AUTHOR=Zhang Meng , Jin Xiaofei , Chen Ying , Wei Mi , Liao Weifang , Zhao Shengying , Fu Chunhua , Yu Longjiang 

TITLE=TcMYC2a, a Basic Helix–Loop–Helix Transcription Factor, Transduces JA-Signals and Regulates Taxol Biosynthesis in Taxus chinensis

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00863

DOI=10.3389/fpls.2018.00863

ISSN=1664-462X

ABSTRACT=<p>The multitherapeutic taxol, which can be obtained from <italic>Taxus</italic> spp., is the most widely used anticancer drug. Taxol biosynthesis is significantly regulated by jasmonate acid (JA), one of the most important endogenous hormones in land plants. Nevertheless, the JA-inducing mechanism remains poorly understood. MYC2 is one of the key regulators of JA signal transfer and the biosynthesis of various secondary metabolites. Here, TcMYC2a was identified to contain a basic helix–loop–helix (bHLH)-leucine zipper domain, a bHLH-MYC_N domain, and a BIF/ACT-like domain. TcMYC2a was also found to bind with TcJAZ3 in yeast, which was a homolog of <italic>Arabidopsis</italic> JASMONATE ZIM-domain JAZ proteins, indicating that TcMYC2a had a similar function to AtMYC2 of JA signal transduction. TcMYC2a was able to affect the expression of GUS reporter gene by binding with the T/G-box, G-box, and E-box, which were the key <italic>cis</italic>-elements of <italic>TASY</italic> and <italic>TcERF12/15</italic> promoter. <italic>TcMYC2a</italic> overexpression also led to significantly increased expression of <italic>TASY</italic>, <italic>tat</italic>, <italic>dbtnbt</italic>, <italic>t13h</italic>, and <italic>t5h</italic> genes. Additionally, TcERF15, which played the positive role to regulate <italic>tasy</italic> gene, was up-regulated by TcMYC2a. All these results revealed that TcMYC2a can regulate taxol biosynthesis either directly or via ERF regulators depending on JA signaling transduction.</p>