Mapping Of Powdery Mildew Resistance Gene Based On SNP Chips

Powdery mildew(Pm),caused by Blumeria graminis f.sp.tritici,is a main foliar disease,and has become important disease challenge that the increasing of yield and improvement of quality must face.To find more powdery mildew resistant genes,and to explore more new resistant varieties to increase the resistant resources,to further andvance the study about molecular breeding are extremely important aspects in wheat's work.Thinopyrum intermedium(Th.Intermedium,2n = 42,JJJsJsStSt)is pool of excellent genes in genetic improment of wheat.By using Wheat-Thinopyrum intermedium partial amphidiploid(TAI7044,TAI7045,TAI7047)as parent,Technical difficulties of hybriding sterility,offspring crazy isolation,long breeding cycle,beneficial genes transferation that the derictly cross between commom wheat and Th.intermedium face could be overcame.CH09W80 developed by team is a variety conferring resistance to powdery mildew.In this experiment,CH09W80 was crossed with MY11 to construct F1,F2,BC1 populations and F2:3 lines.Genetic analysis and molecular mapping of powdery mildew resistant genes was conducted by using SSR markers and SNP chips.The key results in this work are as follows:(1)The Powdery mildew reaction of the Th.Intermedium,TAI7047,CH09W80 and susceptible parents(TY 768,JC 5,and JT170)was tested by inoculating with Bgt isolates.The results show the resistant reaction of CH09W80 to all Bgts is similar to its wild parent Th.intermedium,but the rest of the parents TY 768,JC 5,and JT170 are all susceptible.The result indicates that the resistant gene of CH09W80 was probably derived from Thinopyrum intermedium.(2)The Powdery mildew reaction of the population of F1,F2,BC1 and F2:3 lines from the cross between CH09W80 and MY11 were tested by inoculating with isolate E09.It truns out that the F1 population is resistant,demonstrating that the resistant gene in CH09W80 is dominant.The F2 and BC1 populations,F2:3 lines all are separate,accordingly confirming to segregation ratio of 3R:1S,1R:1S,1R:2H:1S.So resistant gene in CH09W80 tentatively designated as PmCH09W80 is a pair of dominant nuclear gene.(3)There is no distinct single been detected in CH09W80 by using GISH,because the size of introgressed alien segment in CH09W80 probably was very small and cytologically undetectable.It can be gotten that CH09W80 is probably a wheat-Thinopyrum intermedium introgression lines of small fragment.(4)When preliminarily screenning SSR markers and scanning iSelect 90k SNP chips by using BSA method,SSR markers Xwmc522 being on the 2A chromosome have polymorphism between parents and bulks;3198 SNPs(3.92%)detected by using 90k SNP chips have polymorphism.Among them,2A chromosome that contains the most polymorphic SNP markers accounts for 384,of which 313 SNPs are on the 2AL,and 47 SNPs are on the 2AS.In addition,the analysis about chromosomal location of different SNPs show that most of different SNPs lie on the two districts(100-105cM and 150-155cM)of 2A chromosome.In summary,the fllowing work of the powdery mildew resistance gene in CH09W80 focused on the near district of 100-105cM and 50-155cM on 2AL chromosome in wheat.(5)SSR markers are closely linked to PmCH09W80 by conducting marker linkage analysis,and the linking relationship is Xwmc522-Xgwm356-PmCH09W80-Xgwm526,of which Xgwm356 and Xgwm526 locate on the both sides of PmCH09W80 with the linkage distance of 3.5cM,7.8cM.Then PmCH09W80 is located on chromosome 2AL by using CS nullitertrasomic lines,ditelosomic lines.Further more,PmCH09W80 compared with the physical maps of Pm4,Pm50 may be a new gene on the chromosome 2AL.