Location: Plant Science ResearchTitle: Mapping of novel powdery mildew resistance gene Pm53 introgressed from Aegilops speltoides into soft red winter wheat Author
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2014
Publication Date: 11/26/2014
Citation: Petersen, S., Lyerly, J.H., Worthington, M.L., Marshall, D.S., Brown Guedira, G.L., Cowger, C., Parks, W.R., Murphy, J.P. 2014. Mapping of novel powdery mildew resistance gene Pm53 introgressed from Aegilops speltoides into soft red winter wheat. Theoretical and Applied Genetics. 128:303-312. Interpretive Summary: Powdery mildew is an important disease of wheat in most temperate climates, and particularly in the Mid-Atlantic States in the U.S. We identified a new source of resistance to powdery mildew in an ancestoral species of wheat, and crossed the resistance into an adapted, modern wheat variety. We also identified molecular markers that can be used by breeders to easily transfer this new resistance into other wheat varieties.
Technical Abstract: Powdery mildew of wheat (Triticum aestivum L.) is a major fungal disease in many areas of the world, caused by Blumeria graminis f.sp. tritici (Bgt). Host plant resistance is the preferred form of disease prevention because it is both economical and environmentally benign. Identification of new resistance sources and closely linked markers enable breeders to utilize these new sources in marker-assisted selection as well as in gene pyramiding. Aegilops speltoides (2n=2x=14, genome SS), has been a valuable disease resistance donor. The powdery mildew resistant wheat germplasm line NC09BGTS16 (NC-S16) was developed by backcrossing an Ae. speltoides accession, TAU829, to the susceptible soft red winter wheat cultivar ‘Saluda’. NC-S16 was crossed to the susceptible cultivar ‘Coker 68-15’ to develop F2:3 families for gene mapping. Greenhouse and field evaluations of these F2:3 families indicated that a single gene, designated Pm53, conferred resistance to powdery mildew. Bulked segregant analysis showed that multiple simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers specific to chromosome 5BL segregated with the resistance gene. The gene was flanked by markers Xgwm499, Xwmc759, IWA6024 (0.7 cM proximal) and IWA2454 (1.8 cM distal). Pm36, derived from a different wild wheat relative (T. turgidum var. dicoccoides), had previously been mapped to chromosome 5BL in a durum wheat cultivar. Detached leaf tests revealed that NC-S16 and a genotype carrying Pm36 differed in their responses to each of three Bgt isolates. Pm53 therefore appears to be a novel source of powdery mildew resistance.