AUTHOR=Xu Zhangting , Zhang Guihua , Chen Junyu , Ying Yuxin , Yao Lingtiao , Li Xiaoxian , Teixeira da Silva Jaime A. , Yu Zhenming 

TITLE=Role of Rubus chingii BBX gene family in anthocyanin accumulation during fruit ripening

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1427359

DOI=10.3389/fpls.2024.1427359

ISSN=1664-462X

ABSTRACT=<p>The B-box (BBX) family, which is a class of zinc finger transcription factors, exhibits special roles in plant growth and development as well as in plants’ ability to cope with various stresses. Even though <italic>Rubus chingii</italic> is an important traditional medicinally edible plant in east Asia, there are no comprehensive studies of BBX members in <italic>R. chingii</italic>. In this study, 32 RcBBX members were identified, and these were divided into five groups. A collinearity analysis showed that gene duplication events were common, and when combined with a motif analysis of the <italic>RcBBX</italic> genes, it was concluded that group V genes might have undergone deletion of gene fragments or mutations. Analysis of <italic>cis</italic>-acting elements revealed that each <italic>RcBBX</italic> gene contained hormone-, light-, and stress-related elements. Expression patterns of the 32 <italic>RcBBX</italic> genes during fruit ripening revealed that highest expression occurred at the small green fruit stage. Of note, the expression of several <italic>RcBBX</italic> genes increased rapidly as fruit developed. These findings, combined with the expression profiles of anthocyanin biosynthetic genes during fruit ripening, allowed us to identify the nuclear-targeted RcBBX26, which positively promoted anthocyanin production in <italic>R. chingii</italic>. The collective findings of this study shed light on the function of <italic>RcBBX</italic> genes in different tissues, developmental stages, and in response to two abiotic stresses.</p>