Unveiling Dynamic Defense Pathways: Transcriptome Analysis of Phenylpropanoids and (Iso)flavonoids in Cowpea Leaves...

Plants exhibit sophisticated defense mechanisms orchestrated by intricate molecular responses to biotic stresses. Here, we investigate the transcriptional dynamics of the CABMV-resistant cowpea line IT85F-2687 following mechanical injury and Cowpea aphid-borne mosaic virus (CABMV) inoculation. Transcriptome analysis revealed rapid up-regulation of genes associated with the shikimate pathway, notably DAHPS, ADT-PDT, and ADH, within one hour post-inoculation. Subsequent activation of phenylpropanoid and isoflavonoid pathways underscored the cowpea's adaptive responses, probably enhancing the synthesis of secondary metabolites crucial for defense. Transcripts encoding enzymes such as PAL, 4CL, and CHS were prominently upregulated, potentially directing metabolic flux towards lignin, flavonoid, and phytoalexin biosynthesis. The study also identified enrichment of transcription factor families (WRKY, MYB, bHLH) implicated in stress responses and secondary metabolism regulation. Comparative genomics highlighted conservation of orthologs among legume species, suggesting evolutionary significance and potential utility for breeding resilient cultivars. These findings advance our understanding of plant-pathogen interactions and propose strategies for developing cowpea varieties with enhanced resistance to biotic stresses, contributing to sustainable agriculture.