Genetic Basis Identification of a NLR Gene, TaRPM1-2D, That Confers Powdery Mildew Resistance in Wheat Cultivar ‘Brock’

Wheat powdery mildew, caused by <i>Blumeria graminis</i> f. sp. <i>tritici</i>, represents one of the most threatening biotic stresses of this crop. The cultivated wheat variety 'Brock' exhibits resistance not only to rust but also to powdery mildew, making it a valuable resource for exploitation in wheat disease-resistant breeding. This study identified a novel gene in 'Brock' distinct from <i>Pm2</i>. In order to identify the disease resistance gene in 'Brock', genetic mapping was performed using F₂ and F_2:3 populations derived from the cross 'Jing411/Brock'. The candidate powdery mildew resistance gene was located within a 6.88 Mb physical interval on chromosome 2D, which harbors a highly expressed gene, <i>TaRPM1-2D</i>. The protein encoded by <i>TaRPM1-2D</i> possesses a typical nucleotide binding, leucine-rich repeat receptor (NLR) domain, and its sequence significantly differs among 'Jing411', 'BJ-1', and 'Brock'. Expression of <i>TaRPM1-2D</i> was markedly higher in resistant wheat 'Brock' and 'BJ-1' compared to the susceptible 'Jing411'. Both overexpression and gene silencing experiments demonstrated that <i>TaRPM1-2D</i> contributes to enhance resistance against powdery mildew in wheat. These findings reveal the function of <i>TaRPM1-2D</i> in conferring powdery mildew resistance in 'Brock' and provide a candidate gene for disease-resistance breeding.