Conjugation of cis-OPDA with amino acids is a conserved pathway affecting cis-OPDA homeostasis upon stress responses

Brunoni, F.; Siroka, J.; Mik, V.; Pospisil, T.; Kralova, M.; Ament, A.; Pernisova, M.; Karady, M.; Htitich, M.; Ueda, M.; Flokova, K.; Wasternack, C.; Strnad, M.; Novak, O.

doi:10.1101/2023.07.18.549545

bioRxiv · 10.1101/2023.07.18.549545

Conjugation of cis-OPDA with amino acids is a conserved pathway affecting cis-OPDA homeostasis upon stress responses

Brunoni, F.·Siroka, J.·Mik, V.·Pospisil, T.·Kralova, M.·Ament, A.·Pernisova, M.·Karady, M.·Htitich, M.·Ueda, M.·Flokova, K.·Wasternack, C.·Strnad, M.·Novak, O.

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Abstract

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.

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Brunoni, F., Siroka, J., Mik, V., Pospisil, T., Kralova, M., Ament, A., Pernisova, M., Karady, M., Htitich, M., Ueda, M., Flokova, K., Wasternack, C., Strnad, M., Novak, O.. 2023-07-19. Conjugation of cis-OPDA with amino acids is a conserved pathway affecting cis-OPDA homeostasis upon stress responses. https://doi.org/10.1101/2023.07.18.549545

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