|RAHMATOV, MAHBUBJON - Swedish University Of Agricultural Sciences|
|Rouse, Matthew - Matt|
|DANILOVA, TATIANA - Kansas State University|
|FRIEBE, BERND - Kansas State University|
|STEFFENSON, BRIAN - University Of Minnesota|
|JOHANSSON, EVA - Swedish University Of Agricultural Sciences|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2016
Publication Date: 7/1/2016
Citation: Rahmatov, M., Rouse, M.N., Nirmala, J.H., Danilova, T., Friebe, B., Steffenson, B., Johansson, E. 2016. A new 2DS·2RL Robertsonian translocation transfers Sr59 resistance to stem rust into wheat. Theoretical and Applied Genetics. 129(7):1383-1392. doi: 10.1007/s00122-016-2710-6.
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 wheat line called SLU238 has resistance to Ug99, but this resistance is in the form of an entire chromosome of rye. We derived a wheat line from SLU238 that has only one chromosome arm from rye that confers resistance to Ug99. We determined that this resistance is a new stem rust resistance gene called Sr59. The identification this new resistance gene will facilitate the improvement of stem rust resistance in worldwide and United States wheat cultivars. Ug99 resistant wheat cultivars will protect global and United States wheat production from yield loss if a Ug99 epidemic were to occur in the United States.
Technical Abstract: Emerging new races of the wheat stem rust pathogen Puccinia graminis f. sp. tritici Eriks. & E. Henn, especially the Ug99 race group threaten global wheat, Triticum aestivum L., production. Screening of a collection of wheat-rye, Secale cereale L., chromosome substitution lines developed at the Swedish University of Agricultural Sciences identified the line 'SLU238' 2R (2D) as possessing resistance to many stem rust pathogen races including race TTKSK (Ug99). The breakage-fusion mechanism of univalent chromosomes was used to produce a Robertsonian translocation T2DS·2RL. Molecular marker analysis and stem rust seedling assays at multiple generations confirmed that the stem rust resistance from 'SLU238' is present on the rye chromosome arm 2RL. Line TA5094 (#101) was derived from 'SLU238' with the homozygous T2DS·2RL translocation and designated as the source of Sr59 in wheat. Though rye introgressions into wheat have most often been facilitated by irradiation, this study highlights the utility of the breakage-fusion mechanism for rye chromatin introgression. Sr59 provides an additional asset for wheat improvement to mitigate stem rust yield losses.