Elucidating <scp> <i>R</i> </scp> ‐gene‐mediated resistance to wheat dwarf virus in <scp> <i>Triticum aestivum</i> </scp> genotypes

Abstract Wheat dwarf virus (WDV) poses a major limitation to global cereal production, yet reliable genetic sources of resistance remain scarce. In this study, 12 genetically diverse wheat ( Triticum aestivum L.) genotypes exhibiting differential susceptibility to WDV were evaluated under controlled inoculation conditions. Viral titre and the expression profiles of nine candidate resistance genes—representing NBS‐LRR family, kinase family and transcription factor families—were quantified using reverse transcription quantitative polymerase chain reaction. Phenotypic parameters, including plant height and biomass, were assessed to relate molecular responses to disease severity. Statistical analysis using one‐way ANOVA revealed significant genotype‐dependent differences in viral accumulation and resistance gene expression. Notably, genotype VS‐H 09‐4/3 exhibited an approximately 80% reduction in virus titre relative to susceptible lines, accompanied by a 2.5‐fold upregulation of key R ‐genes associated with innate immune responses. In contrast, susceptible genotypes such as Ludwig displayed elevated viral loads and downregulation of these defence‐related genes. Transcriptional modulation of kinase and transcription factor genes (e.g., MYB , GRAS ) further supported the involvement of complex regulatory networks in WDV resistance. Collectively, these findings reveal actionable genetic markers and distinct resistance phenotypes, providing valuable resources for marker‐assisted selection aimed at developing durable WDV‐resistant wheat cultivars and enhancing crop resilience under changing environmental conditions.