Wheat (Triticum aestivum L.) is a major food crop that is severely affected by salt stress, resulting in significant yield losses. Glutamic acid decarboxylase (GAD) catalyzes the irreversible conversion of glutamic acid to γ-aminobutyric acid (GABA) and plays key roles in plant growth, development, and stress responses. However, the GAD gene family in hexaploid wheat and its role in salt tolerance remain poorly understood. In this study, the wheat GAD gene family was systematically identified. Genome-wide analysis revealed seven TaGAD genes with 19 gene copies. A Ka/Ks ratio < 1 indicates strong evolutionary conservation of this family. All TaGAD proteins contain a conserved Glu-decarb-GAD domain with similar motif composition and structural organization. Promoter analysis showed enrichment of stress-responsive cis-elements. Expression profiling demonstrated tissue-specific patterns, with several TaGAD genes significantly induced under salt stress. CRISPR/Cas9-mediated knockout of TaGAD1 led to markedly reduced salt tolerance, accompanied by decreased GABA content and GAD activity, reduced activities of antioxidant enzymes (SOD, POD, and CAT), and excessive accumulation of reactive oxygen species (ROS). These results demonstrate that TaGAD1 positively regulates salt tolerance in wheat through GABA-mediated ROS homeostasis. This study provides a systematic characterization of the wheat TaGAD gene family in the context of salt stress, laying a theoretical foundation for understanding GABA-mediated tolerance mechanisms and identifying TaGAD1 as a potential molecular breeding target for improving salt tolerance in wheat.

Cold stress poses a major threat to rice productivity and grain quality. WRKY transcription factors, one of the largest plant-specific gene families, play crucial roles in plant responses to abiotic stress. However, their functions in cold responses and the evolutionary mechanisms underlying cold adaptation during the long-term domestication of cultivated rice remain poorly understood. Here, we identified OsWRKY26 as an important regulator of cold adaptation in japonica subspecies through transcriptome sequencing (RNA-seq). Subcellular localization analysis showed that the OsWRKY26 protein is localized to the nucleus under both normal and cold-stress conditions. Expression analysis indicated that OsWRKY26 is significantly upregulated at low temperature. Moreover, transgenic validation and measurements of multiple physiological traits demonstrated that OsWRKY26 positively regulates seedling cold tolerance in rice. Evolutionary analyses of OsWRKY26 and OsMYB2, a previously reported positive regulator of rice cold tolerance, suggested that these two genes diverged in wild rice and subsequently experienced directional selection in temperate japonica cultivated in high-altitude and high-latitude regions. Together, these findings provide a theoretical foundation for dissecting cold-tolerance mechanisms in rice, as well as promising genetic resources for molecular breeding in low-temperature environments.