Simons Kristin, Abate Zewdie, Chao Shiaoman, Zhang Wenjun, Rouse Matt, Jin Yue, Elias Elias, Dubcovsky Jorge
Biosciences Research Laboratory, USDA-ARS, U.S. Department of Agriculture, 1605 Albrecht Blvd. N., Fargo, ND 58102-2765, USA.
Theor Appl Genet. 2011 Feb;122(3):649-58. doi: 10.1007/s00122-010-1444-0. Epub 2010 Sep 21.
Wheat stem rust caused by Puccinia graminis f. sp. tritici, can cause significant yield losses. To combat the disease, breeders have deployed resistance genes both individually and in combinations to increase resistance durability. A new race, TTKSK (Ug99), identified in Uganda in 1999 is virulent on most of the resistance genes currently deployed, and is rapidly spreading to other regions of the world. It is therefore important to identify, map, and deploy resistance genes that are still effective against TTKSK. One of these resistance genes, Sr13, was previously assigned to the long arm of chromosome 6A, but its precise map location was not known. In this study, the genome location of Sr13 was determined in four tetraploid wheat (T. turgidum ssp. durum) mapping populations involving the TTKSK resistant varieties Kronos, Kofa, Medora and Sceptre. Our results showed that resistance was linked to common molecular markers in all four populations, suggesting that these durum lines carry the same resistance gene. Based on its chromosome location and infection types against different races of stem rust, this gene is postulated to be Sr13. Sr13 was mapped within a 1.2-2.8 cM interval (depending on the mapping population) between EST markers CD926040 and BE471213, which corresponds to a 285-kb region in rice chromosome 2, and a 3.1-Mb region in Brachypodium chromosome 3. These maps will be the foundation for developing high-density maps, identifying diagnostic markers, and positional cloning of Sr13.
由小麦秆锈菌小麦专化型（Puccinia graminis f. sp. tritici）引起的小麦秆锈病会导致显著的产量损失。为防治该病，育种者已单独或组合部署抗性基因以提高抗性的持久性。1999年在乌干达发现的一个新小种TTKSK（Ug99），对目前部署的大多数抗性基因具有毒性，并且正在迅速传播到世界其他地区。因此，鉴定、定位并部署对TTKSK仍然有效的抗性基因非常重要。这些抗性基因之一，Sr13，先前被定位到6A染色体的长臂上，但其精确的图谱位置尚不清楚。在本研究中，利用四个四倍体小麦（T. turgidum ssp. durum）作图群体（涉及对TTKSK具有抗性的品种Kronos、Kofa、Medora和Sceptre）确定了Sr13的基因组位置。我们的结果表明，在所有四个群体中抗性都与常见分子标记连锁，这表明这些硬粒小麦品系携带相同的抗性基因。基于其染色体位置和对不同秆锈菌小种的侵染类型，推测该基因是Sr13。Sr13被定位在EST标记CD926040和BE471213之间1.2 - 2.8 cM的区间内（取决于作图群体），这对应于水稻第2染色体上的一个285 kb区域，以及短柄草第3染色体上的一个3.1 Mb区域。这些图谱将为构建高密度图谱、鉴定诊断标记以及Sr13的图位克隆奠定基础。
