Identification and Analysis of WRKY Transcription Factors in Response to Cowpea Fusarium Wilt in Cowpea

In plants, WRKY transcription factors play a crucial role in plant growth, development, and response to abiotic and biotic stress. Cowpea (Vigna unguiculata) is an important legume crop. However, cowpea Fusarium wilt (CFW), caused by Fusarium oxysporum f. sp. tracheiphilum (Fot), poses a serious threat to its production. In this study, we systematically identified members of the cowpea WRKY (VuWRKY) gene family and analyzed their expression patterns under CFW stress. A total of 91 WRKY transcription factors were identified in the cowpea genome. Phylogenetic and synteny analyses indicated that the expansion of VuWRKY genes in cowpea is primarily due to recent duplication events. Transcriptome analysis of cowpea inoculated with Fo revealed 31 differentially expressed VuWRKY genes, underscoring their role in the response to CFW infection. Four differentially expressed WRKY genes were selected for validation. Subcellular localization and Western blot assays showed their nuclear localization and normal expression in N. benthamiana. Additionally, yeast one-hybrid assays demonstrated that VuWRKY2 can bind to the promoter region of the Catalase (CAT) gene, indicating its potential role in transcriptional regulation. This study establishes a foundation for further exploration of the role and regulatory mechanisms of VuWRKY genes in response to CFW stress.