Genome-Wide Analysis of Genes Related to Salt Stress in Soybeans ().

The AGC protein kinase family plays a crucial role in regulating plant growth, immunity, and cell death, as well as responses to abiotic stresses such as salt-induced stress, which impact plant development and productivity. While the functions of AGC kinases have been thoroughly studied in model plants such as , their roles in soybeans () remain poorly understood. In this study, we identified 69 kinase genes in soybeans, which are unevenly distributed across 19 chromosomes and classified into five subfamilies: PDK1, AGCVI, AGCVII, AGCVIII, and AGC (other). Each subfamily shares similar exon-intron structures and specific motifs. Gene duplication and selection pressure analyses revealed that the gene family is primarily expanded through segmental or whole-genome duplication, with all genes undergoing purifying selection during evolution. Promoter analysis identified numerous -regulatory elements associated with light, hormonal, and abiotic stress responses, including salt stress. The gene expression analysis demonstrated tissue-specific patterns, with the highest expression levels found in roots (19.7%). Among the 54 genes analyzed using RT-qPCR, significant changes in expression were observed in the roots and leaves treated with sodium chloride, with most genes showing increased expression. These results illustrate the critical role of the soybean kinase gene family in regulating responses to salinity stress. Our findings suggest that targeting specific genes may enhance soybean resistance to salt toxicity, offering valuable insights for future crop improvement strategies.