Epimedium brevicornu is an important medicinal plant in China, whose main bioactive components are flavonoid glycosides. UDP-glycosyltransferases (UGTs) play key roles in flavonoid glycosylation and metabolic diversification. In this study, transcriptome data from four representative production regions in Gansu Province were used to systematically identify and analyze the UGT gene family in E. brevicornu. A total of 359 UGT members were identified, and 168 homologous genes with clear expression evidence were obtained from four geographical populations. Molecular evolutionary analysis showed that most UGT genes were under purifying selection, whereas UGT2, UGT52, UGT57, UGT241, UGT269, and UGT271 exhibited significant signals of positive selection in specific lineages (p < 0.05). Protein interaction analysis indicated that many UGT proteins were closely associated with key enzymes involved in flavonoid biosynthesis, including CHS (TT4), CHI (TT5), F3H, FLS, and DFR, suggesting their potential involvement in flavonoid metabolism. Promoter analysis further revealed a high enrichment of ERF (11,169 occurrences) and MYB (7673 occurrences) transcription factor binding sites in the upstream regions of UGT genes. In addition, UGT57 and UGT241 showed significantly higher expression levels in the QLH population. Molecular docking analysis indicated relatively strong binding affinities with quercetin, with binding energies of −7.23 kcal/mol and −4.62 kcal/mol, respectively. These results suggest that the sequence variation and differential expression of UGT genes may be associated with flavonoid glycosylation and ecological adaptation in Epimedium. This study provides a basis for understanding the evolutionary characteristics and expression patterns of the UGT gene family and offers candidate genes for future studies on flavonoid metabolism.

This study conducted a genome-wide identification and functional analysis of the glutathione S-transferase (GST) gene family in the xerophytic desert shrub Reaumuria soongorica. A total of 67 GST genes were identified, classified into seven subfamilies, including Phi and Tau, with family expansion primarily attributed to small-scale duplication events. The findings revealed that ResoGST52, a member of the Tau subfamily, serves as a core gene in drought response, exhibiting significant upregulation of 2.40-fold in leaves and 9.01-fold in roots under drought stress. Mechanistic investigations indicated that the expression of ResoGST52 is likely directly regulated by the transcription factor ResoDof17, with specific hydrogen bonding interactions identified between the two. Co-expression network analysis further demonstrated that ResoGST52 cooperates with key pathways such as plant hormone signaling, MAPK cascades, and glutathione metabolism to collectively respond to drought stress. Notably, evolutionary analysis revealed that ResoGST52 has undergone positive selection, with three positively selected sites identified. Among these, the p.Ala115Ser mutation increases the volume of the protein’s active site pocket, while the remaining mutations enhance surface hydrophobicity, thereby improving protein stability and catalytic efficiency under extreme drought conditions. In summary, this study not only systematically identifies the GST gene family in R. soongorica but also elucidates the central role of ResoGST52 in drought adaptation through multiple layers—from transcriptional regulation and co-expression networks to protein structural adaptive evolution—providing valuable candidate genes and theoretical insights for genetic improvement of drought tolerance in crops.