Genome-wide identification and characterization of GST gene family associated with heat responses in Plectropomus leopardus

Glutathione S-transferases (GSTs) constitute a multifunctional enzyme superfamily ubiquitous across diverse organisms, playing crucial roles in detoxification, antioxidant defense, and stress adaptation. Despite extensive studies in plants and mammals, systematic characterization of GSTs in teleosts, particularly in economically and ecologically significant species, remains limited. In this study, we performed a comprehensive genome-wide analysis of the GST gene family in the Plectropomus leopardus , a high-value aquaculture species vulnerable to environmental stressors such as thermal fluctuation. Through integrated bioinformatics approaches, we identified 24 GST genes unevenly distributed across 14 chromosomes, which were phylogenetically classified into 13 distinct subfamilies, with the MAPEG subfamily being the most abundant. Structural analyses revealed considerable diversity in gene architecture and conserved protein motifs, suggesting functional divergence among members. Expression profiling under controlled heat stress demonstrated tissue-specific upregulation of multiple GST genes in both liver and gill tissues, highlighting their active involvement in thermal response mechanisms. Furthermore, collinearity analysis indicated that segmental duplication events have contributed to the expansion of the GST family in P. leopardus , with strong evolutionary conservation observed among related fish species. Our findings not only provide a genomic foundation for understanding GST-mediated stress adaptation in marine teleosts but also offer potential candidate genes for future molecular breeding efforts aimed at enhancing thermotolerance in aquaculture. • This is the first comprehensive genome-wide identification and characterization of the GST gene family in Plectropomus leopardus , an economically important marine fish vulnerable to thermal stress. • Tissue-specific expression dynamics of PleGst genes under heat stress are revealed, with distinct functional implications for gill damage repair and liver proteotoxic stress mitigation. • PleGst-CLIC1 shows constitutively high expression, highlighting its fundamental role in cellular homeostasis and providing new insights into fish thermal stress adaptation. • The study provides candidate PleGst genes for molecular breeding of heat-tolerant Plectropomus leopardus , with practical value for marine aquaculture.