Postharvest methyl jasmonate treatment enhanced biological activity by promoting phenylpropanoid metabolic pathways in Lilium brownii var. viridulum

Improving the content of bioactive components in horticultural plants, especially edible and medicinal plants, is of great significance for improving horticultural production efficiency. Methyl jasmonate (MeJA) is an important inducer of phytoactive components, but its role in the secondary metabolism of lily is still unclear. In this study, 0, 50, 100 and 200 μmol/L MeJA were used to treat postharvest scales of Lilium brownii var. viridulum. The results showed that exogenous MeJA increased the total phenolic acid content (TPC) and total flavonoid content (TFC) of lily scales several-fold in a short time (72 h), leading to higher antioxidant abilities. qRT–PCR results indicated that MeJA significantly activated the expression of key genes involved in phenylpropanoid metabolism, including phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate-CoA ligase (4CL), consequently improving their enzyme activities. Consistent with the physiological and gene expression results, metabolome data indicated that multiple metabolic pathways were significantly enhanced by MeJA treatment, including the phenylpropanoid pathway and other downstream metabolic pathways. These results indicated that postharvest treatment with exogenous MeJA promoted the accumulation of secondary metabolites in lily scales by promoting the expression of related genes, which in turn enhanced its nutritional value. The data obtained in this study will not only help to elucidate the regulatory role of MeJA in the secondary metabolism of lily but also provide a low-cost, easy-to-operate, and highly efficient way to enhance the nutrients and medicinal ingredients of horticultural production.