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 <i>Hordeum brevisubulatum</i> (Trin.) Link remains largely unexplored. In this study, 23 WRKY group II genes were identified at the genome-wide level in <i>H. brevisubulatum</i>. 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 <i>HbWRKY</i> genes were responsive to NaHCO₃-induced saline-alkali stress. Notably, <i>HbWRKY11</i> 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 <i>H. brevisubulatum</i> and identifies <i>HbWRKY11</i> as a key candidate gene contributing to saline-alkali stress tolerance.