小麦品系西农1163-4抗叶锈病基因的遗传分析和分子作图

Genetic Analysis and Molecular Mapping of Leaf Rust Resistance Gene in Wheat Line Xinong 1163-4

【目的】小麦品系西农1163-4高抗小麦叶锈、条锈和白粉病,综合农艺性状良好。明确该小麦品系中所含的抗叶锈病基因及遗传特点,找到与其紧密连锁的分子标记,有利于抗病基因利用和培育抗病新品种。【方法】将西农1163-4与感病品种Thatcher杂交,获得F1、F2代群体,利用中国叶锈菌优势小种THTT进行苗期抗性鉴定和抗性遗传分析;采用SSR技术对西农1163-4所携带的抗叶锈基因进行分子标记研究,共筛选了1 273对SSR引物。【结果】小麦品系西农1163-4对多个叶锈菌小种具有良好的抗病性,对THTT的抗性是由1个显性基因控制,该基因暂命名为LrXi。获得了与LrXi紧密连锁的3个微卫星分子标记Xbarc8、Xgwm582、Xwmc269和1个STS标记(ω-secali/Glu-B3),将LrXi定位于小麦1BL染色体上。距离最近的2个微卫星位点是Xgwm582、Xbarc8,与抗叶锈基因间的遗传距离分别为2.3 cM和3.2 cM。【结论】LrXi位于1BL染色体,抗叶锈表现不同于所有已知抗叶锈病基因,该基因的发现将有利于丰富中国抗叶锈病基因资源,为培育持久抗病品种奠定基础。

【Objective】 Xinong 1163-4 is a wheat line with high resistance to wheat leaf rust,stripe rust and powdery mildew.Identification of new leaf rust resistance gene and its closely linked molecular markers in Xinong 1163-4 will be of benefit to the use of the resistance gene and breeding new resistant cultivars.【Method】 F1 and F2 populations from the cross Xinong 1163-4/Thatcher were inoculated with the prevalent Chinese pathotype THTT in a greenhouse.A total of 1 273 SSR primers were used to test the parents and resistant and susceptible bulks.【Result】 Xinong 1163-4 gave low infection types to most of the Chinese current leaf rust pathotypes.Three SSR markers（Xbarc8,Xgwm582 and Xwmc269） and one STS marker（ω-secali/Glu-B3） on chromosome 1B were polymorphic between the two parents as well as resistant and susceptible bulks.The resulted four polymorphic markers were used for genotyping F2 population.Results indicated that Xinong 1163-4 carries a single dominant resistance gene,temporarily designated LrXi,located on 1BL and closely linked to SSR loci Xgwm582 and Xbarc8,with genetic distances of 2.3 and 3.2 cM,respectively.【Conclusion】 LrXi was located on 1BL and its seedling reaction pattern was different from all known leaf rust resistance genes on 1B.The discovery of LrXi will be beneficial to enrich gene resources of wheat leaf rust resistance in China and lay a foundation for breeding cultivars with durable leaf rust resistance.