Sbmyb111 act as a transcriptional activator of flavonoid synthesis in Scutellaria baicalensis.

Scutellaria baicalensis, a traditional medicinal plant originating in China, is widely cultivated for its therapeutic properties. The main bioactive substances in S. baicalensis are flavonoids, which exhibit extensive antibacterial and antiviral activities. However, the contents of these valuable natural product ingredients are relatively low in the plant. MYB transcription factors play crucial roles in regulating plant secondary metabolism, including flavonoid biosynthesis. While the regulation of MYB transcription factors has been extensively studied in various species, research on their role in S. baicalensis remains relatively scarce. In this study, we identified SbMYB111, belonging to the S7 subgroup of R2R3-MYB transcription factors, which functions as a transcriptional activator and is localized in the nucleus. Through heterologous overexpression of SbMYB111 in Arabidopsis thaliana and suppression expression in S. baicalensis, we demonstrated that SbMYB111 acts as a positive regulator in the biosynthesis of flavonoids. Furthermore, the yeast one-hybrid and dual-luciferase reporter gene assays validated that SbMYB111 activates the expression of SbC4H2, a key enzyme gene in the flavonoid biosynthesis pathway. This study provides a theoretical basis for understanding the transcriptional regulation mechanism of flavonoid synthesis and further developing medicinal resources of S.baicalensis.