Regulatory Mechanisms of Benzylisoquinoline Alkaloid Biosynthesis in Coptis chinensis Under Light Quality Treatment.

Coptis chinensis Franch. is a perennial and valuable medicinal plant. The dried rhizome of C. chinensis has been extensively used in traditional Chinese medicine to treat heat-related disorders. Benzylisoquinoline alkaloids (BIAs), including berberine, epiberberine, palmatine, and coptisine, constitute the primary bioactive compounds in this species. Although light quality is recognized as a key regulator of plant growth and metabolism, the specific roles of distinct light spectra in modulating BIA biosynthesis remain poorly understood. In this study, an integrated transcriptomics and metabolomics analysis was conducted to uncover the regulatory mechanisms underlying light quality-mediated BIA production. Results revealed that red light stimulated plant growth, whereas ultraviolet light inhibited it; however, both light qualities significantly enhanced BIA accumulation. We identified 29 candidate transcription factors (TFs) critical for regulating BIA biosynthesis. Subsequent dual-luciferase reporter assays indicated that CcWRKY41 and CcWRKY70 could activate several functional genes (CcCNMT, CcOMT1, and CcOMT2) in the BIA biosynthetic pathway. Further yeast one-hybrid assays revealed that these TFs directly bound to the CcOMT1 promoter, and their transient overexpression significantly elevated BIA levels in C. chinensis. This study demonstrates that CcWRKY41 and CcWRKY70 are key regulators of light-quality-mediated BIA biosynthesis. These findings provide novel insights into precision agriculture strategies aimed at enhancing the production of high-value BIAs in medicinal plants.