AUTHOR=Wu Hualing , Pan Yayan , Ni Erdong , Qin Dandan , Fang Kaixing , Wang Qing , Yang Chengwei , Luo Ming , Liu Jun 

TITLE=CsRAB, a R2R3-MYB transcription factor from purple tea (Camellia sinensis), positively regulates anthocyanin biosynthesis

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1514631

DOI=10.3389/fpls.2024.1514631

ISSN=1664-462X

ABSTRACT=<p>In tea (<italic>Camellia sinensis</italic>), anthocyanins are important secondary metabolites that are linked to leaf color. Anthocyanin biosynthesis is a complex biological process, in which multiple genes including structural and regulatory genes are involved. Here, we describe the cloning and characterizing of a new R2R3-MYB transcription factor gene, <italic>CsRAB</italic>, isolated from purple tea variety ‘<italic>Hongfei</italic>’. Consistent with its predicted role as a transcription factor, the CsRAB protein localized to nuclei when expressed in onion (<italic>Allium cepa</italic>) epidermal cell. A dual-luciferase reporter assay demonstrated that CsRAB acts as a transcriptional activator <italic>in vivo</italic>. <italic>CsRAB</italic> overexpression in <italic>Arabidopsis</italic> seedlings led to higher expression levels of anthocyanin biosynthesis-related genes, and consequently, purple stems and higher anthocyanin contents were exhibited in overexpressing lines compared to wild type. The results indicated that <italic>CsRAB</italic> plays critical roles in positively regulating anthocyanins biosynthesis in tea plants.</p>