Genome-Wide Identification of WRKY Group II Genes and the Role of HbWRKY11 in Hordeum brevisubulatum Under Saline-Alkali Stress

The WRKY group II subfamily, a major conserved and plant-specific WRKY transcription factor family, plays a central role in regulating plant responses to abiotic stresses. However, systematic characterization of WRKY group II genes and their involvement in saline–alkali stress responses in Hordeum brevisubulatum (Trin.) Link remains largely unexplored. In this study, 23 WRKY group II genes were identified at the genome-wide level in H. brevisubulatum. Phylogenetic analysis classified these genes into five subgroups, with members within each subgroup exhibiting highly conserved motif compositions and gene structures. Promoter analysis revealed abundant cis-acting elements related to stress and defense responses, phytohormone signaling, growth and development, and light responsiveness, suggesting diverse regulatory potential. Transcriptome sequencing and qRT-PCR analysis showed that several HbWRKY genes were responsive to NaHCO3-induced saline-alkali stress. Notably, HbWRKY11 displayed sustained up-regulation and significantly enhanced yeast tolerance to NaHCO3 stress. Overall, this study provides the first systematic analysis of WRKY group II genes transcription factors in H. brevisubulatum and identifies HbWRKY11 as a key candidate gene contributing to saline–alkali stress tolerance.