小麦品系M8003-5抗条锈病基因遗传分析和分子作图

Genetic Analysis and Molecular Mapping of Stripe Rust Resistance Gene in Wheat Line M8003-5

为了利用小麦抗条锈病品系M8003-5中的抗病基因,用当前7个流行的条锈菌生理小种对小麦品系M8003-5的抗条锈性进行了鉴定,发现该品种对当前的各优势小种均有良好抗性。在温室内以病菌小种Su11-4对M8003-5在进行苗期抗条锈性鉴定和遗传分析,初步确定M8003-5对Su11-4的抗性由1对显性基因控制,位于7DS上的SSR标记Xbarc5、Xwmc463、Xwmc405、Xbarc126、Xgwm295、Xgwm44、Xwmc702、Xwmc438、Xwmc121、Xgwm111和Xbarc121与该基因连锁,最近的为Xwmc702和Xwmc438,遗传距离分别为3.5 cM和4.3 cM。分子标记及其相关分析表明,此基因可能来自黑麦,与已定位于7D染色体上的抗病基因不同,暂命名为YrM8003。利用与其紧密连锁的标记Xwmc702和Xwmc438测黄淮麦区43个主栽品种,结果显示,有20%的品种具有与YrM8003基因相同的标记位点。这一结果有助于YrM8003在抗条锈病育种的应用。

Strip rust,caused by Puccinia striiformis West.f.sp.tritici（Pst） is a worldwide disease in wheat（Triticum aestivum L.） production.Resistance breeding is constantly pursued for decades to tackle the variations of prevalent Pst races.Wheat genetic resources carrying novel resistance genes always receive great attentions and the utilization study generally initiates from the identification and genetic analysis of the resistance genes.Wheat line M8003-5 is selected from the hybrid progenies of the com-mon wheat variety Chinese Spring and Secale cereale L.,which exhibits not only high resistance to Pst but also high yield,early maturity,and resistance to drought.To map the Pst resistance gene（s） in M8003-5,a segregation population was constructed by crossing M8003-5 and a highly susceptible variety Mingxian 169.Seven prevalent Pst races in China were inoculated in green-house at seedling stage to evaluate the infection type of individuals from the F1,F2,and F3 generations.The results showed that M8003-5 was resistant to all races,whereas Mingxian 169 was highly susceptible to all inoculates.Genetic analysis indicated that the resistance of M8003-5 against race Su11-4 was conferred by a dominant gene,which was tentatively designated YrM8003.This gene was linked to simple sequence repeat（SSR） markers Xbarc5,Xwmc463,Xwmc405,Xbarc126,Xgwm295,Xgwm44,Xwmc702,Xwmc438,Xwmc121,Xgwm111,and Xbarc128,which were all located on chromosome arm 7DS.The closest flanking makers were Xwmc702 and Xwmc438 with genetic distances of 3.5 cM and 4.3 cM,respectively.Gene YrM8003 differs from any other Pst resistance genes on 7DS,and is probably a novel gene.This gene is primarily inferred to originate from S.cereale based on analyses on pedigree and molecular markers data.Forty-three wheat cultivars from Huang-Huai Winter Wheat Region were also tested with YrM8003 markers Xwmc702 and Xwmc438,and 20% cultivars were amplified with the target bands.These culti-vars require further tests to validate the presence of YrM8003.