A Comprehensive Analysis of Transcriptomics and Metabolomics Revealed of LcMYC4 regulating LcDXS3 to promote terpenoids biosynthesis in Litsea cubeba

Terpenoids are present in many plant species and confer various biological activities. Litsea cubeba, a traditional Chinese medicinal plant, exhibits antibacterial, antioxidant, and anti-tumor properties, primarily due to its terpenoid constituents. As important secondary metabolites, terpenoid biosynthesis is often influenced by hormonal treatments; however, the molecular mechanisms underlying hormone-induced terpenoid synthesis remain unclear. This study elucidates the regulatory mechanisms of terpenoid biosynthesis in L. cubeba under jasmonic acid (JA) treatment through comprehensive transcriptome analysis and gene functional characterization. Notably, terpene content in L. cubeba fruit increased substantially within 6 h following JA treatment. Transcriptome analysis revealed that genes involved in JA signal transduction were significantly upregulated after JA induction and were co-expressed with genes associated with the terpenoid biosynthesis pathway. LcMYC4, a core gene in JA signal transduction, exhibited an expression pattern similar to that of LcDXS3, a key enzyme in the terpenoid precursor synthesis pathway. Overexpression of LcMYC4 significantly enhanced terpenoid accumulation in L. cubeba, and this increase in LcMYC4 expression was accompanied by a significant upregulation of LcDXS3 expression. Yeast one-hybrid analysis and dual-luciferase reporter assays demonstrated that LcMYC4 directly binds to the promoter of LcDXS3, activating its expression. In summary, this study provides reference into the molecular regulatory mechanisms of JA-induced terpenoid synthesis in L. cubeba.