Downstream metabolites of (+)-cis-12-oxo-phytodienoic acid function as noncanonical bioactive jasmonates in Arabidopsis thaliana.

(+)- 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 demonstrated that the genuine bioactive forms of cis -OPDA are the downstream metabolites of b-oxidation, which upregulate the expression of the OPDA marker genes such as ZAT10 and ERF5 in a COI1- or JA-Ile-independent manner. These downstream metabolites function independently of the JA-Ile-COI1-JAZ-MYCs canonical jasmonate signaling module, and their electrophilic nature is essential for their bioactivity.