AUTHOR=Wang Cheng , Ye Dan , Li Yan , Hu Peiling , Xu Run , Wang Xiaojing 

TITLE=Genome-wide identification and bioinformatics analysis of the WRKY transcription factors and screening of candidate genes for anthocyanin biosynthesis in azalea (Rhododendron simsii)

JOURNAL=Frontiers in Genetics

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2023.1172321

DOI=10.3389/fgene.2023.1172321

ISSN=1664-8021

ABSTRACT=<p>WRKY transcription factors have been demonstrated to influence the anthocyanin biosynthesis in many plant species. However, there is limited knowledge about the structure and function of <italic>WRKY</italic> genes in the major ornamental plant azalea (<italic>Rhododendron simsii</italic>). In this study, we identified 57 <italic>RsWRKY</italic> genes in the <italic>R. simsii</italic> genome and classified them into three main groups and several subgroups based on their structural and phylogenetic characteristics. Comparative genomic analysis suggested <italic>WRKY</italic> gene family has significantly expanded during plant evolution from lower to higher species. Gene duplication analysis indicated that the expansion of the <italic>RsWRKY</italic> gene family was primarily due to whole-genome duplication (WGD). Additionally, selective pressure analysis (<italic>Ka</italic>/<italic>Ks</italic>) suggested that all <italic>RsWRKY</italic> duplication gene pairs underwent purifying selection. Synteny analysis indicated that 63 and 24 pairs of <italic>RsWRKY</italic> genes were orthologous to <italic>Arabidopsis thaliana</italic> and <italic>Oryza sativa</italic>, respectively. Furthermore, RNA-seq data was used to investigate the expression patterns of <italic>RsWRKYs</italic>, revealing that 17 and 9 candidate genes may be associated with anthocyanin synthesis at the bud and full bloom stages, respectively. These findings provide valuable insights into the molecular mechanisms underlying anthocyanin biosynthesis in <italic>Rhododendron</italic> species and lay the foundation for future functional studies of <italic>WRKY</italic> genes.</p>