Comprehensive genome-wide identification and expression profiling of WRKY transcription factors in Avena sativa under abiotic stresses and phytohormone treatments

WRKY transcription factors are key regulators of plant stress responses and phytohormone signaling; yet, their involvement in stress response in Avena sativa L. is still insufficiently explored. We found 167 WRKY genes ( AsWRKYs ) in the oat genome. Phylogenetic analysis categorized these into three primary groups (I–III), with Group II further subdivided into five subgroups (IIa–IIe). Chromosomal mapping revealed an unequal distribution across the 21 chromosomes, with chromosome 5 harbouring the most genes. Analyses of gene structure and conserved motifs confirmed the presence of the WRKY domain and revealed subgroup-specific diversification. The promoter study revealed various stress- and hormone-responsive cis-regulatory elements, including ABRE, CGTCA, TGACG, MYB, and W-box motifs. Collinearity research revealed that segmental duplication is the principal driver for the proliferation of AsWRKY genes, with duplicated gene pairs demonstrating significant purifying selection. Expression profiling revealed tissue-specific patterns, with several AsWRKY genes ( AsWRKY19 , AsWRKY66 , AsWRKY92 , AsWRKY98 , AsWRKY125 , AsWRKY146 , and AsWRKY156 ) showing significant induction under abiotic stress and in response to phytohormones, including abscisic acid, methyl jasmonate, salicylic acid, and gibberellic acid. Structural modelling validated the conserved β-sheet-rich WRKY structure, whereas protein-protein interaction research indicated their participation in stress-responsive regulatory networks. These findings elucidate the evolution and functional roles of WRKY transcription factors in oats.