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Wasternack, C. Sulfation switch in the shade Nat Plants 6, 186-187, (2020) DOI: 10.1038/s41477-020-0620-8

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.

Wasternack, C.; Strnad, M. Jasmonates are signals in the biosynthesis of secondary metabolites — Pathways, transcription factors and applied aspects — A brief review. New Biotechnol 48, 1-11, (2019) DOI: 10.1016/j.nbt.2017.09.007

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.

Wasternack, C.; Hause, B. The missing link in jasmonic acid biosynthesis Nat Plants 5, 776-777, (2019) DOI: 10.1038/s41477-019-0492-y

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.

Wasternack, C.; Strnad, M. Jasmonates: News on Occurrence, Biosynthesis, Metabolism and Action of an Ancient Group of Signaling Compounds Int J Mol Sci 19, 2539, (2018) DOI: 10.3390/ijms19092539

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.

Bosch, M.; Wright, L. P.; Gershenzon, J.; Wasternack, C.; Hause, B.; Schaller, A.; Stintzi, A. Jasmonic acid and its precursor 12-oxophytodienoic acid control different aspects of constitutive and induced herbivore defenses in tomato Plant Physiology 166, 396-410, (2014) DOI: 10.1104/pp.114.237388

The jasmonate family of growth regulators includes the isoleucine conjugate of jasmonic acid (JA-Ile) and its biosynthetic precursor 12-oxophytodienoic acid (OPDA) as signaling molecules. In order to assess the relative contribution of JA/JA-Ile and OPDA to insect resistance in tomato, we silenced the expression of OPDA reductase (OPR3) by RNA interference. 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 mono- 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 much delayed as compared to development on the JA/JA-Ile insensitive (jai1) mutant. Apparently, signaling through JAI1, the tomato ortholog of COI1 in Arabidopsis, is required for defense while 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.
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