Phytopathology. 2014 Aug;104(8):865-70. doi: 10.1094/PHYTO-10-13-0276-R.
Leaf rust, caused by Puccinia triticina, is the most common and widespread disease of wheat (Triticum aestivum) worldwide. Deployment of host-plant resistance is one of the strategies to reduce losses due to leaf rust disease. The objective of this study was to map genes for adult-plant resistance to leaf rust in a recombinant inbred line (RIL) population originating from MN98550-5/MN99394-1. The mapping population of 139 RILs and five checks were evaluated in 2005, 2009, and 2010 in five environments. Natural infection occurred in the 2005 trials and trials in 2009 and 2010 were inoculated with leaf rust. Four quantitative trait loci (QTL) on chromosomes 2BS, 2DS, 7AL, and 7DS were detected. The QTL on 2BS explained up to 33.6% of the phenotypic variation in leaf rust response, whereas the QTL on 2DS, 7AL, and 7DS explained up to 15.7, 8.1, and 34.2%, respectively. Seedling infection type tests conducted with P. triticina races BBBD and SBDG confirmed that the QTL on 2BS and 2DS were Lr16 and Lr2a, respectively, and these genes were expressed in the seedling and field plot tests. The Lr2a gene mapped at the same location as Sr6. The QTL on 7DS was Lr34. The QTL on 7AL is a new QTL for leaf rust resistance. The joint effects of all four QTL explained 74% of the total phenotypic variation in leaf rust severity. Analysis of different combinations of QTL showed that the RILs containing all four or three of the QTL had the lowest average leaf rust severity in all five environments. Deployment of these QTL in combination or with other effective genes will lead to successful control of leaf rust.
叶锈病由小麦叶锈菌引起，是全球范围内小麦最常见和广泛发生的病害。利用寄主植物抗性是减轻叶锈病损失的策略之一。本研究的目的是利用 MN98550-5/MN99394-1 重组自交系群体定位叶锈病成株期抗性基因。2005、2009 和 2010 年在五个环境下，对由 139 个重组自交系和 5 个对照组成的作图群体进行了评价。2005 年的试验采用自然发病，而 2009 年和 2010 年的试验采用叶锈菌接种。在 2BS、2DS、7AL 和 7DS 染色体上共检测到 4 个数量性状位点（QTL）。2BS 上的 QTL 解释了叶锈病反应表型变异的 33.6%，而 2DS、7AL 和 7DS 上的 QTL 分别解释了 15.7%、8.1%和 34.2%。与 P. triticina 菌株 BBBD 和 SBDG 进行的幼苗感染型试验证实，2BS 上的 QTL 和 2DS 上的 QTL 分别为 Lr16 和 Lr2a，这些基因在幼苗和田间试验中表达。Lr2a 基因与 Sr6 位于同一位置。7DS 上的 QTL 为 Lr34。7AL 上的 QTL 是一个新的叶锈病抗性 QTL。四个 QTL 的共同作用解释了叶锈病严重度总表型变异的 74%。对不同 QTL 组合的分析表明，在所有五个环境中，含有所有四个或三个 QTL 的重组自交系的平均叶锈病严重度最低。这些 QTL 的组合或与其他有效基因的组合部署将导致叶锈病的成功控制。
