AUTHOR=Fang Yuanpeng , Du Qiaoli , Yang Qian , Jiang Junmei , Hou Xiaolong , Yang Zaifu , Zhao Degang , Li Xiangyang , Xie Xin 

TITLE=Identification, characterization, and expression profiling of the putative U-box E3 ubiquitin ligase gene family in Sorghum bicolor

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.942302

DOI=10.3389/fmicb.2022.942302

ISSN=1664-302X

ABSTRACT=<p>The <italic>U-box</italic> family is one of the main E3 ubiquitin ligase families in plants. The <italic>U-box</italic> family has been characterized in several species. However, genome-wide gene identification and expression profiling of the <italic>U-box</italic> family in response to abiotic stress in <italic>Sorghum bicolor</italic> remain unclear. In this study, we broadly identified 68 <italic>U-box</italic> genes in the sorghum genome, including 2 <italic>CHIP</italic> genes, and 1 typical <italic>UFD2</italic> (Ub fusion degradation 2) gene. The <italic>U-box</italic> gene family was divided into eight subclasses based on homology and conserved domain characteristics. Evolutionary analysis identified 14, 66, and 82 <italic>U-box</italic> collinear gene pairs in sorghum compared with arabidopsis, rice, and maize, respectively, and a unique tandem repeat pair (<italic>SbPUB26</italic>/<italic>SbPUB27</italic>) is present in the sorghum genome. Gene Ontology (GO) enrichment analysis showed that U-box proteins were mainly related to ubiquitination and modification, and various stress responses. Comprehensive analysis of promoters, expression profiling, and gene co-regulation networks also revealed that many sorghum <italic>U-box</italic> genes may be correlated with multiple stress responses. In summary, our results showed that sorghum contains 68 <italic>U-box</italic> genes, which may be involved in multiple abiotic stress responses. The findings will support future gene functional studies related to ubiquitination in sorghum.</p>