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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #357136
Research Project: Cereal Rust: Pathogen Biology and Host Resistance

Location: Cereal Disease Lab

Title: Identification of new sources of resistance to wheat stem rust in Aegilops spp. in the tertiary genepool of wheat

Author
item OLIVERA, PABLO - University Of Minnesota
item Rouse, Matthew
item Jin, Yue

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2018
Publication Date: 11/22/2019
Citation: Olivera, P., Rouse, M.N., Jin, Y. 2019. Identification of new sources of resistance to wheat stem rust in Aegilops spp. in the tertiary genepool of wheat. Frontiers in Plant Science. 9:1719. https://doi.org/10.3389/fpls.2018.01719.
DOI: https://doi.org/10.3389/fpls.2018.01719

Interpretive Summary: Recent stem rust epidemics in eastern Africa and elsewhere demonstrated that wheat stem rust is a re-emerging disease posing a threat to wheat production worldwide. The cultivated wheat gene pool has a narrow genetic base for resistance to virulent races of the wheat stem rust pathogen, such as races in the Ug99 race group. Wild relatives of wheat are a tractable source of stem rust resistance genes. Wild Aegilops species in the tertiary genepool (i.e. those species more distantly related to wheat and do not share a genome with wheat) have not been exploited to any great extent as a source of stem rust resistance, however. We evaluated 1,422 accessions of Aegilops spp. from the tertiary genepool for resistance to three highly virulent races of the wheat stem rust pathogen. High frequencies of resistance were found in these materials, and the resistance genes are effective against multiple races. Inheritance studies in selected accessions showed resistance is simply inherited. This information is useful for scientists and wheat breeders to introduce new sources of stem rust resistance into wheat in their crop improvement efforts.

Technical Abstract: Recent stem rust epidemics in eastern Africa and elsewhere demonstrated that wheat stem rust is a re-emerging disease posing a threat to wheat production worldwide. The cultivated wheat gene pool has a narrow genetic base for resistance to virulent races, such as races in the Ug99 race group. Wild relatives of wheat are a tractable source of stem rust resistance genes. Aegilops species in the tertiary genepool have not been exploited to any great extent as a source of stem rust resistance, however. We evaluated 1,422 accessions of Aegilops spp. for resistance to three highly virulent races (TTKSK, TRTTF and TTTTF) of Puccinia graminis f. sp. tritici. Species studied include Ae. biuncialis, Ae. caudata, Ae. comosa, Ae. cylindrica, Ae. geniculata, Ae. neglecta, Ae. peregrina, Ae. triuncialis, and Ae. umbellulata that do not share common genomes with cultivated wheat. High frequencies of resistance were observed as 977 (68.8%), 927 (65.2%), and 850 (59.8%) accessions exhibited low infection types to races TTKSK, TTTTF, and TRTTF, respectively. Association analyses showed strong association for resistance to different races in several Aegilops spp., indicating that for a given species, the resistance genes effective against multiple races. Inheritance studies in selected accessions showed resistance to race TTKSK is simply inherited.