Transcriptomic insights into powdery mildew resistance in contrasting genotypes of Triticum aestivum L.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a major fungal disease that significantly impacts wheat production worldwide. Understanding the molecular mechanisms underlying resistance in wheat (Triticum aestivum L.) genotypes is crucial for developing durable disease management strategies. In this study, we compared the transcriptomic responses of two contrasting bread wheat genotypes, Bolani (sensitive) and TN72 (resistant), to Bgt infection using RNA sequencing. Transcriptome analysis identified 2,827 DEGs in the sensitive genotype (1,507 upregulated and 1,320 downregulated) and 3,105 DEGs in the resistant genotype (1,484 upregulated and 1,621 downregulated). Functional annotation of stress-responsive genes using MapMan revealed key pathways including cell wall biosynthesis, fatty acid metabolism, redox processes, amino acid biosynthesis, and light reactions. Venn diagrams analysis highlighted two protein-coding genes: LOC123103220 (asparagine synthetase [glutamine-hydrolyzing]) and TraesCS6D02G392100 (xyloglucan endotransglycosylase/hydrolase protein 8-like). These genes were upregulated in the resistant genotype but downregulated in the sensitive genotype, playing roles in asparagine biosynthesis, and cell wall biogenesis/xyloglucan metabolism, respectively. The relative expression of six selected genes between resistant and sensitive genotypes, validated using real-time PCR, corroborated the RNA-seq findings. Our findings highlight the molecular basis of Bgt resistance in TN72 and provide valuable insights for breeding programs aimed at enhancing powdery mildew resistance in wheat.