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United States Department of Agriculture

Agricultural Research Service

Research Project: CHARACTERIZATION OF HOST-PATHOGEN INTERACTIONS IN BARLEY AND WHEAT

Location: Cereal Crops Research

Title: New broad-spectrum resistance to septoria tritici blotch derived from synthetic hexaploid wheat

Authors
item Ghaffary, S. Mahmod -
item Faris, Justin
item Friesen, Timothy
item Visser, Richard -
item Van Der Lee, Theo -
item Robert, Olivier -
item Kema, Gert -

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 8, 2011
Publication Date: September 13, 2011
Citation: Ghaffary, S.T., Faris, J.D., Friesen, T.L., Visser, R.G., Van Der Lee, T.A., Robert, O., Kema, G.H. 2011. New broad-spectrum resistance to septoria tritici blotch derived from synthetic hexaploid wheat. Journal of Theoretical and Applied Genetics. 124:125-142.

Interpretive Summary: Septoria tritici blotch (STB) caused by the fungal pathogen Mycosphaerella graminicola is one of the most devastating foliar diseases of wheat. We screened five synthetic hexaploid wheats (SHs) and 13 wheat varieties with a global set of 20 pathogen isolates and discovered exceptionally broad STB resistance in SHs that was not present in the wheat varieties. Subsequent development and analyses of progeny from a genetic cross between the a SH and a highly susceptible bread wheat cultivar revealed two novel resistance loci on chromosomes 3D and 5A. The 3D resistance was expressed in the seedling and adult plant stages. This gene explained from 41 to 71% of the disease variation at the seedling stage and 28 to 31% in adult plants. The resistance locus on chromosome 5A was specifically expressed at the adult plant stage and explained 12 to 32% of the variation in disease. This gene is the first STB adult plant resistance gene to be identified. Our results indicate that common wheat progenitors might be a rich source of new Stb resistance genes that can be deployed in commercial breeding programs.

Technical Abstract: Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola, is one of the most devastating foliar diseases of wheat. We screened five synthetic hexaploid wheats (SHs), 13 wheat varieties that represent the differential set of cultivars and two susceptible checks with a global set of 20 isolates and discovered exceptionally broad STB resistance in SHs. Subsequent development and analyses of recombinant inbred lines (RILs) from a cross between the SH M3 and the highly susceptible bread wheat cv. Kulm revealed two novel resistance loci on chromosomes 3D and 5A. The 3D resistance was expressed in the seedling and adult plant stages, and it controlled necrosis (N) and pycnidia (P) development as well as the latency periods of these parameters. This gene, which is closely linked to the microsatellite marker Xgwm494, was designated Stb16 and explained from 41 to 71% of the phenotypic variation at seedling stage and 28 to 31% in mature plants. The resistance locus on chromosome 5A was specifically expressed at the adult plant stage, associated with SSR marker Xhbg247, and explained 12 to 32% of the variation in disease. This gene was designated as Stb17, and is the first adult plant M. graminicola resistance gene to be identified. Our results indicate that common wheat progenitors might be a rich source of new Stb resistance genes that can be deployed in commercial breeding programs.

Last Modified: 7/24/2014
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