Publication details
Homeostasis of cis-OPDA amide conjugates upon stress responses
| Authors | |
|---|---|
| Year of publication | 2024 |
| Type | Article in Periodical |
| Magazine / Source | Plant Physiology |
| MU Faculty or unit | |
| Citation | |
| Description | 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 perception and metabolism are only partially understood. 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 accumulating in response to biotic and abiotic stress in Arabidopsis. The newly identified OPDA-amino acid conjugates show cis-OPDA-related plant responses in a JA-Ile-dependent manner. We also showed that the synthesis and hydrolysis of cis-OPDA amino acid conjugates are mediated by members of the amidosynthetase GH3 and the amidohydrolase ILR1/ILL families. Thus, OPDA-aa function in the catabolism or temporary storage of cis-OPDA in stress responses instead of acting as chemical signals per se. Collectively, our findings confirm a homeostatic regulation of the cytosolic cis-OPDA pool and propose the existence of a subcellular pathway controlling nuclear cis-OPDA levels. |