Identification and transfer of resistance to Fusarium head blight from Elymus repens chromosome arm 7StL into wheat

Abstract

head blight (FHB), mainly caused by (), is one of the most devastating fungal diseases in wheat production worldwide. (2n=6=42, StStStStHH) is a wild relative of wheat with many biotic and abiotic stress resistance traits. To transfer and apply the wild germplasm's resistance gene (s) for wheat breeding, we identified a new translocation line K140-7 with high resistance to FHB, developed from the derivative progenies of . crossed with common wheat cultivars. Cytogenetic analyses based on genomic hybridization (GISH), non-denaturing fluorescence hybridization (ND-FISH), oligonucleotide-FISH painting (Oligo-FISH painting), and single-gene FISH revealed that K140-7 had 40 wheat chromosomes and two 7DS·7StL translocated chromosomes. Wheat 55K SNP array analysis confirmed that the translocated breakpoint (340.8~342.5 Mb) was close to the centromere region of chromosome 7D (336.3~341.7 Mb), supporting the 7DS·7StL translocation event. Based on the diploid reference St genome of , we developed 21 simple sequence repeats (SSR) markers, specific for chromosome arm 7StL. Genotyping and phenotyping analysis of the 7DS·7StL translocation in different wheat backgrounds demonstrated that the chromosome arm 7StL confers FHB resistance and possesses the dominant FHB resistance locus (s) named .. We further transferred . into three different wheat cultivars, their second 7DS·7StL translocation line-generations showed improved agronomic traits, representing new germplasms that could be used in wheat FHB-resistant breeding programs.