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Publikation

Wasternack, C.; Strnad, M. Jasmonate signaling in plant stress responses and development – active and inactive compounds New Biotechnology 33 B, 604-613, (2016) DOI: 10.1016/j.nbt.2015.11.001

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.
Publikation

Wasternack, C.; Hause, B. OPDA-Ile – a new JA-Ile-independent signal? Plant Signal Behav 11, e125364600, (2016) DOI: 10.1080/15592324.2016.1253646

AbstractExpression 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.
Publikation

Wasternack, C.; Goetz, S.; Hellwege, A.; Forner, S.; Strnad, M.; Hause, B. Another JA/COI1-independent role of OPDA detected in tomato embryo development. Plant Signal Behav 7, 1349-1353, (2012) DOI: 10.4161/psb.21551

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.
Publikation

Wasternack, C.; Xie, D. The genuine ligand of a jasmonic acid receptor: Improved analysis of jasmonates is now required. Plant Signal Behav 5, 337-340, (2010) DOI: 10.4161/psb.5.4.11574

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 signaling. 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 modeling 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 signaling.
Publikation

Feussner, I.; Porzel, A.; Wasternack, C.; Kühn, H. Quantitative Analyse von Lipoxygenase-Metaboliten in Lipiden durch NMR-Spektroskopie Biospektrum 3, 54-58, (1997)

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