|Cai, X -|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 2011
Publication Date: June 11, 2011
Citation: Klindworth, D.L., Niu, Z., Chao, S., Friesen, T.L., Faris, J.D., Jin, Y., Cai, X., Xu, S.S. 2011. Chromosome engineering of wheat stem rust resistance gene Sr47 in a tetraploid wheat background. Meeting Abstract. pg. 182. Technical Abstract: Durum wheat (Triticum turgidum L. ssp. durum) line DAS15 carries Sr47, a gene conferring resistance to races of stem rust (Puccinia graminis f. sp. tritici), including race TTKSK (Ug99). The Ae. speltoides segment harboring Sr47 accounts for most of the T2BL-2SL•2SS chromosome. Our objective was to use high-throughput DNA marker-assisted chromosome engineering to shorten the alien segment present in resistant plants. Following a previously described crossing procedure, we tested 1086 BC2F1 plants (Rusty/3/47-1 5D(5B)//Rusty 5D(5B)/DAS15) for resistance to race TMLK and for dissociation from SSR markers Xgwm55, Xgwm319, Xcfa2278, Xwmc474, and Xbarc55. There were 893 resistant and 193 susceptible plants, indicating strong segregation distortion. Two infection types (IT) were observed among resistant plants: 856 plants had IT 0; and 37 plants had IT 2. Seven IT 0; and three IT 2 plants with a small Ae. speltoides segment were identified based on marker analysis and genomic in situ hybridization. We concluded that the Ae. speltoides segment in DAS15 carried two stem rust resistance genes. The IT 2 gene was located on chromosome arm 2BS/2SS, and close to marker Sr39#22r, indicating that it may be allelic, or possibly identical, to Sr39. Stem rust tests of the dissociation lines with several races also suggested that the IT 2 gene was similar or identical to Sr39. The gene conferring IT 0; was located on 2BL/2SL near dominant markers Xgwm47, Xwmc332, and Xwmc627. The proximity of the gene to these three markers suggested that the gene may be homoeoallelic to Sr9 or Sr28.