Identification and transferring of a new Fusarium head blight resistance gene FhbRc2 from Roegneria ciliaris 3ScL 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 ciliaris and developed FHB resistant germplasm containing this gene. Wheat-R. ciliaris disomic addition line DA3Sc showed 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 3Sc was validated using F2 and F2:3 populations derived from the cross between DA3Sc and susceptible Aikang 58 (a susceptible cultivar), demonstrating that the lines with 3Sc had significantly enhanced FHB resistance compared to the individuals without 3Sc. This was the second resistance gene identified in R. ciliaris, designated FhbRc2. To transfer FhbRc2 to common wheat, we produced a double-monosomic chromosome population by crossing DA3Sc with the Chinese Spring nulli-tetrasomic line N3DT3B. Eight alien chromosome lines containing 3Sc were identified using genomic/fluorescence in situ hybridization and 3Sc-specific marker analysis. Only the lines carrying the long arm of 3Sc conferred FHB resistance, further locating FhbRc2 on 3ScL. A compensating wheat-R. ciliaris Robertsonian translocation line T3DS·3ScL harboring FhbRc2 is developed and provides a potential genetic resource in wheat breeding for enhanced FHB resistance.