Transcriptomic basis of Phytophthora cajani resistance in pigeon pea

Allelopathic resistance to Phytophthora cajani in pigeon pea is associated with enhanced

biosynthesis and release of antimicrobial secondary metabolites (phenolic acids, flavonoids,

isoflavonoids, and terpenoid derivatives) suppressed pathogen growth and zoospore

viability. In this study, RNA sequencing RNA-seq was done to investigate transcriptomic

changes in resistant ICP-7035 and susceptible ICP-2376 genotypes 24 h afterinfection. A

total of 45,672 genes were expressed, among which 3,847 genes were differentially

expressed between the two genotypes. Gene Ontology GO and KEGG pathway analyses

revealed significant enrichment in defence-related processes, including plant-pathogen

interaction, phenylpropanoid biosynthesis and MAPK signalling pathways. Main resistance

genes [NB-LRR proteins, pathogenesis-related proteins, transcription factors WRKY, MYB,

and enzymes] involved in secondary metabolism, were identified. The quantitative real-time

PCR, showed strong agreement with RNA-seq data. This study provides valuable insights

into the molecular mechanisms underlying Phytophthora resistance in pigeon pea and

identifies potential target genes for functional validation and marker-assisted breeding to

improve disease resistance.