|OLIVERA, PABLO - University Of Minnesota|
|ABEYO, BEKELE - International Maize & Wheat Improvement Center (CIMMYT)|
|TADESSE, ZERIHUN - Ethiopian Agricultural Research|
|IMTIAZ, MUHAMMAD - International Maize & Wheat Improvement Center (CIMMYT)|
|TALBERT, LUTHER - Montana State University|
|BLAKE, NANCY - Montana State University|
|AKHUNOV, EDUARD - Kansas State University|
|PUMPHREY, MICHAEL - Washington State University|
|Rouse, Matthew - Matt|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2016
Publication Date: 7/27/2017
Citation: Nirmala, J.H., Chao, S., Olivera, P., Babiker, E.M., Abeyo, B., Tadesse, Z., Imtiaz, M., Talbert, L., Blake, N., Akhunov, E., Pumphrey, M., Rouse, M.N., Jin, Y. 2017. Markers linked to wheat stem rust resistance gene Sr11 effective to Puccinia graminis f. sp. tritici race TKTTF. Phytopathology. 106(11):1352-1358.
Interpretive Summary: Wheat stem rust is a fungal disease of wheat that decreases yield. A strain of the wheat stem rust fungus known as Ug99 emerged in Uganda in 1999 and threatens global wheat production because it is able to infect nearly all wheat varieties. A variety of wheat named 'Digalu' was widely grown in Ethiopia in 2013 and 2014 because of its resistance to Ug99. However, a new strain of the stem rust pathogen named TKTTF caused severe epidemics on Digalu in Ethiopia in 2013 and 2014. We identified molecular markers linked to a wheat stem rust resistance gene named Sr11 that is effective to TKTTF. We validated the markers as predictive of Sr11 in wheat lines from the United States, Pakistan, and Ethiopia. These markers we described could be used by wheat breeders to develop resistant wheat varieties. Resistant wheat cultivars will protect United States wheat production from yield loss if a TKTTF epidemic were to occur in the United States.
Technical Abstract: Wheat stem rust caused by Puccinia graminis f. sp. tritici can cause severe yield losses on susceptible wheat varieties and cultivars. Although stem rust can be controlled by the use of genetic resistance, population dynamics of P. graminis f. sp. tritici can frequently lead to defeat of wheat stem rust resistance genes. P. graminis f. sp. tritici race TKTTF caused a severe epidemic in Ethiopia on the Ug99-resistant cultivar 'Digalu' in 2013 and 2014. The gene Sr11 confers resistance to race TKTTF and is present in cultivar 'Gabo 56'. We identified SNP markers linked to Sr11 from a cross between 'Gabo 56'/'Chinese Spring' exploiting a 90K Infinium iSelect Custom beadchip. Twelve SNP markers were converted to KASP assays and five of them were validated on a 'Berkut'/'Scalavatis' population that segregated for Sr11. Two of the SNP markers, KASP_6BL_IWB10724 and KASP_6BL_IWB72471, were predictive of Sr11 among wheat genetic stocks, cultivars, and breeding lines from North America, Ethiopia, and Pakistan. These markers can be utilized to select for Sr11 in wheat breeding and to detect the presence of Sr11 in uncharacterized germplasm.