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

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, 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 Pm2. In order to identify the disease resistance gene in ‘Brock’, genetic mapping was performed using F2 and F2:3 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, TaRPM1-2D. The protein encoded by TaRPM1-2D possesses a typical nucleotide binding, leucine-rich repeat receptor (NLR) domain, and its sequence significantly differs among ‘Jing411’, ‘BJ-1’, and ‘Brock’. Expression of TaRPM1-2D was markedly higher in resistant wheat ‘Brock’ and ‘BJ-1’ compared to the susceptible ‘Jing411’. Both overexpression and gene silencing experiments demonstrated that TaRPM1-2D contributes to enhance resistance against powdery mildew in wheat. These findings reveal the function of TaRPM1-2D in conferring powdery mildew resistance in ‘Brock’ and provide a candidate gene for disease-resistance breeding.