Comprehensive Genome-Wide Analysis and Expression Profiling of the HVA22 Gene Family Unveils Their Potential Roles in Soybean Responses to Abiotic Stresses

Soybean (Glycine max) is a pivotal oilseed crop that is particularly vulnerable to unfavorable environmental conditions. The HVA22 gene family, known for the TB2/DP1/HVA22 domain, plays a crucial role in stress response across plants. Despite their significance, a thorough genome-wide analysis of the HVA22 family in soybean has not been conducted. In this study, we initially report the identification and chromosomal mapping of forty GmHVA22 genes, which encode the conserved TB2/DP1/HVA22 domain and are predominantly located in transmembrane regions. Phylogenetic analysis revealed that all the GmHVA22 genes are distributed into six distinct subgroups, showing close phylogenetic relationships with HVA22 genes from other species. The gene structures within each subgroup were found to be relatively conserved, whereas significant variations were observed among GmHVA22 genes from different subgroups. Cis-element analysis revealed that most GmHVA22 genes harbor elements pivotal for plant growth and development, especially the Box-4 and G-box motifs. Furthermore, the expression profiles of the majority of GmHVA22 genes were responsive to abscisic acid (ABA) and various abiotic stress treatments, suggesting their potential functions in ABA-mediated abiotic stress responses in soybean. Notably, the pronounced upregulation of six specific GmHVA22 genes (GmHVA22a1, GmHVA22b1, GmHVA22b5, GmHVA22k1, GmHVA22n1, and GmHVA22r3) under drought stress conditions implicates them in soybean’s drought tolerance mechanisms. These findings underscore the potential roles of GmHVA22s in ABA signaling and drought stress tolerance, as well as their participation in the regulation of plant growth and developmental processes.