PatMYC1, a JA-responsive bHLH transcription factor, regulates sesquiterpene biosynthesis by activating the MVA pathway in Pogostemon cablin

Pogostemon cablin (Blanco) Benth. (patchouli) is a commercially valuable spice and medicinal herb, highly valued for its essential oil rich in sesquiterpenoids, with patchoulol as the key component dictating its aromatic and therapeutic properties. With the surging global demand for natural patchoulol, targeted metabolic engineering to enhance the yield and quality of P. cablin is urgently required. MYC transcription factors (TFs) play crucial roles in regulating plant secondary metabolism, but their role in modulating sesquiterpene biosynthesis in P. cablin remains unclear. Here, we characterized PatMYC1 , a jasmonic acid (JA)-responsive bHLH/MYC TF in P. cablin . As a transcriptional activator, PatMYC1 specifically binds to G-box cis-elements in the promoters of PatHMGR and PatGPPS to activate their transcription. Transient overexpression of PatMYC1 markedly upregulates six key genes of the cytoplasmic mevalonate (MVA) pathway and elevates sesquiterpenoid content, whereas VIGS-based gene knockdown causes repressed gene expression and reduced metabolite accumulation. Importantly, PatMYC1 directly targets only PatHMGR and PatGPPS , while transcriptional changes in the other four MVA pathway genes ( PatHMGS , PatPMK , PatMDD , and PatFPPS ) result from indirect regulatory cascades. Collectively, PatMYC1 serves as a positive transcriptional regulator of patchouli sesquiterpene biosynthesis, selectively activating two direct target genes within the MVA pathway. This study provides a potential gene resource for future patchouli metabolic engineering and advances our understanding of JA-dependent terpenoid regulatory networks in medicinal aromatic plants.