Gibberellin-Induced Transcription Factor MYB71 Negatively Regulates Salvianolic Acid Biosynthesis in .

, the valuable traditional Chinese medicinal plant, has been used in clinics for thousands of years. The water-soluble salvianolic acid compounds are bioactive substances used in treating many diseases. Gibberellins (GAs) are growth-promoting phytohormones that regulate plant growth and development. Previous studies have demonstrated that GAs can promote salvianolic acid accumulation in ; however, the underlying mechanism requires further investigation. Here, we identified a GA-induced R2R3MYB transcription factor (TF), MYB71, from a transcriptome library of GA-treated . MYB71 was highly expressed in the root of and localized to the nucleus. MYB71-knockout hairy roots showed higher salvianolic acid accumulation compared to wild lines. Overexpressing MYB71 in hairy roots significantly decreased the content of salvianolic acid by downregulating key salvianolic acid biosynthesis enzymes such as RAS and CYP98A14. The GCC box in the promoter of MYB71 can bind with ERF115, suggesting that MYB71 is regulated by ERF115 in salvianolic acid biosynthesis. These findings demonstrate a novel regulatory role of MYB71 in GA-mediated phenolic acid biosynthesis. With the development of CRISPR/Cas9-based genome editing technology, the MYB71 regulation mechanism of salvianolic acid biosynthesis provides a potential target gene for metabolic engineering to increase the quality of .