International Maize and Wheat Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico, D.F., Mexico.
Theor Appl Genet. 2011 Jan;122(1):239-49. doi: 10.1007/s00122-010-1439-x. Epub 2010 Sep 17.
The common wheat genotype 'RL6077' was believed to carry the gene Lr34/Yr18 that confers slow-rusting adult plant resistance (APR) to leaf rust and stripe rust but located to a different chromosome through inter-chromosomal reciprocal translocation. However, haplotyping using the cloned Lr34/Yr18 diagnostic marker and the complete sequencing of the gene indicated Lr34/Yr18 is absent in RL6077. We crossed RL6077 with the susceptible parent 'Avocet' and developed F(3), F(4) and F(6) populations from photoperiod-insensitive F(3) lines that were segregating for resistance to leaf rust and stripe rust. The populations were characterized for leaf rust resistance at two Mexican sites, Cd. Obregon during the 2008-2009 and 2009-2010 crop seasons, and El Batan during 2009, and for stripe rust resistance at Toluca, a third Mexican site, during 2009. The F(3) population was also evaluated for stripe rust resistance at Cobbitty, Australia, during 2009. Most lines had correlated responses to leaf rust and stripe rust, indicating that either the same gene, or closely linked genes, confers resistance to both diseases. Molecular mapping using microsatellites led to the identification of five markers (Xgwm165, Xgwm192, Xcfd71, Xbarc98 and Xcfd23) on chromosome 4DL that are associated with this gene(s), with the closest markers being located at 0.4 cM. In a parallel study in Canada using a Thatcher × RL6077 F(3) population, the same leaf rust resistance gene was designated as Lr67 and mapped to the same chromosomal region. The pleiotropic, or closely linked, gene derived from RL6077 that conferred stripe rust resistance in this study was designated as Yr46. The slow-rusting gene(s) Lr67/Yr46 can be utilized in combination with other slow-rusting genes to develop high levels of durable APR to leaf rust and stripe rust in wheat.
普通小麦基因型“RL6077”被认为携带 Lr34/Yr18 基因，该基因赋予其对叶锈病和条锈病的慢锈性成株期抗性（APR），但通过染色体间相互易位定位在不同的染色体上。然而，利用克隆的 Lr34/Yr18 诊断标记进行单倍型分析和基因的完整测序表明，RL6077 中不存在 Lr34/Yr18。我们将 RL6077 与易感亲本“Avocet”杂交，并从光周期不敏感的 F3 系中开发出 F(3)、F(4)和 F(6)群体，这些系在叶锈病和条锈病的抗性方面存在分离。这些群体在两个墨西哥地点进行了叶锈病抗性鉴定，即在 2008-2009 和 2009-2010 作物季节的 Cd. Obregon 以及 2009 年的 El Batan；在托卢卡的第三个墨西哥地点进行了条锈病抗性鉴定，该地点在 2009 年进行了鉴定。F(3)群体还在 2009 年澳大利亚的 Cobbitty 进行了条锈病抗性鉴定。大多数系对叶锈病和条锈病表现出相关的反应，表明相同的基因或紧密连锁的基因赋予了对这两种疾病的抗性。利用微卫星进行分子作图导致在 4DL 染色体上鉴定出与该基因相关的五个标记（Xgwm165、Xgwm192、Xcfd71、Xbarc98 和 Xcfd23），最近的标记位于 0.4 cM 处。在加拿大使用 Thatcher×RL6077 F(3)群体进行的平行研究中，将相同的叶锈病抗性基因命名为 Lr67，并将其映射到相同的染色体区域。在本研究中赋予条锈病抗性的来自 RL6077 的多效性或紧密连锁基因被命名为 Yr46。慢锈性基因 Lr67/Yr46 可与其他慢锈性基因结合，在小麦中开发出高水平的持久 APR 对叶锈病和条锈病。
