Saito, R.; Nishizato, Y.; Kitajima, T.; Nakayama, M.; Takaoka, Y.; Kato, N.; Ueda, M.

(+)-cis-12-oxo-phytodienoic acid (cis-OPDA) is a biosynthetic precursor of the plant hormone (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile). It functions as an endogenous chemical signal independent of the JA-Ile receptor COI1-JAZ in Arabidopsis thaliana. The bioactive form of cis-OPDA that induces COI1-JAZ-independent gene expression remains unknown. In this study, we hypothesized that the genuine bioactive forms of cis-OPDA are the downstream metabolites, which upregulate the expression of the OPDA marker genes such as ZAT10/ERF5 in a JA-Ile-independent manner. These downstream metabolites function independently of the JA-Ile-COI1-JAZ-MYCs canonical jasmonate signaling module, and its electrophilic nature is essential for its bioactivity.