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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #372347

Research Project: Cereal Rust: Pathogen Biology and Host Resistance

Location: Cereal Disease Lab

Title: Association mapping of resistance to emerging stem rust pathogen races in spring wheat using genotyping-by-sequencing

Author
item EDAE, ERENA - University Of Minnesota
item Rouse, Matthew - Matt

Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2020
Publication Date: 9/23/2020
Citation: Edae, E.A., Rouse, M.N. 2020. Association mapping of resistance to emerging stem rust pathogen races in spring wheat using genotyping-by-sequencing . The Plant Genome. e20050:1-17. https://doi.org/10.1002/tpg2.20050.
DOI: https://doi.org/10.1002/tpg2.20050

Interpretive Summary: The identification and characterization of resistance genes should outpace the rapid emergence of new wheat stem rust pathogen races to mitigate stem rust damage to wheat. The objective of the current study was to identify and characterize wheat resistance genes effective to recently detected stem rust pathogen races. A total of 250 North American spring wheat lines were evaluated at the seedling stage with a total of seven races in a greenhouse facility at the USDA-ARS Cereal Disease Laboratory located in St. Paul, Minnesota. The lines were genotyped by a GBS platform and 9,042 SNPs were used for identification of chromosome regions associated with resistance against the seven races. All resistance genes detected were race-specific, suggesting the need for identifying and characterizing QTL/genes for newly emerging stem rust pathogen races. Identifying resistance to emerging, virulent, and foreign wheat stem rust pathogen races can facilitate the deployment of resistant wheat varieties in order to protect U.S. wheat production from the threat of such races.

Technical Abstract: The identification and characterization of resistance genes should outpace the rapid emergence of new P. graminis f. sp. tritici races to mitigate stem rust damage to wheat. The objective of the current study was to identify and characterize P. graminis f. sp. tritici race resistance association signals. A total of 250 North American spring wheat lines were evaluated at the seedling stage with a total of seven races in a greenhouse facility at the USDA-ARS Cereal Disease Laboratory. The lines were genotyped by a GBS platform and 9,042 SNPs were used for identification of chromosome regions associated with resistance against the seven races. Strong association signals were detected on chromosomes 6BL (Sr11 gene region) and 4AL, likely Sr7a, for resistance against both TKKTP and TKTTF. Similarly, association signals were also detected on chromosomes 4AL (race TTRTF resistance) and 4BS (race TTKSK and TTKTT resistance). Mapping difference in phenotype between closely related isolates and response of an isolate at two temperatures identified QTL that we not elucidated by direct association mapping of the responses, individually. Overall, with the exception of race TRTTF, each race shared at least one association signal with another race. However, the number of race-specific association signals are larger than that of association signals common among races suggesting the need for identifying and characterizing QTL/genes for newly emerging stem rust pathogen races.