GsZIP28 Confers Alkaline Stress Tolerance in Arabidopsis and Soybean via ROS Scavenging and Activation of Stress‐Responsive Genes

ABSTRACT This study identified 32 putative zinc‐regulated and iron‐regulated protein (ZIP) genes ( GsZIPs ) in the Glycine soja genome using a Hidden Markov Model (HMM)‐based approach. Phylogenetic and motif analyses grouped these genes into six clades, revealing conserved structural features and evolutionary diversification. Chromosomal mapping demonstrated their distribution across 15 chromosomes and uncovered 18 duplicated gene pairs, indicating that both purifying and diversifying selection have shaped this gene family. Promoter analysis revealed an abundance of cis‐regulatory elements associated with abiotic stress and hormonal responses, including MeJA, ABRE, Auxin, GA, and SA, suggesting their potential involvement in stress adaptation. Expression profiling showed that 17 GsZIP genes were responsive to alkaline stress, among which GsZIP28 was selected for functional characterization. Transgenic Arabidopsis plants overexpressing GsZIP28 exhibited enhanced alkaline stress tolerance, as evidenced by reduced superoxide accumulation, strengthened antioxidant defenses, and differential regulation of stress‐responsive marker genes. Moreover, GsZIP28 overexpression in transgenic soybean hairy roots further validated its positive role in stress resilience. Collectively, this study provides a comprehensive characterization of the GsZIP gene family and identifies GsZIP28 as a key regulator of alkaline stress tolerance. These findings offer valuable genetic resources for improving soybean performance and sustainability as well as for other crop species cultivated in saline–alkaline soils.