Functional Characterization of OsWRKY7, a Novel WRKY Transcription Factor in Rice

Transcription factors (TFs) orchestrate plant growth and development, yet the functional landscape of many TF gene families remains incomplete. Here, we systematically characterize <i>OsWRKY7</i>, an unannotated WRKY TF in rice. Phylogenomic analyses revealed that the <i>WRKY7</i> subfamily originated in basal angiosperms and evolved under strong purifying selection. We demonstrate OsWRKY7 functions as a WRKY transcriptional activator, with its activity uniquely encoded within the N-terminal domain-a distinctive mechanism among WRKY proteins. The promoter is enriched with cis-elements responsive to hormone and stress signaling, and the gene shows predominant expression in seeds. Strikingly, haplotype analysis revealed exceptionally low genetic diversity at the <i>OsWRKY7</i> locus, suggesting evolutionary constraint or a recent selective sweep. Our findings establish <i>OsWRKY7</i> as a conserved regulator with unique molecular features, specifically the WRKY domain, providing a strategic target for both fundamental research and crop improvement.