Effect of Methyl Jasmonate Treatment on Phenylpropanoid Pathway in Fresh-cut Melon during Storage

Methyl jasmonate (MeJA), as a natural endogenous substance and a signal molecule, plays an important role in stress response and development in plant. The effect of MeJA fumigation (100 μmol/L, treatment at 20 ℃ for 20 h) on phenylpropanoid pathway during storage of 'Xizhoumi-17' melon was assayed in this study. Results showed that MeJA treatment significantly increased the total phenolics content, and enhanced the activities of phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H) and 4-coumarate: CoA ligase (4CL) (P<0.05). In addition, the expression of CmPAL1/2/3, CmPAL5-9, CmC4H1/2/4, and Cm4CL1/2 was also upregulated by MeJA treatment (P<0.05). Taken together, these results imply that MeJA treatment of fresh-cut melon would elevate the phenylpropanoid pathway and lead to the accumulation of phenolics.