A novel NLR immune receptor from Aegilops tauschii confers resistance to wheat eyespot disease

Eyespot, a stem-base soil-borne fungal disease, is an important constraint on wheat production in temperate regions. Resistance in wheat remains limited, with Pch1 and Pch2 being currently deployed in breeding but no underlying or associated gene identified to date. Here, we phenotyped a sequence-configured diversity panel of Aegilops tauschii , the D subgenome progenitor of bread wheat, with one of the two causative agents of eyespot, Oculimacula yallundae . A k -mer-based genome-wide association mapping approach identified Pch4 , a nucleotide-binding leucine-rich repeat (NLR) gene on chromosome 1DS. Transgenic wheat and synthetic hexaploids carrying Pch4 showed strong resistance to the pathogen. Phylogenetic and synteny analyses revealed that Pch4 belongs to the same NLR lineage as the cereal powdery mildew resistance gene Pm3 , indicating a shared evolutionary origin. The discovery of Pch4 expands the repertoire of available eyespot resistances and provides new opportunities for strategic stacking of resistance genes to enhance disease resilience in wheat.