Abstract

The sugar beet ( Beta vulgaris L.) industry in China occupies a pivotal position in the national sugar supply, yet drought in its major cultivation areas has become a key limiting factor for its high-quality development. Glycosyltransferases (GTs) play a pivotal role in plant responses to abiotic stress, particularly in the regulation of drought resistance. However, the systematic identification of the BvUGT90 gene family in sugar beet and the functional characterization of its members under drought stress remain largely unexplored. In this study, drought stress was simulated in the sugar beet cultivar ‘HI0466’ using the weighing method to regulate soil moisture. Samples were collected at different stress durations and after rewatering for subsequent experimental analyses. In this study, 121 members of the BvUGT90 family were identified in sugar beet, and a comprehensive analysis was conducted on their gene structures, phylogenetic relationships, promoter cis-acting elements and expression patterns under drought stress. The results showed that these 121 members were unevenly distributed across 9 chromosomes. The proteins they encode had an average amino acid length of 474, with molecular weights ranging from 10.78 to 99.10 kDa and theoretical isoelectric points (pI) from 4.68 to 8.69 (with an average of 5.76). Notably, 110 of these members (accounting for 90.91%) were identified as hydrophilic proteins. Synteny analysis indicated a high degree of homology between the BvUGT90 family members in sugar beet and their orthologous genes in Arabidopsis thaliana . Analysis of promoter cis-acting elements revealed the presence of six major categories of core elements in the promoter regions of BvUGT90 genes, including hormone-responsive elements, stress-responsive elements and pathway regulatory elements. Transcriptomic data showed that 45 BvUGT90 family members exhibited significant responsiveness to drought stress. Proteomic analysis demonstrated that 10 of th