Genome-Wide Identification and Expression Analysis of Glutathione S-Transferases (GSTs) in <i>Crocus sativus</i> (Saffron) Reveals Their Roles in Hormone-Mediated Stress Responses

Glutathione S-transferases (GSTs) are multifunctional enzymes involved in stress responses, detoxification, and secondary metabolite transport in plants. In this study, a genome-wide analysis of Crocus sativus identified 60 GST genes containing conserved GST_N and GST_C domains. Phylogenetic analysis classified these genes into multiple subfamilies, including Tau, Phi, and Theta, highlighting lineage-specific evolution. Motif and domain analyses revealed structural diversity within the GST family, while chromosomal mapping identified clustering patterns and hotspots, suggesting gene duplication as a key driver of GST family expansion. Promoter analysis uncovered cis-regulatory elements such as MEJA, ABRE, and GARE motifs, indicating the potential role of GST genes in hormone-mediated stress responses. Subcellular localization predictions placed most GST proteins in the cytoplasm, with some localized to chloroplasts and vacuoles, reflecting their functional diversity. Swiss-Model structural modeling of a representative GST protein revealed a homo-dimeric arrangement, with distinct domains responsible for substrate binding and catalysis. The model, supported by a high QMEANDisCo global score, identified key interactions with S-hexylglutathione. This study provides a comprehensive characterization of the GST gene family in Crocus sativus, offering insights into their structural, evolutionary, and functional attributes. The findings pave the way for further research on GST-mediated stress tolerance and secondary metabolite biosynthesis, with implications for agricultural improvement strategies.