AUTHOR=Guo Dong , Li Hui-Liang , Zhu Jia-Hong , Wang Ying , Peng Shi-Qing 

TITLE=HbTGA1, a TGA Transcription Factor From Hevea brasiliensis, Regulates the Expression of Multiple Natural Rubber Biosynthesis Genes

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.909098

DOI=10.3389/fpls.2022.909098

ISSN=1664-462X

ABSTRACT=<p>The TGA transcription factors are known to modulate the biosynthesis of secondary metabolites in plants. However, their regulatory function in natural rubber (NR) biosynthesis was not revealed in the rubber tree (<italic>Hevea brasiliensis</italic>). Here, 14 genes encoding TGA transcription factors (name <italic>HbTGA1</italic>-<italic>HbTGA14</italic>) were identified in the rubber tree. <italic>HbTGAs</italic> were differentially expressed in different tissues. <italic>HbTGA1</italic> was expressed at its highest level in latex. We found specific <italic>in vitro</italic> and <italic>in vivo</italic> binding of the HbTGA1 protein with promoters of multiple NR biosynthesis genes (<italic>HbHMGS2</italic>, <italic>HbHMGR2</italic>, <italic>HbCPT6</italic>, <italic>HbCPT8</italic>, and <italic>HbSRPP2</italic>). The activation of the promoters of <italic>HbHMGS2</italic> and <italic>HbCPT6</italic> was significantly suppressed by HbTGA1, while the activities of promoters of <italic>HbHMGR2</italic>, <italic>HbCPT8</italic>, and <italic>HbSRPP2</italic> were increased by HbTGA1. The promoter activities of <italic>HbHMGS2</italic>, <italic>HbHMGR2</italic>, <italic>HbCPT6</italic>, <italic>HbCPT8</italic>, and <italic>HbSRPP2</italic> were significantly increased by HbTGA1 under jasmonate stress, while the promoter activities of <italic>HbHMGS2</italic>, <italic>HbHMGR2</italic>, <italic>HbCPT6</italic>, <italic>HbCPT8</italic>, and <italic>HbSRPP2</italic> were also significantly increased by HbTGA1 under salicylic acid stress. The present study provides insights into the role of TGA transcription factors in regulating the expression of NR biosynthesis genes from <italic>H. brasiliensis</italic>.</p>