Difference in the ligand affinity among redundant plant hormone receptors of rice OsCOI1a/1b/2-OsJAZs.

(3R, 7S)-jasmonoyl-L-isoleucine (JA-Ile) is a lipid-derived plant hormone that regulates plant responses, including biotic/abiotic stress adaptation. In the plant cells, JA-Ile is perceived by COI1-JAZ co-receptor by causing protein-protein interaction between COI1 and JAZ proteins to trigger gene expressions. In this study, we focused on Oryza sativa, a model monocot and an important crop, with 45 possible OsCOI-OsJAZ co-receptor pairs composed of three OsCOI homologs (OsCOI1a, OsCOI1b, and OsCOI2) and 15 OsJAZ homologs.

(3R,7S)-12-Hydroxy-jasmonoyl-l-isoleucine is the genuine bioactive stereoisomer of a jasmonate metabolite in Arabidopsis thaliana.

The oxylipin plant hormone (3R,7S)-jasmonoyl-l-isoleucine [or (+)-7-iso-jasmonoyl-l-isoleucine, JA-Ile] is widely recognized as a plant defense hormone against pathogens and chewing insects. The metabolism of JA-Ile into 12-OH-JA-Ile and 12-COOH-JA-Ile is the central mechanism for the inactivation of JA signaling. Recently, 12-OH-JA-Ile was reported to function as a ligand for the JA-Ile co-receptor COI1-JAZ.