Methyl jasmonate maintains postharvest quality of Gastrodia elata by coordinately regulating ROS homeostasis, phenylpropanoid biosynthesis, and energy metabolism.

Gastrodia elata is an economically important medicinal and edible plant, but its fresh tubers are highly susceptible to postharvest decay and quality deterioration during storage. Methyl jasmonate (MeJA) is well established as an effective postharvest treatment for preserving the quality of horticultural produce. In this investigation, we evaluated the potential of MeJA treatment to improve the postharvest quality of G. elata during storage. Our findings indicated that MeJA markedly lowered decay incidence and inhibited the elevation of respiration rate and malondialdehyde (MDA) accumulation. MeJA also decreased superoxide anion generation (O2•-) and hydrogen peroxide (H2O2) levels, while stimulating the activities and transcription levels of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR). In parallel, the levels of the non-enzymatic antioxidants ascorbic acid (AsA) and glutathione (GSH) were elevated. Moreover, MeJA treatment elevated the contents of total phenolics, flavonoids, and lignin in G. elata, accompanied by increased activities and gene expression of major phenylpropanoid-pathway enzymes, including phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). MeJA further enhanced the activities and transcription levels of H+-ATPase, succinate dehydrogenase (SDH), Ca2+-ATPase, and cytochrome c oxidase (CCO), thereby helping maintain cellular energy homeostasis in G. elata. In addition, MeJA upregulated the transcription of the regulatory factors GeMYB86, GeNAC22, and GeWRKY35/70. Overall, these findings suggest that MeJA preserves the postharvest quality of G. elata through coordinated regulation of reactive oxygen species metabolism, phenylpropanoid biosynthesis, and energy metabolism, which in turn reinforces antioxidant defense and reduces oxidative injury.