来自野生二粒小麦的抗白粉病基因PmAS846及其染色体定位和分子标记分析

N9738是经抗性定向选择和农艺性状筛选所培育的抗白粉病普通小麦新种质，携带来自野生二粒小麦As846的抗白粉病基因PmAS846，在苗期和成株期高抗白粉菌生理小种E09和陕西关中地区流行菌系，本研究对该种质携带的抗白粉病基因进行了染色体定位和分子标记分析。对N9738和高感小麦白粉病的普通小麦品种辉县红杂交的F₁、F₂代分离群体和F_2:3代家系进行白粉病抗性鉴定和遗传分析证实，N9738苗期抗性由1个显性抗白粉病基因控制，单(缺)体分析将该基因定位在小麦5B染色体上。采用位于5B染色体的分子标记结合集群分离分析法(BSA法)分析，筛选出与PmAS846连锁的11个SSR标记和2个EST-STS标记，PmAS846两翼的SSR标记Xgwp3191和Xfcp1与该基因的遗传距离分别为7.3 cM和1.8 cM，EST-STS标记BF202652和BF482522与该基因的遗传距离均为5.1 cM。根据该基因两翼SSR标记对中国春5B染色体缺失系(Bin系)的分析将其定位在5B染色体长臂0.75~0.76区域。研究结果为PmAS846的分子标记辅助选择和精细定位奠定了基础。

Chromosome Location and Molecular Mapping of Powdery Mildew Resistance Gene PmAS846 Originated from Wild Emmer (Triticum turgidum var. dicoccoides)

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most important diseases of wheat (Triticum aestivum L.) worldwide. Wheat relativesare important donors of resistance genes against this disease in wheat breeding program. The common wheat line N9738 is highly resistant to Bgt isolate E09 and Shaanxi prevailing races at both seedling and adult plant stages. The PmAS846 gene in line N9738 was derived from wild emmer (Triticum turgidum var. dicoccoides) accession As846. Genetic analysis of an F₂ population and their F₃ families, developed from the cross between N9738 and a susceptible common wheat cultivar Huixianhong, indicated that N9738 carries one dominant resistance gene. A set of common wheat nullisomic (monosomic) lines were used to analyze the chromosomal location of PmAS846. The results revealed that PmAS846 was located on wheat chromosome 5B. Microsatellite markers on wheat chromosome 5B were used to map the gene using bulked segregant analysis. Eleven microsatellite markers were used to construct a linkage map for the gene, and two markers, Xgpw3191 and Xfcp1, ?anking PmAS846 location at 7.3 and 1.8 cM, respectively. Amplification of 5B chromosome deletion lines of Chinese Spring with the flanking markers mapped PmAS846 on chromosome 5BL bin 0.75–0.76. Based on expressed sequence tags (ESTs) information mapped on chromosome 5BL bin 0.75–0.76, we identified EST-derived sequence tagged site (STS) markers BF202652 and BF482522 to be closely linked to PmAS846 with genetic distance of 5.1 cM both. These markers can be used in fine mapping of PmAS846 and marker-assisted selection.