Integrated physiological, metabolomic, and transcriptomic analyses highlight the involvement of JA regulatory pathway in the induced resin biosynthesis of masson pine

Masson pine ( Pinus massoniana Lamb.) is a crucial resin-producing tree species in China. Enhancing induced resin biosynthesis is a vital method to augment resin yield. To elucidate the mechanisms underlying induced resin biosynthesis in masson pine, currently, the stems were subjected to wounding and MeJA treatment for physiological, metabolomic, and transcriptomic analyses, so as to uncover the key genes and regulatory pathways involved in induced resin biosynthesis. The results demonstrated that exogenous MeJA significantly induced the formation of traumatic resin ducts. Both wounding and exogenous MeJA remarkably increased terpene synthase activities and JAs contents. Transcriptome analysis revealed that key genes, e.g. LOX , AOS , OPR , etc., involved in JA biosynthesis were highly up-regulated after wounding and MeJA treatment. JA signaling was activated, and the key transcription factors (JAZs, MYCs, etc.) involved in this pathway were differentially expressed. The expression of the function genes participated in terpenoid biosynthesis ( TPSs , CYP720Bs , HDRs , etc.) was diversely activated. PmHDR2 exhibited high expression in masson pine stems, and its expression level was significantly positively correlated with resin yield. PmHDR2 -overexpressed transgenic tobacco effectively improved its chlorophyll content, plant growth, as well as monoterpenes and sesquiterpenes contents, accordingly promoted highly terpenoids accumulation, further reflecting the regulatory function of JA in resin biosynthesis. Therefore, wounding and exogenous MeJA substantially activated the JA signal transduction pathway, subsequently up-regulating terpenoid biosynthesis-related genes, leading to increased terpenoid biosynthesis. These results provide a theoretical implication for improving resin yield via genetic improvement and plantation technology. • Exogenous MeJA induced the formation of TRDs, and promoted resin biosynthesis. • Wounding and exogenous MeJA significantly increased JAs levels and terpene synthase activities, thereby facilitating terpenoid biosynthesis. • JA signaling modulated induced resin biosynthesis through regulating the expression of terpenoid-biosynthsis-realted genes. • PmHDR2 is a key gene in resin biosynthesis of masson pine.