Tomato CYP94C1 terminates jasmonate signaling during fruit ripening by inactivating bioactive jasmonoyl-L-isoleucine

Abstract

ABSTRACTRipe fruits are more susceptible to necrotrophic pathogens than unripe fruits. Although this phenomenon is widespread across different fruit species and results in substantial economic losses, the underlying mechanism is still poorly understood. Previous studies revealed that ethylene (ET) is a key signal controlling climacteric fruit ripening and that jasmonate (JA) regulates plant resistance to necrotrophs. We investigated the function of tomato cytochrome P450 94 (CYP94) family genes in JA signaling and report here that ET-mediated ripening suppresses JA-mediated defense by promoting the deactivation of bioactive JA-Ile. ETHYLENE-INSENSITIVE 3 (EIN3)/EIN3-LIKE (EIL) transcription factors directly activatedCYP94C1to convert JA-Ile to its inactive form 12-COOH-JA-Ile, thereby terminating JA signaling during fruit ripening. Mutation ofCYP94C1led to increased resistance of ripe fruits to the necrotrophic pathogenBotrytis cinereawithout affecting the ripening process. Additionally, the master transcription factor MYC2 directly activated two other CYP94 membersCYP94B1andCYP94B2to convert JA-Ile to its less active form 12-OH-JA-Ile, thereby attenuating JA signaling in wounded leaves. Simultaneous mutation ofCYP94B1andCYP94B2increased the resistance of leaves toB. cinerea. Thus, differences in the expression and enzymatic activities ofCYP94family gene members precisely control JA-mediated defense responses in tomato.