JA-Responsive Transcription Factor SmMYB97 Promotes Phenolic Acid and Tanshinone Accumulation in <i>Salvia miltiorrhiza</i>

Abstract

Phenolic acids and tanshinones are active principles in <i>Salvia miltiorrhiza</i> Bunge administered for cardiovascular and cerebrovascular diseases. Jasmonic acid (JA) promotes secondary metabolite accumulation, but the regulatory mechanism is unknown in <i>S. miltiorrhiza</i>. We identified and characterized the JA-responsive gene <i>SmMYB97</i>. Multiple sequence alignment and phylogenetic tree analyses showed that SmMYB97 was clustered with AtMYB11, AtMYB12, and ZmP1 in the subgroup S7 regulating flavonol biosynthesis. <i>SmMYB97</i> was highly expressed in <i>S. miltiorrhiza</i> leaves and induced by methyl jasmonate (MeJA). SmMYB97 was localized in the nucleus and had strong transcriptional activation activity. <i>SmMYB</i><i>97</i> 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 <i>PAL1</i>, <i>TAT1</i>, <i>CPS1</i>, and <i>KSL1</i> 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 <i>S. miltiorrhiza</i>.