Da-Silva P R, Brammer S P, Guerra D, Milach S C K, Barcellos A L, Baggio M I
Laboratório de Genética e Biologia Molecular Vegetal, Departamento de Ciências Biológicas, Universidade Estadual do Centro-Oeste, Guarapuava, PR, Brasil.
Genet Mol Res. 2012 Aug 24;11(3):2823-34. doi: 10.4238/2012.August.24.7.
Leaf rust is one of the most destructive diseases affecting wheat worldwide. The most effective way to control it is to use resistant cultivars. Resistance based on slow-rusting adult plant resistance (APR) genes has proven to be the best method for developing cultivars with durable resistance. A source of slow-rusting APR for leaf rust is the Brazilian wheat cultivar Toropi. The Toropi/IAC 13 F₂ and F₇ recombinant inbred lines (RILs) were developed in previous studies. Phenotypic analysis of the F₂ and F₇ RILs showed that 2 recessive genes that were temporarily named trp-1 and trp-2 conferred APR in Toropi. In the present study, we used monosomic families and amplified fragment length polymorphism (AFLP), sequence-tagged site, and simple sequence repeat (SSR) markers to map trp-1 and trp-2 on wheat chromosomes. Analysis of the F₂ monosomic RIL showed that trp- 1 and trp-2 were located on chromosomes 1A and 4D, respectively. AFLP analysis of the F₇ RIL identified 2 independent AFLP markers, XPacgMcac3 and XPacgMcac6, which were associated with Toropi APR. These markers explained 71.5% of the variation in the phenotypic data in a multiple linear regression model. The AFLP markers XPacg/ Mcac3 and XPacg/Mcac6 were anchored by SSR markers previously mapped on the short arms of chromosomes 1A (1AS) and 4D (4DS), respectively. The trp-2 gene is the first leaf rust resistance gene mapped on wheat chromosome 4DS. The mapping of trp-1 and trp-2 provides novel and valuable information that could be used in future studies involving the fine mapping of these genes, as well as in the identification of molecular markers that are closely related to these genes for marker-assisted selection of this important trait in wheat.
叶锈病是影响全球小麦的最具破坏性的病害之一。控制该病最有效的方法是使用抗病品种。基于慢锈性成株抗性（APR）基因的抗性已被证明是培育具有持久抗性品种的最佳方法。巴西小麦品种托罗皮（Toropi）是叶锈病慢锈性APR的一个来源。托罗皮/IAC 13 F₂和F₇重组自交系（RIL）是在先前的研究中培育出来的。对F₂和F₇ RIL的表型分析表明，两个暂时命名为trp - 1和trp - 2的隐性基因赋予了托罗皮慢锈性APR。在本研究中，我们使用单体家系以及扩增片段长度多态性（AFLP）、序列标签位点和简单序列重复（SSR）标记将trp - 1和trp - 2定位到小麦染色体上。对F₂单体RIL的分析表明，trp - 1和trp - 2分别位于1A和4D染色体上。对F₇ RIL的AFLP分析鉴定出两个独立的AFLP标记，XPacgMcac3和XPacgMcac6，它们与托罗皮的慢锈性APR相关。在多元线性回归模型中，这些标记解释了表型数据中71.5%的变异。AFLP标记XPacg/ Mcac3和XPacg/Mcac6分别由先前定位在1A染色体短臂（1AS）和4D染色体短臂（4DS）上的SSR标记锚定。trp - 2基因是第一个定位在小麦4DS染色体上的叶锈病抗性基因。trp - 1和trp - 2的定位提供了新的有价值的信息，可用于未来涉及这些基因精细定位的研究，以及用于鉴定与这些基因密切相关的分子标记，以便在小麦中对这一重要性状进行标记辅助选择。
