Methyl jasmonate alleviates the husk browning and regulates expression of genes related to phenolic metabolism of pomegranate fruit

Pomegranate is sensitive to low temperature and is susceptible to chilling injury (CI), resulting in husk browning. The effects of Methyl jasmonate (MeJA), hot water treatment (HWT), and control treatments on the quality of pomegranate fruit during low temperature storage were investigated. The results showed that MeJA and HWT treatments could effectively inhibit the increase of browning index, color difference, relative conductivity, polyphenol oxidase (PPO) and peroxidase (POD) activities, maintain phenolic substances and the activity of phenylalanine ammonia-lyase (PAL). The browning index of MeJA treatment was 55.42 % lower than control treatment on the 70th day, the relative conductivity and MDA content were 24.32 % and 51.67 % lower than control treatment, respectively. Furthermore, MeJA treatment delayed the increase of PgPPO and PgPOD gene expression levels, upregulated the expression levels of PgPAL gene. Overall, MeJA treatment could improve antioxidant capacities, alleviate CI by regulating phenolic metabolism and gene expression levels.