Identification and transferring of a new Fusarium head blight resistance gene FhbRc2from Roegneria ciliaris3ScL chromosome arm into common wheat

Fusarium head blight (FHB) threatens wheat production worldwide. Utilization of FHB resistant varieties is the most effective solution for disease control. Owing to the limited sources of FHB resistance, mining of novel resistance genes is crucial. Here, we report an FHB resistance gene from a wild wheat relative species, Roegneria ciliarisand developed FHB resistant germplasm containing this gene. Wheat-R. ciliarisdisomic addition line DA3Scshowed enhanced type II FHB resistance compared to its sister line 3Sc-Null without chromosome 3Sc, indicating that the resistance was contributed by the addition of 3Sc. The resistance gene on 3Scwas validated using F2and F2:3populations derived from the cross between DA3Scand susceptible Aikang 58 (a susceptible cultivar), demonstrating that the lines with 3Schad significantly enhanced FHB resistance compared to the individuals without 3Sc. This was the second resistance gene identified in R. ciliaris, designated FhbRc2. To transfer FhbRc2to common wheat, we produced a double-monosomic chromosome population by crossing DA3Scwith the Chinese Spring nulli-tetrasomic line N3DT3B. Eight alien chromosome lines containing 3Scwere identified using genomic/fluorescence in situhybridization and 3Sc-specific marker analysis. Only the lines carrying the long arm of 3Scconferred FHB resistance, further locating FhbRc2on 3ScL. A compensating wheat-R. ciliarisRobertsonian translocation line T3DS·3ScL harboring FhbRc2is developed and provides a potential genetic resource in wheat breeding for enhanced FHB resistance.