Genetic Mapping And Application Of Powdery Mildew Resistance Gene PmSNDH180 From Aegilops Tauschii

Wheat powdery mildew（Blumeria graminis f.sp.Tritici,Bgt）is a fungal airborne disease caused by the fungus Blumenella graminalis.It has been developed from a secondary disease to a major disease,seriously affecting wheat yield.Breeding and cultivating resistant varieties is the most economical,safe and effective way to resist powdery mildew.Aegilops tauschii（2n=14,DD）,As the donor of D gene group of wheat,it has rich genetic variation,excellent genes for high yield,good quality and disease resistance,and it is easy to transfer to wheat.In this study,we extracted excellent and effective powdery mildew resistance germplasm from Aegilops tauschii.A total of 71 accessions of Aegilops tauschii and 38 accessions from synthetic hexaploid wheat were identified for resistance to powdery mildew.The genetic characteristics of SNDH180 powdery mildew resistance genes were studied in detail.The main results were as follows:1.Identification of powdery mildew resistance of Aegilops tauschii at seedling stage:E09was used to identify powdery mildew resistance of Aegilops tauschii.The results showed that there were 30 Aegilops tauschii resistant to E09（IT=0-2）,accounting for 42.25%of the tested materials（71）.2.Synthetic Doubled Haploid and identification of powdery mildew at seedling stage:resistant materials and cultivated tetraploid durum wheat Langdon（T.turgidum ssp.durum（Desf.）Mac Key,AABB,2n=4x=28）.After embryo rescue and natural doubling,10 Doubled Haploid were synthesized.38 Doubled Haploid were identified to be resistant to powdery mildew at one leaf stage.Only SNDH222 was found to be immune to powdery mildew E09,SNDH179 and SNDH180 were highly resistant to powdery mildew E09,the other materials were susceptible phenotype.3.The F₂ isolated population was constructed of double diploid SNDH180 with high resistance to wheat powdery mildew E09 and highly susceptible SNDH2147 as parents.The results showed that SNDH180 was controlled by a single dominant gene,and was temporarily named Pm SNDH180.By bulked segregant analysis（BSA）and molecular markers,Pm SNDH180 was initially located in the short arm of wheat 5D chromosome.Further study based on the resequencing results of two Aegilops tauschii germplasms WC-62 and WC-18,The Pm SNDH180 was located in a physical interval of 5.9 Mb.Molecular markers of sdau5DS5-3 and sdau5DS6-1 on both sides,distance 0.6 c M and 1.3 c M respectively.4.The results showed that the powdery mildew resistance genes of Aegilops tauschii were often suppressed in hexaploid background,and the effective resistance genes of Aegilops tauschii could be discovered by using synthetic hexaploid wheat for powdery mildew resistance identification.The SNDH179 and SNDH180 germplasm with high resistance to wheat powdery mildew were successfully transferred into hexaploid background,which could be crossbred with common wheat without barrier,and provided germplasm resources for wheat powdery mildew resistance breeding.The genetic mapping of Pm SNDH180 lays a foundation for its transfer to common wheat through marker-assisted selection.