AUTHOR=Wu Yucui , Zhang Yuan , Li Lin , Guo Xiaorong , Wang Bin , Cao Xiaoyan , Wang Zhezhi 

TITLE=AtPAP1 Interacts With and Activates SmbHLH51, a Positive Regulator to Phenolic Acids Biosynthesis in Salvia miltiorrhiza

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01687

DOI=10.3389/fpls.2018.01687

ISSN=1664-462X

ABSTRACT=<p>Phenolic acids from <italic>Salvia miltiorrhiza</italic> have drawn considerable attention in recent years because of their remarkable pharmacological activities. We previously reported that <italic>Arabidopsis thaliana</italic> transcription factor production of anthocyanin pigment 1 (AtPAP1) has strong capability to promote the production of phenolic acids in <italic>S. miltiorrhiza</italic>. However, the responsible molecular mechanism is unclear. Here, we analyzed the transcriptome of transgenic <italic>S. miltiorrhiza</italic> that over-expressed <italic>AtPAP1</italic>. Transcriptome analysis revealed 4,152 genes that were differentially expressed due to ectopic <italic>AtPAP1</italic> overexpression. <italic>SmbHLH51</italic>, a novel bHLH gene significantly up-regulated by constitutive expression of <italic>AtPAP1</italic>, was isolated from <italic>S. miltiorrhiza</italic> for detailed functional characterization. SmbHLH51 localizes in the nuclei and interacts with AtPAP1, indicating that they probably comprise a regulatory transcription complex. Enhanced or reduced expression of <italic>SmbHLH51</italic> was achieved in <italic>S. miltiorrhiza</italic> by gain- or loss-of-function assays, respectively, revealing that SmbHLH51 is a positive transcriptional regulator of the pathway for phenolic acid biosynthesis. We propose that applying this functional genomics approach through the transcriptomic analyses is an efficient means for identifying novel genes involved in plant secondary metabolism.</p>