State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
National Engineering Laboratory for Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Theor Appl Genet. 2021 Aug;134(8):2469-2479. doi: 10.1007/s00122-021-03836-9. Epub 2021 May 13.
Powdery mildew resistance gene MlIW39, originated from wild emmer wheat accession IW39, was mapped to a 460.3 kb genomic interval on wheat chromosome arm 2BS. Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is destructive disease and a significant threat to wheat production globally. The most effective way to control this disease is genetic resistance. However, when resistance genes become widely deployed in agriculture, their effectiveness is compromised by virulent variants that were previously minor components of the pathogen population or that arise from mutation. This necessitates continual search for new sources of resistance in both wheat and its near relatives. In this study, we produced a common wheat line 8D49 (87-1/IW39//2*87-1), which has all-stage immunity to Bgt isolate E09 and many other Chinese Bgt isolates, by transferring powdery mildew resistance from Israeli wild emmer wheat (WEW) accession IW39 to the susceptible common wheat line 87-1. Genetic analysis indicated that the powdery mildew resistance in 8D49 was controlled by a single dominant gene, temporarily designated MlIW39. Genetic linkage analyses with molecular markers showed that MlIW39 was located in a 0.7 cm genetic region between markers QB-3-16 and 7Seq546 on the short arm of chromosome 2B. Fine mapping using three large F populations delimited MlIW39 to a physical interval of approximately 460.3 kb region in the WEW reference genome (Zavitan v1.0) that contained six annotated protein-coding genes, four of which had gene structures similar to known disease resistance genes. This provides a foundation for map-based cloning of MlIW39. Markers 7Seq622 and 7Seq727 co-segregating with MlIW39 can be utilized for marker-assisted selection in further genetic studies and wheat breeding.
粉状锈病抗性基因 MlIW39 来源于野生二粒小麦品系 IW39，被定位到小麦 2BS 染色体臂上的一个 460.3 kb 基因组区间。由禾本科布氏白粉菌引起的小麦白粉病是一种破坏性疾病，也是全球小麦生产的重大威胁。控制这种疾病的最有效方法是遗传抗性。然而，当抗性基因在农业中广泛应用时，它们的有效性会受到以前是病原体种群中次要成分的毒力变体或突变产生的变体的影响。这就需要在小麦及其近缘种中不断寻找新的抗性来源。在这项研究中，我们通过将来自以色列野生二粒小麦（WEW）品系 IW39 的抗白粉病性转移到易感普通小麦品系 87-1 上，培育出了对 Bgt 分离物 E09 和许多其他中国 Bgt 分离物具有全生育期抗性的普通小麦品系 8D49。遗传分析表明，8D49 中的白粉病抗性由一个单一显性基因控制，暂时命名为 MlIW39。利用分子标记进行的遗传连锁分析表明，MlIW39 位于染色体 2B 短臂上标记 QB-3-16 和 7Seq546 之间的 0.7 cm 遗传区域。利用三个大 F 群体进行的精细定位将 MlIW39 限定在 WEW 参考基因组（Zavitan v1.0）中大约 460.3 kb 的物理区间内，该区间包含六个注释的蛋白质编码基因，其中四个具有与已知抗病基因相似的基因结构。这为 MlIW39 的基于图谱的克隆提供了基础。与 MlIW39 共分离的标记 7Seq622 和 7Seq727 可用于进一步遗传研究和小麦育种中的标记辅助选择。
