Fig. 7: Model depicting the mechanisms of SlMYB in enhancing triterpenoid biosynthesis under PBZ induction in S. lonicericola.

The SlMYB transcription factor is downregulated by PBZ induction. SlMYB directly interacts with the promoter regions of MVD, IDI, and FDPS. Downregulated SlMYB promotes the transcription of its target genes that are involved in triterpenoid biosynthesis in the MVA pathway. Triterpenoid yield and diversity increase, and the representative triterpenoid compounds that significantly accumulated are displayed.