School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, 141004, India.
Theor Appl Genet. 2012 Apr;124(6):1051-8. doi: 10.1007/s00122-011-1768-4. Epub 2011 Dec 24.
Powdery mildew (PM) caused by Blumeria graminis f. sp. tritici (Bgt), is one of the important foliar diseases of wheat that can cause serious yield losses. Breeding for cultivars with diverse resources of resistance is the most promising approach for combating this disease. The diploid A genome progenitor species of wheat are an important resource for new variability for disease resistance genes. An accession of Triticum boeoticum (A(b)A(b)) showed resistance against a number of Bgt isolates, when tested using detached leaf segments. Inheritance studies in a recombinant inbred line population (RIL), developed from crosses of PM resistant T. boeoticum acc. pau5088 with a PM susceptible T. monococcum acc. pau14087, indicated the presence of two powdery mildew resistance genes in T. boeoticum acc. pau5088. Analysis of powdery mildew infection and molecular marker data of the RIL population revealed that both powdery mildew resistance genes are located on the long arm of chromosome 7A. Mapping was conducted using an integrated linkage map of 7A consisting of SSR, RFLP, STS, and DArT markers. These powdery mildew resistance genes are tentatively designated as PmTb7A.1 and PmTb7A.2. The PmTb7A.2 is closely linked to STS markers MAG2185 and MAG1759 derived from RFLP probes which are linked to powdery mildew resistance gene Pm1. This indicated that PmTb7A.2 might be allelic to Pm1. The PmTb7A.1, flanked by a DArT marker wPt4553 and an SSR marker Xcfa2019 in a 4.3 cM interval, maps proximal to PmT7A.2. PmTb7A.1 is putatively a new powdery mildew resistance gene. The powdery mildew resistance genes from T. boeoticum are currently being transferred to cultivated wheat background through marker-assisted backcrossing, using T. durum as bridging species.
小麦白粉病（PM）由禾谷布氏白粉菌（Bgt）引起，是小麦叶片的重要病害之一，可导致严重的产量损失。培育具有多种抗性资源的品种是防治该病的最有前途的方法。小麦的二倍体 A 基因组祖先是抗病基因新变异的重要资源。当使用离体叶片片段测试时，小麦的一个 Triticum boeoticum（A(b)A(b)）品系对许多 Bgt 分离物表现出抗性。来自对 PM 有抗性的 T. boeoticum 品系 pau5088 与对 PM 敏感的 T. monococcum 品系 pau14087 杂交而开发的重组自交系群体（RIL）的遗传研究表明，T. boeoticum 品系 pau5088 中存在两个白粉病抗性基因。对 RIL 群体的白粉病感染和分子标记数据的分析表明，这两个白粉病抗性基因都位于 7A 染色体的长臂上。作图使用由 SSR、RFLP、STS 和 DArT 标记组成的 7A 综合连锁图谱进行。这些白粉病抗性基因暂定为 PmTb7A.1 和 PmTb7A.2。PmTb7A.2 与来自 RFLP 探针的 STS 标记 MAG2185 和 MAG1759 紧密连锁，这些探针与白粉病抗性基因 Pm1 连锁。这表明 PmTb7A.2 可能与 Pm1 等位。PmTb7A.1 位于 DArT 标记 wPt4553 和 SSR 标记 Xcfa2019 之间，相距 4.3 cM，靠近 PmT7A.2。PmTb7A.1 是一个新的白粉病抗性基因。目前正在通过标记辅助回交将来自 T. boeoticum 的白粉病抗性基因转移到栽培小麦背景中，使用 T. durum 作为桥梁物种。
