Exogenous methyl jasmonate regulates phenolic compounds biosynthesis during postharvest tomato ripening

Methyl jasmonate (MeJA) acts as an elicitor to stimulate phenolic compounds in fruit and vegetables. To explore the regulation of MeJA on phenolic compounds biosynthesis during postharvest tomato ripening, mature green tomato fruit were treated by 0.5 mM MeJA or deionized water under vacuum, and then kept in darkness for 16 d. Total phenolics and total flavonoids contents, phenolic compounds contents, enzymatic activities, as well as expression levels of genes in response to phenylpropanoid pathway were determined in the present study. Results showed exogenous MeJA enhanced total phenolics and flavonoids contents, augmented the contents of most phenolic compounds, as well as promoted enzymatic activities associated with phenylpropanoid pathway (PAL, C4H, 4CL, CHS, and CHI) during tomato ripening. Furthermore, MeJA up-regulated the expressions of the corresponding genes (1.16- to 19.32-fold) involved in phenylpropanoid pathway during the first 7 d. Results suggested MeJA enhanced phenolic compounds biosynthesis during postharvest tomato ripening via influencing the enzymatic activities and gene expressions. These results may provide valuable information for exploring technical means for the regulation of phenylpropanoid pathway during tomato ripening.