Methyl Jasmonate Maintains Postharvest Quality of ‘Kyoho’ Grape During Low-Temperature Storage by Modulating Antioxidant Metabolism and Cell Wall Degradation

MeJA (Methyl jasmonate) acts as a crucial regulatory phytohormone that mediates plant responses to biotic and abiotic stresses. Nevertheless, systematic studies on the effects and underlying regulatory mechanisms of MeJA on the postharvest quality of table grapes during low-temperature storage remain limited. In this study, physiological measurements combined with transcriptomic data demonstrated that MeJA treatment effectively maintained the postharvest quality of ‘Kyoho’ grapes under low-temperature storage. Physiological results showed that MeJA significantly enhanced the activities of antioxidant enzymes, inhibited the activities of cell wall softening-related enzymes PG and PE, promoted lignin accumulation, and delayed cellulose degradation. Furthermore, transcriptomic analysis verified that MeJA markedly upregulated the expression of genes associated with lignin biosynthesis. Collectively, MeJA maintains the postharvest quality of ‘Kyoho’ grapes during low-temperature storage by modulating antioxidant metabolism and cell wall metabolism, exhibiting great potential as an effective postharvest regulatory technique.