Suppression of the Jasmonate Signaling Pathway by Increases Postharvest Susceptibility to Gray Mold in Ripening Tomato Fruits.

Postharvest decay, primarily occurring after ripening, leads to substantial losses. Ripening increases tomato susceptibility to , linked to desensitization of jasmonate (JA) biosynthesis and defense signaling. During ripening, key JA biosynthesis genes such as () and () were downregulated in response to wounding or fungal challenges. The mutants with impaired JA responses showed heightened pathogen sensitivity. Conversely, mutants exhibited elevated levels, which increased expression of JA biosynthesis genes such as (), , , and () alongside defense genes including , , , and , thereby enhancing resistance. Treatment with DNA methyltransferase inhibitor 5-azacytidine increased JA content, suggesting epigenetic regulation of JA-mediated defense. Collectively, intensified ethylene signaling during ripening, mediated by , suppressed JA-dependent responses against , highlighting ethylene-JA antagonism as a key driver of postharvest decay.