Genome-Wide Identification of the PsatGST Gene Family and Expression Analysis Under Freezing Stress in Peas (Pisum sativum L.)

Abstract

Background: Glutathione S-transferases (GSTs) play pivotal roles in plant growth, abiotic stress responses, detoxification of xenobiotics, and maintenance of redox homeostasis. Methods: In this study, transcriptomic analysis was employed to identify differentially expressed genes (DEGs) in the pea cultivar DX27 under freezing stress (−4 °C) at 3, 6, and 12 h. Results:GO and KEGG enrichment analyses of global transcriptomic data further reveal that DEGs are significantly enriched in the following functional categories: oxidation–reduction processes, stress responses, glutathione metabolism, and secondary metabolite biosynthesis. A total of 52 PsatGST genes were identified and classified into nine subfamilies based on phylogenetic relationships. Chromosomal localization revealed a non-random distribution across seven chromosomes. Promoter cis-element analysis indicated that PsatGST genes harbor diverse regulatory elements associated with light responsiveness, hormone signaling (auxin, abscisic acid, gibberellin, salicylic acid, and MeJA), and abiotic/biotic stress responses. PsatGSTF2 expression analysis showed pronounced up-regulation under freezing stress (−4 °C) at 3, 6, and 12 h. Conclusions: These findings provide a foundational framework for understanding the evolutionary history and functional diversification of the PsatGST gene family and offer valuable candidate genes for the breeding of stress-tolerant pea varieties.