来自西尔斯山羊草的抗小麦白粉病基因Pm57抗性丧失突变体的筛选与鉴定

小麦近缘种属来源的抗白粉病基因是培育小麦抗病品种,防治白粉病危害的最重要基因来源。Pm57是位于西尔斯山羊草2S^s#l染色体长臂上的一个外源基因,对小麦白粉病具有苗期和成株期广谱抗性。为了创制Pm57白粉病抗性丧失突变体,利用基于基因突变体的植物抗病基因克隆新兴技术分离Pm57基因,选用0.625%的甲基磺酸乙酯(EMS)对1万粒小麦-西尔斯山羊草Pm57易位系89(5)69种子进行了诱变处理,M1大田密播种植,收获了1598个M2可育株系。初步对其中300个M2株系进行苗期白粉病抗性接种鉴定,并利用2个Pm57基因特异分子标记X2L4g9P4/HaeⅢ和X284274及小麦全国区试品系DUS测试所用的42对SSR核心引物对Pm57抗性丧失突变体进行鉴定,筛选出来自27个M2株系的真实抗性丧失突变体70个,Pm57基因抗性丧失突变体频率达到9.0%。本研究所获得的白粉病抗性丧失突变体为Pm57基因的后续克隆与抗白粉病分子机理研究提供了重要的材料基础。

Screening and Identification of Pm57 Mutants with Loss of Resistance to Powdery Mildew Derived from Aegilops searsii

Wheat relatives-derived alien genes provide most important resource to develop resistant varieties and protect wheat from the damage of powdery mildew.Pm57,a gene resided on the long arm of chromosome 2 Ss#1 from Aegilops searsii caused broad-spectrum resistance against powdery mildew isolates at seedling and adult plant stage.In order to develop Pm57 mutants with loss of resistance to powdery mildew for further gene isolation using susceptible mutant-based resistant gene cloning approache,10000 seeds of 89(5)69,a wheat-Ae.searsii recombinant stock containing Pm57 genes,were treated using 0.625%ethyl methane sulfonate(EMS).M1 seeds were then dense sowed in experiment station,and 1598 M2 lines were harvested.Of which 300 M2 lines randomly selected were used for resistance test by inoculation at seedling stage.After further validation of susceptible individual plants using two Pm57 specific molecular markers(X2L4g9P4/HaeⅢand X284274)and 42 pairs of core primers,which are applied in DUS identification of wheat lines,70 Pm57 mutants with loss of resistance to powdery mildew from 27 independent M2 lines were identified,with a mutant ratio as high as 9.0%.Thus,the newly-identified resistance-compromised mutants might lay a foundation for further cloning of the Pm57 gene.