Uncovering the interaction between PatJAZs and PatSWC4 to control the expression of the PatPTS gene and the biosynthesis of patchouli alcohol

The biosynthesis regulation mechanism of patchouli alcohol (PA), a key medicinal component of Pogostemon cablin (Blanco) Benth, requires further analysis. Although the structural genes of the relevant synthetic pathway have been identified, the regulatory network of transcription factors in this process is unclear. In this study, we focused on the regulatory interaction network between the PatSWC4 protein and the PatJAZ proteins to systematically reveal the molecular regulatory mechanism of patchouli alcohol synthesis. Using yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays, we confirmed that PatSWC4 interacts with PatJAZ5 and PatJAZ9 in the nucleus. Co-immunoprecipitation (Co-IP) experiments further verified the interactions between PatJAZ5 and PatSWC4. We demonstrated that transient overexpression PatJAZ5 and PatJAZ9 significantly inhibited PatSWC4 expression and that of its downstream key synthase gene, PatPTS . This led to a decrease in patchouli alcohol content. Yeast one-hybrid (Y1H) and electrophoretic mobility shift assays (EMSA) experiments precisely located the binding site of PatSWC4 in the promoter region of PatPTS . Virus-induced PatSWC4 gene silencing experiments confirmed its positive regulation of patchouli alcohol synthesis. Based on these findings, the study proposes a novel regulatory model. PatJAZs can inhibit the transcriptional expression of PatPTS by interacting with the PatSWC4 protein. These results not only help elucidate the regulatory mechanism of patchouli alcohol synthesis induced by the interaction between PatJAZs and PatSWC4 but also provide a foundation for applying metabolic engineering to enhance quality control in P. cablin.