Methyl jasmonate induced tolerance effect of Pinus koraiensis to Bursaphelenchus xylophilus

Abstract BACKGROUND Methyl jasmonate (MeJA) can affect the balance of hormones and regulate the disease resistance of plants. Exploring the application and mechanism of MeJA in inducing the tolerance of Pinus koraiensis to pine wood nematode (PWN) infection is of great significance for developing new strategies for pine wilt disease control. RESULTS Different concentrations (0.1, 1, 5 and 10 m m ) of MeJA treatment groups showed differences in relative tolerance index and relative anti‐nematode index of P. koraiensis seedlings to PWN infection. The treatment of 5 m m MeJA solution induced the best tolerance effect, followed by the 1 m m MeJA solution. Transcriptome analysis indicated that many plant defense‐related genes upregulated after treatment with 1, 5 and 10 m m MeJA solutions. Among them, genes such as jasmonate ZIM domain‐containing protein , phenylalanine ammonia‐lyase and peroxidase also continuously upregulated after PWN infection. Metabolome analysis indicated that jasmonic acid (JA) was significantly increased at 7 days postinoculation with PWN, and after treatment with both 1 and 5 m m MeJA solutions. Integrated analysis of transcriptome and metabolome indicated that differences in JA accumulation might lead to ubiquitin‐mediated proteolysis, and expression changes in trans‐caffeic acid and trans‐cinnamic acid‐related genes, leading to the abundance differences of these two metabolisms and the formation of multiple lignin and glucosides. CONCLUSIONS MeJA treatment could activate the expression of defense‐related genes that correlated with JA, regulate the abundance of defense‐related secondary metabolites, and improve the tolerance of P. koraiensis seedlings to PWN infection. © 2024 Society of Chemical Industry.