Genome-Wide Analysis of Soybean GS3-Family Genes and Functional Characterization of GmGS3-1 Responses to Saline and Drought Stresses

The GS3 protein is a G protein widely conserved in plants, playing a pivotal role in growth, development, and stress responses. With the protein sequence of the AT1/GS3 gene in sorghum as a query, this study identified five GS3 gene family members in the soybean genome database and designated GmGS3-1 to GmGS3-5. Promoter cis-element analysis suggested that soybean GS3 is implicated in responses to abiotic stress. Additionally, collinearity analysis indicated that soybean GS3 genes are subject to purifying selection. Transcriptomic data of the five soybean GS3 genes revealed that the nuclear-localized gene GmGS3-1 is highly expressed in root tissues and significantly upregulated under salt and drought stress, as confirmed by qRT-PCR assays. Functional validation for salt and drought tolerance demonstrated that transgenic Arabidopsis plants exhibited higher fresh weight compared to wild-type (WT) controls. Furthermore, GmGS3-1 was found to interact with multiple G proteins, suggesting its synergistic role in the abiotic stress tolerance of soybean. These findings establish a theoretical framework for understanding the functional role of the GS3 gene family in soybean stress tolerance and development.