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United States Department of Agriculture

Agricultural Research Service

Research Project: CEREAL RUST FUNGI: GENETICS, POPULATION BIOLOGY, AND HOST-PATHOGEN INTERACTIONS

Location: Cereal Disease Laboratory

Title: Development and characterization of a compensating wheat-Thinopyrum intermedium Robertsonian translocation with Sr44 resistance to stem rust (Ug99)

Authors
item Li, Wenxuan -
item Danilova, Tatiana -
item Rouse, Matthew
item Bowden, Robert
item Friebe, Bernd -
item Gill, Bikram -
item Pumphrey, Michael -

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2013
Publication Date: January 29, 2013
Citation: Li, W., Danilova, T., Rouse, M.N., Bowden, R.L., Friebe, B., Gill, B.S., Pumphrey, M.0. 2013. Development and characterization of a compensating wheat-Thinopyrum intermedium Robertsonian translocation with Sr44 resistance to stem rust (Ug99). Theoretical and Applied Genetics. 126:1167-1177.

Interpretive Summary: A race (strain) of the wheat stem rust pathogen, known as Ug99, threatens global wheat production because of its virulence to wheat cultivars worldwide. Breeding resistant cultivars of wheat may mediate the threat of Ug99. Unfortunately, very few sources of resistance that are usable in wheat breeding are available for resistance to Ug99. We transferred a single chromosome arm possessing a stem rust resistance gene effective to Ug99 from a wheat line with a whole chromosome from the wheat relative intermediate wheatgrass to it's compensating location in wheat. This resulted in a wheat line with just a single chromosome arm from intermediate wheatgrass. This research makes possible the shortening of the chromosome arm with the stem rust resistance so that the stem rust resistance can be used in wheat breeding. Once this resistance gene is able to be used in wheat breeding, it will provide wheat breeders with an option to protect wheat from yield losses to stem rust disease.

Technical Abstract: The emergence of virulent race Ug99 and derivatives of the stem rust fungus (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.) threatens wheat (Triticum aestivum L.) production worldwide. One of the effective genes against the Ug99 race complex is Sr44 which was derived from Thinopyrum intermedium (Host) Barkworth & D.R. Dewey and mapped to the short 7J#1S arm present in the noncompensating T7DS-7J#1L.7J#1S translocation. Noncompensating wheat-alien translocations are known to cause genomic duplications and deficiencies leading to poor agronomic performance, and prohibiting their direct use in wheat improvement. The present study was initiated to produce compensating wheat-Th. intermedium Robertsonian translocations (RobTs) with Sr44 resistance. One compensating RobT was identified consisting of the wheat 7DL arm translocated to the Th. intermedium 7J#1S arm resulting in T7DL.7J#1S. The 7DL.7J#1S stock confers resistance to race Ug99 and derivatives. In addition we identified a second so far unnamed stem rust resistance gene located on the 7J#1L arm that confers resistance not only to race Ug99 and derivatives but also to race TRTTF which has virulence to Sr44. However, the action of this gene can be modified by the presence of suppressors in the recipient wheat cultivars. The identification of a compensating T7DL.7J#1S RobT with Sr44 resistance is the first step for utilizing this gene in wheat improvement.

Last Modified: 4/17/2014
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