Pan-Genome-Wide Analysis and Expression Profiling of the Potato GST Gene Family

Glutathione S-transferases (GSTs) are an important family of enzymes involved in plant detoxification, maintenance of redox homeostasis, and responses to abiotic stresses. However, the evolutionary characteristics and functional roles of the potato GST pan-gene family have not yet been systematically investigated at the pan-genome level. In this study, based on high-quality potato genomes constructed from 45 diploid accessions, GST gene family members were systematically identified, and their evolutionary features and expression patterns were analyzed. Phylogenetic analysis classified the GST family into six subgroups, among which the soft-core gene StGST7 and the near-core genes StGST8 and StGST16 were assigned to the Phi and Tau subgroups, respectively. Selection pressure analysis indicated that five StGST genes may have undergone positive selection, whereas most of the remaining genes were mainly subjected to purifying selection. Structural variation significantly affected the expression of StGST42 and the conserved domains of its encoded protein. Expression profiling revealed that GST family members exhibited clear tissue-specific expression patterns and responded differentially to drought, salt, high temperature, ABA, and IAA treatments. Co-expression network analysis revealed significant positive and negative correlations between multiple transcription factors and StGST gene expression, suggesting their potential involvement in the coordinated regulation of StGST genes. Further analyses demonstrated that StGST7 was significantly differentially expressed under multiple stress conditions, and its heterologous expression enhanced yeast tolerance to salt and drought stress. This study revealed the evolutionary characteristics and potential functions of the potato GST gene family and provides a theoretical basis for elucidating the molecular mechanisms underlying its regulation of environmental adaptation.