小麦-高大山羊草Pm13微小片段易位系的创制与鉴定OA

Wheat powdery mildew,caused by the obligate biotrophic fungus Blumeria graminis f.sp.tritici,is a globally prevalent disease that poses a severe threat to wheat yield and quality.Breeding resistant varieties through the deployment of resistance genes is widely recognized as the most economical and effective strategy for disease management.The Pm13 gene,a broad-spectrum powdery mildew resistance gene located on chromosome 3S1 of Aegilops longissima,a wild relative of common wheat,was introduced into common wheat through wheat-Ae.longissima 3S1 chromosome translocation in the 1990s.However,the large size of the alien chromosomal segment carrying Pm13 resulted in linkage drag,which has constrained its utility in wheat breeding programs.In this study,theph1b gene was employed to promote homoeologous recombination between Ae.longissima 3S1#2 chromosome and wheat homoeologous group 3 chromosomes.Consequently,three powdery mildew-resistant translocation lines with minimal introgressed segments carrying Pm13(W12-3A,W12-3G,and W12-3H)were successfully developed.Marker enrichment analysis revealed that the size of the introgressed 3S1 chromosomal segments in these translocation lines were 1.886 Mb,699 kb,and 196 kb,accounting for only 0.24％,0.087％,and 0.024％of the entire 3S1 chromosome,respectively.Genetic analysis of self-pollinated F2 populations derived from these translocation lines showed that the segregation ratio of resistant to susceptible plants fitted the expected 3∶1,indicating stable inheritance of Pm13.Furthermore,agronomic evaluation of the translocation line W12-3H with the smallest introgressed 3 S1 chromosome segment revealed no adverse effects on key agronomic performance traits.Resistance assessment across different genetic backgrounds demonstrated that Pm13 confers effective powdery mildew resistance in diverse wheat lines.Collectively,this study successfully developed disease-resistant Pm13 tiny-segment translocation lines with no linkage drag,providing valuable genetic resources to facilitate the efficient utilization of the Pm13 gene in wheat powdery mildew resistance breeding.