The dual-function protein complex SnRK2.6-WRKY70 synergistically enhances the tanshinones biosynthesis and drought stress adaptation in Salvia miltiorrhiza.

Long-term domestication and cultivation have led to the differentiation of Salvia miltiorrhiza genetic resources in different regions of China, accompanied by differences in the accumulation of pharmacological components represented by tanshinones in the roots. Tanshinone, as a key biomarker with significant therapeutic effects on cardiovascular and cerebrovascular diseases, has become the primary target for improvement in S. miltiorrhiza breeding. It is particularly important to deeply analyze the differentiation of tanshinones biosynthetic pathways in S. miltiorrhiza of different ecotypes, systematically revealing the evolution mechanism of geoherbs driven by metabolic networks. Based on integrated omics strategies, the metabolic regulatory network of tanshinones was constructed in different ecotypes, and WRKY70 was identified as a core transcription factor in the regulatory network of tanshinones metabolism. Transgene, Yeast-one-hybrid, EMSA, and Dual-LUC demonstrated that WRKY70 positively regulates tanshinones biosynthesis by targeting the promoter of CYP76AK1 and ABCG1. Yeast-two-hybrid, BiFC, Luciferase complementation, and Co-IP confirmed that WRKY70 formed a stable protein complex with SnRK2.6, which in turn mediated the ABA signaling pathway dependent tanshinones metabolic regulation and drought stress adaptation. Overall, we report that a bifunctional transcription factor, WRKY70, promotes tanshinones synthesis while enhancing plant adaptation to drought, which is expected to be used as a breeding target to save the deficiency of tanshinones and enhance stress resistance in specific ecotype S. miltiorrhiza.