Mapping And Cloning Of Broad-spectrum Resistance Gene EIF4E_HOR3298 Of Barley Yellow Mosaic Disease Based On BSR-seq

The soil-borne yellow mosaic virus disease caused by different strains of Barley yellow mosic virus（BaYMV）and Barley mild mosaic virus（BaMMV）is a major threat to winter barley（Hordeum vulgare L.）production in Europe and East Asia.Some barley germplasms exhibited the genetic resistance to the barley yellow mosaic disease,and deployment of resistance genes into barley varieties can prevent the disease occurrence.However,the exploration of resistant germplasm or casual genes for barley breeding is rather limited in relation to the rapid diversification of viral strains.Previously,we identified an Iranian barley landrace"HOR3298",which showed complete resistance to isolates of BaYMV and BaMMV in Germany.Within this study,I constructed a F₂ genetic mapping population derived from a cross of"HOR3298"x"W757/612".By employment of bulked segregant RNA sequencing（BSR-seq）,test for allelism,and haplotype analysis,the resistance in HOR3298 was resulted from a novel rare allele of the host factor gene eIF4E.The results mainly included:1.In contrast to rym4 and rym5,which act as the predominant source in Europe and East Asia for breeding resistant cultivars over decades and which have been overcome by several virulent isolates,tests for resistance in multiple years and locations showed that"HOR3298"was resistant to multiple isolates of BaYMV/BaMMV in the fields of Germany and China.2.Using the BSR-seq strategy and tests for allelism,a single recessive resistance gene in"HOR3298"was genetically mapped coincident with the host factor eukaryotic translation initiation factor 4E（eIF4E,causal gene of rym4 and rym5）.3.By re-sequencing and haplotype analysis of eIF4E,the resistance in HOR3298 was found to be derived from a rare novel eIF4E haplotype that contained an exclusive nucleotide mutation（G565A）in the coding sequence.The easily handled markers were developed based on the exclusively rare variation,providing precise selection of this allele in barley resistance breeding.