Cloning and characterization of a putative R2R3 MYB transcriptional repressor of the rosmarinic acid biosynthetic pathway from Salvia miltiorrhiza

• Published in: PloS one 2013-09, Vol.8 (9), p.e73259-e73259
• Main Authors: Zhang, Shuncang, Ma, Pengda, Yang, Dongfeng, Li, Wenjing, Liang, Zongsuo, Liu, Yan, Liu, Fenghua
• Format: Article
• Language: English
• Subjects: Acids; Amino Acid Sequence; Analysis; Arabidopsis; Arabidopsis thaliana; Base Sequence; Biosynthesis; Biosynthetic Pathways; Chinese medicine; Cinnamates - metabolism; Cloning; Cloning, Organism; Coumaric acid; Deoxyribonucleic acid; Depsides - metabolism; DNA; DNA binding proteins; Enzymatic activity; Enzymes; Gene Expression Regulation, Plant; Genes; Genetic aspects; Genomes; Herbal medicine; Hydroxylase; Life sciences; Lignin; Medicinal plants; Metabolism; Metabolites; Molecular Sequence Data; Panicum virgatum; Phenolic acids; Phenols; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plants (botany); Proteins; RNA-mediated interference; Rosmarinic Acid; Salvia miltiorrhiza; Salvia miltiorrhiza - genetics; Salvia miltiorrhiza - metabolism; Transcription (Genetics); Transcription factors; Transcription Factors - chemistry; Transcription Factors - genetics; Transcription Factors - metabolism; Tyrosine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0073259

Salvia miltiorrhiza Bunge is one of the most renowned traditional medicinal plants in China. Phenolic acids that are derived from the rosmarinic acid pathway, such as rosmarinic acid and salvianolic acid B, are important bioactive components in S. miltiorrhiza. Accumulations of these compounds have been reported to be induced by various elicitors, while little is known about transcription factors that function in their biosynthetic pathways. We cloned a subgroup 4 R2R3 MYB transcription factor gene (SmMYB39) from S. miltiorrhiza and characterized its roles through overexpression and RNAi-mediated silencing. As the results showed, the content of 4-coumaric acid, rosmarinic acid, salvianolic acid B, salvianolic acid A and total phenolics was dramatically decreased in SmMYB39-overexpressing S. miltiorrhiza lines while being enhanced by folds in SmMYB39-RNAi lines. Quantitative real-time PCR and enzyme activities analyses showed that SmMYB39 negatively regulated transcripts and enzyme activities of 4-hydroxylase (C4H) and tyrosine aminotransferase (TAT). These data suggest that SmMYB39 is involved in regulation of rosmarinic acid pathway and acts as a repressor through suppressing transcripts of key enzyme genes.