Genome-Wide Identification of WRKY Transcription Factors in Pea (pisum Sativum L.) and Their Response to Sulfur and Water Stress

The WRKY gene family is widely distributed in plants and plays essential roles in plant development and stress response. Despite extensive characterization of WRKY transcription factors in many plants, a genome-wide analysis of the WRKY gene family in Pisum sativum is still lacking. The central method of this study focused on the retrieval and characterization of WRKY gene sequences in the pea genome and further looking up for their modulation in response to sulfur and water stress. This involved a combination of bioinformatics tools and gene expression study to identify, characterize, and understand the properties of the WRKY gene family in pea. In this study, 86 PsWRKY genes were identified in the pea genome, categorized into five phylogenetic groups. They were dispersed across all seven chromosomes, with Chromosome 5 showing the highest enrichment. Synteny analysis revealed orthologs of 69 PsWRKY genes in Arabidopsis and Medicago. Transcriptome analysis identified 36 differentially expressed PsWRKY genes in response to sulfur (S) stress, water (W) stress, and their combination (W + S). Real-time PCR validation confirmed significant upregulation of PsWRKY23, PsWRKY58, PsWRKY64, and PsWRKY83 under water stress, PsWRKY58 and PsWRKY84 under sulfur stress, and PsWRKY03 under combined (W + S) stress. Overall, this study provides important insights on genetic information of the WRKY gene family in Pea and its possible role in water and sulfur stress, which will help further to study these candidate WRKY gene with a future objective of understanding their role in abiotic stress.