesis of racemic cis-OPDA conjugates with amino acids (OPDA-aa) and their deuterium-labeled analogs, which enables the unambiguous identification and accurate quantification of these compounds in plants. We have developed a highly sensitive liquid chromatography-tandem mass spectrometry-based method for the reliable determination of seven OPDA-aa (OPDA-Alanine, OPDA-Aspartate, OPDA-Glutamate, OPDA-Glycine, OPDA-Isoleucine, OPDA-Phenylalanine, and OPDA-Valine) from minute amount of plant material. The extraction from 10 mg of fresh plant tissue by 10% aqueous methanol followed by single-step sample clean-up on hydrophilic–lipophilic balanced columns prior to final analysis was optimized. The method was validated in terms of accuracy and precision, and the method parameters such as process efficiency, recovery and matrix effects were evaluated. In mechanically wounded 30-day-old Arabidopsis thaliana leaves, five endogenous (+)-OPDA-aa were identified and their endogenous levels were estimated. The time-course accumulation revealed a peak 60 min after the wounding, roughly corresponding to the accumulation of cis-(+)-OPDA. Our synthetic and analytical methodologies will support studies on cis-(+)-OPDA conjugation with amino acids and research into the biological significance of these metabolites in plants. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 405 TI - Deciphering the oxylipin signatures of necrotrophic infection in plants. A commentary on: Differential modulation of the lipoxygenase cascade during typical and latent Pectobacterium atrosepticum infections JO - Ann. Bot. PY - 2022 SP - i-iii AU - Wasternack, C. AU - VL - 129 UR - https://doi.org/10.1093/aob/mcab142 DO - 10.1093/aob/mcab142 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 619 TI - Sulfation switch in the shade JO - Nat. Plants PY - 2020 SP - 186-187 AU - Wasternack, C. AU - VL - 6 UR - DO - 10.1038/s41477-020-0620-8 AB - Plants adjust the balance between growth and defence using photoreceptors and jasmonates. Levels of active jasmonates are reduced in a phytochrome B-dependent manner by upregulation of a 12-hydroxyjasmonate sulfotransferase, leading to increase in shade avoidance and decrease in defence. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 618 TI - Determination of sex by jasmonate JO - J. Integr. Plant Biol. PY - 2020 SP - 162-164 AU - Wasternack, C. AU - VL - 62 UR - DO - 10.1111/jipb.12840 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 750 TI - The missing link in jasmonic acid biosynthesis JO - Nat. Plants PY - 2019 SP - 776-777 AU - Wasternack, C. AU - Hause, B. AU - VL - 5 UR - DO - 10.1038/s41477-019-0492-y AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 749 TI - Termination in Jasmonate Signaling by MYC2 and MTBs JO - Trends Plant Sci. PY - 2019 SP - 667-669 AU - Wasternack, C. AU - VL - 24 UR - DO - 10.1016/j.tplants.2019.06.001 AB - Jasmonic acid (JA) signaling can be switched off by metabolism of JA. The master regulator MYC2, interacting with MED25, has been shown to be deactivated by the bHLH transcription factors MTB1, MTB2, and MTB3. An autoregulatory negative feedback loop has been proposed for this termination in JA signaling. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 748 TI - New Light on Local and Systemic Wound Signaling JO - Trends Plant Sci. PY - 2019 SP - 102-105 AU - Wasternack, C. AU - VL - 24 UR - DO - 10.1016/j.tplants.2018.11.009 AB - Electric signaling and Ca2+ waves were discussed to occur in systemic wound responses. Two new overlapping scenarios were identified: (i) membrane depolarization in two special cell types followed by an increase in systemic cytoplasmic Ca2+ concentration ([Ca2+]cyt), and (ii) glutamate sensed by GLUTAMATE RECEPTOR LIKE proteins and followed by Ca2+-based defense in distal leaves. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 747 TI - Jasmonates are signals in the biosynthesis of secondary metabolites — Pathways, transcription factors and applied aspects — A brief review JO - New Biotechnol. PY - 2019 SP - 1-11 AU - Wasternack, C. AU - Strnad, M. AU - VL - 48 UR - DO - 10.1016/j.nbt.2017.09.007 AB - Jasmonates (JAs) are signals in plant stress responses and development. One of the first observed and prominent responses to JAs is the induction of biosynthesis of different groups of secondary compounds. Among them are nicotine, isoquinolines, glucosinolates, anthocyanins, benzophenanthridine alkaloids, artemisinin, and terpenoid indole alkaloids (TIAs), such as vinblastine. This brief review describes modes of action of JAs in the biosynthesis of anthocyanins, nicotine, TIAs, glucosinolates and artemisinin. After introducing JA biosynthesis, the central role of the SCFCOI1-JAZ co-receptor complex in JA perception and MYB-type and MYC-type transcription factors is described. Brief comments are provided on primary metabolites as precursors of secondary compounds. Pathways for the biosynthesis of anthocyanin, nicotine, TIAs, glucosinolates and artemisinin are described with an emphasis on JA-dependent transcription factors, which activate or repress the expression of essential genes encoding enzymes in the biosynthesis of these secondary compounds. Applied aspects are discussed using the biotechnological formation of artemisinin as an example of JA-induced biosynthesis of secondary compounds in plant cell factories. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 746 TI - Benno Parthier (1932–2019) JO - Plant Mol. Biol. PY - 2019 SP - 519-520 AU - Wasternack, C. AU - Hause, B. AU - Abel, S. AU - VL - 101 UR - DO - 10.1007/s11103-019-00927-6 AB - A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 852 TI - The Oxylipin Pathways: Biochemistry and Function JO - Annu. Rev. Plant Biol. PY - 2018 SP - 363-386 AU - Wasternack, C. AU - Feussner, I. AU - VL - 69 UR - DO - 10.1146/annurev-arplant-042817-040440 AB - Plant oxylipins form a constantly growing group of signaling molecules that comprise oxygenated fatty acids and metabolites derived therefrom. In the last decade, the understanding of biosynthesis, metabolism, and action of oxylipins, especially jasmonates, has dramatically improved. Additional mechanistic insights into the action of enzymes and insights into signaling pathways have been deepened for jasmonates. For other oxylipins, such as the hydroxy fatty acids, individual signaling properties and cross talk between different oxylipins or even with additional phytohormones have recently been described. This review summarizes recent understanding of the biosynthesis, regulation, and function of oxylipins. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 851 TI - Jasmonates: News on Occurrence, Biosynthesis, Metabolism and Action of an Ancient Group of Signaling Compounds JO - Int. J. Mol. Sci. PY - 2018 SP - 2539 AU - Wasternack, C. AU - Strnad, M. AU - VL - 19 UR - DO - 10.3390/ijms19092539 AB - Jasmonic acid (JA) and its related derivatives are ubiquitously occurring compounds of land plants acting in numerous stress responses and development. Recent studies on evolution of JA and other oxylipins indicated conserved biosynthesis. JA formation is initiated by oxygenation of α-linolenic acid (α-LeA, 18:3) or 16:3 fatty acid of chloroplast membranes leading to 12-oxo-phytodienoic acid (OPDA) as intermediate compound, but in Marchantiapolymorpha and Physcomitrellapatens, OPDA and some of its derivatives are final products active in a conserved signaling pathway. JA formation and its metabolic conversion take place in chloroplasts, peroxisomes and cytosol, respectively. Metabolites of JA are formed in 12 different pathways leading to active, inactive and partially active compounds. The isoleucine conjugate of JA (JA-Ile) is the ligand of the receptor component COI1 in vascular plants, whereas in the bryophyte M. polymorpha COI1 perceives an OPDA derivative indicating its functionally conserved activity. JA-induced gene expressions in the numerous biotic and abiotic stress responses and development are initiated in a well-studied complex regulation by homeostasis of transcription factors functioning as repressors and activators. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 850 TI - A Bypass in Jasmonate Biosynthesis – the OPR3-independent Formation JO - Trends Plant Sci. PY - 2018 SP - 276-279 AU - Wasternack, C. AU - Hause, B. AU - VL - 23 UR - DO - 10.1016/j.tplants.2018.02.011 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 952 TI - The Trojan horse coronatine: the COI1-JAZ2-MYC2,3,4-ANAC019,055,072 module in stomata dynamics upon bacterial infection JO - New Phytol. PY - 2017 SP - 972-975 AU - Wasternack, C. AU - VL - 213 UR - DO - 10.1111/nph.14417 AB - This article is a Commentary on Gimenez‐Ibanez et al., 213: 1378–1392. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 951 TI - Jasmonates: biosynthesis, metabolism, and signaling by proteins activating and repressing transciption JO - J. Exp. Bot. PY - 2017 SP - 1303-1321 AU - Wasternack, C. AU - Song, S. AU - VL - 68 UR - DO - 10.1093/jxb/erw443 AB - The lipid-derived phytohormone jasmonate (JA) regulates plant growth, development, secondary metabolism, defense against insect attack and pathogen infection, and tolerance to abiotic stresses such as wounding, UV light, salt, and drought. JA was first identified in 1962, and since the 1980s many studies have analyzed the physiological functions, biosynthesis, distribution, metabolism, perception, signaling, and crosstalk of JA, greatly expanding our knowledge of the hormone’s action. In response to fluctuating environmental cues and transient endogenous signals, the occurrence of multilayered organization of biosynthesis and inactivation of JA, and activation and repression of the COI1–JAZ-based perception and signaling contributes to the fine-tuning of JA responses. This review describes the JA biosynthetic enzymes in terms of gene families, enzymatic activity, location and regulation, substrate specificity and products, the metabolic pathways in converting JA to activate or inactivate compounds, JA signaling in perception, and the co-existence of signaling activators and repressors. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 950 TI - A plant's balance of growth and defense - revisited JO - New Phytol. PY - 2017 SP - 1291-1294 AU - Wasternack, C. AU - VL - 215 UR - DO - 10.1111/nph.14720 AB - This article is a Commentary on Major et al., 215: 1533–1547. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1063 TI - OPDA-Ile – a new JA-Ile-independent signal? JO - Plant Signal Behav. PY - 2016 SP - e1253646 AU - Wasternack, C. AU - Hause, B. AU - VL - 11 UR - DO - 10.1080/15592324.2016.1253646 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1062 TI - Jasmonate signaling in plant stress responses and development – active and inactive compounds JO - New Biotechnol. PY - 2016 SP - 604-613 AU - Wasternack, C. AU - Strnad, M. AU - VL - 33 UR - DO - 10.1016/j.nbt.2015.11.001 AB - Jasmonates (JAs) are lipid-derived signals mediating plant responses to biotic and abiotic stresses and in plant development. Following the elucidation of each step in their biosynthesis and the important components of perception and signaling, several activators, repressors and co-repressors have been identified which contribute to fine-tuning the regulation of JA-induced gene expression. Many of the metabolic reactions in which JA participates, such as conjugation with amino acids, glucosylation, hydroxylation, carboxylation, sulfation and methylation, lead to numerous compounds with different biological activities. These metabolites may be highly active, partially active in specific processes or inactive. Hydroxylation, carboxylation and sulfation inactivate JA signaling. The precursor of JA biosynthesis, 12-oxo-phytodienoic acid (OPDA), has been identified as a JA-independent signaling compound. An increasing number of OPDA-specific processes is being identified. To conclude, the numerous JA compounds and their different modes of action allow plants to respond specifically and flexibly to alterations in the environment. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 991 TI - A previously undescribed jasmonate compound in flowering Arabidopsis thaliana – The identification of cis-(+)-OPDA-Ile JO - Phytochemistry PY - 2016 SP - 230-237 AU - Floková, K. AU - Feussner, K. AU - Herrfurth, C. AU - Miersch, O. AU - Mik, V. AU - Tarkowská, D. AU - Strnad, M. AU - Feussner, I. AU - Wasternack, C. AU - Novák, O. AU - VL - 122 UR - DO - 10.1016/j.phytochem.2015.11.012 AB - Jasmonates (JAs) are plant hormones that integrate external stress stimuli with physiological responses. (+)-7-iso-JA-L-Ile is the natural JA ligand of COI1, a component of a known JA receptor. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-(+)-OPDA) has been reported to act independently of COI1 as an essential signal in several stress-induced and developmental processes. Wound-induced increases in the endogenous levels of JA/JA-Ile are accompanied by two to tenfold increases in the concentration of OPDA, but its means of perception and metabolism are unknown. To screen for putative OPDA metabolites, vegetative tissues of flowering Arabidopsis thaliana were extracted with 25% aqueous methanol (v/v), purified by single-step reversed-phase polymer-based solid-phase extraction, and analyzed by high throughput mass spectrometry. This enabled the detection and quantitation of a low abundant OPDA analog of the biologically active (+)-7-iso-JA-L-Ile in plant tissue samples. Levels of the newly identified compound and the related phytohormones JA, JA-Ile and cis-(+)-OPDA were monitored in wounded leaves of flowering Arabidopsis lines (Col-0 and Ws) and compared to the levels observed in Arabidopsis mutants deficient in the biosynthesis of JA (dde2-2, opr3) and JA-Ile (jar1). The observed cis-(+)-OPDA-Ile levels varied widely, raising questions concerning its role in Arabidopsis stress responses. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 968 TI - 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 JO - PLOS ONE PY - 2016 SP - e0162829 AU - Arnold, M. D. AU - Gruber, C. AU - Floková, K. AU - Miersch, O. AU - Strnad, M. AU - Novák, O. AU - Wasternack, C. AU - Hause, B. AU - VL - 11 UR - DO - 10.1371/journal.pone.0162829 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1028 TI - Activity Regulation by Heteromerization of Arabidopsis Allene Oxide Cyclase Family Members JO - Plants PY - 2016 SP - 3 AU - Otto, M. AU - Naumann, C. AU - Brandt, W. AU - Wasternack, C. AU - Hause, B. AU - VL - 5 UR - DO - 10.3390/plants5010003 AB - 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. A2 - C1 - Cell and Metabolic Biology; Bioorganic Chemistry; Molecular Signal Processing ER - TY - CHAP ID - 57 TI - Jasmonates: Synthesis, Metabolism, Signal Transduction and Action T2 - eLS PB - PY - 2016 SP - AU - Wasternack, C. AU - VL - UR - DO - 10.1002/9780470015902.a0020138.pub2 AB - Jasmonic acid and other fatty‐acid‐derived compounds called oxylipins are signals in stress responses and development of plants. The receptor complex, signal transduction components as well as repressors and activators in jasmonate‐induced gene expression have been elucidated. Different regulatory levels and cross‐talk with other hormones are responsible for the multiplicity of plant responses to environmental and developmental cues. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1171 TI - How Jasmonates Earned their Laurels: Past and Present JO - J. Plant Growth Regul. PY - 2015 SP - 761-794 AU - Wasternack, C. AU - VL - 34 UR - DO - 10.1007/s00344-015-9526-5 AB - The histories of research regarding all plant hormones are similar. Identification and structural elucidation have been followed by analyses of their biosynthesis, distributions, signaling cascades, roles in developmental or stress response programs, and crosstalk. Jasmonic acid (JA) and its derivatives comprise a group of plant hormones that were discovered recently, compared to auxin, abscisic acid, cytokinins, gibberellic acid, and ethylene. Nevertheless, there have been tremendous advances in JA research, following the general progression outlined above and parallel efforts focused on several other “new” plant hormones (brassinosteroids, salicylate, and strigolactones). This review focuses on historical aspects of the identification of jasmonates, and characterization of their biosynthesis, distribution, perception, signaling pathways, crosstalk with other hormones and roles in plant stress responses and development. The aim is to illustrate how our present knowledge on jasmonates was generated and how that influences current efforts to extend our knowledge. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1188 TI - Jasmonic Acid and Its Precursor 12-Oxophytodienoic Acid Control Different Aspects of Constitutive and Induced Herbivore Defenses in Tomato JO - Plant Physiol. PY - 2014 SP - 396-410 AU - Bosch, M. AU - Wright, L. P. AU - Gershenzon, J. AU - Wasternack, C. AU - Hause, B. AU - Schaller, A. AU - Stintzi, A. AU - VL - 166 UR - DO - 10.1104/pp.114.237388 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1213 TI - UHPLC–MS/MS based target profiling of stress-induced phytohormones JO - Phytochemistry PY - 2014 SP - 147-157 AU - Floková, K. AU - Tarkowská, D. AU - Miersch, O. AU - Strnad, M. AU - Wasternack, C. AU - Novák, O. AU - VL - 105 UR - DO - 10.1016/j.phytochem.2014.05.015 AB - Stress-induced changes in phytohormone metabolite profiles have rapid effects on plant metabolic activity and growth. The jasmonates (JAs) are a group of fatty acid-derived stress response regulators with roles in numerous developmental processes. To elucidate their dual regulatory effects, which overlap with those of other important defence-signalling plant hormones such as salicylic acid (SA), abscisic acid (ABA) and indole-3-acetic acid (IAA), we have developed a highly efficient single-step clean-up procedure for their enrichment from complex plant matrices that enables their sensitive quantitative analysis using hyphenated mass spectrometry technique. The rapid extraction of minute quantities of plant material (less than 20 mg fresh weight, FW) into cold 10% methanol followed by one-step reversed-phase polymer-based solid phase extraction significantly reduced matrix effects and increased the recovery of labile JA analytes. This extraction and purification protocol was paired with a highly sensitive and validated ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method and used to simultaneously profile sixteen stress-induced phytohormones in minute plant material samples, including endogenous JA, several of its biosynthetic precursors and derivatives, as well as SA, ABA and IAA. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1276 TI - Perception, signaling and cross-talk of jasmonates and the seminal contributions of the Daoxin Xie’s lab and the Chuanyou Li’s lab JO - Plant Cell Rep. PY - 2014 SP - 707-718 AU - Wasternack, C. AU - VL - 33 UR - DO - 10.1007/s00299-014-1608-5 AB - Jasmonates (JAs) are lipid-derived signals in plant responses to biotic and abiotic stresses and in development. The most active JA compound is (+)-7-iso-JA-Ile, a JA conjugate with isoleucine. Biosynthesis, metabolism and key components of perception and signal transduction have been identified and numerous JA-induced gene expression data collected. For JA-Ile perception, the SCFCOI1–JAZ co-receptor complex has been identified and crystalized. Activators such as MYC2 and repressors such as JAZs including their targets were found. Involvement of JA-Ile in response to herbivores and pathogens and in root growth inhibition is among the most studied aspects of JA-Ile signaling. There are an increasing number of examples, where JA-Ile shows cross-talk with other plant hormones. Seminal contributions in JA/JA-Ile research were given by Daoxin Xie’s lab and Chuanyou Li’s lab, both in Beijing. Here, characterization was done regarding components of the JA-Ile receptor, such as COI1 (JAI1) and SCF, regarding activators (MYCs, MYBs) and repressors (JAV1, bHLH IIId’s) of JA-regulated gene expression, as well as regarding components of auxin biosynthesis and action, such as the transcription factor PLETHORA active in the root stem cell niche. This overview reflects the work of both labs in the light of our present knowledge on biosynthesis, perception and signal transduction of JA/JA-Ile and its cross-talk to other hormones. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1275 TI - Blütenduft, Abwehr, Entwicklung: Jasmonsäure - ein universelles Pflanzenhormon JO - Biologie in unserer Zeit PY - 2014 SP - 164-171 AU - Wasternack, C. AU - Hause, B. AU - VL - 44 UR - DO - 10.1002/biuz.201410535 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1274 TI - Action of jasmonates in plant stress responses and development — Applied aspects JO - Biotechnol. Adv. PY - 2014 SP - 31-39 AU - Wasternack, C. AU - VL - 32 UR - DO - 10.1016/j.biotechadv.2013.09.009 AB - Jasmonates (JAs) are lipid-derived compounds acting as key signaling compounds in plant stress responses and development. The JA co-receptor complex and several enzymes of JA biosynthesis have been crystallized, and various JA signal transduction pathways including cross-talk to most of the plant hormones have been intensively studied. Defense to herbivores and necrotrophic pathogens are mediated by JA. Other environmental cues mediated by JA are light, seasonal and circadian rhythms, cold stress, desiccation stress, salt stress and UV stress. During development growth inhibition of roots, shoots and leaves occur by JA, whereas seed germination and flower development are partially affected by its precursor 12-oxo-phytodienoic acid (OPDA). Based on these numerous JA mediated signal transduction pathways active in plant stress responses and development, there is an increasing interest in horticultural and biotechnological applications. Intercropping, the mixed growth of two or more crops, mycorrhization of plants, establishment of induced resistance, priming of plants for enhanced insect resistance as well as pre- and post-harvest application of JA are few examples. Additional sources for horticultural improvement, where JAs might be involved, are defense against nematodes, biocontrol by plant growth promoting rhizobacteria, altered composition of rhizosphere bacterial community, sustained balance between growth and defense, and improved plant immunity in intercropping systems. Finally, biotechnological application for JA-induced production of pharmaceuticals and application of JAs as anti-cancer agents were intensively studied. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1267 TI - Jasmonate signaling and crosstalk with gibberellin and ethylene JO - Curr. Opin. Plant Biol. PY - 2014 SP - 112-119 AU - Song, S. AU - Qi, T. AU - Wasternack, C. AU - Xie, D. AU - VL - 21 UR - DO - 10.1016/j.pbi.2014.07.005 AB - The phytohormone jasmonate (JA) plays essential roles in plant growth, development and defense. In response to the JA signal, the CORONATINE INSENSITIVE 1 (COI1)-based SCF complexes recruit JASMONATE ZIM-domain (JAZ) repressors for ubiquitination and degradation, and subsequently regulate their downstream signaling components essential for various JA responses. Tremendous progress has been made in understanding the JA signaling pathway and its crosstalk with other phytohormone pathways during the past two decades. Recent studies have revealed that a variety of positive and negative regulators act as targets of JAZs to control distinctive JA responses, and that JAZs and these regulators function as crucial interfaces to mediate synergy and antagonism between JA and other phytohormones. Owing to different regulatory players in JA perception and JA signaling, a fine-tuning of JA-dependent processes in plant growth, development and defense is achieved. In this review, we will summarize the latest progresses in JA signaling and its crosstalk with gibberellin and ethylene. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 74 TI - Jasmonates in Plant Growth and Stress Responses T2 - Phytohormones: A Window to Metabolism, Signaling and Biotechnological Applications PB - PY - 2014 SP - 221-263 AU - Wasternack, C. AU - VL - UR - SN - 978-1-4939-0491-4 DO - 10.1007/978-1-4939-0491-4_8 AB - Jasmonates are lipid-derived compounds which are signals in plant stress responses and development. They are synthesized in chloroplasts and peroxisomes. An endogenous rise occurs upon environmental stimuli or in distinct stages of development such as that of anthers and trichomes or in root growth. Hydroxylation, carboxylation, glucosylation, sulfation, methylation, or conjugation of jasmonic acid (JA) leads to numerous metabolites. Many of them are at least partially biologically inactive. The most bioactive JA is the (+)-7-iso-JA–isoleucine conjugate. Its perception takes place by the SCFCOI1-JAZ-co-receptor complex. At elevated levels of JAs, negative regulators such as JAZ, or JAV are subjected to proteasomal degradation, thereby allowing positively acting transcription factors of the MYC or MYB family to switch on JA-induced gene expression. In case of JAM negative regulation takes place by anatagonism to MYC2. JA and COI1 are dominant signals in gene expression after wounding or in response to necrotrophic pathogens. Cross-talk to salicylic acid, ethylene, auxin, and other hormones occurs. Growth is inhibited by JA, thereby counteracting the growth stimulation by gibberellic acid. Senescence, trichome formation, arbuscular mycorrhiza, and formation of many secondary metabolites are induced by jasmonates. Effects in cold acclimation; in intercropping; during response to herbivores, nematodes, or necrotrophic pathogens; in pre- and post-harvest; in crop quality control; and in biosynthesis of secondary compounds led to biotechnological and agricultural applications. A2 - Tran, L.-S. P. & Pal, S., eds. C1 - Molecular Signal Processing ER - TY - JOUR ID - 1360 TI - Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in Annals of Botany JO - Ann. Bot. PY - 2013 SP - 1021-1058 AU - Wasternack, C. AU - Hause, B. AU - VL - 111 UR - DO - 10.1093/aob/mct067 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1359 TI - Jasmonates in flower and seed development JO - Biochimie PY - 2013 SP - 79-85 AU - Wasternack, C. AU - Forner, S. AU - Strnad, M. AU - Hause, B. AU - VL - 95 UR - DO - 10.1016/j.biochi.2012.06.005 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - CHAP ID - 85 TI - Benno Parthier und die Jasmonatforschung in Halle T2 - Festkolloquium der Leopoldina anlässlich des 80. Geburtstages von Herrn Altpräsidenten Benno Parthier PB - Nova Acta Leopoldina PY - 2013 SP - 29-38 AU - Wasternack, C. AU - Hause, B. AU - VL - Supplementum Nr. 28 UR - https://www.leopoldina.org/publikationen/detailansicht/publication/festkolloquium-der-leopoldina-anlaesslich-des-80-geburtstages-von-herrn-altpraesidenten-benno-parthie/ AB - A2 - Hacker, J., ed. C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1408 TI - Role of cis-12-Oxo-Phytodienoic Acid in Tomato Embryo Development JO - Plant Physiol. PY - 2012 SP - 1715-1727 AU - Goetz, S. AU - Hellwege, A. AU - Stenzel, I. AU - Kutter, C. AU - Hauptmann, V. AU - Forner, S. AU - McCaig, B. AU - Hause, G. AU - Miersch, O. AU - Wasternack, C. AU - Hause, B. AU - VL - 158 UR - DO - 10.1104/pp.111.192658 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1455 TI - Another JA/COI1-independent role of OPDA detected in tomato embryo development JO - Plant Signal Behav. PY - 2012 SP - 1349-1353 AU - Wasternack, C. AU - Goetz, S. AU - Hellwege, A. AU - Forner, S. AU - Strnad, M. AU - Hause, B. AU - VL - 7 UR - DO - 10.4161/psb.21551 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1445 TI - ALLENE OXIDE CYCLASE (AOC) gene family members of Arabidopsis thaliana: tissue- and organ-specific promoter activities and in vivo heteromerization JO - J. Exp. Bot. PY - 2012 SP - 6125-6138 AU - Stenzel, I. AU - Otto, M. AU - Delker, C. AU - Kirmse, N. AU - Schmidt, D. AU - Miersch, O. AU - Hause, B. AU - Wasternack, C. AU - VL - 63 UR - DO - 10.1093/jxb/ers261 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1435 TI - Changes in the levels of jasmonates and free polyamines induced by Na2SO4 and NaCl in roots and leaves of the halophyte Prosopis strombulifera JO - Biologia PY - 2012 SP - 689-697 AU - Reginato, M. AU - Abdala, G. AU - Miersch, O. AU - Ruiz, O. AU - Moschetti, E. AU - Luna, V. AU - VL - 67 UR - DO - 10.2478/s11756-012-0052-7 AB - Prosopis strombulifera, a common legume in high-salinity soils of Argentina, is a useful model for elucidation of salt tolerance mechanisms and specific biochemical pathways in halophytes, since its NaCl tolerance exceeds the limit described for most halophytic plants. We analyzed the effects of the increasing concentration of two main soil salts, Na2SO4 and NaCl, on growth parameters of P. strombulifera, chlorophyll levels, and content of jasmonates (JAs) and polyamines (PAs), which are key molecules involved in stress responses. P. strombulifera showed a halophytic response (growth promotion) to NaCl, but strong growth inhibition by iso-osmotic solutions of Na2SO4. Chlorophyll levels, number of leaves and leaf area were also differentially affected. An important finding was the partial alleviation of SO42− toxicity by treatment with two-salt mixture. JAs are not directly involved in salt tolerance in this species since its levels decrease under all salt treatments. Beneficial effects of Putrescine (Put) accumulation in NaCl treated plants maybe inferred probably associated with the antioxidative defense system. Another novel finding is the accumulation of the uncommon PA cadaverine in roots under high Na2SO4, which may be related to SO42− toxicity. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1595 TI - The genuine ligand of a jasmonic acid receptor: Improved analysis of jasmonates is now required JO - Plant Signal Behav. PY - 2010 SP - 337-340 AU - Wasternack, C. AU - Xie, D. AU - VL - 5 UR - DO - 10.4161/psb.5.4.11574 AB - Jasmonic acid (JA), its metabolites, such as the methyl ester or amino acid conjugates as well as its precursor 12-oxophytodienoic acid (OPDA) are lipid-derived signals. JA, OPDA and JA-amino acid conjugates are known to function as signals in plant stress responses and development. More recently, formation of JA-amino acid conjugates and high biological activity of JA-Isoleucine (JA-Ile) were found to be essential in JA signalling. A breakthrough was the identification of JAZ proteins which interact with the F-box protein COI1 if JA-Ile is bound. This interaction leads to proteasomal degradation of JAZs being negative regulators of JA-induced transcription. Surprisingly, a distinct stereoisomer of JA-Ile, the (+)-7-iso-JA-Ile ((3R,7S) form) is most active. Coronatine, a bacterial phytotoxine with an identical stereochemistry at the cyclopentanone ring, has a similar bioactivity . This was explained by the recent identification of COI1 as the JA receptor and accords well with molecular modelling studies. Whereas over the last two decades JA was quantified to describe any JA dependent process, now we have to take into account a distinct stereoisomer of JA-Ile. Until recently a quantitative analysis of (+)-7-iso-JA-Ile was missing presumable due to its equilibration to (-)-JA-Ile. Now such an analysis was achieved. These aspects will be discussed based on our new knowledge on JA perception and signalling. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1594 TI - Jasmonates: Structural Requirements for Lipid-Derived Signals Active in Plant Stress Responses and Development JO - ACS Chem. Biol. PY - 2010 SP - 63-77 AU - Wasternack, C. AU - Kombrink, E. AU - VL - 5 UR - DO - 10.1021/cb900269u AB - Jasmonates are lipid-derived signals that mediate plant stress responses and development processes. Enzymes participating in biosynthesis of jasmonic acid (JA) (1, 2) and components of JA signaling have been extensively characterized by biochemical and molecular-genetic tools. Mutants of Arabidopsis and tomato have helped to define the pathway for synthesis of jasmonoyl-isoleucine (JA-Ile), the active form of JA, and to identify the F-box protein COI1 as central regulatory unit. However, details of the molecular mechanism of JA signaling have only recently been unraveled by the discovery of JAZ proteins that function in transcriptional repression. The emerging picture of JA perception and signaling cascade implies the SCFCOI1 complex operating as E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S-proteasome pathway, thereby allowing the transcription factor MYC2 to activate gene expression. The fact that only one particular stereoisomer, (+)-7-iso-JA-l-Ile (4), shows high biological activity suggests that epimerization between active and inactive diastereomers could be a mechanism for turning JA signaling on or off. The recent demonstration that COI1 directly binds (+)-7-iso-JA-l-Ile (4) and thus functions as JA receptor revealed that formation of the ternary complex COI1-JA-Ile-JAZ is an ordered process. The pronounced differences in biological activity of JA stereoisomers also imply strict stereospecific control of product formation along the JA biosynthetic pathway. The pathway of JA biosynthesis has been unraveled, and most of the participating enzymes are well-characterized. For key enzymes of JA biosynthesis the crystal structures have been established, allowing insight into the mechanisms of catalysis and modes of substrate binding that lead to formation of stereospecific products. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1585 TI - The moss Physcomitrella patens contains cyclopentenones but no jasmonates: mutations in allene oxide cyclase lead to reduced fertility and altered sporophyte morphology JO - New Phytol. PY - 2010 SP - 740-749 AU - Stumpe, M. AU - Göbel, C. AU - Faltin, B. AU - Beike, A. K. AU - Hause, B. AU - Himmelsbach, K. AU - Bode, J. AU - Kramell, R. AU - Wasternack, C. AU - Frank, W. AU - Reski, R. AU - Feussner, I. AU - VL - 188 UR - DO - 10.1111/j.1469-8137.2010.03406.x AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1584 TI - De-regulation of abscisic acid contents causes abnormal endosperm development in the barley mutant seg8 JO - Plant J. PY - 2010 SP - 589-603 AU - Sreenivasulu, N. AU - Radchuk, V. AU - Alawady, A. AU - Borisjuk, L. AU - Weier, D. AU - Staroske, N. AU - Fuchs, J. AU - Miersch, O. AU - Strickert, M. AU - Usadel, B. AU - Wobus, U. AU - Grimm, B. AU - Weber, H. AU - Weschke, W. AU - VL - 64 UR - DO - 10.1111/j.1365-313X.2010.04350.x AB - Grain development of the maternal effect shrunken endosperm mutant seg8 was analysed by comprehensive molecular, biochemical and histological methods. The most obvious finding was de‐regulation of ABA levels, which were lower compared to wild‐type during the pre‐storage phase but higher during the transition from cell division/differentiation to accumulation of storage products. Ploidy levels and ABA amounts were inversely correlated in the developing endosperms of both mutant and wild‐type, suggesting an influence of ABA on cell‐cycle regulation. The low ABA levels found in seg8 grains between anthesis and beginning endosperm cellularization may result from a gene dosage effect in the syncytial endosperm that causes impaired transfer of ABA synthesized in vegetative tissues into filial grain parts. Increased ABA levels during the transition phase are accompanied by higher chlorophyll and carotenoid/xanthophyll contents. The data suggest a disturbed ABA‐releasing biosynthetic pathway. This is indicated by up‐regulation of expression of the geranylgeranyl reductase (GGR) gene, which may be induced by ABA deficiency during the pre‐storage phase. Abnormal cellularization/differentiation of the developing seg8 endosperm and reduced accumulation of starch are phenotypic characteristics that reflect these disturbances. The present study did not reveal the primary gene defect causing the seg8 phenotype, but presents new insights into the maternal/filial relationships regulating barley endosperm development. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1579 TI - Jasmonate and Phytochrome A Signaling in Arabidopsis Wound and Shade Responses Are Integrated through JAZ1 Stability JO - Plant Cell PY - 2010 SP - 1143-1160 AU - Robson, F. AU - Okamoto, H. AU - Patrick, E. AU - Harris, S.-R. AU - Wasternack, C. AU - Brearley, C. AU - Turner, J. G. AU - VL - 22 UR - DO - 10.1105/tpc.109.067728 AB - Jasmonate (JA) activates plant defense, promotes pollen maturation, and suppresses plant growth. An emerging theme in JA biology is its involvement in light responses; here, we examine the interdependence of the JA- and light-signaling pathways in Arabidopsis thaliana. We demonstrate that mutants deficient in JA biosynthesis and signaling are deficient in a subset of high irradiance responses in far-red (FR) light. These mutants display exaggerated shade responses to low, but not high, R/FR ratio light, suggesting a role for JA in phytochrome A (phyA) signaling. Additionally, we demonstrate that the FR light–induced expression of transcription factor genes is dependent on CORONATINE INSENSITIVE1 (COI1), a central component of JA signaling, and is suppressed by JA. phyA mutants had reduced JA-regulated growth inhibition and VSP expression and increased content of cis-(+)-12-oxophytodienoic acid, an intermediate in JA biosynthesis. Significantly, COI1-mediated degradation of JASMONATE ZIM DOMAIN1-β-glucuronidase (JAZ1-GUS) in response to mechanical wounding and JA treatment required phyA, and ectopic expression of JAZ1-GUS resulted in exaggerated shade responses. Together, these results indicate that JA and phyA signaling are integrated through degradation of the JAZ1 protein, and both are required for plant responses to light and stress. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1567 TI - Salicylate-mediated suppression of jasmonate-responsive gene expression in Arabidopsis is targeted downstream of the jasmonate biosynthesis pathway JO - Planta PY - 2010 SP - 1423-1432 AU - Leon-Reyes, A. AU - Van der Does, D. AU - De Lange, E. S. AU - Delker, C. AU - Wasternack, C. AU - Van Wees, S. C. M. AU - Ritsema, T. AU - Pieterse, C. M. J. AU - VL - 232 UR - DO - 10.1007/s00425-010-1265-z AB - Jasmonates (JAs) and salicylic acid (SA) are plant hormones that play pivotal roles in the regulation of induced defenses against microbial pathogens and insect herbivores. Their signaling pathways cross-communicate providing the plant with a regulatory potential to finely tune its defense response to the attacker(s) encountered. In Arabidopsis thaliana, SA strongly antagonizes the jasmonic acid (JA) signaling pathway, resulting in the downregulation of a large set of JA-responsive genes, including the marker genes PDF1.2 and VSP2. Induction of JA-responsive marker gene expression by different JA derivatives was equally sensitive to SA-mediated suppression. Activation of genes encoding key enzymes in the JA biosynthesis pathway, such as LOX2, AOS, AOC2, and OPR3 was also repressed by SA, suggesting that the JA biosynthesis pathway may be a target for SA-mediated antagonism. To test this, we made use of the mutant aos/dde2, which is completely blocked in its ability to produce JAs because of a mutation in the ALLENE OXIDE SYNTHASE gene. Mutant aos/dde2 plants did not express the JA-responsive marker genes PDF1.2 or VSP2 in response to infection with the necrotrophic fungus Alternaria brassicicola or the herbivorous insect Pieris rapae. Bypassing JA biosynthesis by exogenous application of methyl jasmonate (MeJA) rescued this JA-responsive phenotype in aos/dde2. Application of SA suppressed MeJA-induced PDF1.2 expression to the same level in the aos/dde2 mutant as in wild-type Col-0 plants, indicating that SA-mediated suppression of JA-responsive gene expression is targeted at a position downstream of the JA biosynthesis pathway. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 100 TI - Jasmonates in Stress, Growth, and Development T2 - Plant Stress Biology: From Genomics to Systems Biology PB - PY - 2010 SP - 91-118 AU - Wasternack, C. AU - VL - UR - SN - 9783527628964 DO - 10.1002/9783527628964.ch5 AB - This chapter contains sections titled:IntroductionJA BiosynthesisJA MetabolismBound OPDA – ArabidopsidesMutants of JA Biosynthesis and SignalingCOI1–JAZ–JA‐Ile‐Mediated JA SignalingTranscription Factors Involved in JA SignalingJasmonates and Oxylipins in DevelopmentConclusionsAcknowledgmentsReferences A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1673 TI - Removal of Substrate Inhibition and Increase in Maximal Velocity in the Short Chain Dehydrogenase/Reductase Salutaridine Reductase Involved in Morphine Biosynthesis JO - J. Biol. Chem. PY - 2009 SP - 26758-26767 AU - Ziegler, J. AU - Brandt, W. AU - Geißler, R. AU - Facchini, P. J. AU - VL - 284 UR - DO - 10.1074/jbc.M109.030957 AB - Salutaridine reductase (SalR, EC 1.1.1.248) catalyzes the stereospecific reduction of salutaridine to 7(S)-salutaridinol in the biosynthesis of morphine. It belongs to a new, plant-specific class of short-chain dehydrogenases, which are characterized by their monomeric nature and increased length compared with related enzymes. Homology modeling and substrate docking suggested that additional amino acids form a novel α-helical element, which is involved in substrate binding. Site-directed mutagenesis and subsequent studies on enzyme kinetics revealed the importance of three residues in this element for substrate binding. Further replacement of eight additional residues led to the characterization of the entire substrate binding pocket. In addition, a specific role in salutaridine binding by either hydrogen bond formation or hydrophobic interactions was assigned to each amino acid. Substrate docking also revealed an alternative mode for salutaridine binding, which could explain the strong substrate inhibition of SalR. An alternate arrangement of salutaridine in the enzyme was corroborated by the effect of various amino acid substitutions on substrate inhibition. In most cases, the complete removal of substrate inhibition was accompanied by a substantial loss in enzyme activity. However, some mutations greatly reduced substrate inhibition while maintaining or even increasing the maximal velocity. Based on these results, a double mutant of SalR was created that exhibited the complete absence of substrate inhibition and higher activity compared with wild-type SalR. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 1672 TI - Evolution of morphine biosynthesis in opium poppy JO - Phytochemistry PY - 2009 SP - 1696-1707 AU - Ziegler, J. AU - Facchini, P. J. AU - Geißler, R. AU - Schmidt, J. AU - Ammer, C. AU - Kramell, R. AU - Voigtländer, S. AU - Gesell, A. AU - Pienkny, S. AU - Brandt, W. AU - VL - 70 UR - DO - 10.1016/j.phytochem.2009.07.006 AB - Benzylisoquinoline alkaloids (BIAs) are a group of nitrogen-containing plant secondary metabolites comprised of an estimated 2500 identified structures. In BIA metabolism, (S)-reticuline is a key branch-point intermediate that can be directed into several alkaloid subtypes with different structural skeleton configurations. The morphinan alkaloids are one subclass of BIAs produced in only a few plant species, most notably and abundantly in the opium poppy (Papaver somniferum). Comparative transcriptome analysis of opium poppy and several other Papaver species that do not accumulate morphinan alkaloids showed that known genes encoding BIA biosynthetic enzymes are expressed at higher levels in P. somniferum. Three unknown cDNAs that are co-ordinately expressed with several BIA biosynthetic genes were identified as enzymes in the pathway. One of these enzymes, salutaridine reductase (SalR), which is specific for the production of morphinan alkaloids, was isolated and heterologously overexpressed in its active form not only from P. somniferum, but also from Papaver species that do not produce morphinan alkaloids. SalR is a member of a class of short chain dehydrogenase/reductases (SDRs) that are active as monomers and possess an extended amino acid sequence compared with classical SDRs. Homology modelling and substrate docking revealed the substrate binding site for SalR. The amino acids residues conferring salutaridine binding were compared to several members of the SDR family from different plant species, which non-specifically reduce (−)-menthone to (+)-neomenthol. Previously, it was shown that some of these proteins are involved in plant defence. The recruitment of specific monomeric SDRs from monomeric SDRs involved in plant defence is discussed. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 1668 TI - ADP-Glucose Pyrophosphorylase-Deficient Pea Embryos Reveal Specific Transcriptional and Metabolic Changes of Carbon-Nitrogen Metabolism and Stress Responses JO - Plant Physiol. PY - 2009 SP - 395-411 AU - Weigelt, K. AU - Küster, H. AU - Rutten, T. AU - Fait, A. AU - Fernie, A. R. AU - Miersch, O. AU - Wasternack, C. AU - Emery, R. J. N. AU - Desel, C. AU - Hosein, F. AU - Müller, M. AU - Saalbach, I. AU - Weber, H. AU - VL - 149 UR - DO - 10.1104/pp.108.129940 AB - We present a comprehensive analysis of ADP-glucose pyrophosphorylase (AGP)-repressed pea (Pisum sativum) seeds using transcript and metabolite profiling to monitor the effects that reduced carbon flow into starch has on carbon-nitrogen metabolism and related pathways. Changed patterns of transcripts and metabolites suggest that AGP repression causes sugar accumulation and stimulates carbohydrate oxidation via glycolysis, tricarboxylic acid cycle, and mitochondrial respiration. Enhanced provision of precursors such as acetyl-coenzyme A and organic acids apparently support other pathways and activate amino acid and storage protein biosynthesis as well as pathways fed by cytosolic acetyl-coenzyme A, such as cysteine biosynthesis and fatty acid elongation/metabolism. As a consequence, the resulting higher nitrogen (N) demand depletes transient N storage pools, specifically asparagine and arginine, and leads to N limitation. Moreover, increased sugar accumulation appears to stimulate cytokinin-mediated cell proliferation pathways. In addition, the deregulation of starch biosynthesis resulted in indirect changes, such as increased mitochondrial metabolism and osmotic stress. The combined effect of these changes is an enhanced generation of reactive oxygen species coupled with an up-regulation of energy-dissipating, reactive oxygen species protection, and defense genes. Transcriptional activation of mitogen-activated protein kinase pathways and oxylipin synthesis indicates an additional activation of stress signaling pathways. AGP-repressed embryos contain higher levels of jasmonate derivatives; however, this increase is preferentially in nonactive forms. The results suggest that, although metabolic/osmotic alterations in iAGP pea seeds result in multiple stress responses, pea seeds have effective mechanisms to circumvent stress signaling under conditions in which excessive stress responses and/or cellular damage could prematurely initiate senescence or apoptosis. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1667 TI - Emerging complexity: jasmonate-induced volatiles affect parasitoid choice JO - J. Exp. Bot. PY - 2009 SP - 2451-2453 AU - Wasternack, C. AU - Hause, B. AU - VL - 60 UR - DO - 10.1093/jxb/erp197 AB - A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1665 TI - Spodoptera littoralis-Induced Lectin Expression in Tobacco JO - Plant Cell Physiol. PY - 2009 SP - 1142-1155 AU - Vandenborre, G. AU - Miersch, O. AU - Hause, B. AU - Smagghe, G. AU - Wasternack, C. AU - Van Damme, E. J. AU - VL - 50 UR - DO - 10.1093/pcp/pcp065 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1652 TI - Functional characterization of a novel benzylisoquinoline O-methyltransferase suggests its involvement in papaverine biosynthesis in opium poppy (Papaver somniferum L) JO - Plant J. PY - 2009 SP - 56-67 AU - Pienkny, S. AU - Brandt, W. AU - Schmidt, J. AU - Kramell, R. AU - Ziegler, J. AU - VL - 60 UR - DO - 10.1111/j.1365-313X.2009.03937.x AB - The benzylisoquinoline alkaloids are a highly diverse group of about 2500 compounds which accumulate in a species‐specific manner. Despite the numerous compounds which could be identified, the biosynthetic pathways and the participating enzymes or cDNAs could be characterized only for a few selected members, whereas the biosynthesis of the majority of the compounds is still largely unknown. In an attempt to characterize additional biosynthetic steps at the molecular level, integration of alkaloid and transcript profiling across Papaver species was performed. This analysis showed high expression of an expressed sequence tag (EST) of unknown function only in Papaver somniferum varieties. After full‐length cloning of the open reading frame and sequence analysis, this EST could be classified as a member of the class II type O ‐methyltransferase protein family. It was related to O ‐methyltransferases from benzylisoquinoline biosynthesis, and the amino acid sequence showed 68% identical residues to norcoclaurine 6‐O ‐methyltransferase. However, rather than methylating norcoclaurine, the recombinant protein methylated norreticuline at position seven with a K m of 44 μm using S ‐adenosyl‐l ‐methionine as a cofactor. Of all substrates tested, only norreticuline was converted. Even minor changes in the benzylisoquinoline backbone were not tolerated by the enzyme. Accordingly, the enzyme was named norreticuline 7–O ‐methyltransferase (N7OMT). This enzyme represents a novel O ‐methyltransferase in benzylisoquinoline metabolism. Expression analysis showed slightly increased expression of N7OMT in P. somniferum varieties containing papaverine, suggesting its involvement in the partially unknown biosynthesis of this pharmaceutically important compound. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 1649 TI - Disruption of Adenosine-5′-Phosphosulfate Kinase in Arabidopsis Reduces Levels of Sulfated Secondary Metabolites JO - Plant Cell PY - 2009 SP - 910-927 AU - Mugford, S. G. AU - Yoshimoto, N. AU - Reichelt, M. AU - Wirtz, M. AU - Hill, L. AU - Mugford, S. T. AU - Nakazato, Y. AU - Noji, M. AU - Takahashi, H. AU - Kramell, R. AU - Gigolashvili, T. AU - Flügge, U.-I. AU - Wasternack, C. AU - Gershenzon, J. AU - Hell, R. AU - Saito, K. AU - Kopriva, S. AU - VL - 21 UR - DO - 10.1105/tpc.109.065581 AB - Plants can metabolize sulfate by two pathways, which branch at the level of adenosine 5′-phosphosulfate (APS). APS can be reduced to sulfide and incorporated into Cys in the primary sulfate assimilation pathway or phosphorylated by APS kinase to 3′-phosphoadenosine 5′-phosphosulfate, which is the activated sulfate form for sulfation reactions. To assess to what extent APS kinase regulates accumulation of sulfated compounds, we analyzed the corresponding gene family in Arabidopsis thaliana. Analysis of T-DNA insertion knockout lines for each of the four isoforms did not reveal any phenotypical alterations. However, when all six combinations of double mutants were compared, the apk1 apk2 plants were significantly smaller than wild-type plants. The levels of glucosinolates, a major class of sulfated secondary metabolites, and the sulfated 12-hydroxyjasmonate were reduced approximately fivefold in apk1 apk2 plants. Although auxin levels were increased in the apk1 apk2 mutants, as is the case for most plants with compromised glucosinolate synthesis, typical high auxin phenotypes were not observed. The reduction in glucosinolates resulted in increased transcript levels for genes involved in glucosinolate biosynthesis and accumulation of desulfated precursors. It also led to great alterations in sulfur metabolism: the levels of sulfate and thiols increased in the apk1 apk2 plants. The data indicate that the APK1 and APK2 isoforms of APS kinase play a major role in the synthesis of secondary sulfated metabolites and are required for normal growth rates. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1641 TI - Agrobacterium tumefaciens Promotes Tumor Induction by Modulating Pathogen Defense in Arabidopsis thaliana JO - Plant Cell PY - 2009 SP - 2948-2962 AU - Lee, C.-W. AU - Efetova, M. AU - Engelmann, J. C. AU - Kramell, R. AU - Wasternack, C. AU - Ludwig-Müller, J. AU - Hedrich, R. AU - Deeken, R. AU - VL - 21 UR - DO - 10.1105/tpc.108.064576 AB - Agrobacterium tumefaciens causes crown gall disease by transferring and integrating bacterial DNA (T-DNA) into the plant genome. To examine the physiological changes and adaptations during Agrobacterium-induced tumor development, we compared the profiles of salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and auxin (indole-3-acetic acid [IAA]) with changes in the Arabidopsis thaliana transcriptome. Our data indicate that host responses were much stronger toward the oncogenic strain C58 than to the disarmed strain GV3101 and that auxin acts as a key modulator of the Arabidopsis–Agrobacterium interaction. At initiation of infection, elevated levels of IAA and ET were associated with the induction of host genes involved in IAA, but not ET signaling. After T-DNA integration, SA as well as IAA and ET accumulated, but JA did not. This did not correlate with SA-controlled pathogenesis-related gene expression in the host, although high SA levels in mutant plants prevented tumor development, while low levels promoted it. Our data are consistent with a scenario in which ET and later on SA control virulence of agrobacteria, whereas ET and auxin stimulate neovascularization during tumor formation. We suggest that crosstalk among IAA, ET, and SA balances pathogen defense launched by the host and tumor growth initiated by agrobacteria. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1628 TI - (+)-7-iso-Jasmonoyl-L-isoleucine is the endogenous bioactive jasmonate JO - Nat. Chem. Biol. PY - 2009 SP - 344-350 AU - Fonseca, S. AU - Chini, A. AU - Hamberg, M. AU - Adie, B. AU - Porzel, A. AU - Kramell, R. AU - Miersch, O. AU - Wasternack, C. AU - Solano, R. AU - VL - 5 UR - DO - 10.1038/nchembio.161 AB - Hormone-triggered activation of the jasmonate signaling pathway in Arabidopsis thaliana requires SCFCOI1-mediated proteasome degradation of JAZ repressors. (−)-JA-L-Ile is the proposed bioactive hormone, and SCFCOI1 is its likely receptor. We found that the biological activity of (−)-JA-L-Ile is unexpectedly low compared to coronatine and the synthetic isomer (+)-JA-L-Ile, which suggests that the stereochemical orientation of the cyclopentanone-ring side chains greatly affects receptor binding. Detailed GC-MS and HPLC analyses showed that the (−)-JA-L-Ile preparations currently used in ligand binding studies contain small amounts of the C7 epimer (+)-7-iso-JA-L-Ile. Purification of each of these molecules demonstrated that pure (−)-JA-L-Ile is inactive and that the active hormone is (+)-7-iso-JA-L-Ile, which is also structurally more similar to coronatine. In addition, we show that pH changes promote conversion of (+)-7-iso-JA-L-Ile to the inactive (−)-JA-L-Ile form, thus providing a simple mechanism that can regulate hormone activity through epimerization. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 1616 TI - Jasmonates act with salicylic acid to confer basal thermotolerance in Arabidopsis thaliana JO - New Phytol. PY - 2009 SP - 175-187 AU - Clarke, S. M. AU - Cristescu, S. M. AU - Miersch, O. AU - Harren, F. J. M. AU - Wasternack, C. AU - Mur, L. A. J. AU - VL - 182 UR - DO - 10.1111/j.1469-8137.2008.02735.x AB - The cpr5‐1 Arabidopsis thaliana mutant exhibits constitutive activation of salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) signalling pathways and displays enhanced tolerance of heat stress (HS).cpr5‐1 crossed with jar1‐1 (a JA‐amino acid synthetase) was compromised in basal thermotolerance, as were the mutants opr3 (mutated in OPDA reductase3) and coi1‐1 (affected in an E3 ubiquitin ligase F‐box; a key JA‐signalling component). In addition, heating wild‐type Arabidopsis led to the accumulation of a range of jasmonates: JA, 12‐oxophytodienoic acid (OPDA) and a JA‐isoleucine (JA‐Ile) conjugate. Exogenous application of methyl jasmonate protected wild‐type Arabidopsis from HS.Ethylene was rapidly produced during HS, with levels being modulated by both JA and SA. By contrast, the ethylene mutant ein2‐1 conferred greater thermotolerance.These data suggest that JA acts with SA, conferring basal thermotolerance while ET may act to promote cell death. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1634 TI - Jasmonates in stress responses and development JO - Phytochemistry PY - 2009 SP - 1483-1484 AU - Hause, B. AU - Wasternack, C. AU - Strack, D. AU - VL - 70 UR - DO - 10.1016/j.phytochem.2009.07.004 AB - A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1633 TI - PAMP-induced defense responses in potato require both salicylic acid and jasmonic acid JO - Plant J. PY - 2009 SP - 230-242 AU - Halim, V. A. AU - Altmann, S. AU - Ellinger, D. AU - Eschen-Lippold, L. AU - Miersch, O. AU - Scheel, D. AU - Rosahl, S. AU - VL - 57 UR - DO - 10.1111/j.1365-313X.2008.03688.x AB - To elucidate the molecular mechanisms underlying pathogen‐associated molecular pattern (PAMP)‐induced defense responses in potato (Solanum tuberosum ), the role of the signaling compounds salicylic acid (SA) and jasmonic acid (JA) was analyzed. Pep‐13, a PAMP from Phytophthora , induces the accumulation of SA, JA and hydrogen peroxide, as well as the activation of defense genes and hypersensitive‐like cell death. We have previously shown that SA is required for Pep‐13‐induced defense responses. To assess the importance of JA, RNA interference constructs targeted at the JA biosynthetic genes, allene oxide cyclase and 12‐oxophytodienoic acid reductase, were expressed in transgenic potato plants. In addition, expression of the F‐box protein COI1 was reduced by RNA interference. Plants expressing the RNA interference constructs failed to accumulate the respective transcripts in response to wounding or Pep‐13 treatment, neither did they contain significant amounts of JA after elicitation. In response to infiltration of Pep‐13, the transgenic plants exhibited a highly reduced accumulation of reactive oxygen species as well as reduced hypersensitive cell death. The ability of the JA‐deficient plants to accumulate SA suggests that SA accumulation is independent or upstream of JA accumulation. These data show that PAMP responses in potato require both SA and JA and that, in contrast to Arabidopsis, these compounds act in the same signal transduction pathway. Despite their inability to fully respond to PAMP treatment, the transgenic RNA interference plants are not altered in their basal defense against Phytophthora infestans . A2 - C1 - Molecular Signal Processing; Biochemistry of Plant Interactions ER - TY - CHAP ID - 103 TI - Chronobiologische Phänomene und Jasmonatgehalt bei Viscum album L. T2 - Die Mistel in der Tumortherapie 2. Aktueller Stand der Forschung und klinische Anwendung PB - PY - 2009 SP - 49-66 AU - Dorka, R. AU - Miersch, O. AU - Hause, B. AU - Weik, P. AU - Wasternack, C. AU - VL - UR - AB - A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 1753 TI - Multifunctional Enzymes in Oxylipin Metabolism JO - ChemBioChem PY - 2008 SP - 2373-2375 AU - Wasternack, C. AU - Feussner, I. AU - VL - 9 UR - DO - 10.1002/cbic.200800582 AB - For the first time a member of the CYP74 enzyme subfamily (9‐AOS) from tomato has been shown by chemical and analytical approaches to catalyze multiple reactions. These multifunctional properties of 9‐AOS from the oxylipin‐forming lipoxygenase (LOX) pathway raise several new questions on lipid‐derived signaling. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1740 TI - The AOC promoter of tomato is regulated by developmental and environmental stimuli JO - Phytochemistry PY - 2008 SP - 1859-1869 AU - Stenzel, I. AU - Hause, B. AU - Proels, R. AU - Miersch, O. AU - Oka, M. AU - Roitsch, T. AU - Wasternack, C. AU - VL - 69 UR - DO - 10.1016/j.phytochem.2008.03.007 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1732 TI - Glutaminyl cyclases from animals and plants: a case of functionally convergent protein evolution JO - Biol. Chem. PY - 2008 SP - AU - Schilling, S. AU - Wasternack, C. AU - Demuth, H.-U. AU - VL - 389 UR - DO - 10.1515/BC.2008.111 AB - Several mammalian peptide hormones and proteins from plant and animal origin contain an N-terminal pyroglutamic acid (pGlu) residue. Frequently, the moiety is important in exerting biological function in either mediating interaction with receptors or stabilizing against N-terminal degradation. Glutaminyl cyclases (QCs) were isolated from different plants and animals catalyzing pGlu formation. The recent resolution of the 3D structures of Carica papaya and human QCs clearly supports different evolutionary origins of the proteins, which is also reflected by different enzymatic mechanisms. The broad substrate specificity is revealed by the heterogeneity of physiological substrates of plant and animal QCs, including cytokines, matrix proteins and pathogenesis-related proteins. Moreover, recent evidence also suggests human QC as a catalyst of pGlu formation at the N-terminus of amyloid peptides, which contribute to Alzheimer's disease. Obviously, owing to its biophysical properties, the function of pGlu in plant and animal proteins is very similar in terms of stabilizing or mediating protein and peptide structure. It is possible that the requirement for catalysis of pGlu formation under physiological conditions may have triggered separate evolution of QCs in plants and animals. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1726 TI - A MYB Transcription Factor Regulates Very-Long-Chain Fatty Acid Biosynthesis for Activation of the Hypersensitive Cell Death Response in Arabidopsis JO - Plant Cell PY - 2008 SP - 752-767 AU - Raffaele, S. AU - Vailleau, F. AU - Léger, A. AU - Joubès, J. AU - Miersch, O. AU - Huard, C. AU - Blée, E. AU - Mongrand, S. AU - Domergue, F. AU - Roby, D. AU - VL - 20 UR - DO - 10.1105/tpc.107.054858 AB - Plant immune responses to pathogen attack include the hypersensitive response (HR), a form of programmed cell death occurring at invasion sites. We previously reported on Arabidopsis thaliana MYB30, a transcription factor that acts as a positive regulator of a cell death pathway conditioning the HR. Here, we show by microarray analyses of Arabidopsis plants misexpressing MYB30 that the genes encoding the four enzymes forming the acyl-coA elongase complex are putative MYB30 targets. The acyl-coA elongase complex synthesizes very-long-chain fatty acids (VLCFAs), and the accumulation of extracellular VLCFA-derived metabolites (leaf epidermal wax components) was affected in MYB30 knockout mutant and overexpressing lines. In the same lines, a lipid extraction procedure allowing high recovery of sphingolipids revealed changes in VLCFA contents that were amplified in response to inoculation. Finally, the exacerbated HR phenotype of MYB30-overexpressing lines was altered by the loss of function of the acyl-ACP thioesterase FATB, which causes severe defects in the supply of fatty acids for VLCFA biosynthesis. Based on these findings, we propose a model in which MYB30 modulates HR via VLCFAs by themselves, or VLCFA derivatives, as cell death messengers in plants. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1719 TI - Hydroxylated jasmonates are commonly occurring metabolites of jasmonic acid and contribute to a partial switch-off in jasmonate signaling JO - New Phytol. PY - 2008 SP - 114-127 AU - Miersch, O. AU - Neumerkel, J. AU - Dippe, M. AU - Stenzel, I. AU - Wasternack, C. AU - VL - 177 UR - DO - 10.1111/j.1469-8137.2007.02252.x AB - In potato 12‐hydroxyjasmonic acid (12‐OH‐JA) is a tuber‐inducing compound. Here, it is demonstrated that 12‐OH‐JA, as well as its sulfated and glucosylated derivatives, are constituents of various organs of many plant species. All accumulate differentially and usually to much higher concentrations than jasmonic acid (JA).In wounded tomato leaves, 12‐OH‐JA and its sulfated, as well as glucosylated, derivative accumulate after JA, and their diminished accumulation in wounded leaves of the JA‐deficient mutants spr2 and acx1 and also a JA‐deficient 35S::AOCantisense line suggest their JA‐dependent formation.To elucidate how signaling properties of JA/JAME (jasmonic acid methyl ester) are affected by hydroxylation and sulfation, germination and root growth were recorded in the presence of the different jasmonates, indicating that 12‐OH‐JA and 12‐hydroxyjasmonic acid sulfate (12‐HSO4‐JA) were not bioactive. Expression analyses for 29 genes showed that expression of wound‐inducible genes such as those coding for PROTEINASE INHIBITOR2, POLYPHENOL OXIDASE, THREONINE DEAMINASE or ARGINASE was induced by JAME and less induced or even down‐regulated by 12‐OH‐JA and 12‐HSO4‐JA. Almost all genes coding for enzymes in JA biosynthesis were up‐regulated by JAME but down‐regulated by 12‐OH‐JA and 12‐HSO4‐JA.The data suggest that wound‐induced metabolic conversion of JA/JAME into 12‐OH‐JA alters expression pattern of genes including a switch off in JA signaling for a subset of genes. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1716 TI - Functions of Chloroplastic Adenylate Kinases in Arabidopsis JO - Plant Physiol. PY - 2008 SP - 492-504 AU - Lange, P. R. AU - Geserick, C. AU - Tischendorf, G. AU - Zrenner, R. AU - VL - 146 UR - DO - 10.1104/pp.107.114702 AB - Adenosine monophosphate kinase (AMK; adenylate kinase) catalyses the reversible formation of ADP by the transfer of one phosphate group from ATP to AMP, thus equilibrating adenylates. The Arabidopsis (Arabidopsis thaliana) genome contains 10 genes with an adenylate/cytidylate kinase signature; seven of these are identified as putative adenylate kinases. Encoded proteins of at least two members of this Arabidopsis adenylate kinase gene family are targeted to plastids. However, when the individual genes are disrupted, the phenotypes of both mutants are strikingly different. Although absence of AMK2 causes only 30% reduction of total adenylate kinase activity in leaves, there is loss of chloroplast integrity leading to small, pale-looking plantlets from embryo to seedling development. In contrast, no phenotype for disruption of the second plastid adenylate kinase was found. From this analysis, we conclude that AMK2 is the major activity for equilibration of adenylates and de novo synthesis of ADP in the plastid stroma. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1709 TI - Jasmonates meet fatty acids: functional analysis of a new acyl-coenzyme A synthetase family from Arabidopsis thaliana JO - J. Exp. Bot. PY - 2008 SP - 403-419 AU - Kienow, L. AU - Schneider, K. AU - Bartsch, M. AU - Stuible, H.-P. AU - Weng, H. AU - Miersch, O. AU - Wasternack, C. AU - Kombrink, E. AU - VL - 59 UR - DO - 10.1093/jxb/erm325 AB - Arabidopsis thaliana contains a large number of genes encoding carboxylic acid-activating enzymes, including long-chain fatty acyl-CoA synthetase (LACS), 4-coumarate:CoA ligases (4CL), and proteins closely related to 4CLs with unknown activities. The function of these 4CL-like proteins was systematically explored by applying an extensive substrate screen, and it was uncovered that activation of fatty acids is the common feature of all active members of this protein family, thereby defining a new group of fatty acyl-CoA synthetase, which is distinct from the known LACS family. Significantly, four family members also displayed activity towards different biosynthetic precursors of jasmonic acid (JA), including 12-oxo-phytodienoic acid (OPDA), dinor-OPDA, 3-oxo-2(2′-[Z]-pentenyl)cyclopentane-1-octanoic acid (OPC-8), and OPC-6. Detailed analysis of in vitro properties uncovered significant differences in substrate specificity for individual enzymes, but only one protein (At1g20510) showed OPC-8:CoA ligase activity. Its in vivo function was analysed by transcript and jasmonate profiling of Arabidopsis insertion mutants for the gene. OPC-8:CoA ligase expression was activated in response to wounding or infection in the wild type but was undetectable in the mutants, which also exhibited OPC-8 accumulation and reduced levels of JA. In addition, the developmental, tissue- and cell-type specific expression pattern of the gene, and regulatory properties of its promoter were monitored by analysing promoter::GUS reporter lines. Collectively, the results demonstrate that OPC-8:CoA ligase catalyses an essential step in JA biosynthesis by initiating the β-oxidative chain shortening of the carboxylic acid side chain of its precursors, and, in accordance with this function, the protein is localized in peroxisomes. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1706 TI - Pyrone polyketides synthesized by a type III polyketide synthase from Drosophyllum lusitanicum JO - Phytochemistry PY - 2008 SP - 3043-3053 AU - Jindaprasert, A. AU - Springob, K. AU - Schmidt, J. AU - De-Eknamkul, W. AU - Kutchan, T. M. AU - VL - 69 UR - DO - 10.1016/j.phytochem.2008.03.013 AB - To isolate cDNAs involved in the biosynthesis of acetate-derived naphthoquinones in Drosophyllum lusitanicum, an expressed sequence tag analysis was performed. RNA from callus cultures was used to create a cDNA library from which 2004 expressed sequence tags were generated. One cDNA with similarity to known type III polyketide synthases was isolated as full-length sequence and termed DluHKS. The translated polypeptide sequence of DluHKS showed 51–67% identity with other plant type III PKSs. Recombinant DluHKS expressed in Escherichia coli accepted acetyl-coenzyme A (CoA) as starter and carried out sequential decarboxylative condensations with malonyl-CoA yielding α-pyrones from three to six acetate units. However, naphthalenes, the expected products, were not isolated. Since the main compound produced by DluHKS is a hexaketide α-pyrone, and the naphthoquinones in D. lusitanicum are composed of six acetate units, we propose that the enzyme provides the backbone of these secondary metabolites. An involvement of accessory proteins in this biosynthetic pathway is discussed. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 1700 TI - A novel plastidial lipoxygenase of maize (Zea mays) ZmLOX6 encodes for a fatty acid hydroperoxide lyase and is uniquely regulated by phytohormones and pathogen infection JO - Planta PY - 2008 SP - 491-503 AU - Gao, X. AU - Stumpe, M. AU - Feussner, I. AU - Kolomiets, M. AU - VL - 227 UR - DO - 10.1007/s00425-007-0634-8 AB - Lipoxygenases (LOXs) are members of a large enzyme family that catalyze oxygenation of free polyunsaturated fatty acids into diverse hydroperoxide compounds, collectively called oxylipins. Although LOXs have been well studied in dicot species, reports of the genes encoding these enzymes are scarce for monocots, especially maize. Herein, we reported the cloning, characterization and molecular functional analysis of a novel maize LOX gene, ZmLOX6. The ZmLOX6 nucleotide sequence encodes a deduced translation product of 892 amino acids. Phylogenetic analysis showed that ZmLOX6 is distantly related to previously reported 9- or 13-LOXs from maize and other plant species, including rice and Arabidopsis. Although sequence prediction suggested cytoplasmic localization of this protein, ZmLOX6 protein has been reportedly isolated from mesophyll cell chloroplasts, emphasizing the unique features of this protein. Plastidial localization was confirmed by chloroplast uptake experiments with the in vitro translated protein. Analysis of recombinant protein revealed that ZmLOX6 has lost fatty acid hydroperoxide forming activity but 13-LOX-derived fatty acid hydroperoxides were cleaved into odd-chain ω-oxo fatty acids and as yet not identified C5-compound. In line with its reported abundance in mesophyll cells, ZmLOX6 was predominantly expressed in leaf tissue. Northern blot analysis demonstrated that ZmLOX6 was induced by jasmonic acid, but repressed by abscisic acid, salicylic acid and ethylene and was not responsive to wounding or insects. Further, this gene was strongly induced by the fungal pathogen Cochliobolus carbonum during compatible interactions, suggesting that ZmLOX6 may contribute to susceptibility to this pathogen. The potential involvement of ZmLOX6 in maize interactions with pathogens is discussed. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1697 TI - 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 JO - Plant J. PY - 2008 SP - 86-100 AU - Floß, D. S. AU - Hause, B. AU - Lange, P. R. AU - Küster, H. AU - Strack, D. AU - Walter, M. H. AU - VL - 56 UR - DO - 10.1111/j.1365-313X.2008.03575.x AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1696 TI - Tapetum-specific location of a cation-dependent O-methyltransferase in Arabidopsis thaliana JO - Plant J. PY - 2008 SP - 132-145 AU - Fellenberg, C. AU - Milkowski, C. AU - Hause, B. AU - Lange, P.-R. AU - Böttcher, C. AU - Schmidt, J. AU - Vogt, T. AU - VL - 56 UR - DO - 10.1111/j.1365-313X.2008.03576.x AB - 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 . A2 - C1 - Bioorganic Chemistry; Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1687 TI - Reduced V-ATPase Activity in the trans-Golgi Network Causes Oxylipin-Dependent Hypocotyl Growth Inhibition in Arabidopsis JO - Plant Cell PY - 2008 SP - 1088-1100 AU - Brüx, A. AU - Liu, T.-Y. AU - Krebs, M. AU - Stierhof, Y.-D. AU - Lohmann, J. U. AU - Miersch, O. AU - Wasternack, C. AU - Schumacher, K. AU - VL - 20 UR - DO - 10.1105/tpc.108.058362 AB - Regulated cell expansion allows plants to adapt their morphogenesis to prevailing environmental conditions. Cell expansion is driven by turgor pressure created by osmotic water uptake and is restricted by the extensibility of the cell wall, which in turn is regulated by the synthesis, incorporation, and cross-linking of new cell wall components. The vacuolar H+-ATPase (V-ATPase) could provide a way to coordinately regulate turgor pressure and cell wall synthesis, as it energizes the secondary active transport of solutes across the tonoplast and also has an important function in the trans-Golgi network (TGN), which affects synthesis and trafficking of cell wall components. We have previously shown that det3, a mutant with reduced V-ATPase activity, has a severe defect in cell expansion. However, it was not clear if this is caused by a defect in turgor pressure or in cell wall synthesis. Here, we show that inhibition of the tonoplast-localized V-ATPase subunit isoform VHA-a3 does not impair cell expansion. By contrast, inhibition of the TGN-localized isoform VHA-a1 is sufficient to restrict cell expansion. Furthermore, we provide evidence that the reduced hypocotyl cell expansion in det3 is conditional and due to active, hormone-mediated growth inhibition caused by a cell wall defect. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1830 TI - Immunomodulation of jasmonate to manipulate the wound response JO - J. Exp. Bot. PY - 2007 SP - 2525-2535 AU - ten Hoopen, P. AU - Hunger, A. AU - Muller, A. AU - Hause, B. AU - Kramell, R. AU - Wasternack, C. AU - Rosahl, S. AU - Conrad, U. AU - VL - 58 UR - DO - 10.1093/jxb/erm122 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing; Biochemistry of Plant Interactions ER - TY - JOUR ID - 1821 TI - Isolation and characterization of the glutaminyl cyclases from Solanum tuberosum and Arabidopsis thaliana: implications for physiological functions JO - Biol. Chem. PY - 2007 SP - 145-153 AU - Schilling, S. AU - Stenzel, I. AU - von Bohlen, A. AU - Wermann, M. AU - Schulz, K. AU - Demuth, H.-U. AU - Wasternack, C. AU - VL - 388 UR - DO - 10.1515/BC.2007.016 AB - Glutaminyl cyclases (QCs) catalyze the formation of pyroglutamic acid at the N-terminus of several peptides and proteins. On the basis of the amino acid sequence of Carica papaya QC, we identified cDNAs of the putative counterparts from Solanum tuberosum and Arabidopsis thaliana. Upon expression of the corresponding cDNAs from both plants via the secretory pathway of Pichia pastoris, two active QC proteins were isolated. The specificity of the purified proteins was assessed using various substrates with different amino acid composition and length. Highest specificities were observed with substrates possessing large hydrophobic residues adjacent to the N-terminal glutamine and for fluorogenic dipeptide surrogates. However, compared to Carica papaya QC, the specificity constants were approximately one order of magnitude lower for most of the QC substrates analyzed. The QCs also catalyzed the conversion of N-terminal glutamic acid to pyroglutamic acid, but with approximately 105- to 106-fold lower specificity. The ubiquitous distribution of plant QCs prompted a search for potential substrates in plants. Based on database entries, numerous proteins, e.g., pathogenesis-related proteins, were found that carry a pyroglutamate residue at the N-terminus, suggesting QC involvement. The putative relevance of QCs and pyroglutamic acid for plant defense reactions is discussed. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1813 TI - Cold and water stresses produce changes in endogenous jasmonates in two populations of Pinus pinaster Ait JO - Plant Growth Regul. PY - 2007 SP - 111-116 AU - Pedranzani, H. AU - Sierra-de-Grado, R. AU - Vigliocco, A. AU - Miersch, O. AU - Abdala, G. AU - VL - 52 UR - DO - 10.1007/s10725-007-9166-2 AB - There is considerable evidence suggesting that jasmonates (JAs) play a role in plant resistance against abiotic stress. It is well known that in Angiosperms JAs are involved in the defense response, however there is little information about their role in Gymnosperms. Our proposal was to study the involvement of JAs in Pinus pinaster Ait. reaction to cold and water stress, and to compare the response of two populations of different provenances (Gredos and Bajo Tiétar) to these stresses. We detected 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), and the hydroxylates 11-hydroxyjasmonate and 12-hydroxyjasmonate in foliage and shoots of P. pinaster plants. The response of the Gredos population to cold stress differed from that of Bajo Tiétar. Gredos plants showed a lower JA-basal level than Bajo Tiétar; under cold stress JA increased twofold at 72 h, while it decreased in Bajo Tiétar plants. The hydroxylates slightly increased in both populations due to cold stress treatment. Under water stress, plants from Gredos showed a remarkable JA-increase; thus the JA-response was much more prominent under water stress than under cold stress. In contrast, no change was found in JA-level in Bajo Tiétar plants under water stress. The level of JA-precursor, OPDA, was very low in control plants from Gredos and Bajo Tiétar. Under water stress OPDA increased only in plants from Bajo Tiétar. Therefore, we inform here of a different JAs-accumulation pattern after the stress treatment in P. pinaster from two provenances, and suggest a possible correlation with adaptations to diverse ecological conditions. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1801 TI - The Jasmonate-Induced Expression of the Nicotiana tabacum Leaf Lectin JO - Plant Cell Physiol. PY - 2007 SP - 1207-1218 AU - Lannoo, N. AU - Vandenborre, G. AU - Miersch, O. AU - Smagghe, G. AU - Wasternack, C. AU - Peumans, W. J. AU - Van Damme, E. J. M. AU - VL - 48 UR - DO - 10.1093/pcp/pcm090 AB - Previous experiments with tobacco (Nicotiana tabacum L. cv Samsun NN) plants revealed that jasmonic acid methyl ester (JAME) induces the expression of a cytoplasmic/nuclear lectin in leaf cells and provided the first evidence that jasmonates affect the expression of carbohydrate-binding proteins in plant cells. To corroborate the induced accumulation of relatively large amounts of a cytoplasmic/nuclear lectin, a detailed study was performed on the induction of the lectin in both intact tobacco plants and excised leaves. Experiments with different stress factors demonstrated that the lectin is exclusively induced by exogeneously applied jasmonic acid and JAME, and to a lesser extent by insect herbivory. The lectin concentration depends on leaf age and the position of the tissue in the leaf. JAME acts systemically in intact plants but very locally in excised leaves. Kinetic analyses indicated that the lectin is synthesized within 12 h exposure time to JAME, reaching a maximum after 60 h. After removal of JAME, the lectin progressively disappears from the leaf tissue. The JAME-induced accumulation of an abundant nuclear/cytoplasmic lectin is discussed in view of the possible role of this lectin in the plant. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1792 TI - Substrate specificity and products of side-reactions catalyzed by jasmonate:amino acid synthetase (JAR1) JO - FEBS Lett. PY - 2007 SP - 815-820 AU - Guranowski, A. AU - Miersch, O. AU - Staswick, P. E. AU - Suza, W. AU - Wasternack, C. AU - VL - 581 UR - DO - 10.1016/j.febslet.2007.01.049 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1783 TI - “Chromoplast” development in arbuscular mycorrhizal roots JO - Phytochemistry PY - 2007 SP - 92-100 AU - Fester, T. AU - Lohse, S. AU - Halfmann, K. AU - VL - 68 UR - DO - 10.1016/j.phytochem.2006.09.034 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1781 TI - Reduction of divinyl ether-containing polyunsaturated fatty acids in transgenic potato plants JO - Phytochemistry PY - 2007 SP - 797-801 AU - Eschen-Lippold, L. AU - Rothe, G. AU - Stumpe, M. AU - Göbel, C. AU - Feussner, I. AU - Rosahl, S. AU - VL - 68 UR - DO - 10.1016/j.phytochem.2006.12.010 AB - Oxygenated polyunsaturated fatty acids synthesized via the lipoxygenase pathway play a role in plant responses to pathogen attack. In solanaceous plants, the preferential stimulation of the 9-lipoxygenase pathway in response to pathogen infection leads to the formation of the divinyl ether-containing polyunsaturated fatty acids colneleic and colnelenic acid, as well as hydroxy and trihydroxy polyunsaturated fatty acids. To functionally assess the role of divinyl ethers, transgenic potato plants were generated which express an RNA interference construct directed against the pathogen-inducible 9-divinyl ether synthase. Efficient reduction of 9-divinyl ether synthase transcript accumulation correlated with reduced levels of colneleic and colnelenic acid. However, in response to infection with virulent Phytophthora infestans, the causal agent of late blight disease, no significant differences in pathogen biomass could be detected suggesting that the levels of antimicrobial divinyl ethers are not critical for defense against Phytophthora infestans in a compatible interaction. A2 - C1 - Molecular Signal Processing; Biochemistry of Plant Interactions ER - TY - JOUR ID - 1780 TI - Chronobiological phenomena and seasonal changes in jasmonate levels during the course of the year and under constant conditions in mistletoe (Viscum album L.) JO - Phytomedicine PY - 2007 SP - 15 AU - Dorka, R. AU - Miersch, O. AU - Wasternack, C. AU - Weik, P. AU - VL - 14 UR - DO - 10.1016/j.phymed.2007.07.014 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1776 TI - Jasmonate biosynthesis in Arabidopsis thaliana requires peroxisomal β-oxidation enzymes – Additional proof by properties of pex6 and aim1 JO - Phytochemistry PY - 2007 SP - 1642-1650 AU - Delker, C. AU - Zolman, B. K. AU - Miersch, O. AU - Wasternack, C. AU - VL - 68 UR - DO - 10.1016/j.phytochem.2007.04.024 AB - Jasmonic acid (JA) is an important regulator of plant development and stress responses. Several enzymes involved in the biosynthesis of JA from α-linolenic acid have been characterized. The final biosynthesis steps are the β-oxidation of 12-oxo-phytoenoic acid. We analyzed JA biosynthesis in the Arabidopsis mutants pex6, affected in peroxisome biogenesis, and aim1, disrupted in fatty acid β-oxidation. Upon wounding, these mutants exhibit reduced JA levels compared to wild type. pex6 accumulated the precursor OPDA. Feeding experiments with deuterated OPDA substantiate this accumulation pattern, suggesting the mutants are impaired in the β-oxidation of JA biosynthesis at different steps. Decreased expression of JA-responsive genes, such as VSP1, VSP2, AtJRG21 and LOX2, following wounding in the mutants compared to the wild type reflects the reduced JA levels of the mutants. By use of these additional mutants in combination with feeding experiments, the necessity of functional peroxisomes for JA-biosynthesis is confirmed. Furthermore an essential function of one of the two multifunctional proteins of fatty acid β-oxidation (AIM1) for wound-induced JA formation is demonstrated for the first time. These data confirm that JA biosynthesis occurs via peroxisomal fatty acid β-oxidation machinery. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1840 TI - Jasmonates: An Update on Biosynthesis, Signal Transduction and Action in Plant Stress Response, Growth and Development JO - Ann. Bot. PY - 2007 SP - 681-697 AU - Wasternack, C. AU - VL - 100 UR - DO - 10.1093/aob/mcm079 AB - BackgroundJasmonates are ubiquitously occurring lipid-derived compounds with signal functions in plant responses to abiotic and biotic stresses, as well as in plant growth and development. Jasmonic acid and its various metabolites are members of the oxylipin family. Many of them alter gene expression positively or negatively in a regulatory network with synergistic and antagonistic effects in relation to other plant hormones such as salicylate, auxin, ethylene and abscisic acid.ScopeThis review summarizes biosynthesis and signal transduction of jasmonates with emphasis on new findings in relation to enzymes, their crystal structure, new compounds detected in the oxylipin and jasmonate families, and newly found functions.ConclusionsCrystal structure of enzymes in jasmonate biosynthesis, increasing number of jasmonate metabolites and newly identified components of the jasmonate signal-transduction pathway, including specifically acting transcription factors, have led to new insights into jasmonate action, but its receptor(s) is/are still missing, in contrast to all other plant hormones. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1839 TI - Clarence A. “Bud” Ryan (29.09.1931–07.10.2007) JO - Plant Mol. Biol. PY - 2007 SP - 709-709 AU - Wasternack, C. AU - VL - 65 UR - DO - 10.1007/s11103-007-9254-8 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1837 TI - Endogenous jasmonates in dry and imbibed sunflower seeds from plants grown at different soil moisture contents JO - Seed Sci. Res. PY - 2007 SP - 91-98 AU - Vigliocco, A. AU - Alemano, S. AU - Miersch, O. AU - Alvarez, D. AU - Abdala, G. AU - VL - 17 UR - DO - 10.1017/S0960258507708371 AB - In this study, we characterized two sunflower (Helianthus annuus L.) lines with differential sensitivity to drought, the sensitive line B59 and the tolerant line B71. Using both lines, we compared the content of endogenous jasmonates (JAs) in dry and imbibed seeds from plants grown under irrigation and drought. Jasmonic acid (JA), 12-oxo-phytodienoic acid (OPDA), 11-hydroxyjasmonate (11-OH-JA) and 12-hydroxyjasmonate (12-OH-JA) were detected in dry and imbibed sunflower seeds. Seeds from plants grown under drought had a lower content of total JAs and exhibited higher germination percentages than seeds from irrigated plants, demonstrating that environmental conditions have a strong influence on the progeny. OPDA and 12-OH-JA were the main compounds found in dry seeds of both lines. Imbibed seeds showed an enhanced amount of total JAs with respect to dry seeds produced by plants grown in both soil moisture conditions. Imbibition triggered a dramatic OPDA increase in the embryo, suggesting a role of this compound in germination. We conclude that JAs patterns vary during sunflower germination and that the environmental conditions experienced by the mother plant modify the hormonal content of the seed progeny. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 118 TI - Jasmonate signaling in tomato – The input of tissue-specific occurrence of allene oxide cyclase and JA metabolites T2 - Proceeding of the 17th Int. Symp. on Plant Lipids PB - PY - 2007 SP - 107-111 AU - Wasternack, C. AU - Hause, B. AU - Stenzel, I. AU - Goetz, S. AU - Feussner, I. AU - Miersch, O. AU - VL - UR - AB - A2 - Benning C., Ollrogge, J. C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 1904 TI - Transgenic barley plants overexpressing a 13-lipoxygenase to modify oxylipin signature JO - Phytochemistry PY - 2006 SP - 264-276 AU - Sharma, V. K. AU - Monostori, T. AU - Göbel, C. AU - Hänsch, R. AU - Bittner, F. AU - Wasternack, C. AU - Feussner, I. AU - Mendel, R. R. AU - Hause, B. AU - Schulze, J. AU - VL - 67 UR - DO - 10.1016/j.phytochem.2005.11.009 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1889 TI - The Outcomes of Concentration-Specific Interactions between Salicylate and Jasmonate Signaling Include Synergy, Antagonism, and Oxidative Stress Leading to Cell Death JO - Plant Physiol. PY - 2006 SP - 249-262 AU - Mur, L. A. AU - Kenton, P. AU - Atzorn, R. AU - Miersch, O. AU - Wasternack, C. AU - VL - 140 UR - DO - 10.1104/pp.105.072348 AB - Salicylic acid (SA) has been proposed to antagonize jasmonic acid (JA) biosynthesis and signaling. We report, however, that in salicylate hydroxylase-expressing tobacco (Nicotiana tabacum) plants, where SA levels were reduced, JA levels were not elevated during a hypersensitive response elicited by Pseudomonas syringae pv phaseolicola. The effects of cotreatment with various concentrations of SA and JA were assessed in tobacco and Arabidopsis (Arabidopsis thaliana). These suggested that there was a transient synergistic enhancement in the expression of genes associated with either JA (PDF1.2 [defensin] and Thi1.2 [thionin]) or SA (PR1 [PR1a-β-glucuronidase in tobacco]) signaling when both signals were applied at low (typically 10–100 μm) concentrations. Antagonism was observed at more prolonged treatment times or at higher concentrations. Similar results were also observed when adding the JA precursor, α-linolenic acid with SA. Synergic effects on gene expression and plant stress were NPR1- and COI1-dependent, SA- and JA-signaling components, respectively. Electrolyte leakage and Evans blue staining indicated that application of higher concentrations of SA + JA induced plant stress or death and elicited the generation of apoplastic reactive oxygen species. This was indicated by enhancement of hydrogen peroxide-responsive AoPR10-β-glucuronidase expression, suppression of plant stress/death using catalase, and direct hydrogen peroxide measurements. Our data suggests that the outcomes of JA-SA interactions could be tailored to pathogen/pest attack by the relative concentration of each hormone. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1928 TI - Comparative transcript and alkaloid profiling in Papaver species identifies a short chain dehydrogenase/reductase involved in morphine biosynthesis JO - Plant J. PY - 2006 SP - 177-192 AU - Ziegler, J. AU - Voigtländer, S. AU - Schmidt, J. AU - Kramell, R. AU - Miersch, O. AU - Ammer, C. AU - Gesell, A. AU - Kutchan, T. M. AU - VL - 48 UR - DO - 10.1111/j.1365-313X.2006.02860.x AB - Plants of the order Ranunculales, especially members of the species Papaver , accumulate a large variety of benzylisoquinoline alkaloids with about 2500 structures, but only the opium poppy (Papaver somniferum ) and Papaver setigerum are able to produce the analgesic and narcotic morphine and the antitussive codeine. In this study, we investigated the molecular basis for this exceptional biosynthetic capability by comparison of alkaloid profiles with gene expression profiles between 16 different Papaver species. Out of 2000 expressed sequence tags obtained from P. somniferum , 69 show increased expression in morphinan alkaloid‐containing species. One of these cDNAs, exhibiting an expression pattern very similar to previously isolated cDNAs coding for enzymes in benzylisoquinoline biosynthesis, showed the highest amino acid identity to reductases in menthol biosynthesis. After overexpression, the protein encoded by this cDNA reduced the keto group of salutaridine yielding salutaridinol, an intermediate in morphine biosynthesis. The stereoisomer 7‐epi ‐salutaridinol was not formed. Based on its similarities to a previously purified protein from P. somniferum with respect to the high substrate specificity, molecular mass and kinetic data, the recombinant protein was identified as salutaridine reductase (SalR; EC 1.1.1.248). Unlike codeinone reductase, an enzyme acting later in the pathway that catalyses the reduction of a keto group and which belongs to the family of the aldo‐keto reductases, the cDNA identified in this study as SalR belongs to the family of short chain dehydrogenases/reductases and is related to reductases in monoterpene metabolism. A2 - C1 - Bioorganic Chemistry; Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1919 TI - The wound response in tomato – Role of jasmonic acid JO - J. Plant Physiol. PY - 2006 SP - 297-306 AU - Wasternack, C. AU - Stenzel, I. AU - Hause, B. AU - Hause, G. AU - Kutter, C. AU - Maucher, H. AU - Neumerkel, J. AU - Feussner, I. AU - Miersch, O. AU - VL - 163 UR - DO - 10.1016/j.jplph.2005.10.014 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1918 TI - Jasmonates - Biosynthesis, Signal Transduction and Action (Annals of Botany Lecture) JO - Jap. Soc. Chem. Regul Plants, Abstr. PY - 2006 SP - 11 AU - Wasternack, C. AU - VL - 41 UR - DO - 10.18978/jscrpanb.41.0_11 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1907 TI - Gene expression patterns reveal tissue-specific signaling networks controlling programmed cell death and ABA- regulated maturation in developing barley seeds JO - Plant J. PY - 2006 SP - 310-327 AU - Sreenivasulu, N. AU - Radchuk, V. AU - Strickert, M. AU - Miersch, O. AU - Weschke, W. AU - Wobus, U. AU - VL - 47 UR - DO - 10.1111/j.1365-313X.2006.02789.x AB - Gene expression patterns covering over 10 000 seed‐expressed sequences were analyzed by macroarray technology in maternal tissue (mainly pericarp) and filial endosperm and embryo during barley seed development from anthesis until late maturation. Defined sets of genes showing distinct expression patterns characterized both tissue type and major developmental phases. The analysis focused on regulatory networks involved in programmed cell death (PCD) and abscisic acid (ABA)‐mediated maturation. These processes were similar in the different tissues, but typically involved the expression of alternative members of a common gene family. The analysis of co‐expressed gene sets and the identification of cis regulatory elements in orthologous rice gene ‘promoter’ regions suggest that PCD in the pericarp is mediated by distinct classes of proteases and is under the hormonal control of both jasmonic acid (JA) and ethylene via ethylene‐responsive element binding protein (EREBP) transcription factors (TFs). On the other hand, PCD in endosperm apparently involves only the ethylene pathway, but employs distinct gene family members from those active in the pericarp, and a different set of proteases and TFs. JA biosynthetic genes are hardly activated. Accordingly, JA levels are high in the pericarp but low in the endosperm during middle and late developmental stages. Similarly, genes acting in the deduced ABA biosynthetic pathway and signaling network differ between endosperm and embryo. ABA in the endosperm appears to exert an influence over storage product synthesis via SNF1 kinase. In the embryo, ABA seems to influence the acquisition of desiccation tolerance via ABA response element binding factors, but the data also suggest the existence of an ABA‐independent but interactive pathway acting via the dehydration‐responsive element binding (DREB) 2A TF. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1864 TI - Interaction between Nitric Oxide and Ethylene in the Induction of Alternative Oxidase in Ozone-Treated Tobacco Plants JO - Plant Physiol. PY - 2006 SP - 595-608 AU - Ederli, L. AU - Morettini, R. AU - Borgogni, A. AU - Wasternack, C. AU - Miersch, O. AU - Reale, L. AU - Ferranti, F. AU - Tosti, N. AU - Pasqualini, S. AU - VL - 142 UR - DO - 10.1104/pp.106.085472 AB - The higher plant mitochondrial electron transport chain contains, in addition to the cytochrome chain, an alternative pathway that terminates with a single homodimeric protein, the alternative oxidase (AOX). We recorded temporary inhibition of cytochrome capacity respiration and activation of AOX pathway capacity in tobacco plants (Nicotiana tabacum L. cv BelW3) fumigated with ozone (O3). The AOX1a gene was used as a molecular probe to investigate its regulation by signal molecules such as hydrogen peroxide, nitric oxide (NO), ethylene (ET), salicylic acid, and jasmonic acid (JA), all of them reported to be involved in the O3 response. Fumigation leads to accumulation of hydrogen peroxide in mitochondria and early accumulation of NO in leaf tissues. Although ET accumulation was high in leaf tissues 5 h after the start of O3 fumigation, it declined during the recovery period. There were no differences in the JA and 12-oxo-phytodienoic acid levels of treated and untreated plants. NO, JA, and ET induced AOX1a mRNA accumulation. Using pharmacological inhibition of ET and NO, we demonstrate that both NO- and ET-dependent pathways are required for O3-induced up-regulation of AOX1a. However, only NO is indispensable for the activation of AOX1a gene expression. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1861 TI - Jasmonate Biosynthesis in Arabidopsis thaliana - Enzymes, Products, Regulation JO - Plant Biol. PY - 2006 SP - 297-306 AU - Delker, C. AU - Stenzel, I. AU - Hause, B. AU - Miersch, O. AU - Feussner, I. AU - Wasternack, C. AU - VL - 8 UR - DO - 10.1055/s-2006-923935 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - CHAP ID - 126 TI - Oxylipins: Biosynthesis, Signal Transduction and Action T2 - Plant Hormone Signaling PB - Annu. Plant Rev. PY - 2006 SP - 185-228 AU - Wasternack, C. AU - VL - 24 UR - SN - 9780470988800 DO - 10.1002/9780470988800.ch7 AB - This chapter contains sections titled:Introductionα‐Dioxygenase, phytoprostanes and electrophile compoundsThe LOX pathwayMutants in JA biosynthesis and in JA signalingJA, OPDA and related compounds in plant‐defense reactionsJA in developmentConcluding remarksAcknowledgements A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1931 TI - Endogenous jasmonates and octadecanoids in hypersensitive tomato mutants during germination and seedling development in response to abiotic stress JO - Seed Sci. Res. PY - 2005 SP - 309-318 AU - Andrade, A. AU - Vigliocco, A. AU - Alemano, S. AU - Miersch, O. AU - Botella, M. A. AU - Abdala, G. AU - VL - 15 UR - DO - 10.1079/SSR2005219 AB - Although jasmonates (JAs) are involved in germination and seedling development, the regulatory mechanism of JAs, and their relation with endogenous level modifications in these processes, is not well understood. We report here the detection of 12-oxo-phytodienoic acid (OPDA), jasmonic acid (JA), 11-hydroxyjasmonate (11-OH-JA), 12-hydroxyjasmonate (12-OH-JA) and methyljasmonate (JAME) in unimbibed seeds and seedlings of tomato Lycopersicon esculentum Mill cv. Moneymaker (wild type) and tss1, tss2, tos1 mutants. The main compounds in wild-type and tss1, tss2, tos1 seeds were the hydroxylate-JAs; 12-OH-JA was the major component in dry seeds of the wild type and in tss2 and tos1. The amounts of these derivatives were higher in seeds than in seedlings. Changes in JAs during wild-type and tss1 imbibition were analysed in seeds and the imbibition water. In wild-type imbibed seeds, 11-OH-JA content was higher than in tss1. 12-OH-JA showed a different tendency with respect to 11-OH-JA, with high levels in the wild type at early imbibition. In tss1, levels of 12-OH-JA rose from 24 to 48 h of imbibition. At 72 h of imbibition, when radicles had emerged, the amounts of both hydroxylates in wild-type and tss1 seeds were minimal. An important release of the hydroxylate forms was observed in the imbibition water. 11-OH-JA decreased in the imbibition water of wild-type seeds at 48 h. On the contrary, a high and sustained liberation of this compound was observed in tss1 after 24 h. 12-OH-JA increased in wild-type as well in tss1 until 24 h. Thereafter, a substantial reduction in the content of this compound was registered. NaCl-treated wild-type seedlings increased their 12-OH-JA, but tss1 seedlings increased their JA in response to salt treatment. In tss2 seedlings, NaCl caused a slight decrease in 11-OH-JA and JAME, whereas tos1 seedlings showed a dramatic OPDA and 12-OH-JA decrease in response to salt treatment. Under salt stress the mutant seedlings showed different patterns of JAs according to their differential hypersensitivity to abiotic stress. The JA-hydroxylate forms found, and the differential accumulation of JAs during germination, imbibition and seedling development, as well as their response to NaCl stress, provide new evidence about the control of many developmental processes by JA. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1941 TI - Hydroxylated jasmonate levels during stolon to tuber transition in Solarium tuberosum L JO - Potato Res. PY - 2005 SP - 107 AU - Cenzano, A. AU - Vigliocc, A. AU - Miersch, O. AU - Abdala, G. AU - VL - 48 UR - DO - 10.1007/BF02742370 AB - Various octadecanoids and derived compounds have been identified in potato leaves. However, information regarding jasmonate hydroxylated forms in stolons or tubers is scarce. We investigated endogenous jasmonates in stolon material ofSolarium tuberosum cv. Spunta. Stolons and incipient tubers were collected from 8 weeks old plants. The material was cut into apical regions and stolons. We identified jasmonic acid (JA), methyl jasmonate, 11-OH-JA, 12-OH-JA, 12-oxo-phytodienoic acid (OPDA) and a conjugate. The content of JA and 12OH-JA decreased in the apical region but remained high in stolons during tuberization. Thus the apical region might be a site of JAs-utilization or metabolization and stolons might supply JAs to that region. The content of 12-OH-JA was higher than that of 11-OH-JA in all stages analyzed, both in apical regions and stolons. However, these compounds showed a different time-course in the apical region: while 11-OH-JA increased, 12-OH-JA decreased. Thus, JA from leaves or roots could be transported as 12-OH-JA to the apical region, stimulating tuber formation. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1960 TI - Suppression of Allene Oxide Cyclase in Hairy Roots of Medicago truncatula Reduces Jasmonate Levels and the Degree of Mycorrhization with Glomus intraradices JO - Plant Physiol. PY - 2005 SP - 1401-1410 AU - Isayenkov, S. AU - Mrosk, C. AU - Stenzel, I. AU - Strack, D. AU - Hause, B. AU - VL - 139 UR - DO - 10.1104/pp.105.069054 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 1952 TI - Lipoxygenase-mediated metabolism of storage lipids in germinating sunflower cotyledons and β-oxidation of (9Z,11E,13S)-13-hydroxy-octadeca-9,11-dienoic acid by the cotyledonary glyoxysomes JO - Planta PY - 2005 SP - 919-930 AU - Gerhardt, B. AU - Fischer, K. AU - Balkenhohl, T. J. AU - Pohnert, G. AU - Kühn, H. AU - Wasternack, C. AU - Feussner, I. AU - VL - 220 UR - DO - 10.1007/s00425-004-1408-1 AB - During the early stages of germination, a lipid-body lipoxygenase is expressed in the cotyledons of sunflowers (Helianthus annuus L.). In order to obtain evidence for the in vivo activity of this enzyme during germination, we analyzed the lipoxygenase-dependent metabolism of polyunsaturated fatty acids esterified in the storage lipids. For this purpose, lipid bodies were isolated from etiolated sunflower cotyledons at different stages of germination, and the storage triacylglycerols were analyzed for oxygenated derivatives. During the time course of germination the amount of oxygenated storage lipids was strongly augmented, and we detected triacylglycerols containing one, two or three residues of (9Z,11E,13S)-13-hydro(pero)xy-octadeca-9,11-dienoic acid. Glyoxysomes from etiolated sunflower cotyledons converted (9Z,11E,13S)-13-hydroxy-octadeca-9,11-dienoic acid to (9Z,11E)-13-oxo-octadeca-9,11-dienoic acid via an NADH-dependent dehydrogenase reaction. Both oxygenated fatty acid derivatives were activated to the corresponding CoA esters and subsequently metabolized to compounds of shorter chain length. Cofactor requirement and formation of acetyl-CoA indicate degradation via β-oxidation. However, β-oxidation only proceeded for two consecutive cycles, leading to accumulation of a medium-chain metabolite carrying an oxo group at C-9, equivalent to C-13 of the parent (9Z,11E,13S)-13-hydroxy-octadeca-9,11-dienoic acid. Short-chain β-oxidation intermediates were not detected during incubation. Similar results were obtained when 13-hydroxy octadecanoic acid was used as β-oxidation substrate. On the other hand, the degradation of (9Z,11E)-octadeca-9,11-dienoic acid was accompanied by the appearance of short-chain β-oxidation intermediates in the reaction mixture. The results suggest that the hydroxyl/oxo group at C-13 of lipoxygenase-derived fatty acids forms a barrier to continuous β-oxidation by glyoxysomes. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1949 TI - Expression of Allene Oxide Cyclase and Accumulation of Jasmonates during Organogenic Nodule Formation from Hop (Humulus lupulus var. Nugget) Internodes JO - Plant Cell Physiol. PY - 2005 SP - 1713-1723 AU - Fortes, A. M. AU - Miersch, O. AU - Lange, P. R. AU - Malhó, R. AU - Testillano, P. S. AU - Risueño, M. d. C. AU - Wasternack, C. AU - Pais, M. S. AU - VL - 46 UR - DO - 10.1093/pcp/pci187 AB - A crucial step in the biosynthesis of jasmonic acid (JA) is the formation of its stereoisomeric precursor, cis-(+)-12-oxophytodienoic acid (OPDA), which is catalyzed by allene oxide cyclase (AOC, EC 5.3.99.6). A cDNA of AOC was isolated from Humulus lupulus var. Nugget. The ORF of 765 bp encodes a 255 amino acid protein, which carries a putative chloroplast targeting sequence. The recombinant protein without its putative chloroplast target sequence showed significant AOC activity. Previously we demonstrated that wounding induces organogenic nodule formation in hop. Here we show that the AOC transcript level increases in response to wounding of internodes, peaking between 2 and 4 h after wounding. In addition, Western blot analysis showed elevated levels of AOC peaking 24 h after internode inoculation. The AOC increase was accompanied by increased JA levels 24 h after wounding, whereas OPDA had already reached its highest level after 12 h. AOC is mostly present in the vascular bundles of inoculated internodes. During prenodule and nodule formation, AOC levels were still high. JA and OPDA levels decreased down to 10 and 118 pmol (g FW)–1, respectively, during nodule formation, but increased during plantlet regeneration. Double immunolocalization analysis of AOC and Rubisco in connection with lugol staining showed that AOC is present in amyloplasts of prenodular cells and in the chloroplasts of vacuolated nodular cells, whereas meristematic cells accumulated little AOC. These data suggest a role of AOC and jasmonates in organogenic nodule formation and plantlet regeneration from these nodules. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1944 TI - Simultaneous Determination of Multiple Phytohormones in Plant Extracts by Liquid Chromatography−Electrospray Tandem Mass Spectrometry JO - J. Agr. Food Chem. PY - 2005 SP - 8437-8442 AU - Durgbanshi, A. AU - Arbona, V. AU - Pozo, O. AU - Miersch, O. AU - Sancho, J. V. AU - Gómez-Cadenas, A. AU - VL - 53 UR - DO - 10.1021/jf050884b AB - A rapid multiresidue method to quantify three different classes of plant hormones has been developed. The reduced concentrations of these metabolites in real samples with complex matrixes require sensitive techniques for their quantification in small amounts of plant tissue. The method described combines high-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Deuterium-labeled standards were added prior to sample extraction to achieve an accurate quantification of abscisic acid, indole-3-acetic acid, and jasmonic acid in a single run. A simple method of extraction and purification involving only centrifugation, a partition against diethyl ether, and filtration was developed and the analytical method validated in four different plant tissues, citrus leaves, papaya roots, barley seedlings, and barley immature embryos. This method represents a clear advantage because it extensively reduces sample preparation and total time for routine analysis of phytohormones in real plant samples. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1942 TI - Concurrent activation of cell death-regulating signaling pathways by singlet oxygen in Arabidopsis thaliana JO - Plant J. PY - 2005 SP - 68-80 AU - Danon, A. AU - Miersch, O. AU - Felix, G. AU - op den Camp, R. G. L. AU - Apel, K. AU - VL - 41 UR - DO - 10.1111/j.1365-313X.2004.02276.x AB - Upon a dark/light shift the conditional flu mutant of Arabidopsis starts to generate singlet oxygen (1O2), a non‐radical reactive oxygen species that is restricted to the plastid compartment. Immediately after the shift, plants stop growing and develop necrotic lesions. We have established a protoplast system, which allows detection and characterization of the death response in flu induced by the release of 1O2. Vitamin B6 that quenches 1O2 in fungi was able to protect flu protoplasts from cell death. Blocking ethylene production was sufficient to partially inhibit the death reaction. Similarly, flu mutant seedlings expressing transgenic NahG were partially protected from the death provoked by the release of 1O2, indicating a requirement for salicylic acid (SA) in this process, whereas in cells depleted of both, ethylene and SA, the extent of cell death was reduced to the wild‐type level. The flu mutant was also crossed with the jasmonic acid (JA)‐depleted mutant opr3 , and with the JA, OPDA and dinor OPDA (dnOPDA)‐depleted dde2‐2 mutant. Analysis of the resulting double mutants revealed that in contrast to the JA‐induced suppression of H2O2/superoxide‐dependent cell death reported earlier, JA promotes singlet oxygen‐mediated cell death in flu , whereas other oxylipins such as OPDA and dnOPDA antagonize this death‐inducing activity of JA. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1990 TI - Lipid metabolism in arbuscular mycorrhizal roots of Medicago truncatula JO - Phytochemistry PY - 2005 SP - 781-791 AU - Stumpe, M. AU - Carsjens, J.-G. AU - Stenzel, I. AU - Göbel, C. AU - Lang, I. AU - Pawlowski, K. AU - Hause, B. AU - Feussner, I. AU - VL - 66 UR - DO - 10.1016/j.phytochem.2005.01.020 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 1989 TI - Genetic transformation of barley to modify expression of a 13-lipoxygenase JO - Acta Biol. Szeged. PY - 2005 SP - 33-34 AU - Sharma, V. K. AU - Monostori, T. AU - Hause, B. AU - Maucher, H. AU - Göbel, C. AU - Hornung, E. AU - Hänsch, R. AU - Bittner, F. AU - Wasternack, C. AU - Feussner, I. AU - Mendel, R. R. AU - Schulze, J. AU - VL - 49 UR - http://abs.bibl.u-szeged.hu/index.php/abs/article/view/2409 AB - 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. A2 - C1 - Cell and Metabolic Biology; Molecular Signal Processing ER - TY - JOUR ID - 1988 TI - A New Type of Peroxisomal Acyl-Coenzyme A Synthetase from Arabidopsis thaliana Has the Catalytic Capacity to Activate Biosynthetic Precursors of Jasmonic Acid JO - J. Biol. Chem. PY - 2005 SP - 13962-13972 AU - Schneider, K. AU - Kienow, L. AU - Schmelzer, E. AU - Colby, T. AU - Bartsch, M. AU - Miersch, O. AU - Wasternack, C. AU - Kombrink, E. AU - Stuible, H.-P. AU - VL - 280 UR - DO - 10.1074/jbc.M413578200 AB - Arabidopsis thaliana contains a large number of genes that encode carboxylic acid-activating enzymes, including nine long-chain fatty acyl-CoA synthetases, four 4-coumarate:CoA ligases (4CL), and 25 4CL-like proteins of unknown biochemical function. Because of their high structural and sequence similarity with bona fide 4CLs and their highly hydrophobic putative substrate-binding pockets, the 4CL-like proteins At4g05160 and At5g63380 were selected for detailed analysis. Following heterologous expression, the purified proteins were subjected to a large scale screen to identify their preferred in vitro substrates. This study uncovered a significant activity of At4g05160 with medium-chain fatty acids, medium-chain fatty acids carrying a phenyl substitution, long-chain fatty acids, as well as the jasmonic acid precursors 12-oxo-phytodienoic acid and 3-oxo-2-(2′-pentenyl)-cyclopentane-1-hexanoic acid. The closest homolog of At4g05160, namely At5g63380, showed high activity with long-chain fatty acids and 12-oxo-phytodienoic acid, the latter representing the most efficiently converted substrate. By using fluorescent-tagged variants, we demonstrated that both 4CL-like proteins are targeted to leaf peroxisomes. Collectively, these data demonstrate that At4g05160 and At5g63380 have the capacity to contribute to jasmonic acid biosynthesis by initiating the β-oxidative chain shortening of its precursors. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1985 TI - Changes in jasmonates and 12-oxophytodienoic acid contents of Medicago sativa L. during somatic embryogenesis JO - Acta Physiol. Plant. PY - 2005 SP - 497-504 AU - Rudus, I. AU - Kepczynska, E. AU - Kepczynski, J. AU - Wasternack, C. AU - Miersch, O. AU - VL - 27 UR - DO - 10.1007/s11738-005-0055-x AB - Jasmonic acid (JA), its methyl ester (MeJA) and the biosynthetic precursor 12-oxophytodienoic acid (OPDA) were detected quantitatively during somatic embryogenesis of Medicago sativa L. Using GC-MS analysis, these compounds were found in initial explants, in calli and in somatic embryos in the nanogram range per gram of fresh weight. In distinct stages of somatic embryogenesis, JA and 12-OPDA accumulated preferentially in cotyledonary embryos. Initial explants exhibited about five-fold higher JA content than OPDA content, whereas in other stages OPDA accumulated predominantly. These data suggest that also in embryogenic tissues OPDA and JA may have individual signalling properties. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1972 TI - Lack of mycorrhizal autoregulation and phytohormonal changes in the supernodulating soybean mutant nts1007 JO - Planta PY - 2005 SP - 709-715 AU - Meixner, C. AU - Ludwig-Müller, J. AU - Miersch, O. AU - Gresshoff, P. AU - Staehelin, C. AU - Vierheilig, H. AU - VL - 222 UR - DO - 10.1007/s00425-005-0003-4 AB - Autoregulatory mechanisms have been reported in the rhizobial and the mycorrhizal symbiosis. Autoregulation means that already existing nodules or an existing root colonization by an arbuscular mycorrhizal fungus systemically suppress subsequent nodule formation/root colonization in other parts of the root system. Mutants of some legumes lost their ability to autoregulate the nodule number and thus display a supernodulating phenotype. On studying the effect of pre-inoculation of one side of a split-root system with an arbuscular mycorrhizal fungus on subsequent mycorrhization in the second side of the split-root system of a wild-type soybean (Glycine max L.) cv. Bragg and its supernodulating mutant nts1007, we observed a clear suppressional effect in the wild-type, whereas further root colonization in the split-root system of the mutant nts1007 was not suppressed. These data strongly indicate that the mechanisms involved in supernodulation also affect mycorrhization and support the hypothesis that the autoregulation in the rhizobial and the mycorrhizal symbiosis is controlled in a similar manner. The accumulation patterns of the plant hormones IAA, ABA and Jasmonic acid (JA) in non-inoculated control plants and split-root systems of inoculated plants with one mycorrhizal side of the split-root system and one non-mycorrhizal side, indicate an involvement of IAA in the autoregulation of mycorrhization. Mycorrhizal colonization of soybeans also resulted in a strong induction of ABA and JA levels, but on the basis of our data the role of these two phytohormones in mycorrhizal autoregulation is questionable. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 1971 TI - Ethylene-mediated cross-talk between calcium-dependent protein kinase and MAPK signaling controls stress responses in plants JO - Proc. Natl. Acad. Sci. U.S.A. PY - 2005 SP - 10736-10741 AU - Ludwig, A. A. AU - Saitoh, H. AU - Felix, G. AU - Freymark, G. AU - Miersch, O. AU - Wasternack, C. AU - Boller, T. AU - Jones, J. D. G. AU - Romeis, T. AU - VL - 102 UR - DO - 10.1073/pnas.0502954102 AB - Plants are constantly exposed to environmental changes and need to integrate multiple external stress cues. Calcium-dependent protein kinases (CDPKs) are implicated as major primary Ca2+ sensors in plants. CDPK activation, like activation of mitogen-activated protein kinases (MAPKs), is triggered by biotic and abiotic stresses, although distinct stimulus-specific stress responses are induced. To investigate whether CDPKs are part of an underlying mechanism to guarantee response specificity, we identified CDPK-controlled signaling pathways. A truncated form of Nicotiana tabacum CDPK2 lacking its regulatory autoinhibitor and calcium-binding domains was ectopically expressed in Nicotiana benthamiana. Infiltrated leaves responded to an abiotic stress stimulus with the activation of biotic stress reactions. These responses included synthesis of reactive oxygen species, defense gene induction, and SGT1-dependent cell death. Furthermore, N-terminal CDPK2 signaling triggered enhanced levels of the phytohormones jasmonic acid, 12-oxo-phytodienoic acid, and ethylene but not salicylic acid. These responses, commonly only observed after challenge with a strong biotic stimulus, were prevented when the CDPK's intrinsic autoinhibitory peptide was coexpressed. Remarkably, elevated CDPK signaling compromised stress-induced MAPK activation, and this inhibition required ethylene synthesis and perception. These data indicate that CDPK and MAPK pathways do not function independently and that a concerted activation of both pathways controls response specificity to biotic and abiotic stress. A2 - C1 - Molecular Signal Processing; Biochemistry of Plant Interactions ER - TY - JOUR ID - 2029 TI - Phloem-specific expression of the wound-inducible ribonuclease LE from tomato (Lycopersicon esculentum cv. Lukullus) JO - Planta PY - 2004 SP - 233-242 AU - Köck, M. AU - Groß, N. AU - Stenzel, I. AU - Hause, G. AU - VL - 219 UR - DO - 10.1007/s00425-004-1227-4 AB - Ribonuclease LE (RNaseLE) from tomato (Lycopersicon esculentum Mill. cv. Lukullus) belongs to the widespread RNase T2 family of ribonucleases. With the exception of S-RNases of the solanaceous self-incompatibility system the functions of other members of the RNase T2 family are only barely understood. Using a 2.6-kbp putative promoter sequence of RNaseLE in front of the uidA reporter gene, expression of β-glucuronidase in developing phloem tissue and, especially, in the meristematic and elongation zones at root tips was detected. The tissue-specific expression accords with the range of cis-acting elements detected in the RNaseLE promoter. RNaseLE mRNA was localized in developing phloem cells but not in mature phloem tissue, suggesting association of RNaseLE expression with phloem development. Histochemical staining of β-glucuronidase activity as well as detailed inspection of RNaseLE at mRNA, protein and enzyme activity levels revealed that the wound-induced expression of RNaseLE was also restricted to vascular tissue. RNaseLE transcript accumulation detected by in situ hybridization occurred preferentially in phloem and cambial cells of stem sections upon wounding. The data provide evidence for a role of RNaseLE in a tissue-specific wound response and in wound healing of tomato. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2019 TI - Wound-induced RNaseLE expression is jasmonate and systemin independent and occurs only locally in tomato (Lycopersicon esculentum cv. Lukullus) JO - Phytochemistry PY - 2004 SP - 1343-1350 AU - Groß, N. AU - Wasternack, C. AU - Köck, M. AU - VL - 65 UR - DO - 10.1016/j.phytochem.2004.04.036 AB - Tomato RNaseLE is induced by phosphate deficiency and wounding and may play a role in macromolecular recycling as well as wound healing. Here, we analyzed the role of jasmonate and systemin in the wound-induced RNaseLE activation. The rapid expression of RNaseLE upon wounding of leaves leading to maximal RNase activity within 10 h, appeared only locally. Jasmonic acid (JA) or its molecular mimic ethyl indanoyl isoleucine conjugate did not induce RNaseLE expression. Correspondingly, RNaseLE was expressed upon wounding of 35S::allene oxide cyclase antisense plants known to be JA deficient. RNaseLE was not expressed upon systemin treatment, but was locally expressed in the spr1 mutant which is affected in systemin perception. In tomato plants carrying a PromLE::uidA construct, GUS activity could be detected upon wounding, but not following treatment with JA or systemin. The data indicate a locally acting wound-inducible systemin- and JA-independent signaling pathway for RNaseLE expression.RNaseLE expression was analyzed by pharmacological studies of different tomato lines and upon wounding of leaves. The gene is only locally activated via a new type of wound-induced signaling pathway in a jasmonate/systemin-independent manner. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2011 TI - Applied jasmonates accumulate extracellularly in tomato, but intracellularly in barley JO - FEBS Lett. PY - 2004 SP - 45-50 AU - Bücking, H. AU - Förster, H. AU - Stenzel, I. AU - Miersch, O. AU - Hause, B. AU - VL - 562 UR - DO - 10.1016/S0014-5793(04)00178-4 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2064 TI - Introductory Remarks on Biosynthesis and Diversity in Actions JO - J. Plant Growth Regul. PY - 2004 SP - 167-169 AU - Wasternack, C. AU - VL - 23 UR - DO - 10.1007/s00344-004-0051-1 AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2052 TI - Coronalon: a powerful tool in plant stress physiology JO - FEBS Lett. PY - 2004 SP - 17-22 AU - Schüler, G. AU - Mithöfer, A. AU - Baldwin, I. T. AU - BERGER, S. AU - Ebel, J. AU - Santos, J. G. AU - Herrmann, G. AU - Hölscher, D. AU - Kramell, R. AU - Kutchan, T. M. AU - Maucher, H. AU - Schneider, B. AU - Stenzel, I. AU - Wasternack, C. AU - Boland, W. AU - VL - 563 UR - DO - 10.1016/S0014-5793(04)00239-X AB - Coronalon, a synthetic 6‐ethyl indanoyl isoleucine conjugate, has been designed as a highly active mimic of octadecanoid phytohormones that are involved in insect and disease resistance. The spectrum of biological activities that is affected by coronalon was investigated in nine different plant systems specifically responding to jasmonates and/or 12‐oxo‐phytodienoic acid. In all bioassays analyzed, coronalon demonstrated a general strong activity at low micromolar concentrations. The results obtained showed the induction of (i) defense‐related secondary metabolite accumulation in both cell cultures and plant tissues, (ii) specific abiotic and biotic stress‐related gene expression, and (iii) root growth retardation. The general activity of coronalon in the induction of plant stress responses together with its simple and efficient synthesis suggests that this compound might serve as a valuable tool in the examination of various aspects in plant stress physiology. Moreover, coronalon might become employed in agriculture to elicit plant resistance against various aggressors. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2038 TI - 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 JO - Phytochemistry PY - 2004 SP - 847-856 AU - Miersch, O. AU - Weichert, H. AU - Stenzel, I. AU - Hause, B. AU - Maucher, H. AU - Feussner, I. AU - Wasternack, C. AU - VL - 65 UR - DO - 10.1016/j.phytochem.2004.01.016 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2036 TI - The allene oxide cyclase of barley (Hordeum vulgare L.)—cloning and organ-specific expression JO - Phytochemistry PY - 2004 SP - 801-811 AU - Maucher, H. AU - Stenzel, I. AU - Miersch, O. AU - Stein, N. AU - Prasad, M. AU - Zierold, U. AU - Schweizer, P. AU - Dorer, C. AU - Hause, B. AU - Wasternack, C. AU - VL - 65 UR - DO - 10.1016/j.phytochem.2004.01.009 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - CHAP ID - 143 TI - Jasmonates—Biosynthesis and Role in Stress Responses and Developmental Processes T2 - Plant Cell Death Processes PB - PY - 2004 SP - 143-155 AU - Wasternack, C. AU - VL - UR - DO - 10.1016/B978-012520915-1/50012-6 AB - This chapter presents jasmonates and their related compounds and discusses jasmonate-induced alteration of gene expression. Jasmonates exerts two different changes in gene expression— decrease in the expression of nuclear- and chloroplast-encoded genes and increase in the expression of specific genes. Jasmonates are shown to alter sink-source relationships such as JA promotes formation of the N-rich vegetative storage proteins—VSPα and VSPβ—of soybean, including reallocation in pod filling. In addition to such nutrient reallocation to other parts of the plant, jasmonates cause decreases in photosynthesis and chlorophyll content, the most significant manifestations of senescence in leaves. The rise of endogenous jasmonates upon stress or exogenous treatment with jasmonates correlates in time with the expression of various genes. The promotion of senescence by jasmonates is counteracted by cytokinins. The capacity of jasmonates to down regulate photosynthetic genes may also be one determinant in the onset of senescence. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2071 TI - Jasmonate and octadecanoid occurrence in tomato hairy roots. Endogenous level changes in response to NaCl JO - Plant Growth Regul. PY - 2003 SP - 21-27 AU - Abdala, G. AU - Miersch, O. AU - Kramell, R. AU - Vigliocco, A. AU - Agostini, E. AU - Forchetti, G. AU - Alemano, S. AU - VL - 40 UR - DO - 10.1023/A:1023016412454 AB - Jasmonic acid biosynthesis occurs in leaves and there is also evidence of a similar pathway in roots. The expression of lipoxygenase, allene oxide cyclase and low amounts of transcripts of allene oxide synthase in tomato roots indicates that some steps of the jasmonate synthesis may occur in these organs. Thus, the aim of the present work was to study the jasmonate and octadecanoid occurrence in tomato roots using isolated cultures of hairy roots. These were obtained by the transformation of cv. Pera roots with Agrobacterium rhyzogenes. Also we investigated the effect of NaCl stress on the endogenous levels of these compounds. Jasmonic acid, 12-oxophytodienoic acid and their methylated derivatives, as well as a jasmonate-isoleucine conjugate, were present in control hairy roots of 30 d of culture. The 12-oxophytodienoic acid and its methylated derivative showed higher levels than jasmonic acid and its methylated form, although the content of the conjugate was the same as that of jasmonic acid. After salinization of hairy roots for 14, 20 and 30 d, free jasmonates and octadecanoids were measured. Fourteen days after salt treatment, increased levels of these compounds were found, jasmonic acid and 12-oxophytodienoic acid showed the most remarkable rise. 11-OH-jasmonic acid was found at 14 d of culture in control and salt-treated hairy roots; whereas the 12-OH- form of jasmonic acid was only detected in the salt-treated hairy roots. Agrobacterium rhizogenes cultures did not produce jasmonates and/or octadecanoids. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2107 TI - Multiple Hormones Act Sequentially to Mediate a Susceptible Tomato Pathogen Defense Response JO - Plant Physiol. PY - 2003 SP - 1181-1189 AU - O'Donnell, P. J. AU - Schmelz, E. AU - Block, A. AU - Miersch, O. AU - Wasternack, C. AU - Jones, J. B. AU - Klee, H. J. AU - VL - 133 UR - DO - 10.1104/pp.103.030379 AB - Phytohormones regulate plant responses to a wide range of biotic and abiotic stresses. How a limited number of hormones differentially mediate individual stress responses is not understood. We have used one such response, the compatible interaction of tomato (Lycopersicon esculentum) and Xanthomonas campestris pv vesicatoria (Xcv), to examine the interactions of jasmonic acid (JA), ethylene, and salicylic acid (SA). The role of JA was assessed using an antisense allene oxide cyclase transgenic line and the def1 mutant to suppress Xcv-induced biosynthesis of jasmonates. Xcv growth was limited in these lines as was subsequent disease symptom development. No increase in JA was detected before the onset of terminal necrosis. The lack of a detectable increase in JA may indicate that an oxylipin other than JA regulates basal resistance and symptom proliferation. Alternatively, there may be an increase in sensitivity to JA or related compounds following infection. Hormone measurements showed that the oxylipin signal must precede subsequent increases in ethylene and SA accumulation. Tomato thus actively regulates the Xcv-induced disease response via the sequential action of at least three hormones, promoting expansive cell death of its own tissue. This sequential action of jasmonate, ethylene, and SA in disease symptom development is different from the hormone interactions observed in many other plant-pathogen interactions. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2103 TI - Novel plasmid vectors for homologous transformation of barley (Hordeum vulgare L.) with JIP23 cDNA in sense and antisense orientation JO - Cereal Res. Commun. PY - 2003 SP - 17-24 AU - Monostori, T. AU - Schulze, J. AU - Sharma, V. K. AU - Maucher, H. AU - Wasternack, C. AU - Hause, B. AU - VL - 31 UR - DO - 10.1007/BF03543245 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2090 TI - Occurrence of the allene oxide cyclase in different organs and tissues of Arabidopsis thaliana JO - Phytochemistry PY - 2003 SP - 971-980 AU - Hause, B. AU - Stenzel, I. AU - Miersch, O. AU - Wasternack, C. AU - VL - 64 UR - DO - 10.1016/S0031-9422(03)00447-3 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2089 TI - Enzymes of Jasmonate Biosynthesis Occur in Tomato Sieve Elements JO - Plant Cell Physiol. PY - 2003 SP - 643-648 AU - Hause, B. AU - Hause, G. AU - Kutter, C. AU - Miersch, O. AU - Wasternack, C. AU - VL - 44 UR - DO - 10.1093/pcp/pcg072 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2087 TI - Biochemical and Molecular Characterization of a Hydroxyjasmonate Sulfotransferase from Arabidopsis thaliana JO - J. Biol. Chem. PY - 2003 SP - 17895-17900 AU - Gidda, S. K. AU - Miersch, O. AU - Levitin, A. AU - Schmidt, J. AU - Wasternack, C. AU - Varin, L. AU - VL - 278 UR - DO - 10.1074/jbc.M211943200 AB - 12-Hydroxyjasmonate, also known as tuberonic acid, was first isolated from Solanum tuberosum and was shown to have tuber-inducing properties. It is derived from the ubiquitously occurring jasmonic acid, an important signaling molecule mediating diverse developmental processes and plant defense responses. We report here that the gene AtST2a from Arabidopsis thaliana encodes a hydroxyjasmonate sulfotransferase. The recombinant AtST2a protein was found to exhibit strict specificity for 11- and 12-hydroxyjasmonate with Km values of 50 and 10 μm, respectively. Furthermore, 12-hydroxyjasmonate and its sulfonated derivative are shown to be naturally occurring inA. thaliana. The exogenous application of methyljasmonate to A. thaliana plants led to increased levels of both metabolites, whereas treatment with 12-hydroxyjasmonate led to increased level of 12-hydroxyjasmonate sulfate without affecting the endogenous level of jasmonic acid. AtST2a expression was found to be induced following treatment with methyljasmonate and 12-hydroxyjasmonate. In contrast, the expression of the methyljasmonate-responsive gene Thi2.1, a marker gene in plant defense responses, is not induced upon treatment with 12-hydroxyjasmonate indicating the existence of independent signaling pathways responding to jasmonic acid and 12-hydroxyjasmonic acid. Taken together, the results suggest that the hydroxylation and sulfonation reactions might be components of a pathway that inactivates excess jasmonic acid in plants. Alternatively, the function of AtST2a might be to control the biological activity of 12-hydroxyjasmonic acid. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 2085 TI - Selective desensitization of jasmonate- and pH-dependent signaling in the induction of benzophenanthridine biosynthesis in cells of Eschscholzia californica JO - Phytochemistry PY - 2003 SP - 491-500 AU - Färber, K. AU - Schumann, B. AU - Miersch, O. AU - Roos, W. AU - VL - 62 UR - DO - 10.1016/S0031-9422(02)00562-9 AB - The biosynthesis of benzophenanthridine alkaloids, phytoalexins of Eschscholzia californica, in cultured cells can be induced by a glycoprotein preparation from yeast, methyljasmonate, artificial acidification with permeant acids, or mild osmotic stress. Each of these stimuli strongly attenuated the subsequent response to the same stimulus (homologous desensitization). Elicitor contact and artificial acidification mutually desensitized the cells for either signal. In contrast, elicitor-treated cells maintained their responsiveness to methyljasmonate or hyperosmolarity (sorbitol). Elicitor concentrations that nearly saturated the alkaloid response did not cause a detectable increase of jasmonate content. Transient acidification of the cytoplasm is a necessary step of signaling by low elicitor concentrations but was not detectable after jasmonate treatment. Seen together, the data indicate the existence of a jasmonate-dependent and jasmonate-independent (ΔpH controlled) signal pathway towards the expression of benzophenanthridine biosynthesis. Selective desensitization allows either stimulus to activate a distinct share of the biosynthetic capacity of the cell and limits the accumulation of toxic defense metabolites.Yeast elicitor and jasmonate trigger alkaloid production via different signal pathways that show selective desensitization. Elicitor treatment (bottom cells) but not jasmonate (top cells) evokes intracellular pH shifts. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2125 TI - Jasmonate biosynthesis and the allene oxide cyclase family of Arabidopsis thaliana JO - Plant Mol. Biol. PY - 2003 SP - 895-911 AU - Stenzel, I. AU - Hause, B. AU - Miersch, O. AU - Kurz, T. AU - Maucher, H. AU - Weichert, H. AU - Ziegler, J. AU - Feussner, I. AU - Wasternack, C. AU - VL - 51 UR - DO - 10.1023/A:1023049319723 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2124 TI - Differential expression of the LePS2 phosphatase gene family in response to phosphate availability, pathogen infection and during development JO - Physiol. Plant. PY - 2003 SP - 138-146 AU - Stenzel, I. AU - Ziethe, K. AU - Schurath, J. AU - Hertel, S. C. AU - Bosse, D. AU - Köck, M. AU - VL - 118 UR - DO - 10.1034/j.1399-3054.2003.00091.x AB - In this study, we report the cloning of the three‐member LePS2 gene family of acid phosphatases via subtractive screening of a cDNA library of Pi‐starved cultivated tomato cells (Lycopersicon esculentum Mill. cv. Lukullus). As members of the plant Pi‐starvation response, LePS2 genes were tightly regulated in cultivated cells and tomato seedlings by Pi availability. The LePS2 enzymes which are most likely expressed in the cytoplasma could be involved in processes that are accompanied by degradation of phosphorylated organic substrates. Independently from exogenous phosphate supply LePS2 expression was detected in tomato endosperm during germination. LePS2 genes were differentially induced after infection with the bacterial pathogen Pseudomonas syringae and in the early stages of flower development. Using RT–PCR it was found that the gene LePS2B was the most abundant transcript in phosphate‐depleted cells, but a reduced expression was determined in floral buds and it was not found during pathogen interaction. In this respect, it is interesting that the promoter sequences of the LePS2 genes are also divergent. LePS2 gene products may have functions in developmental processes which are restricted to distinct plant tissues or cell types. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2123 TI - Allene oxide cyclase dependence of the wound response and vascular bundle-specific generation of jasmonates in tomato - amplification in wound signalling JO - Plant J. PY - 2003 SP - 577-589 AU - Stenzel, I. AU - Hause, B. AU - Maucher, H. AU - Pitzschke, A. AU - Miersch, O. AU - Ziegler, J. AU - Ryan, C. A. AU - Wasternack, C. AU - VL - 33 UR - DO - 10.1046/j.1365-313X.2003.01647.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2118 TI - Substrate Specificity of Glutaminyl Cyclases from Plants and Animals JO - Biol. Chem. PY - 2003 SP - 1583-1592 AU - Schilling, S. AU - Manhart, S. AU - Hoffmann, T. AU - Ludwig, H.-H. AU - Wasternack, C. AU - Demuth, H.-U. AU - VL - 384 UR - DO - 10.1515/BC.2003.175 AB - Glutaminyl cyclases (QC) catalyze the intramolecular cyclization of N-terminal glutamine residues of peptides and proteins. For a comparison of the substrate specificity of human and papaya QC enzymes, a novel continuous assay was established by adapting an existing discontinuous method. Specificity constants (kcat/Km) of dipeptides and dipeptide surrogates were higher for plant QC, whereas the selectivity for oligopeptides was similar for both enzymes. However, only the specificity constants of mammalian QC were dependent on size and composition of the substrates. Specificity constants of both enzymes were equally pH-dependent in the acidic pH-region, revealing a pKa value identical to the pKa of the substrate, suggesting similarities in the substrate conversion mode. Accordingly, both QCs converted the L-?homoglutaminyl residue in the peptide H-?homoGln-Phe-Lys-Arg-Leu-Ala-NH2 and the glutaminyl residues of the branched peptide H-Gln-Lys(Gln)-Arg-Leu-Ala-NH2 as well as the partially cyclized peptide H-Gln-cyclo( N?-Lys-Arg-Pro-Ala-Gly-Phe). In contrast, only QC from C. papaya was able to cyclize a methylated glutamine residue, while this compound did not even inhibit human QC-catalysis, suggesting distinct substrate recognition pattern. The conversion of the potential physiological substrates gastrin, neurotensin and [GlN1]-fertilization promoting peptide indicates that human QC may play a key role in posttranslational modification of most if not all pGlu-containing hormones. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2117 TI - Identification of Human Glutaminyl Cyclase as a Metalloenzyme JO - J. Biol. Chem. PY - 2003 SP - 49773-49779 AU - Schilling, S. AU - Niestroj, A. J. AU - Rahfeld, J.-U. AU - Hoffmann, T. AU - Wermann, M. AU - Zunkel, K. AU - Wasternack, C. AU - Demuth, H.-U. AU - VL - 278 UR - DO - 10.1074/jbc.M309077200 AB - Human glutaminyl cyclase (QC) was identified as a metalloenzyme as suggested by the time-dependent inhibition by the heterocyclic chelators 1,10-phenanthroline and dipicolinic acid. The effect of EDTA on QC catalysis was negligible. Inactivated enzyme could be fully restored by the addition of Zn2+ in the presence of equimolar concentrations of EDTA. Little reactivation was observed with Co2+ and Mn2+. Other metal ions such as K+, Ca2+, and Ni2+ were inactive under the same conditions. Additionally, imidazole and imidazole derivatives were identified as competitive inhibitors of QC. An initial structure activity-based inhibitor screening of imidazole-derived compounds revealed potent inhibition of QC by imidazole N-1 derivatives. Subsequent data base screening led to the identification of two highly potent inhibitors, 3-[3-(1H-imidazol-1-yl)propyl]-2-thioxoimidazolidin-4-one and 1,4-bis-(imidazol-1-yl)-methyl-2,5-dimethylbenzene, which exhibited respective Ki values of 818 ± 1 and 295 ± 5 nm. The binding properties of the imidazole derivatives were further analyzed by the pH dependence of QC inhibition. The kinetically obtained pKa values of 6.94 ± 0.02, 6.93 ± 0.03, and 5.60 ± 0.05 for imidazole, methylimidazole, and benzimidazole, respectively, match the values obtained by titrimetric pKa determination, indicating the requirement for an unprotonated nitrogen for binding to QC. Similarly, the pH dependence of the kinetic parameter Km for the QC-catalyzed conversion of H-Gln-7-ami-no-4-methylcoumarin also implies that only N-terminally unprotonated substrate molecules are bound to the active site of the enzyme, whereas turnover is not affected. The results reveal human QC as a metal-dependent transferase, suggesting that the active site-bound metal is a potential site for interaction with novel, highly potent competitive inhibitors. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 149 TI - Shift in Fatty Acid and Oxylipin Pattern of Tomato Leaves Following Overexpression of the Allene Oxide Cyclase T2 - Advanced Research on Plant Lipids PB - PY - 2003 SP - 275-278 AU - Weichert, H. AU - Maucher, H. AU - Hornung, E. AU - Wasternack, C. AU - Feussner, I. AU - VL - UR - DO - 10.1007/978-94-017-0159-4_64 AB - Polyunsaturated fatty acids (PUFAs) are a source of numerous oxidation products, the oxylipins. In leaves, α-linolenic acid (α-LeA) is the preferential substrate for lipid peroxidation reactions. This reaction may be catalyzed either by a 9-lipoxygenase (9-LOX) or by a 13-LOX and oxygen is inserted regioselectively as well as stereospecifically leading to formation of 13S- or 9S-hydroperoxy octadecatrienoic acid (13-/9-HPOT; Brash, 1999). At least, seven different enzyme families or reaction branches within the LOX pathway can use these HPOTs or other hydroperoxy PUFAs leading to (i) keto-PUFAs (LOX); (ii) epoxy hydroxy-PUFAs (epoxy alcohol synthase, EAS); (iii) octadecanoids and jasmonates (allene oxide synthase, AOS); (iv) leaf aldehydes and leaf alcohols (hydroperoxide lyase, HPL); (v) hydroxy PUFAs (reductase); (vi) divinyl ether PUFAs (divinyl ether synthase, DES); and (vii) epoxy- or dihydrodiol-PUFAs (peroxygenase, PDX; Fig. 1; Feussner and Wasternack, 2002). A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 147 TI - The Lipoxygenase Pathway in Mycorrhizal Roots of Medicago Truncatula T2 - Advanced Research on Plant Lipids PB - PY - 2003 SP - 287-290 AU - Stumpe, M. AU - Stenzel, I. AU - Weichert, H. AU - Hause, B. AU - Feussner, I. AU - VL - UR - DO - 10.1007/978-94-017-0159-4_67 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - CHAP ID - 145 TI - Transcriptional Activation of Jasmonate Biosynthesis Enzymes is not Reflected at Protein Level T2 - Advanced Research on Plant Lipids PB - PY - 2003 SP - 267-270 AU - Stenzel, I. AU - Hause, B. AU - Feussner, I. AU - Wasternack, C. AU - VL - UR - DO - 10.1007/978-94-017-0159-4_62 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2197 TI - Metabolic profiling of oxylipins in germinating cucumber seedlings - lipoxygenase-dependent degradation of triacylglycerols and biosynthesis of volatile aldehydes JO - Planta PY - 2002 SP - 612-619 AU - Weichert, H. AU - Kolbe, A. AU - Kraus, A. AU - Wasternack, C. AU - Feussner, I. AU - VL - 215 UR - DO - 10.1007/s00425-002-0779-4 AB - A particular isoform of lipoxygenase (LOX) localized on lipid bodies was shown by earlier investigations to play a role in initiating the mobilization of triacylglycerols during seed germination. Here, further physiological functions of LOXs within whole cotyledons of cucumber (Cucumis sativus L.) were analyzed by measuring the endogenous amounts of LOX-derived products. The lipid-body LOX-derived esterified (13S)-hydroperoxy linoleic acid was the dominant metabolite of the LOX pathway in this tissue. It accumulated to about 14 µmol/g fresh weight, which represented about 6% of the total amount of linoleic acid in cotyledons. This LOX product was not only reduced to its hydroxy derivative, leading to degradation by β-oxidation, but alternatively it was metabolized by fatty acid hydroperoxide lyase leading to formation of hexanal as well. Furthermore, the activities of LOX forms metabolizing linolenic acid were detected by measuring the accumulation of volatile aldehydes and the allene oxide synthase-derived metabolite jasmonic acid. The first evidence is presented for an involvement of a lipid-body LOX form in the production of volatile aldehydes. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2192 TI - Stimulation of jasmonic acid production in Zea Mays L. infected by the maize rough dwarf virus - Río Cuarto. Reversion of symptoms by salicylic acid JO - Biocell PY - 2002 SP - 369-374 AU - Vigliocco, A. AU - Bonamico, B. AU - Alemano, S. AU - Miersch, O. AU - Abdala, G. AU - VL - 26 UR - https://www.techscience.com/biocell/v26n3/34012 AB - In the present paper we study the possible biological relevance of endogenous jasmonic acid (JA) and exogenous salicylic acid (SA) in a plant-microbial system maize-virus. The virus disease "Mal de Río Cuarto" is caused by the maize rough dwarf virus - Río Cuarto. The characteristic symptoms are the appearance of galls or "enations" in leaves, shortening of the stem internodes, poor radical system and general stunting. Changes in JA and protein pattern in maize control and infected plants of a virus-tolerant cultivar were investigated. Healthy and infected-leaf discs were collected for JA measurement at different post-infection times (20, 40, 60 and 68 days). JA was also measured in roots on day 60 after infection. For SDS-PAGE protein analysis, leaf discs were also harvested on day 60 after infection. Infected leaves showed higher levels of JA than healthy leaves, and the rise in endogenous JA coincided with the enation formation. The soluble protein amount did not show differences between infected and healthy leaves; moreover, no difference in the expression of soluble protein was revealed by SDS-PAGE. Our results show that the octadecanoid pathway was stimulated in leaves and roots of the tolerant maize cultivar when infected by this virus. This finding, together with fewer plants with the disease symptoms, suggest that higher foliar and roots JA content may be related to disease tolerance. SA exogenous treatment caused the reversion of the dwarfism symptom. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2185 TI - Heterologous Expression and Characterization of Human Glutaminyl Cyclase: Evidence for a Disulfide Bond with Importance for Catalytic Activity JO - Biochemistry PY - 2002 SP - 10849-10857 AU - Schilling, S. AU - Hoffmann, T. AU - Rosche, F. AU - Manhart, S. AU - Wasternack, C. AU - Demuth, H.-U. AU - VL - 41 UR - DO - 10.1021/bi0260381 AB - Glutaminyl cyclase (QC, EC 2.3.2.5) catalyzes the formation of pyroglutamate residues from glutamine at the N-terminus of peptides and proteins. In the current study, human QC was functionally expressed in the secretory pathway of Pichia pastoris, yielding milligram quantities after purification from the supernatant of a 5 L fermentation. Initial characterization studies of the recombinant QC using MALDI-TOF mass spectrometry revealed correct proteolytic processing and N-glycosylation at both potential sites with similar 2 kDa extensions. CD spectral analysis indicated a high α-helical content, which contrasts with plant QC from Carica papaya. The kinetic parameters for conversion of H-Gln-Tyr-Ala-OH by recombinant human QC were almost identical to those previously reported for purified bovine pituitary QC. However, the results obtained for conversion of H-Gln-Gln-OH, H-Gln-NH2, and H-Gln-AMC were found to be contradictory to previous studies on human QC expressed intracellularly in E. coli. Expression of QC in E. coli showed that approximately 50% of the protein did not contain a disulfide bond that is present in the entire QC expressed in P. pastoris. Further, the enzyme was consistently inactivated by treatment with 15 mM DTT, whereas deglycosylation had no effect on enzymatic activity. Analysis of the fluorescence spectra of the native, reduced, and unfolded human QC point to a conformational change of the protein upon treatment with DTT. In terms of the different enzymatic properties, the consequences of QC expression in different environments are discussed. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2184 TI - Continuous Spectrometric Assays for Glutaminyl Cyclase Activity JO - Anal. Biochem. PY - 2002 SP - 49-56 AU - Schilling, S. AU - Hoffmann, T. AU - Wermann, M. AU - Heiser, U. AU - Wasternack, C. AU - Demuth, H.-U. AU - VL - 303 UR - DO - 10.1006/abio.2001.5560 AB - The enzymatic conversion of one chromogenic substrate, -glutamine-p-nitroanilide, and two fluorogenic substrates, -glutaminyl-2-naphthylamide and -glutaminyl-4-methylcoumarinylamide, into their respective pyroglutamic acid derivatives by glutaminyl cyclase (QC) was estimated by introducing a new coupled assay using pyroglutamyl aminopeptidase as the auxiliary enzyme. For the purified papaya QC, the kinetic parameters were found to be in the range of those previously reported for other glutaminyl peptides, such as Gln-Gln, Gln-Ala, or Gln-tert-butyl ester. The assay can be performed in the presence of ammonia up to a concentration of 50 mM. Increasing ionic strength, e.g., potassium chloride up to 300 mM, resulted in an increase in enzymatic activity of about 20%. This is the first report of a fast, continuous, and reliable determination of QC activity, even in the presence of ammonium ions, during the course of protein purification and enzymatic analysis. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2180 TI - Cell death and salicylate- and jasmonate-dependent stress responses in Arabidopsis are controlled by single cet genes JO - Planta PY - 2002 SP - 120-128 AU - Nibbe, M. AU - Hilpert, B. AU - Wasternack, C. AU - Miersch, O. AU - Apel, K. AU - VL - 216 UR - DO - 10.1007/s00425-002-0907-1 AB - The jasmonic acid (JA)-dependent regulation of the Thi2.1 gene had previously been exploited for setting up a genetic screen for the isolation of signal transduction mutants of Arabidopsis thaliana (L.) Heynh. that constitutively express the thionin gene. Several cet mutants had been isolated which showed a constitutive expression of the thionin gene. These cet mutants, except for one, also showed spontaneous leaf cell necrosis and were up-regulated in the expression of the PR1 gene, reactions often associated with the systemic acquired resistance (SAR) pathway. Four of these cet mutants, cet1, cet2, cet3 and cet4.1 were crossed with the fad triple and coi1 mutants that are blocked at two steps within the JA-dependent signaling pathway, and with transgenic NahG plants that are deficient in salicylic acid (SA) and are unable to activate SAR. Analysis of the various double-mutant lines revealed that the four cet genes act within a signaling cascade at or prior to branch points from which not only JA-dependent signals but also SA-dependent signaling and cell death pathways diverge. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2165 TI - Induction of Jasmonate Biosynthesis in Arbuscular Mycorrhizal Barley Roots JO - Plant Physiol. PY - 2002 SP - 1213-1220 AU - Hause, B. AU - Maier, W. AU - Miersch, O. AU - Kramell, R. AU - Strack, D. AU - VL - 130 UR - DO - 10.1104/pp.006007 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2157 TI - The lipoxygenase pathway JO - Annu. Rev. Plant Biol. PY - 2002 SP - 275-297 AU - Feussner, I. AU - Wasternack, C. AU - VL - 53 UR - DO - 10.1146/annurev.arplant.53.100301.135248 AB - Lipid peroxidation is common to all biological systems, both appearing in developmentally and environmentally regulated processes of plants. The hydroperoxy polyunsaturated fatty acids, synthesized by the action of various highly specialized forms of lipoxygenases, are substrates of at least seven different enzyme families. Signaling compounds such as jasmonates, antimicrobial and antifungal compounds such as leaf aldehydes or divinyl ethers, and a plant-specific blend of volatiles including leaf alcohols are among the numerous products. Cloning of many lipoxygenases and other key enzymes within the lipoxygenase pathway, as well as analyses by reverse genetic and metabolic profiling, revealed new reactions and the first hints of enzyme mechanisms, multiple functions, and regulation. These aspects are reviewed with respect to activation of this pathway as an initial step in the interaction of plants with pathogens, insects, or abiotic stress and at distinct stages of development. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2152 TI - The Arabidopsis Mutant cev1 Links Cell Wall Signaling to Jasmonate and Ethylene Responses JO - Plant Cell PY - 2002 SP - 1557-1566 AU - Ellis, C. AU - Karafyllidis, I. AU - Wasternack, C. AU - Turner, J. G. AU - VL - 14 UR - DO - 10.1105/tpc.002022 AB - Biotic and abiotic stresses stimulate the synthesis of jasmonates and ethylene, which, in turn, induce the expression of genes involved in stress response and enhance defense responses. The cev1 mutant has constitutive expression of stress response genes and has enhanced resistance to fungal pathogens. Here, we show that cev1 plants have increased production of jasmonate and ethylene and that its phenotype is suppressed by mutations that interrupt jasmonate and ethylene signaling. Genetic mapping, complementation analysis, and sequence analysis revealed that CEV1 is the cellulose synthase CeSA3. CEV1 was expressed predominantly in root tissues, and cev1 roots contained less cellulose than wild-type roots. Significantly, the cev1 mutant phenotype could be reproduced by treating wild-type plants with cellulose biosynthesis inhibitors, and the cellulose synthase mutant rsw1 also had constitutive expression of VSP. We propose that the cell wall can signal stress responses in plants. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2138 TI - Jasmonate-Induced Lipid Peroxidation in Barley Leaves Initiated by Distinct 13-LOX Forms of Chloroplasts JO - Biol. Chem. PY - 2002 SP - 1645-1657 AU - Bachmann, A. AU - Hause, B. AU - Maucher, H. AU - Garbe, E. AU - Vörös, K. AU - Weichert, H. AU - Wasternack, C. AU - Feussner, I. AU - VL - 383 UR - DO - 10.1515/BC.2002.185 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2134 TI - Changes in jasmonate and gibberellin levels during development of potato plants (Solanum tuberosum) JO - Plant Growth Regul. PY - 2002 SP - 121-126 AU - Abdala, G. AU - Castro, G. AU - Miersch, O. AU - Pearce, D. AU - VL - 36 UR - DO - 10.1023/A:1015065011536 AB - Among the multiple environmental signals and hormonal factors regulatingpotato plant morphogenesis and controlling tuber induction, jasmonates (JAs)andgibberellins (GAs) are important components of the signalling pathways in theseprocesses. In the present study, with Solanum tuberosum L.cv. Spunta, we followed the endogenous changes of JAs and GAs during thedevelopmental stages of soil-grown potato plants. Foliage at initial growthshowed the highest jasmonic acid (JA) concentration, while in roots the highestcontent was observed in the stage of tuber set. In stolons at the developmentalstage of tuber set an important increase of JA was found; however, in tubersthere was no change in this compound during tuber set and subsequent growth.Methyl jasmonate (Me-JA) in foliage did not show the same pattern as JA; Me-JAdecreased during the developmental stages in which it was monitored, meanwhileJA increased during those stages. The highest total amount of JAs expressed asJA + Me-JA was found at tuber set. A very important peak ofJA in roots was coincident with that observed in stolons at tuber set. Also, aprogressive increase of this compound in roots was shown during the transitionof stolons to tubers. Of the two GAs monitored, gibberellic acid(GA3) was the most abundant in all the organs. While GA1and GA3 were also found in stolons at the time of tuber set, noothermeasurements of GAs were obtained for stolons at previous stages of plantdevelopment. Our results indicate that high levels of JA and GAs are found indifferent tissues, especially during stolon growth and tuber set. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 159 TI - Jasmonates and octadecanoids: Signals in plant stress responses and development T2 - PB - Prog. Nucleic Acid Res. Mol. Biol. PY - 2002 SP - 165-221 AU - Wasternack, C. AU - Hause, B. AU - VL - 72 UR - DO - 10.1016/S0079-6603(02)72070-9 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2202 TI - Enzymatic and non-enzymatic lipid peroxidation in leaf development JO - BBA-Mol. Cell Biol. Lipids PY - 2001 SP - 266-276 AU - BERGER, S. AU - Weichert, H. AU - Porzel, A. AU - Wasternack, C. AU - Kühn, H. AU - Feussner, I. AU - VL - 1533 UR - DO - 10.1016/S1388-1981(01)00161-5 AB - Enzymatic and non-enzymatic lipid peroxidation has been implicated in programmed cell death, which is a major process of leaf senescence. To test this hypothesis we developed a high-performance liquid chromatography (HPLC) method for a simultaneous analysis of the major hydro(pero)xy polyenoic fatty acids. Quantities of lipid peroxidation products in leaves of different stages of development including natural senescence indicated a strong increase in the level of oxygenated polyenoic fatty acids (PUFAs) during the late stages of leaf senescence. Comprehensive structural elucidation of the oxygenation products by means of HPLC, gas chromatography/mass spectrometry and 1H nuclear magnetic resonance suggested a non-enzymatic origin. However, in some cases a small share of specifically oxidized PUFAs was identified suggesting involvement of lipid peroxidizing enzymes. To inspect the possible role of enzymatic lipid peroxidation in leaf senescence, we analyzed the abundance of lipoxygenases (LOXs) in rosette leaves of Arabidopsis. LOXs and their product (9Z,11E,13S,15Z)-13-hydroperoxy-9,11,15-octadecatrienoic acid were exclusively detected in young green leaves. In contrast, in senescing leaves the specific LOX products were overlaid by large amounts of stereo-random lipid peroxidation products originating from non-enzymatic oxidation. These data indicate a limited contribution of LOXs to total lipid peroxidation, and a dominant role of non-enzymatic lipid peroxidation in late stages of leaf development. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 2221 TI - Isolation and characterization of signal transduction mutants of Arabidopsis thaliana that constitutively activate the octadecanoid pathway and form necrotic microlesions JO - Plant J. PY - 2001 SP - 435-446 AU - Hilpert, B. AU - Bohlmann, H. AU - Den Camp, R. o. AU - Przybyla, D. AU - Miersch, O. AU - Buchala, A. AU - Apel, K. AU - VL - 26 UR - DO - 10.1046/j.1365-313X.2001.2641036.x AB - Thionins are a group of antimicrobial polypeptides that form part of the plant's defense mechanism against pathogens. The Thi 2.1 thionin gene of Arabidopsis thaliana has been shown to be inducible by jasmonic acid (JA), an oxylipin‐like hormone derived from oxygenated linolenic acid and synthesized via the octadecanoid pathway. The JA‐dependent regulation of the Thi 2.1 gene has been exploited for setting up a genetic screen for the isolation of signal transduction mutants that constitutively express the Thi 2.1 gene. Ten cet‐mutants have been isolated which showed a c onstitutive e xpression of the t hionin gene. Allelism tests revealed that they represent at least five different loci. Some mutants are dominant, others recessive, but all cet mutations behaved as monogenic traits when backcrossed with Thi 2.1‐GUS plants. Some of the mutants overproduce JA and its bioactive precursor 12‐oxophytodienoic acid (OPDA) up to 40‐fold while others have the same low levels as the control wildtype plants. Two of the mutants showed a strong induction of both the salicylic acid (SA)‐ and the JA‐dependent signaling pathways, while the majority seems to be affected only in the octadecanoid pathway. The Thi 2.1 thionin gene and the Pdf 1.2 defensin gene are activated independently, though both are regulated by JA. The cet‐mutants, except for one, also show a spontaneous leaf cell necrosis, a reaction often associated with the systemic acquired resistance (SAR) pathway. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2214 TI - Lipoxygenase-dependent degradation of storage lipids JO - Trends Plant Sci. PY - 2001 SP - 268-273 AU - Feussner, I. AU - Kühn, H. AU - Wasternack, C. AU - VL - 6 UR - DO - 10.1016/S1360-1385(01)01950-1 AB - Oilseed germination is characterized by the mobilization of storage lipids as a carbon source for the germinating seedling. In spite of the importance of lipid mobilization, its mechanism is only partially understood. Recent data suggest that a novel degradation mechanism is initiated by a 13-lipoxygenase during germination, using esterified fatty acids specifically as substrates. This 13-lipoxygenase reaction leads to a transient accumulation of ester lipid hydroperoxides in the storage lipids, and the corresponding oxygenated fatty acid moieties are preferentially removed by specific lipases. The free hydroperoxy fatty acids are subsequently reduced to their hydroxy derivatives, which might in turn undergo β-oxidation. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2243 TI - Metabolic profiling of oxylipins upon sorbitol treatment in barley leaves JO - Biochem. Soc. Trans. PY - 2001 SP - 861-862 AU - Weichert, H. AU - Kohlmann, M. AU - Wasternack, C. AU - Feussner, I. AU - VL - 28 UR - DO - 10.1042/bst0280861 AB - In barley leaves 13-lipoxygenases (LOXs) are induced by salicylate and jasmonate. Here, we analyse by metabolic profiling the accumulation of oxylipins upon sorbitol treatment. Although 13-LOX-derived products are formed and specifically directed into the reductase branch of the LOX pathway, accumulation is much later than in the cases of salicylate and jasmonate treatment. In addition, under these conditions only the accumulation of jasmonates as additional products of the LOX pathway has been found. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2272 TI - Octadecanoid and Jasmonate Signaling in Tomato (Lycopersicon esculentum Mill.) Leaves: Endogenous Jasmonates Do Not Induce Jasmonate Biosynthesis JO - Biol. Chem. PY - 2000 SP - 715-722 AU - Miersch, O. AU - Wasternack, C. AU - VL - 381 UR - DO - 10.1515/BC.2000.092 AB - Jasmonates and their precursors, the octadecanoids, are signals in stress-induced alteration of gene expression. Several mRNAs coding for enzymes of jasmonic acid (JA) biosynthesis are up-regulated upon JA treatment or endogenous increase of the JA level. Here we investigated the positive feedback of endogenous JA on JA formation, as well as its β-oxidation steps. JA-responsive gene expression was recorded in terms of proteinase inhibitor2 (pin2) mRNA accumulation. JA formed upon treatment of tomato (Lycopersicon esculentum cv. Moneymaker) leaves with JA derivatives carrying different lengths of the carboxylic acid side chain was quantified by gas chromatography-mass spectrometry (GC-MS). The data revealed that β-oxidation of the side chain occurs up to a butyric acid moiety. The amount of JA formed from side-chain modified JA derivatives correlated with pin2-mRNA accumulation. JA derivatives with a carboxylic side chain of 3, 5 or 7 carbon atoms were unable to form JA and to express on pin2, whereas evennumbered derivatives were active.After treatment of tomato leaves with (10-2H)-(–)-12-oxophytoenoic acid, (4-2H)-(–)-JA and its methyl ester were formed and could be quantified separately from the endogenously nonlabeled JA pool by GC-MS analysis via isotopic discrimination. The level of 8 nmol per g fresh weight JA and its methyl ester originated exclusively from labeled 12-oxophytoenic acid. This and further data indicate that endogenous synthesis of the JA precursor 12-oxophytodienoic acid, as well as of JA and its methyl ester, are not induced in tomato leaves, suggesting that positive feedback in JA biosynthesis does not function in vivo. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2271 TI - Allene oxide synthases of barley (Hordeum vulgare cv. Salome): tissue specific regulation in seedling development JO - Plant J. PY - 2000 SP - 199-213 AU - Maucher, H. AU - Hause, B. AU - Feussner, I. AU - Ziegler, J. AU - Wasternack, C. AU - VL - 21 UR - DO - 10.1046/j.1365-313x.2000.00669.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2266 TI - Octadecanoid-Derived Alteration of Gene Expression and the “Oxylipin Signature” in Stressed Barley Leaves. Implications for Different Signaling Pathways JO - Plant Physiol. PY - 2000 SP - 177-188 AU - Kramell, R. AU - Miersch, O. AU - Atzorn, R. AU - Parthier, B. AU - Wasternack, C. AU - VL - 123 UR - DO - 10.1104/pp.123.1.177 AB - Stress-induced gene expression in barley (Hordeum vulgare cv Salome) leaves has been correlated with temporally changing levels of octadecanoids and jasmonates, quantified by means of gas chromatography/mass spectrometry-single ion monitoring. Application of sorbitol-induced stress led to a low and transient rise of jasmonic acid (JA), its precursor 12-oxophytodienoic acid (OPDA), and the methyl esters JAME and OPDAME, respectively, followed by a large increase in their levels. JA and JAME peaked between 12 and 16 h, about 4 h before OPDA and OPDAME. However, OPDA accumulated up to a 2.5-fold higher level than the other compounds. Dihomo-JA and 9,13-didehydro-OPDA were identified as minor components. Kinetic analyses revealed that a transient threshold of jasmonates or octadecanoids is necessary and sufficient to initiate JA-responsive gene expression. Although OPDA and OPDAME applied exogenously were metabolized to JA in considerable amounts, both of them can induce gene expression, as evidenced by those genes that did not respond to endogenously formed JA. Also, coronatine induces JA-responsive genes independently from endogenous JA. Application of deuterated JA showed that endogenous synthesis of JA is not induced by JA treatment. The data are discussed in terms of distinct signaling pathways. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2258 TI - Tissue-specific oxylipin signature of tomato flowers: allene oxide cyclase is highly expressed in distinct flower organs and vascular bundles JO - Plant J. PY - 2000 SP - 113-126 AU - Hause, B. AU - Stenzel, I. AU - Miersch, O. AU - Maucher, H. AU - Kramell, R. AU - Ziegler, J. AU - Wasternack, C. AU - VL - 24 UR - DO - 10.1046/j.1365-313x.2000.00861.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2293 TI - Molecular Cloning of Allene Oxide Cyclase JO - J. Biol. Chem. PY - 2000 SP - 19132-19138 AU - Ziegler, J. AU - Stenzel, I. AU - Hause, B. AU - Maucher, H. AU - Hamberg, M. AU - Grimm, R. AU - Ganal, M. AU - Wasternack, C. AU - VL - 275 UR - DO - 10.1074/jbc.M002133200 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2290 TI - Formation of 4-hydroxy-2-alkenals in barley leaves JO - Biochem. Soc. Trans. PY - 2000 SP - 850-851 AU - Weichert, H. AU - Kolbe, A. AU - Wasternack, C. AU - Feussner, I. AU - VL - 28 UR - DO - 10.1042/bst0280850 AB - In barley leaves 13-lipoxygenases are induced by jasmonates. This leads to induction of lipid peroxidation. Here we show by in vitro studies that these processes may further lead to autoxidative formation of (2E)-4-hydroxy-2-hexenal from (3Z)-hexenal. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2289 TI - Stressabwehr und Entwicklung: Jasmonate — chemische Signale in Pflanzen JO - Biologie in unserer Zeit PY - 2000 SP - 312-320 AU - Wasternack, C. AU - Hause, B. AU - VL - 30 UR - DO - 10.1002/1521-415X(200011)30:6<312::AID-BIUZ312>3.0.CO;2-8 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2311 TI - (—)-Jasmonic Acid Accumulation in Tobacco Hypersensitive Response Lesions JO - Mol. Plant Microbe Interact. PY - 1999 SP - 74-78 AU - Kenton, P. AU - Mur, L. A. J. AU - Atzorn, R. AU - Wasternack, C. AU - Draper, J. AU - VL - 12 UR - DO - 10.1094/MPMI.1999.12.1.74 AB - Tobacco infected with Pseudomonas syringae pv. phaseolicola undergoes a hypersensitive response (HR). Jasmonic acid (JA) accumulated within the developing lesion 3 to 9 h after infection and this accumulation preceded protein loss, cell death, and malondialdehyde accumulation. Accumulating JA consisted largely of the (—)-JA stereoisomer and was essentially restricted to the HR lesion. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2310 TI - Electric Signaling and Pin2 Gene Expression on Different Abiotic Stimuli Depend on a Distinct Threshold Level of Endogenous Abscisic Acid in Several Abscisic Acid-Deficient Tomato Mutants JO - Plant Physiol. PY - 1999 SP - 213-218 AU - Herde, O. AU - Peña Cortés, H. AU - Wasternack, C. AU - Willmitzer, L. AU - Fisahn, J. AU - VL - 119 UR - DO - 10.1104/pp.119.1.213 AB - Experiments were performed on three abscisic acid (ABA)-deficient tomato (Lycopersicon esculentum Mill.) mutants, notabilis,flacca, and sitiens, to investigate the role of ABA and jasmonic acid (JA) in the generation of electrical signals and Pin2 (proteinaseinhibitor II) gene expression. We selected these mutants because they contain different levels of endogenous ABA. ABA levels in the mutant sitiens were reduced to 8% of the wild type, in notabilis they were reduced to 47%, and in flacca they were reduced to 21%. In wild-type and notabilis tomato plants the induction ofPin2 gene expression could be elicited by heat treatment, current application, or mechanical wounding. Inflacca and sitiens only heat stimulation induced Pin2 gene expression. JA levels inflacca and sitiens plants also accumulated strongly upon heat stimulation but not upon mechanical wounding or current application. Characteristic electrical signals evolved in the wild type and in the notabilis andflacca mutants consisting of a fast action potential and a slow variation potential. However, in sitiens only heat evoked electrical signals; mechanical wounding and current application did not change the membrane potential. In addition, exogenous application of ABA to wild-type tomato plants induced transient changes in membrane potentials, indicating the involvement of ABA in the generation of electrical signals. Our data strongly suggest the presence of a minimum threshold value of ABA within the plant that is essential for the early events in electrical signaling and mediation of Pin2 gene expression upon wounding. In contrast, heat-induced Pin2 gene expression and membrane potential changes were not dependent on the ABA level but, rather, on the accumulation of JA. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2309 TI - 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 JO - Plant Biol. PY - 1999 SP - 83-89 AU - Hause, B. AU - Hertel, S. C. AU - Klaus, D. AU - Wasternack, C. AU - VL - 1 UR - DO - 10.1111/j.1438-8677.1999.tb00712.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2308 TI - A Jasmonate-responsive Lipoxygenase of Barley Leaves is Induced by Plant Activators but not by Pathogens JO - J. Plant Physiol. PY - 1999 SP - 459-462 AU - Hause, B. AU - Vörös, K. AU - Kogel, K.-H. AU - Besser, K. AU - Wasternack, C. AU - VL - 154 UR - DO - 10.1016/S0176-1617(99)80283-1 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2323 TI - Jasmonate-induced gene expression of barley (Hordeum vulgare) leaves - the link between jasmonate and abscisic acid JO - Plant Growth Regul. PY - 1999 SP - 113-122 AU - Ortel, B. AU - Atzorn, R. AU - Hause, B. AU - Feussner, I. AU - Miersch, O. AU - Wasternack, C. AU - VL - 29 UR - DO - 10.1023/A:1006212017458 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2320 TI - Structure–activity relations of substituted, deleted or stereospecifically altered jasmonic acid in gene expression of barley leaves JO - Phytochemistry PY - 1999 SP - 353-361 AU - Miersch, O. AU - Kramell, R. AU - Parthier, B. AU - Wasternack, C. AU - VL - 50 UR - DO - 10.1016/S0031-9422(98)00597-4 AB - Jasmonic acid and 66 structurally related compounds were tested to find the structural requirements which induce the expression of jasmonate-responsive genes in barley. An intact cyclopentanone ring as well as a pentenyl side chain exhibiting only minor alterations are necessary for this activity. The (−)-enantiomeric and the (+)-7-iso-enantiomeric structure increase activity of jasmonoyl compounds. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2319 TI - Microbial conversion of jasmonates - hydroxylations by Aspergillus niger JO - Phytochemistry PY - 1999 SP - 1147-1152 AU - Miersch, O. AU - Porzel, A. AU - Wasternack, C. AU - VL - 50 UR - DO - 10.1016/S0031-9422(98)00698-0 AB - Aspergillus niger is able to hydroxylate the pentenyl side chain of (−)-jasmonic acid (JA) leading to (11S)- (−)-hydroxy-JA/ (11R)- (−)-hydroxy-JA (2:1) and (−)-11,12-didehydro-JA. Methyl (−)-jasmonate (JA-Me) is converted upon hydrolysis. During prolonged cultivation or at non-optimized isolation procedures, the 11-hydroxy- (9Z)-pentenyl side chain may isomerize to (10E)-9-hydroxy- and (9E)-11-hydroxy-compounds by allylic rearrangement. The fungus hydroxylates (±)-9,10-dihydro-JA at position C-11 into 11j-hydroxy-9,10-dihydro-JA. As JA-Me, the methyl dihydro-JA is hydroxylated only upon hydrolysis into the free acid. A2 - C1 - Molecular Signal Processing; Bioorganic Chemistry ER - TY - JOUR ID - 2318 TI - Jasmonates and related compounds from Fusarium oxysporum JO - Phytochemistry PY - 1999 SP - 517-523 AU - Miersch, O. AU - Bohlmann, H. AU - Wasternack, C. AU - VL - 50 UR - DO - 10.1016/S0031-9422(98)00596-2 AB - The culture filtrate of Fusarium oxysporum f sp matthiolae was inspected on the occurrence of jasmonates and related compounds. Among compounds described for the first time of biological origin are 7-iso-cucurbic acid, (1S,2S)- and (1S,2R)-3-oxo-2-pentylcyclopentane-1-butyric acid, (1S,2S)- and (1S,2R)-3-oxo-2-(2Z-pentenyl)cyclopentane-1-hexanoic acid, (1S,2S)- and (1S,2R)-3-oxo-2-pentylcyclopentane-1-hexanoic acid, (1S,2S)-3-oxo-2-(2Z-pentenyl)cyclopentane-1-octanoic acid, (1S,2S)-3-oxo-2-pentylcyclopentane-1-octanoic acid and N-[9,10-dihydro-7-iso-jasmonoyl]-(S)-isoleucine. The following metabolites were identified for the first time for this fungus: (−)-Jasmonic acid, 9,10-dihydrojasmonic acid and N-[(−)-jasmonoyl-(S)]-isoleucine were major constituents of the culture filtrate, whereas as minor metabolites occurred N-[9,10-dihydrojasmonoyl]-(S)-isoleucine, cucurbic acid and 3-oxo-2-(2Z-pentenyl)cyclopentane-1-butyric acid, 3-oxo-2-(2Z-pentenyl)cyclopentane-1-octanoic acid and 3-oxo-2-pentylcyclopentane-1-octanoic acid. All cyclopentanones found carried a cis- or trans-attached side chain. Didehydro-jasmonates, hydroxylated jasmonates or 12-oxophytodienoic acid could not be detected in the culture filtrate. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2314 TI - Liquid chromatography of jasmonic acid amine conjugates JO - Chromatographia PY - 1999 SP - 42-46 AU - Kramell, R. AU - Miersch, O. AU - Schneider, G. AU - Wasternack, C. AU - VL - 49 UR - DO - 10.1007/BF02467185 AB - Racemic jasmonic acid (3R,7R/3S,7S)-(±)-JA) was chemically conjugated with different biogenic amines originating from aliphatic and aromatic α-amino acids by decarboxylation. The resulting isomeric compounds were subjected to reversed-phase high-performance liquid chromatography (HPLC) and to HPLC on the chiral stationary phases Chiralpak AS and Nucleodex β-PM. Under reversed-phase conditions, all the homologous amine derivatives tested could be separated from each other except the JA-conjugates containing 2-phenyl-ethylamine and 3-methylbutylamine. On both chiral supports the (3R,7R)-(−)-JA conjugates eluted earlier than those of the enantiomeric counterpart (3S,7S)-(+)-JA. On Chiralpak AS all the isomers studied could be separated to baseline with a mobile phase containingn-hexane and 2-propanol. The calculated resolution factors were between 1.80 and 4.17. The pairs of isomers were also chromatographed on the cyclodextrin stationary phase Nucleodex β-PM with methanol-triethylammonium acetate buffer as mobile phase. Under these conditions resolution factors were between 0.74 and 1.29. The individual isomers were chiroptically characterized by measurement of their circular dichroism. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2313 TI - Chromatographic resolution of peptide-like conjugates of jasmonic acid and of cucurbic acid isomers JO - J. Chromatogr. A PY - 1999 SP - 103-107 AU - Kramell, R. AU - Porzel, A. AU - Miersch, O. AU - Schneider, G. AU - Wasternack, C. AU - VL - 847 UR - DO - 10.1016/S0021-9673(99)00335-0 AB - The chiral separation of peptide-like conjugates of jasmonic acid and of cucurbic acid isomers was investigated by liquid chromatography on Chiralpak AS and Nucleodex β-PM. The retention sequences reflect distinct chromatographic properties with respect to the chirality of the jasmonic acid part or of the cucurbic acid isomers. The chromatographic behaviour of the amide conjugates on a reversed-phase C18 column provides evidence for the resolution of diastereomeric conjugates depending on the chirality of both constituents of the conjugate molecule. The chromatographic procedures are suitable for the analytical and preparative separation of such conjugates. A2 - C1 - Molecular Signal Processing; Bioorganic Chemistry ER - TY - JOUR ID - 2377 TI - Jasmonic acid: biosynthesis, signal transduction, gene expression JO - Fett/Lipid PY - 1998 SP - 139-146 AU - Wasternack, C. AU - Miersch, O. AU - Kramell, R. AU - Hause, B. AU - Ward, J. AU - Beale, M. AU - Boland, W. AU - Parthier, B. AU - Feussner, I. AU - VL - 100 UR - DO - 10.1002/(SICI)1521-4133(19985)100:4/5<139::AID-LIPI139>3.0.CO;2-5 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2376 TI - Diversity in octadecanoid-induced gene expression of tomato JO - J. Plant Physiol. PY - 1998 SP - 345-352 AU - Wasternack, C. AU - Ortel, B. AU - Miersch, O. AU - Kramell, R. AU - Beale, M. AU - Greulich, F. AU - Feussner, I. AU - Hause, B. AU - Krumm, T. AU - Boland, W. AU - Parthier, B. AU - VL - 152 UR - DO - 10.1016/S0176-1617(98)80149-1 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2375 TI - Characterization of a methyljasmonate-inducible lipoxygenase from barley (Hordeum vulgare cv. Salome) leaves JO - Eur. J. Biochem. PY - 1998 SP - 36-44 AU - Vörös, K. AU - Feussner, I. AU - Kühn, H. AU - Lee, J. AU - Graner, A. AU - Löbler, M. AU - Parthier, B. AU - Wasternack, C. AU - VL - 251 UR - DO - 10.1046/j.1432-1327.1998.2510036.x AB - We found three methyl jasmonate−induced lipoxygenases with molecular masses of 92 kDa, 98 kDa, and 100 kDa (LOX‐92, ‐98 and ‐100) [Feussner, I., Hause, B., Vörös, K., Parthier, B. & Wasternack, C. (1995) Plant J. 7 , 949−957]. At least two of them (LOX‐92 and LOX‐100), were shown to be localized within chloroplasts of barley leaves. Here, we describe the isolation of a cDNA (3073 bp) coding for LOX‐100, a protein of 936 amino acid residues and a molecular mass of 106 kDa. By sequence comparison this lipoxygenase could be identified as LOX2‐type lipoxygenase and was therefore designated LOX2 : Hv : 1 . The recombinant lipoxygenase was expressed in Escherichia coli and characterized as linoleate 13‐LOX and arachidonate 15‐LOX, respectively. The enzyme exhibited a pH optimum around pH 7.0 and a moderate substrate preference for linoleic acid. The gene was transiently expressed after exogenous application of jasmonic acid methyl ester with a maximum between 12 h and 18 h. Its expression was not affected by exogenous application of abscisic acid. Also a rise of endogenous jasmonic acid resulting from sorbitol stress did not induce LOX2 : Hv : 1 , suggesting a separate signalling pathway compared with other jasmonate‐induced proteins of barley. The properties of LOX2 : Hv : 1 are discussed in relation to its possible involvement in jasmonic acid biosynthesis and other LOX forms of barley identified so far. A2 - C1 - Molecular Signal Processing; Biochemistry of Plant Interactions ER - TY - JOUR ID - 2374 TI - Systemic and local induction of an Arabidopsis thionin gene by wounding and pathogens JO - Plant J. PY - 1998 SP - 285-295 AU - Vignutelli, A. AU - Wasternack, C. AU - Apel, K. AU - Bohlmann, H. AU - VL - 14 UR - DO - 10.1046/j.1365-313X.1998.00117.x AB - The Arabidopsis Thi2.1 thionin gene was cloned and sequenced. The promoter was fused to the uidA gene and stably transformed into Arabidopsis to study its regulation. GUS expression levels correlated with the steady‐state levels of Thi2.1 mRNA, thus demonstrating that the promoter is sufficient for the regulation of the Thi2.1 gene. The sensitivity of the Thi2.1 gene to methyl jasmonate was found to be developmentally determined. Systemic and local expression could be induced by wounding and inoculation with Fusarium oxysporum f sp. matthiolae . A deletion analysis of the promoter identified a fragment of 325 bp upstream of the start codon, which appears to contain all the elements necessary for the regulation of the Thi2.1 gene. These results support the view that thionins are defence proteins, and indicate the possibility that resistance of Arabidopsis plants to necrotrophic fungal pathogens is mediated through the octadecanoid pathway. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2343 TI - Association of γ-tubulin with kinetochore/centromeric region of plant chromosomes JO - Plant J. PY - 1998 SP - 751-757 AU - Binarová, P. AU - Hause, B. AU - Doležel, J. AU - Dráber, P. AU - VL - 14 UR - DO - 10.1046/j.1365-313x.1998.00166.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2365 TI - Alteration of V-type H+-ATPase during methyljasmonate-induced senescence in barley (Hordeum vulgare L. cv. Salome) JO - J. Plant Physiol. PY - 1998 SP - 199-206 AU - Ratajczak, R. AU - Feussner, I. AU - Hause, B. AU - Böhm, A. AU - Parthier, B. AU - Wasternack, C. AU - VL - 152 UR - DO - 10.1016/S0176-1617(98)80133-8 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2358 TI - A jasmonic acid conjugate, N-[(—)-jasmonoyl]-tyramine, from Petunia pollen JO - Phytochemistry PY - 1998 SP - 327-329 AU - Miersch, O. AU - Knöfel, H.-D. AU - Schmidt, J. AU - Kramell, R. AU - Parthier, B. AU - VL - 47 UR - DO - 10.1016/S0031-9422(97)00617-1 AB - A new jasmonate, N-[(—)-jasmonoyl]-tyramine, was identified from petunia pollen in which (—)-jasmonic acid was detected and quantified. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 2352 TI - Lipoxygenase catalyzed oxygenation of lipids JO - Fett/Lipid PY - 1998 SP - 146-152 AU - Feussner, I. AU - Wasternack, C. AU - VL - 100 UR - DO - 10.1002/(SICI)1521-4133(19985)100:4/5<146::AID-LIPI146>3.0.CO;2-D AB - Lipoxygenases (LOXs) and other LOX pathway enzymes are potentially able to form a large set of compounds being of commercial interest. Among them are conjugated dienic acids, jasmonates, and volatile aldehydes. Additionally, fatty acid hydroperoxides, formed by LOX, can serve as precursors for further transformation by either enzymes of the so‐called LOX pathway or by chemical reactions. In the case of linoleic acid more than one hundred products generated from its LOX‐derived fatty acid hydroperoxides have been described. Many of these products exhibit biological activity, suggesting a significant biological function of LOXs. This will be described for two different 13‐LOXs. (I) In various oilseeds we found that specific 13‐LOXs are localized at the lipid body membrane. They are capable of oxygenating esterified polyenoic fatty acids, such as triacylglycerols and phospho‐lipids. In addition, they form with arachidonic acid as substrate preferentially either 8‐ or 11‐hydroperoxy eicosatetraenoic acid, which is a very unusual positional specificity for plant LOXs. (II) From barley leaves we isolated another linoleate 13‐LOX form, which is localized within chloroplasts and is induced by jasmonic acid methyl ester. It is suggested, that this LOX form is capable of oxygenating linolenic acid residues of galactolipids. Examples will be presented for barley leaves of oxygenated derivatives of linolenic acid and compounds resulting from the hydroperoxide lyase‐branch of the LOX pathway. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2347 TI - Cloning and expression of a new cDNA from monocotyledonous plants coding for a diadenosine 5′,5′′′-P1,P4-tetraphosphate hydrolase from barley (Hordeum vulgare) JO - FEBS Lett. PY - 1998 SP - 481-485 AU - Churin, J. AU - Hause, B. AU - Feussner, I. AU - Maucher, H. P. AU - Feussner, K. AU - Börner, T. AU - Wasternack, C. AU - VL - 431 UR - DO - 10.1016/S0014-5793(98)00819-9 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2344 TI - Wounding and chemicals induce expression of the Arabidopsis thaliana gene Thi2.1, encoding a fungal defense thionin, via the octadecanoid pathway JO - FEBS Lett. PY - 1998 SP - 281-286 AU - Bohlmann, H. AU - Vignutelli, A. AU - Hilpert, B. AU - Miersch, O. AU - Wasternack, C. AU - Apel, K. AU - VL - 437 UR - DO - 10.1016/S0014-5793(98)01251-4 AB - In seedlings of Arabidopsis thaliana the thionin gene Thi2.1 is inducible by methyl jasmonate, wounding, silver nitrate, coronatine, and sorbitol. We have used a biochemical and genetic approach to test the signal transduction of these different inducers. Both exogenously applied jasmonates and jasmonates produced endogenously upon stress induction, lead to GUS expression in a Thi2.1 promoter-uidA transgenic line. No GUS expression was observed in a coi1 mutant background which lacks jasmonate perception whereas methyl jasmonate and coronatine but not the other inducers were able to overcome the block in jasmonic acid production in a fad3-2 fad7-2 fad8 mutant background. Our results show conclusively that all these inducers regulate Thi2-1 gene expression via the octadecanoid pathway. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 178 TI - Characterization of Isoleucine Conjugates of Cucurbic Acid Isomers by Reversed-Phase and Chiral High-Performance Liquid Chromatography T2 - Natural Product Analysis. Chromatography-Spectroscopy-Biological Testing PB - PY - 1998 SP - 77-78 AU - Kramell, R. AU - Porzel, A. AU - Miersch, O. AU - Schneider, G. AU - VL - UR - https://de.book-info.com/isbn/3-528-06923-6.htm AB - A2 - C1 - Molecular Signal Processing; Bioorganic Chemistry ER - TY - CHAP ID - 177 TI - Effect of Jasmonic Acid Methyl Ester on Enzymes of Lipoxygenase Pathway in Barley Leaves T2 - Natural Product Analysis. Chromatography-Spectroscopy-Biological Testing PB - PY - 1998 SP - 339-340 AU - Kohlmann, M. AU - Kuntzsch, A. AU - Wasternack, C. AU - Feussner, I. AU - VL - UR - https://de.book-info.com/isbn/3-528-06923-6.htm AB - A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 175 TI - Structural Elucidation of Oxygenated Triacylglycerols in Cucumber and Sunflower Cotyledons T2 - Natural Product Analysis. Chromatography-Spectroscopy-Biological Testing PB - PY - 1998 SP - 57-58 AU - Feussner, I. AU - Balkenhohl, T. J. AU - Porzel, A. AU - Kühn, H. AU - Wasternack, C. AU - VL - UR - https://de.book-info.com/isbn/3-528-06923-6.htm AB - A2 - C1 - Molecular Signal Processing; Bioorganic Chemistry ER - TY - CHAP ID - 174 TI - Fatty Acid Catabolism at the Lipid Body Membrane of Germinating Cucumber Cotyledons T2 - Advances in Plant Lipid Research PB - PY - 1998 SP - 311-313 AU - Feussner, I. AU - Blée, E. AU - Weichert, H. AU - Rousset, C. AU - Wasternack, C. AU - VL - UR - https://books.google.de/books?id=ilWa3Amo7AYC&lpg=PA288&ots=CGmFChqH-J&dq=%22Oxylipins%20in%20sorbitol-stressed%20barley%20leaf%20segments%22&hl=de&pg=PA311#v=onepage&q=%22Oxylipins%20in%20sorbitol-stressed%20barley%20leaf%20segments%22&f=false AB - A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 172 TI - A Lipase Specific for Esterified Oxygenated Polyenoic Fatty Acids in Lipid Bodies of Cucumber Cotyledons T2 - Advances in Plant Lipid Research PB - PY - 1998 SP - 320-322 AU - Balkenhohl, T. AU - Kühn, H. AU - Wasternack, C. AU - Feussner, I. AU - VL - UR - https://books.google.de/books?id=ilWa3Amo7AYC&lpg=PA288&ots=CGmFChqH-J&dq=%22Oxylipins%20in%20sorbitol-stressed%20barley%20leaf%20segments%22&hl=de&pg=PA320#v=onepage&q=%22Oxylipins%20in%20sorbitol-stressed%20barley%20leaf%20segments%22&f=false AB - A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 171 TI - Oxylipins in Sorbitol-Stressed Barley Leaf Segments T2 - Advances in Plant Lipid Research PB - PY - 1998 SP - 288-290 AU - Bachmann, A. AU - Kohlmann, M. AU - Wasternack, C. AU - Feussner, I. AU - VL - UR - https://books.google.de/books?id=ilWa3Amo7AYC&lpg=PA288&ots=CGmFChqH-J&dq=%22Oxylipins%20in%20sorbitol-stressed%20barley%20leaf%20segments%22&hl=de&pg=PA288#v=onepage&q=%22Oxylipins%20in%20sorbitol-stressed%20barley%20leaf%20segments%22&f=false AB - A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2426 TI - Purification and Characterization of Allene Oxide Cyclase from Dry Corn Seeds JO - Plant Physiol. PY - 1997 SP - 565-573 AU - Ziegler, J. AU - Hamberg, M. AU - Miersch, O. AU - Parthier, B. AU - VL - 114 UR - DO - 10.1104/pp.114.2.565 AB - Allene oxide cyclase (AOC; EC 5.3.99.6) catalyzes the cyclization of 12,13(S)-epoxy-9(Z),11,15(Z)-octadecatrienoic acid to 12-oxo- 10,15(Z)-phytodienoic acid, the precursor of jasmonic acid (JA). This soluble enzyme was purified 2000-fold from dry corn (Zea mays L.) kernels to apparent homogeneity. The dimeric protein has a molecular mass of 47 kD. Allene oxide cyclase activity was not affected by divalent ions and was not feedback-regulated by its product, 12-oxo-l0,15(Z)-phytodienoic acid, or by JA. ([plus or minus])-cis- 12,13-Epoxy-9(Z)-octadecenoic acid, a substrate analog, strongly inhibited the enzyme, with 50% inhibition at 20 [mu]M. Modification of the inhibitor, such as methylation of the carboxyl group or a shift in the position of the epoxy group, abolished the inhibitory effect, indicating that both structural elements and their position are essential for binding to AOC. Nonsteroidal anti-inflammatory drugs, which are often used to interfere with JA biosynthesis, did not influence AOC activity. The purified enzyme catalyzed the cyclization of 12,13(S)-epoxy-9(Z),11,15(Z)-octadecatrienoic acid derived from linolenic acid, but not that of 12,13(S)-epoxy-9(Z),11- octadecadienoic acid derived from linoleic acid. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2425 TI - Concentration of Dilute Protein Solutions Prior to Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis JO - Anal. Biochem. PY - 1997 SP - 257-260 AU - Ziegler, J. AU - Vogt, T. AU - Miersch, O. AU - Strack, D. AU - VL - 250 UR - DO - 10.1006/abio.1997.2248 AB - A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2416 TI - Jasmonate-signalled plant gene expression JO - Trends Plant Sci. PY - 1997 SP - 302-307 AU - Wasternack, C. AU - Parthier, B. AU - VL - 2 UR - DO - 10.1016/S1360-1385(97)89952-9 AB - Jasmonic acid is distributed throughout higher plants, synthesized from linolenic acid via the octadecanoic pathway. An important and probably essential role seems to be its operation as a ‘master switch’, responsible for the activation of signal transduction pathways in response to predation and pathogen attack. Proteins encoded by jasmonate-induced genes include enzymes of alkaloid and phytoalexin synthesis, storage proteins, cell wall constituents and stress protectants. The wound-induced formation of proteinase inhibitors is a well-studied example, in which jasmonic acid combines with abscisic acid and ethylene to protect the plant from predation. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2415 TI - Molecular modelling, synthesis and biological activity of methyl 3-methyljasmonate and related derivatives JO - Tetrahedron PY - 1997 SP - 8181-8194 AU - Ward, J. L. AU - Gaskin, P. AU - Beale, M. H. AU - Sessions, R. AU - Koda, Y. AU - Wasternack, C. AU - VL - 53 UR - DO - 10.1016/S0040-4020(97)00485-7 AB - Methyl 3-methyljasmonate was synthesised from methyl jasmonate via methyl 3,7-dehydrojasmonate. Molecular modelling predicted an increase in the proportion of cis-orientated side-chains for equilibrated 3-methyl-substituted jasmonate. The synthetic 3-methyljasmonate was shown by gc-ms analysis to equilibrate to a 2:1 ratio of isomers, which appeared from the NMR spectra to comprise mainly the cis-isomer. Surprisingly, both 3,7-dehydro- and 3-methyl-derivatives were inactive in four well established jasmonate bioassays. Methyl-2-methyljasmonate was synthesised and also found to be inactive. Methyl 4,5-dehydrojasmonate was prepared, via the 5-diazo derivative. Both of these compounds have low activity. Our results are discussed with reference to previous knowledge of jasmonate structure-activity relationships and indicate that there are stringent steric demands in jasmonate-receptor interactions. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2403 TI - Chiral separation of amide conjugates of jasmonic acid by liquid chromatography JO - Chromatographia PY - 1997 SP - 104-108 AU - Kramell, R. AU - Schneider, G. AU - Miersch, O. AU - VL - 45 UR - DO - 10.1007/BF02505545 AB - Synthetic amide conjugates of (−)-jasmonic acid and its (+)-enantiomer were resolved by means of chiral liquid chromatography. The diastereomeric pairs prepared by chemical reaction of (±)-jasmonic acid with a series of (S)- or (R)-amino acids and with some (S)-amino acid alcohols were completely separated on Chiralpak AS using a mixture of n-hexane/2-propanal as mobile phase. The retention data indicate that the (−)-jasmonic acid conjugates eluted faster than those of the (+)-enantiomer, independent on the configuration of the bound amino acid. Likewise, enantiomeric derivatives of (±)-jasmonic acid and non-chiral amino acids were completely separated on the chiral stationary phase and showed the same elution sequence. The resolution factors,Rs, were found to range between 1.13 and 6.64. The separated compounds were chiropatically analyzed by measurement of the circular dichroism. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2402 TI - Amino acid conjugates of jasmonic acid induce jasmonate-responsive gene expression in barley (Hordeum vulgare L.) leaves JO - FEBS Lett. PY - 1997 SP - 197-202 AU - Kramell, R. AU - Miersch, O. AU - Hause, B. AU - Ortel, B. AU - Parthier, B. AU - Wasternack, C. AU - VL - 414 UR - DO - 10.1016/S0014-5793(97)01005-3 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2398 TI - Partial purification and characterization of a jasmonic acid conjugate cleaving amidohydrolase from the fungus Botryodiplodia theobromae JO - FEBS Lett. PY - 1997 SP - 105-110 AU - Hertel, S. C. AU - Knöfel, H.-D. AU - Kramell, R. AU - Miersch, O. AU - VL - 407 UR - DO - 10.1016/S0014-5793(97)00307-4 AB - A protein preparation from the mycelium of the tropical pathogenic fungus Botryodiplodia theobromae revealed a novel peptidase activity. This enzyme was capable of cleaving conjugates of jasmonic acid with α-amino acids. The protein was enriched 108-fold by gel filtration, ion exchange and hydrophobic interaction chromatography. The enzyme was found to be a glycoprotein with a molecular mass of about 107 kDa. The amidohydrolase seems to be very specific with regard to (−)-jasmonic acid and α-amino acids with (S)-configuration. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2397 TI - Nuclear Location of a Diadenosine 5′,5′”-P1,P4Tetraphosphate (Ap4A) Hydrolase in Tomato Cells Grown in Suspension Cultures JO - Bot. Acta PY - 1997 SP - 452-457 AU - Hause, B. AU - Feussner, K. AU - Wasternack, C. AU - VL - 110 UR - DO - 10.1111/j.1438-8677.1997.tb00662.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2396 TI - 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) JO - J. Plant Physiol. PY - 1997 SP - 127-132 AU - Hause, B. AU - Kogel, K.-H. AU - Parthier, B. AU - Wasternack, C. AU - VL - 150 UR - DO - 10.1016/S0176-1617(97)80191-5 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2395 TI - Overexpression of the jasmonate-inducible 23 kDa protein (JIP 23) from barley in transgenic tobacco leads to the repression of leaf proteins JO - FEBS Lett. PY - 1997 SP - 58-62 AU - Görschen, E. AU - Dunaeva, M. AU - Reeh, I. AU - Wasternack, C. AU - VL - 419 UR - DO - 10.1016/S0014-5793(97)01433-6 AB - We investigated transgenic tobacco lines which express different amounts of the barley JIP 23. In these plants the amount of several proteins decreased proportionally to increasing amounts of JIP 23 whereas the transcript levels were constant as determined for the small and the large subunit of RuBPCase. However, the translation initiation of the rbcS transcript was found to be less efficient than in the wild type. In contrast, the jip 23 transcript was efficiently initiated, indicating that no unspecific impairment of initiation occurred. The data suggest that the barley JIP 23 leads to discrimination among certain tobacco transcripts during translation initiation. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2394 TI - Expression of the ribosome-inactivating protein JIP60 from barley in transgenic tobacco leads to an abnormal phenotype and alterations on the level of translation JO - Planta PY - 1997 SP - 470-478 AU - Görschen, E. AU - Dunaeva, M. AU - Hause, B. AU - Reeh, I. AU - Wasternack, C. AU - Parthier, B. AU - VL - 202 UR - DO - 10.1007/s004250050151 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2390 TI - Structural Elucidation of Oxygenated Storage Lipids in Cucumber Cotyledons JO - J. Biol. Chem. PY - 1997 SP - 21635-21641 AU - Feussner, I. AU - Balkenhohl, T. J. AU - Porzel, A. AU - Kühn, H. AU - Wasternack, C. AU - VL - 272 UR - DO - 10.1074/jbc.272.34.21635 AB - At early stages of germination, a special lipoxygenase is expressed in cotyledons of cucumber and several other plants. This enzyme is localized at the lipid storage organelles and oxygenates their storage triacylglycerols. We have isolated this lipid body lipoxygenase from cucumber seedlings and found that it is capable of oxygenating in vitro di- and trilinolein to the corresponding mono-, di-, and trihydroperoxy derivatives. To investigate the in vivo activity of this enzyme during germination, lipid bodies were isolated from cucumber seedlings at different stages of germination, and the triacylglycerols were analyzed for oxygenated derivatives by a combination of high pressure liquid chromatography, gas chromatography/mass spectrometry, and nuclear magnetic resonance spectroscopy. We identified as major oxygenation products triacylglycerols that contained one, two, or three 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid residues. During germination, the amount of oxygenated lipids increased strongly, reaching a maximum after 72 h and declining afterward. The highly specific pattern of hydroperoxy lipids formed suggested the involvement of the lipid body lipoxygenase in their biosynthesis.These data suggest that this lipoxygenase may play an important role during the germination process of cucumber and other plants and support our previous hypothesis that the specific oxygenation of the storage lipids may initiate their mobilization as a carbon and energy source for the growing seedling. A2 - C1 - Molecular Signal Processing; Bioorganic Chemistry ER - TY - JOUR ID - 2389 TI - Quantitative Analyse von Lipoxygenase-Metaboliten in Lipiden durch NMR-Spektroskopie JO - BIOspektrum PY - 1997 SP - 54-58 AU - Feussner, I. AU - Porzel, A. AU - Wasternack, C. AU - Kühn, H. AU - VL - 3 UR - AB - A2 - C1 - Molecular Signal Processing; Bioorganic Chemistry ER - TY - JOUR ID - 2388 TI - Isolation of a cDNA coding for an ubiquitin-conjugating enzyme UBC1 of tomato - the first stress-induced UBC of higher plants JO - FEBS Lett. PY - 1997 SP - 211-215 AU - Feussner, K. AU - Feussner, I. AU - Leopold, I. AU - Wasternack, C. AU - VL - 409 UR - DO - 10.1016/S0014-5793(97)00509-7 AB - A clone of an ubiquitin‐conjugating enzyme (UBC) was isolated from a λ‐ZAP‐cDNA library, generated from mRNA of tomato (Lycopersicon esculentum) cells grown in suspension for 3 days. The open reading frame called Le UBC1, encodes for a polypeptide with a predicted molecular mass of 21.37 kDa, which was confirmed by bacterial overexpression and SDS‐PAGE. Database searches with Le UBC1 showed highest sequence similarities to UBC1 of bovine and yeast. By Southern blot analysis Le UBC1 was identified as a member of a small E2 subfamily of tomato, presumably consisting of at least two members. As revealed by Northern blot analysis Le UBC1 is constitutively expressed in an exponentially growing tomato cell culture. In response to heat shock an increase in Le UBC1‐mRNA was detectable. A strong accumulation of the Le UBC1‐transcript was observed by exposure to heavy metal stress which was performed by treatment with cadmium chloride (CdCl2). The cellular uptake of cadmium was controlled via ICP‐MS measurements. The data suggest that like in yeast, in plants a certain subfamily of UBC is specifically involved in the proteolytic degradation of abnormal proteins as result of stress. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2387 TI - Induction of a new Lipoxygenase Form in Cucumber Leaves by Salicylic Acid or 2,6-Dichloroisonicotinic Acid JO - Bot. Acta PY - 1997 SP - 101-108 AU - Feussner, I. AU - Fritz, I. G. AU - Hause, B. AU - Ullrich, W. R. AU - Wasternack, C. AU - VL - 110 UR - DO - 10.1111/j.1438-8677.1997.tb00616.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2386 TI - Do specific linoleate 13-lipoxygenases initiate β-oxidation? JO - FEBS Lett. PY - 1997 SP - 1-5 AU - Feussner, I. AU - Kühn, H. AU - Wasternack, C. AU - VL - 406 UR - DO - 10.1016/S0014-5793(97)00218-4 AB - The germination process of oilseed plants is characterized by a mobilization of the storage lipids which constitute the major carbon source for the growing seedling. Despite the physiological importance of the lipid mobilization, the mechanism of this process is not well understood. Recently, it was found that a specific linoleate 13-lipoxygenase is induced during the stage of lipid mobilization in various oilseed plants and that this enzyme is translocated to the membranes of the lipid storage organelles, the so called lipid bodies. Lipoxygenase expression was paralleled by the occurrence of enantiospecific hydro(pero)xy polyenoic fatty acid derivatives in the storage lipids suggesting the in vivo action of the enzyme. Furthermore, it was reported that oxygenated polyenoic fatty acids, in particular as 13(S)-hydro(pero)xy-9(Z),11(E)-octadecanoic acid [13(S)-H(P)ODE], are cleaved preferentially from the storage lipids when compared with their non-oxygenated linoleate residues. These findings may suggest that 13(S)-H(P)ODE may constitute the endogenous substrate for β-oxidation during lipid mobilization of oilseed plants. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 185 TI - Allene Oxide Cyclase from Corn: Partial Purification and Characterization T2 - Physiology, Biochemistry and Molecular Biology of Plant Lipids PB - PY - 1997 SP - 99-101 AU - Ziegler, J. AU - Hamberg, M. AU - Miersch, O. AU - VL - UR - DO - 10.1007/978-94-017-2662-7_32 AB - In plants, the oxylipin pathway gives rise to several oxygenated fatty acid derivatives such as hydroxy- and keto fatty acids as well as volatile aldehydes and cyclic compounds, which are, in part, physiologically active [1]. Among these, jasmonic acid is discussed as signalling molecule during several stress responses, wounding, senescense and plant pathogen interactions [2]. A2 - C1 - Molecular Signal Processing ER - TY - CHAP ID - 181 TI - Do Lipoxygenases Initiate β-Oxidation? T2 - Physiology, Biochemistry and Molecular Biology of Plant Lipids PB - PY - 1997 SP - 250-252 AU - Feussner, I. AU - Kühn, H. AU - Wasternack, C. AU - VL - UR - DO - 10.1007/978-94-017-2662-7_79 AB - The etiolated germination process of oilseed plants is characterized by the mobilization of storage lipids which serve as a major carbon source for the seedlings growth. During this stage the lipid storing organelles, the lipid bodies, are degraded and a new set of proteins, including a specific form of lipoxygenase (LOX), is detectable at their membranes in different plants [1,2]. LOXs are widely distributed in plants and animals and catalyze the regio- and stereo-specific oxygenation of polyunsaturated fatty acids [3]. The enzymatic transformations of the resulting fatty acid hydroperoxides have been extensively studied [4]. Three well characterized enzymes, a lyase, an allene oxide synthase, and a peroxygenase, were shown to degrade hydroperoxides into compounds of physiological importance, such as odors, oxylipins, and jasmonates. We have recently reported a new LOX reaction in plants where a specific LOX, the lipid body LOX, metabolizes esterified fatty acids. This reaction resulted in the formation of 13(S)-hydroxy-linoleic acid (13-HODE) and lead us to propose an additional branch of the LOX pathway: the reductase pathway. Besides a specific LOX form we suggest two additional enzyme activities, a lipid hydroperoxide reductase and a lipid hydroxide-specific lipase which lead to the formation of 13-HODE. 13-HODE might be the endogenous substrate for β-oxidation in the glyoxysomes during germination of oilseeds containing high amounts of polyunsaturated fatty acids. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2442 TI - Abscisic acid-deficient plants do not accumulate proteinase inhibitor II following systemin treatment JO - Planta PY - 1996 SP - 447-451 AU - Peña-Cortés, H. AU - Prat, S. AU - Atzorn, R. AU - Wasternack, C. AU - Willmitzer, L. AU - VL - 198 UR - DO - 10.1007/BF00620062 AB - The role of systemin in Pin2 gene expression was analyzed in wild-type plants of potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.), as well as in abscisic acid (ABA)-deficient tomato (sitiens) and potato (droopy) plants. The results showed that systemin initiates Pin2 mRNA accumulation only in wildtype tomato and potato plants. As in the situation after mechanical wounding,Pin2 gene expression in ABA-deficient plants was not activated by systemin. Increased endogenous levels of jasmonic acid (JA) and accumulation of Pin2 mRNA were observed following treatment with α-linolenic acid, the precursor of JA biosynthesis, suggesting that these ABA mutants still have the capability to synthesize de novo JA. Measurement of endogenous levels of ABA and JA showed that systemin leads to an increase of both phytohormones (ABA and JA) only in wild-type but not in ABA-deficient plants. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2441 TI - Ethylene as a Signal Mediating the Wound Response of Tomato Plants JO - Science PY - 1996 SP - 1914-1917 AU - O'Donnell, P. J. AU - Calvert, C. AU - Atzorn, R. AU - Wasternack, C. AU - Leyser, H. M. O. AU - Bowles, D. J. AU - VL - 274 UR - DO - 10.1126/science.274.5294.1914 AB - Plants respond to physical injury, such as that caused by foraging insects, by synthesizing proteins that function in general defense and tissue repair. In tomato plants, one class of wound-responsive genes encodes proteinase inhibitor (pin) proteins shown to block insect feeding. Application of many different factors will induce or inhibit pin gene expression. Ethylene is required in the transduction pathway leading from injury, and ethylene and jasmonates act together to regulate pin gene expression during the wound response. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2439 TI - Isolation, characterization and expression of a cDNA coding for a jasmonate-inducible protein of 37 kDa in barley leaves JO - Plant Cell Environ. PY - 1996 SP - 675-684 AU - Leopold, J. AU - Hause, B. AU - Lehmann, J. AU - Graner, A. AU - Parthier, B. AU - Wasternack, C. AU - VL - 19 UR - DO - 10.1111/j.1365-3040.1996.tb00402.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2434 TI - Localized Wounding by Heat Initiates the Accumulation of Proteinase Inhibitor II in Abscisic Acid-Deficient Plants by Triggering Jasmonic Acid Biosynthesis JO - Plant Physiol. PY - 1996 SP - 853-860 AU - Herde, O. AU - Atzorn, R. AU - Fisahn, J. AU - Wasternack, C. AU - Willmitzer, L. AU - Pena-Cortes, H. AU - VL - 112 UR - DO - 10.1104/pp.112.2.853 AB - To test whether the response to electrical current and heat treatment is due to the same signaling pathway that mediates mechanical wounding, we analyzed the effect of electric-current application and localized burning on proteinase inhibitor II (Pin2) gene expression in both wild-type and abscisic acid (ABA)-deficient tomato (Lycopersicon esculentum Mill.) and potato (Solanum phureja) plants. Electric-current application and localized burning led to the accumulation of Pin2 mRNA in potato and tomato wild-type plants. Among the treatments tested, only localized burning of the leaves led to an accumulation of Pin2 mRNA in the ABA-deficient plants. Electric-current application, like mechanical injury, was able to initiate ABA and jasmonic acid (JA) accumulation in wild-type but not in ABA-deficient plants. In contrast, heat treatment led to an accumulation of JA in both wild-type and ABA-deficient plants. Inhibition of JA biosynthesis by aspirin blocked the heat-induced Pin2 gene expression in tomato wild-type leaves. These results suggest that electric current, similar to mechanical wounding, requires the presence of ABA to induce Pin2 gene expression. Conversely, burning of the leaves activates Pin2 gene expression by directly triggering the biosynthesis of JA by an alternative pathway that is independent of endogenous ABA levels. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2433 TI - Developmental and Tissue-Specific Expression of JIP-23, a Jasmonate-Inducible Protein of Barley JO - Plant Cell Physiol. PY - 1996 SP - 641-649 AU - Hause, B. AU - Demus, U. AU - Teichmann, C. AU - Parthier, B. AU - Wasternack, C. AU - VL - 37 UR - DO - 10.1093/oxfordjournals.pcp.a028993 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2432 TI - Lipid-body lipoxygenase is expressed in cotyledons during germination prior to other lipoxygenase forms JO - Planta PY - 1996 SP - 288-293 AU - Feussner, I. AU - Hause, B. AU - Nellen, A. AU - Wasternack, C. AU - Kindl, H. AU - VL - 198 UR - DO - 10.1007/BF00206255 AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2431 TI - Diadenosine 5′,5‴- P1,P4-tetraphosphate (Ap4A) Hydrolase from Tomato (Lycopersicon esculentum cv. Lukullus) -Purification, Biochemical Properties and Behaviour during Stress JO - Z. Naturforsch. C PY - 1996 SP - 477-486 AU - Feussner, K. AU - Guranowski, A. AU - Kostka, S. AU - Wasternack, C. AU - VL - 51 UR - DO - 10.1515/znc-1996-7-805 AB - Dinucleoside 5′,5‴-P1,P4-tetraphosphate hydrolase (EC 3.6.1.17) has been purified to homogeneity from tomato (Lycopersicon esculentum) cells grown in suspension. The purification procedure comprised ammonium sulphate fractionation following five standard chroma­ tography steps and a final chromatography on Ap4A-Sepharose. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2428 TI - Occurrence of jasmonic acid in organs of Solanum tuberosum L. and its effect on tuberization JO - Plant Growth Regul. PY - 1996 SP - 139-143 AU - Abdala, G. AU - Castro, G. AU - Guiñazú, M. M. AU - Tizio, R. AU - Miersch, O. AU - VL - 19 UR - DO - 10.1007/BF00024580 AB - The aims of this study were to demonstrate the endogenous presence of jasmonic acid (JA) in roots, stolons and periderm of new formed tubers, by means of bioassays, ELISA and GC-MS, and to test a microdrop bioassay using the leaflets of potato cuttings cultured in vitro. Our results confirm the existence of JA by bioassays and GC-MS in foliage, stolons, roots and tuber periderm. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2447 TI - Alteration of Gene Expression by Jasmonate and ABA in Tobacco and Tomato JO - J. Plant Physiol. PY - 1996 SP - 503-510 AU - Wasternack, C. AU - Atzorn, R. AU - Peña-Cortés, H. AU - Parthier, B. AU - VL - 147 UR - DO - 10.1016/S0176-1617(96)80038-1 AB - 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. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2467 TI - Synthesis of jasmonate-induced proteins in barley (Hordeum vulgare) is inhibited by the growth retardant tetcyclacis JO - Physiol. Plant. PY - 1995 SP - 335-341 AU - Wasternack, C. AU - Atzorn, R. AU - Leopold, J. AU - Feussner, I. AU - Rademacher, W. AU - Parthier, B. AU - VL - 94 UR - DO - 10.1111/j.1399-3054.1995.tb05320.x AB - BarJey leaf segments treated with jasmonate respond with the synthesis of specific proseins, referred to as jasmonate‐induced proteins (JIPs). Application of abscisic acid (ABAl also induced JIP synthesis (Weidhase et al. 1987). In this study the effects of inhibitors on sorbitol‐induced increases of endogenous jasmonates and ABA were investigated. The promotion of jasmonates by sorbitol was inhibited by the growth retardant tetcyclacis at concentrations as low as 1 ftM. In parallel with the decrease of jasmonates, JIP gene expression was reduced as reflected by a decline in the level of a 23‐kDa protein UIP‐23) and mRNAs of JIP‐6 and JIP‐23. 12‐Oxo‐phytodienoic acid, an inlermediale in the lipoxygenase (LOX) pathway leading to jasmonic acid was able to overcome the inhibition by tetcyclacis and increases both the endogenous jasmonate content and transcript accumulation. This suggests that tetcyclacis acts upstream of 12‐oxo‐phytodienoic acid and in keeping with this proposal, an increase in relative LOX activity was detected after tetcyclacis treatment. Although tetcyclacis was shown to inhibit the degradation of ABA to phaseic acid, its effect on jasmonate synthesis is much more pronounced. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2461 TI - Accumulation of jasmonate, abscisic acid, specific transcripts and proteins in osmotically stressed barley leaf segments JO - Planta PY - 1995 SP - 156-192 AU - Lehmann, J. AU - Atzorn, R. AU - Brückner, C. AU - Reinbothe, S. AU - Leopold, J. AU - Wasternack, C. AU - Parthier, B. AU - VL - 197 UR - DO - 10.1007/BF00239952 AB - The accumulation of abundant proteins and their respective transcripts, induced by 10−4 M cisabscisic acid or 10−5 M jasmonic acid methyl ester, was studied in barley (Hordeum vulgare L.) leaf segments and compared to that resulting from osmotic stress caused by floating the segments on solutions of sorbitol, glucose, polyethyleneglycol (PEG)-6000 or NaCl. Osmotic stress or treatment with abscisic acid led to the synthesis of novel proteins which were identical to jasmonateinduced proteins (JIPs) with respect to immunological properties and molecular masses. The most prominent polypeptides were characterized by molecular masses of 66, 37 and 23 kDa and were newly synthesized. Whereas sorbitol, mannitol, sucrose, glucose and PEG provoked the synthesis of JIPs, 2deoxyglucose and NaCl did not. We provide evidence that the synthesis of JIPs induced by osmotic stress is directly correlated with a preceding rise in endogenous jasmonates. These jasmonates, quantified by an enzyme immunoassay specific for (−)jasmonic acid and its aminoacid conjugates, increased remarkably in leaf segments treated with sorbitol, glucose or other sugars. In contrast, no increase in jasmonates could be observed in tissues exposed to salts (NaCl). The results strengthen the hypothesis that the accumulation of jasmonates, probably by de-novo synthesis, is an intermediate and essential step in a signalling pathway between (osmotic) stress and activation of genes coding for polypeptides of high abundance. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2460 TI - Occurrence and identification of jasmonic acid and its amino acid conjugates induced by osmotic stress in barley leaf tissue JO - J. Plant Growth Regul. PY - 1995 SP - 29-36 AU - Kramell, R. AU - Atzorn, R. AU - Schneider, G. AU - Miersch, O. AU - Brückner, C. AU - Schmidt, J. AU - Sembdner, G. AU - Parthier, B. AU - VL - 14 UR - DO - 10.1007/BF00212643 AB - The effect of osmotically active substances on the alteration of endogenous jasmonates was studied in barley (Hordeum vulgare L. cv. Salome) leaf tissue. Leaf segments were subjected to solutions of d-sorbitol, d-mannitol, polyethylene glycol 6000, sodium chloride, or water as a control. Alterations of endogenous jasmonates were monitored qualitatively and quantitatively using immunoassays. The structures of jasmonates isolated were determined on the basis of authentic substances by capillary gas chromatography-mass spectrometry. The stereochemistry of the conjugates was confirmed by high performance liquid chromatography with diastereoisomeric references. In barley leaves, jasmonic acid and its amino acid conjugates, for example, with valine, leucine, and isoleucine, are naturally occurring jasmonates. In untreated leaf segments, only low levels of these native jasmonates were found. After treatment of the leaf tissues with sorbitol, mannitol, as well as with polyethylene glycol, an increase of both jasmonic acid and its conjugates could be observed, depending on the stress conditions used. In contrast, salt stress was without any stimulating effect on the levels of endogenous jasmonates. From barley leaf segments exposed to sorbitol (1m) for 24 h, jasmonic acid was identified as the major accumulating compound. Jasmonic acid-amino acid conjugates increased likewise upon stress treatment. A2 - C1 - Bioorganic Chemistry; Molecular Signal Processing ER - TY - JOUR ID - 2459 TI - Resistance in barley against the powdery mildew fungus (Erysiphe graminis f.sp.hordei) is not associated with enhanced levels of endogenous jasmonates JO - Eur. J. Plant Pathol. PY - 1995 SP - 319-332 AU - Kogel, K.-H. AU - Ortel, B. AU - Jarosch, B. AU - Atzorn, R. AU - Schiffer, R. AU - Wasternack, C. AU - VL - 101 UR - DO - 10.1007/BF01874788 AB - Onset of acquired resistance of barley (Hordeum vulgare) chemically induced by 2,6-dichloroisonicotinic acid (DCINA) correlated with the accumulation of mRNA homologous to cDNA pHvJ256 which codes for a soluble leaf-thionin with a Mr. of 6 kDa [Wasternacket al., 1994a]. In the present work, we extend this finding by showing that the thionin transcript also accumulated following treatment of barley with the resistance-inducing compounds 3,5-dichlorosalicylic acid (DCSA), salicylic acid (SA), and an extract fromBacillus subtilis. The polypeptide showed antifungal activity against the biotrophic cereal pathogensErysiphe graminis f.sp.hordei andPuccinia graminis f.sp.tritici which may indicate a possible role in the mechanism of acquired resistance in barley. A thionin transcript hybridizing to pHvJ256 accumulated also in response to application of jasmonates, or treatments that elevated endogenous amounts of the plant growth substance, pointing to the possibility that signaling mediating defense responses in barley involves jasmonates. However, a topical spray application of jasmonic acid (JA) or jasmonate methyl ester (JM) did not protect barley leaves against infection byE. graminis. Performing a kinetic analysis by an enzyme immunoassay specific for (−)-JA, (−)-JM, and its amino acid conjugates, accumulation of jasmonates was detected in osmotically stressed barley but not at the onset of chemically induced or genetically based resistance governed by the powdery mildew resistance genesMlg, Mla 12, ormlo 5. Furthermore, the jasmonate-inducible proteins JIP-23 and JIP-60 were strongly induced following JM- but not DCINA-treatment or inoculation withE. graminis. Hence, in barley, no indications were found in favour for the previously proposed model of a lipid-based signaling pathway via jasmonates mediating expression of resistance in plants against pathogens. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2456 TI - Expression of a Flax Allene Oxide Synthase cDNA Leads to Increased Endogenous Jasmonic Acid (JA) Levels in Transgenic Potato Plants but Not to a Corresponding Activation of JA-Responding Genes JO - Plant Cell PY - 1995 SP - 1645-1654 AU - Harms, K. AU - Atzorn, R. AU - Brash, A. AU - Kühn, H. AU - Wasternack, C. AU - Willmitzer, L. AU - Pena-Cortes, H. AU - VL - 7 UR - DO - 10.1105/tpc.7.10.1645 AB - Both jasmonic acid (JA) and its methyl ester, methyl jasmonate (MeJA), are thought to be significant components of the signaling pathway regulating the expression of plant defense genes in response to various stresses. JA and MeJA are plant lipid derivatives synthesized from [alpha]-linolenic acid by a lipoxygenase-mediated oxygenation leading to 13-hydroperoxylinolenic acid, which is subsequently transformed by the action of allene oxide synthase (AOS) and additional modification steps. AOS converts lipoxygenase-derived fatty acid hydroperoxide to allene epoxide, which is the precursor for JA formation. Overexpression of flax AOS cDNA under the regulation of the cauliflower mosaic virus 35S promoter in transgenic potato plants led to an increase in the endogenous level of JA. Transgenic plants had six- to 12-fold higher levels of JA than the nontransformed plants. Increased levels of JA have been observed when potato and tomato plants are mechanically wounded. Under these conditions, the proteinase inhibitor II (pin2) genes are expressed in the leaves. Despite the fact that the transgenic plants had levels of JA similar to those found in nontransgenic wounded plants, pin2 genes were not constitutively expressed in the leaves of these plants. Transgenic plants with increased levels of JA did not show changes in water state or in the expression of water stress-responsive genes. Furthermore, the transgenic plants overexpressing the flax AOS gene, and containing elevated levels of JA, responded to wounding or water stress by a further increase in JA and by activating the expression of either wound- or water stress-inducible genes. Protein gel blot analysis demonstrated that the flax-derived AOS protein accumulated in the chloroplasts of the transgenic plants. A2 - C1 - Molecular Signal Processing ER - TY - JOUR ID - 2455 TI - Jasmonate-induced lipoxygenase forms are localized in chloroplasts of barley leaves (Hordeum vulgare cv. Salome) JO - Plant J. PY - 1995 SP - 949-957 AU - Feussner, I. AU - Hause, B. AU - Vörös, K. AU - Parthier, B. AU - Wasternack, C. AU - VL - 7 UR - DO - 10.1046/j.1365-313X.1995.07060949.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER - TY - JOUR ID - 2474 TI - Intracellular Localization of Jasmonate-Induced Proteins in Barley Leaves JO - Bot. Acta PY - 1994 SP - 333-341 AU - Hause, B. AU - zur Nieden, U. AU - Lehmann, J. AU - Wasternack, C. AU - Parthier, B. AU - VL - 107 UR - DO - 10.1111/j.1438-8677.1994.tb00804.x AB - 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. A2 - C1 - Molecular Signal Processing; Cell and Metabolic Biology ER -