从野生二粒小麦导入普通小麦的抗白粉病基因MlWE18分子标记定位

野生二粒小麦(Triticum turgidumvar. dicoccoides)是小麦抗白粉病遗传改良的重要基因资源。利用野生二粒小麦WE18与普通小麦品种(系)连续多次杂交和自交，育成对白粉病菌生理小种E09高度抵抗的小麦新品系3D249(京双27//燕大1817/WE18/3/温麦4，F₇)。利用高感白粉病品系薛早和3D249组配杂交组合，获得杂种F₁代、F₂分离群体和F₃代家系，进行苗期白粉病抗性鉴定和遗传分析。结果表明，小麦品系3D249对E09小种的抗性受显性单基因控制，暂命名该基因为MlWE18。利用集群分离分析法(BSA)和分子标记分析，发现4个简单重复序列(SSR)标记(Xwmc525、Xwmc273、Xcfa2040和Xcfa2240)、1个EST-STS标记(Xmag1759)和1个EST-STS序列标记(XE13-2)与抗白粉病基因MlWE18连锁，在遗传连锁图谱上的顺序为Xwmc525–Xcfa2040–Xwmc273–XE13-2–Xmag1759–MlWE18–Xcfa2240。SSR标记的染色体缺失系物理定位结果表明，抗白粉病基因MlWE18位于小麦7A染色体长臂末端的Bin 7AL 16–0.85–1.00。与已知定位于该染色体区域的Pm基因遗传连锁图谱比较表明，MlWE18与抗白粉病基因Pm1、MlIW72、PmU、Mlm2033和Mlm80均位于7AL相同染色体区段。

Molecular Mapping of Powdery Mildew Resistance Gene MlWE18 in Wheat Originated from Wild Emmer (Triticum turgidum var. dicoccoides)

Wild emmer (Triticum turgidum var. dicoccoides) is an important germplasm for wheat improvement especially for resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. Common wheat line 3D249 (Jingshuang 27//Yanda 1817/WE18/3/Wenmai 4, F₇), a derivative of wild emmer accession WE18 and susceptible elite common wheat lines, was found highly resistant to prevailing powdery mildew isolate E09 at both seedling and adult plant stages in Beijing, China. Genetic analyses of the F₁, F₂ segregating population and their F₃ progenies derived from a cross between susceptible line Xuezao and resistant line 3D249 indicated that the powdery mildew resistance of line 3D249 was controlled by a single dominant gene, temporarily designated MlWE18. By bulked segregant analysis (BSA), four SSR markers (Xwmc525, Xwmc273, Xcfa2040, and Xcfa2240), one RFLP-derived STS marker (Xmag1759) and one EST-STS marker (XE13-2) were found to be linked to MlWE18, with an order of Xwmc525–Xcfa2040–Xwmc273–XE13-2–Xmag1759–MlWE18–Xcfa2240 in the genetic linkage map. Using Chinese Spring nullisomic-tetrasomics, ditelosomics, and deletion lines, MlWE18 was physically mapped on chromosome 7AL terminal bin 7AL 16–0.85–1.00. However, the allelism of wild emmer derived MlWE18 to known powdery mildew resistance genes Pm1, PmU, MlIW72, Mlm2033, and Mlm80, all located on the same chromosome bin, need to be characterized in the future. The common wheat powdery mildew resistance line 3D249 provides useful new germplasm for disease resistance genes pyramiding and marker-assisted selection (MAS) in wheat breeding program.