Transcriptional Profiles of SmWRKY Family Genes and Their Putative Roles in the Biosynthesis of Tanshinone and Phenolic Acids in Salvia miltiorrhiza.

Haizheng Yu,Zongsuo Liang,Zhuoni Hou,Dongfeng Yang,Wanli Guo

doi:10.3390/ijms19061593

Abstract

Salvia miltiorrhiza Bunge is a Chinese traditional herb for treating cardiovascular and cerebrovascular diseases, and tanshinones and phenolic acids are the dominated medicinal and secondary metabolism constituents of this plant. WRKY transcription factors (TFs) can function as regulators of secondary metabolites biosynthesis in many plants. However, studies on the WRKY that regulate tanshinones and phenolics biosynthesis are limited. In this study, 69 SmWRKYs were identified in the transcriptome database of S. miltiorrhiza, and phylogenetic analysis indicated that some SmWRKYs had closer genetic relationships with other plant WRKYs, which were involved in secondary metabolism. Hairy roots of S. miltiorrhiza were treated by methyl jasmonate (MeJA) to detect the dynamic change trend of SmWRKY, biosynthetic genes, and medicinal ingredients accumulation. Base on those date, a correlation analysis using Pearson’s correlation coefficient was performed to construct gene-to-metabolite network and identify 9 SmWRKYs (SmWRKY1, 7, 19, 29, 45, 52, 56, 58, and 68), which were most likely to be involved in tanshinones and phenolic acids biosynthesis. Taken together, this study has provided a significant resource that could be used for further research on SmWRKY in S. miltiorrhiza and especially could be used as a cue for further investigating SmWRKY functions in secondary metabolite accumulation.

Highlights

Salvia miltiorrhiza Bunge is a well-known Chinese herb with significant medicinal and economic value
The hairy root of S. miltiorrhiza was treated by methyl jasmonate (MeJA); we investigated the expression level of SmWRKYs, biosynthetic genes (SmPAL, SmTAT, SmC4H, Sm4CL, SmHPPR, SmRAS, SmCYP98A14, SmDXS1, SmDXS2, SmHMGR, SmDXR, SmGGPPS, SmCPS, SmKSL, and SmCYP76H1), and the accumulation of secondary metabolites
Li et al have been genome-wide characterized, molecularly cloned, and expression analyzed by WRKY in S. miltiorrhiza [34], rare information has been provided by this key transcription factor in tanshinones and phenolic acid biosynthesis

Summary

Introduction

Salvia miltiorrhiza Bunge is a well-known Chinese herb with significant medicinal and economic value. The major bioactive constituents of S. miltiorrhiza are classified into two categories: lipophilic tanshinones and hydrophilic phenolic acids [2]. More than 40 tanshinones (tanshinone I, tanshinone IIA, cryptotanshinone, dihydrotanshinone I, and so on) and 20 hydrophilic phenolic acids (salvianolic acid B, rosmarinic acid, dihydroxyphenyllactic acid, and lithospermic acid) have been isolated and identified from S. miltiorrhiza [3]. Phenolic acids in S. miltiorrhiza are biosynthesized through the phenylpropanoid and tyrosine-derived pathways. It has been suggested that salvianolic acid B (SAB) is derived from the rosmarinic acid (RA) pathway. The biosynthetic pathway of rosmarinic acid (RA) is well characterized in plants [4,5]. Tanshinones in S. miltiorrhiza are produced through the mevalonate (MVA) and methylerythritol phosphate (MEP) pathways, and the biosynthetic pathway of ferruginol is well characterized. The regulatory mechanisms of tanshinones and phenolic acids biosynthesis are largely unresolved

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