SmMYB4 Is a R2R3-MYB Transcriptional Repressor Regulating the Biosynthesis of Phenolic Acids and Tanshinones in Salvia miltiorrhiza

Abstract

Salvia miltiorrhiza Bunge is one of the most famous traditional Chinese medicinal plants. The two most important classes of pharmaceutically relevant compounds in S. miltiorrhiza are phenolic acids and tanshinones. The MYB family of transcription factors may efficiently regulate the secondary metabolism in plants. In this study, a subgroup 4 R2R3MYB transcription factor gene, SmMYB4, was isolated from S. miltiorrhiza and functionally characterized using overexpression and a RNAi-mediated silencing. We achieved a total of six overexpressions and eight RNAi transgenic lines from the Agrobacterium leaf disc method. The content of the total phenolics, rosmarinic acid, and salvianolic acid B markedly decreased in the SmMYB4-overexpressing lines but increased in the SmMYB4-RNAi lines. The content of the total tanshinones, cryptotanshinone, and tanshinone IIA decreased in the SmMYB4-overexpressing transgenic lines but increased in the SmMYB4-RNAi lines. A gene expression analysis demonstrated that SmMYB4 negatively regulated the transcription of the critical enzyme genes involved in the phenolic acid and tanshinone biosynthesis. The genetic control of this transcriptional repressor may be used to improve the content of these bioactive compounds in the cultivated S. miltiorrhiza.

The Transcriptional Regulatory Mechanisms Exploration of Jujube Biological Traits through Multi-omics Analysis

“…In jujube, Wen et al (2022) [56] conducted a comprehensive study using metabolite profiling and transcriptomic data analysis on cultivated jujube, which revealed that terpenoids were mainly concentrated in ZjSQS1 (evm.model. Many transcription factors (TFs) have been confirmed roles in regulating terpenes accumulation by affecting the expression of genes related to terpene synthesis in other plants , such as WRKY [59,60], bHLH [61][62][63], AP2/ERF [64][65][66], MYB [67][68][69][70][71], and bZIP [72][73][74], among others. Notable examples of these regulators include PnbHLH1, which controls the biosynthesis of triterpene saponins in Panax notoginseng [61,75], ERF189, an ethylene response factor implicated in the biosynthesis of steroidal glycoalkaloids in potatoes and tomatoes [75,76], and SmERF1L1, which regulates the biosynthesis of tanshinones in Salvia miltiorrhiza Bunge [77].…”

The Transcriptional Regulatory Mechanisms Exploration of Jujube Biological Traits through Multi-Omics Analysis

“…However, the corresponding transcription factor of ZjSQE is still unclear (Figure 2). Many transcription factors (TFs) have been confirmed to have roles in regulating terpene accumulation by affecting the expression of genes related to terpene synthesis in other plants, such as WRKY [65,66], bHLH [67][68][69], AP2/ERF [70][71][72], MYB [73][74][75][76][77], and bZIP [78][79][80]. Notable examples of these regulators include PnbHLH1, which controls the biosynthesis of triterpene saponins in Panax notoginseng [67,81], ERF189, an ethylene response factor implicated in the biosynthesis of steroidal glycoalkaloids in potatoes and tomatoes [81,82], and SmERF1L1, which regulates the biosynthesis of tanshinones in Salvia miltiorrhiza Bunge [83].…”