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.
Zhao et al. (Tue,) studied this question.