TY - JOUR ID - 12333 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 - 12332 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 - 12432 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 - 13173 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 - 13793 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 - 13822 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 - 13869 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 - 13976 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 - 13966 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 - 13995 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 - 14038 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 - 14053 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 -