Cloning and functional validation of UDP-glycosyltransferase gene <italic>StUGT52</italic> in potato

UDP-glycosyltransferase (UGT) genes, the largest family of glycosyltransferases, play diverse roles in regulating plant growth and enhancing stress tolerance. Potato (Solanum tuberosum), a vital dual-purpose crop (used both as food and vegetable) in China, suffers significant yield losses under salinity stress. However, the specific UGT genes involved in salt stress responses in potato and their underlying mechanisms remain poorly understood. In this study, StUGT52 was identified through transcriptomic analysis of salt-stressed potato and subsequently cloned. The StUGT52 gene contains a 1488 bp coding sequence encoding 495 amino acids. Protein sequence analysis indicated that StUGT52 is an unstable, hydrophilic protein, and phylogenetic analysis revealed its closest homologs to be SlLS1-like from tomato and SpLS1-like from eggplant. RT-qPCR analysis confirmed that StUGT52 expression is significantly upregulated under salt stress. Subcellular localization analysis showed that the protein predominantly localizes to the cytoplasm and nucleus. Seven independent Arabidopsis thaliana transgenic lines overexpressing StUGT52 were generated via Agrobacterium-mediated floral dip transformation. Under salt stress conditions, transgenic lines exhibited significantly higher seed germination rates and longer root lengths compared to wild-type plants. Additionally, transgenic lines showed increased Fv/Fm ratios and soluble sugar contents, while exhibiting reduced ion leakage, malondialdehyde (MDA) levels, and superoxide anion (O2܋) accumulation. These findings demonstrate that StUGT52 enhances salt tolerance in transgenic Arabidopsis by promoting the accumulation of osmoregulatory substances and reducing reactive oxygen species (ROS) production, thereby mitigating membrane lipid peroxidation damage. This study provides novel insights into the role of StUGT52 in potato salt stress adaptation and offers a promising genetic resource for improving salinity tolerance in crops through molecular breeding.