Briggs Jordan, Chen Shisheng, Zhang Wenjun, Nelson Sarah, Dubcovsky Jorge, Rouse Matthew N
First, fourth, and sixth authors: Department of Plant Pathology, University of Minnesota, St. Paul 55108; second, third, and fifth author: Department of Plant Sciences, University of California, Davis 95616; second author: Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, 611130, P.R. China; fifth author: Howard Hughes Medical Institute, Chevy Chase, MD 20815; and sixth author: USDA-ARS Cereal Disease Laboratory, St. Paul, MN 55108.
Phytopathology. 2015 Oct;105(10):1347-54. doi: 10.1094/PHYTO-12-14-0382-R. Epub 2015 Sep 4.
Race TTKSK (or Ug99) of Puccinia graminis f. sp. tritici, the causal agent of wheat stem rust, is a serious threat to wheat production worldwide. Diploid wheat, Triticum monococcum (genome Am), has been utilized previously for the introgression of stem rust resistance genes Sr21, Sr22, and Sr35. Multipathotype seedling tests of biparental populations demonstrated that T. monococcum accession PI 306540 collected in Romania contains a recessive resistance gene effective to all P. graminis f. sp. tritici races screened, including race TTKSK. We will refer to this gene as SrTm4, which is the fourth stem rust resistance gene characterized from T. monococcum. Using two mapping populations derived from crosses of PI 272557×PI 306540 and G3116×PI 306540, we mapped SrTm4 on chromosome arm 2AmL within a 2.1 cM interval flanked by sequence-tagged markers BQ461276 and DR732348, which corresponds to a 240-kb region in Brachypodium chromosome 5. The eight microsatellite and nine sequence-tagged markers linked to SrTm4 will facilitate the introgression and accelerate the deployment of SrTm4-mediated Ug99 resistance in wheat breeding programs.
小麦秆锈病的病原菌——小麦秆锈菌（Puccinia graminis f. sp. tritici）的TTKSK小种（又称Ug99），是全球小麦生产的严重威胁。二倍体小麦一粒小麦（Triticum monococcum，基因组为Am）此前已被用于导入秆锈病抗性基因Sr21、Sr22和Sr35。对双亲群体进行的多致病型幼苗测试表明，在罗马尼亚收集的一粒小麦种质PI 306540含有一个隐性抗性基因，对所有测试的小麦秆锈菌小种均有效，包括TTKSK小种。我们将该基因命名为SrTm4，这是从一粒小麦中鉴定出的第四个秆锈病抗性基因。利用从PI 272557×PI 306540和G3116×PI 306540杂交产生的两个作图群体，我们将SrTm4定位在2AmL染色体臂上，位于序列标签标记BQ461276和DR732348两侧的2.1 cM区间内，该区间对应于短柄草属植物第5号染色体上的一个240 kb区域。与SrTm4连锁的8个微卫星标记和9个序列标签标记将有助于在小麦育种计划中导入并加速部署由SrTm4介导的对Ug99的抗性。
