JA-Responsive Transcription Factor SmMYB97 Promotes Phenolic Acid and Tanshinone Accumulation in Salvia miltiorrhiza

Phenolic acids and tanshinones are
active principles in Salvia miltiorrhiza Bunge administered for cardiovascular
and cerebrovascular diseases. Jasmonic acid (JA) promotes secondary
metabolite accumulation, but the regulatory mechanism is unknown in S. miltiorrhiza. We identified and characterized
the JA-responsive gene SmMYB97. Multiple sequence
alignment and phylogenetic tree analyses showed that SmMYB97 was clustered
with AtMYB11, AtMYB12, and ZmP1 in the subgroup S7 regulating flavonol
biosynthesis. SmMYB97 was highly expressed in S. miltiorrhiza leaves and induced by methyl jasmonate
(MeJA). SmMYB97 was localized in the nucleus and had strong transcriptional
activation activity. SmMYB97 overexpression
increased phenolic acid and tanshinone biosynthesis and upregulated
the genes implicated in these processes. Yeast one-hybrid and transient
transcriptional activity assays disclosed that SmMYB97 binds the PAL1, TAT1, CPS1, and KSL1 promoter regions. SmJAZ8 interacts with SmMYB97 and
downregulates the genes that it controls. This study partially clarified
the regulatory network of MeJA-mediated secondary metabolite biosynthesis
in S. miltiorrhiza.