Genetic Mapping Of Powdery Mildew Resistance Gene From Wild Emmer Wheat And Its Application In Wheat Germplasm Innovation

Wheat（Triticum aestivum L.）,one of the three major food crops,provides about 20percent of human energy.Powdery mildew of wheat is a worldwide widespread fungal disease caused by Blumeria graminis f.sp.tritici（Bgt）.The previous study showed that wild emmer wheat from the wet south slope of“Evolution Canyon”of Mount Carmel in Israel display high resistance to 11 Bgt isolates from different wheat producing areas in China.In order to explore the powdery mildew resistance gene,NFS-10 and SFS2-12 were used to construct a genetic mapping population and molecular markers closely linked to Ml NFS10were developed by BSR-seq and whole genome resequencing design,so as to fine-map the powdery mildew resistance gene Ml NFS10.The research results are as follows:1.The resistance of NFS-10 and SFS2-12 as well as the offspring F₁,F₂and F_2:3populations were identified at seedling stage using the epidemic Bgt isolate E09,and the genetic model of resistance of NFS-10 to powdery mildew was analyzed.The F₁plants showed resistance to Bgt isolate E09,the isolation ratio of F₂isolated population and F_2:3family was controlled by a single dominant gene.2.The powdery mildew resistance gene Ml NFS10 was mapped to 4AL by BSR-seq and three existing SSR markers Xwmc313,Xwmc722 and Xgpw3079.Molecular markers were developed using the SNPs of parental differences obtained by BSR-seq and whole genome resequencing,and 31 recombinant single strains were screened by combining F₂population and F_2:3derived families for genetic mapping of powdery mildew resistance gene Ml NFS10,Ml NFS10 was mapped to a 0.3 c M genetic interval on chromosome arm 4AL,which was aligned to a 2.1 Mb physical interval.3.34 annotated genes were retrieved in the 2.1Mb localization region of Ml NFS10 on chromosome 4A of Chinese Spring reference genome,and four R genes were specifically expressed in the leaves of disease-resistant parent NFS-10,according to the results of RNA-Seq,which laid the foundation for the cloning and further functional verification of Ml NFS10.4.Ml NFS10 was located onchromosome arm 4AL,and two genes Ml IW30 and Pm61were also located on chromosome arm 4AL.Through literature review and correlation analysis of the three genes,it was found that Ml NFS10 was different from the other two genes in gene source,physical location,gene recessive and resistance spectrum.Therefore,Ml NFS10 is a new powdery mildew resistance gene,which can provide a new broad spectrum resistance source for the genetic improvement of wheat powdery mildew resistance.5.In order to accelerate the application of Ml NFS10 in breeding,NFS-10 was crossbred with SN533491,SN10995 and SN11132 respectively and backcrossed for 2-3 successive generations.Starting from BC₁F₁population,markers XWsdau73447 and XWsdau72928 were used for auxiliary selection and identification of resistance to powdery mildew.BC₂F₃population with the genetic background of Shannong533491 contained Ml NFS10 and significantly improved its resistance to powdery mildew.A new powdery mildew resistant wheat material was developed through germplasm innovation.