中文摘要：

来源于长穗偃麦草的基因Lr24对小麦叶锈病具有很高的抗性,本研究旨在开发用于Lr24基因分子标记辅助育种的新的分子标记。从定位于小麦3D染色体的22对SSR、EST-SSR引物中筛选出4对揭示TcLr24多态性的引物,用468株F2抗感群体对这4对引物进一步检测,得到1个与Lr24共分离的EST-SSR标记Xcwem17。对该标记进行测序,并设计了STS引物。用该STS引物及已知的Lr24SCAR引物对试验群体进行验证,两对引物在该F2群体中均表现共分离,且Xcwem17可在TcLr24单基因系和已知含Lr24的农家品种泰山1号中可扩增出180bp单一条带,感病对照及其余7个近等基因系无扩增。该EST-SSR标记可直接用于分子标记辅助选择。

英文摘要：

Wheat （Triticum aestivum L.） leaf rust, caused by Puccinia triticina （formerly P. recondita f. sp. tritici）, is one of the most destructive diseases on wheat production throughout the world. The use of resistant varieties is an economical, efficient and environmental-friendly way for minimizing the losses caused by wheat leaf rust. To date, about 90 leaf rust resistance genes have been found or identified in wheat and its relatives. The resistance gene Lr24, derived from Thinopyrum ponticum （2n = 70）, confers very strong resistance to wheat leaf rust. Eight molecular markers of Lr24 have been developed, however more markers are needed for identifying and mapping the gene. In the present study, Xcweml7 was discovered as a new EST-SSR marker of Lr24 with the susceptible line Thatcher and 468 individuals of F2 progeny derived from a cross between TcLr24 and Thatcher. The wheat seedlings of parents and Fz generation were inoculated solely with leaf rust spores, and cultured in greenhouse at （20±5）℃. The infection types （IT） of all plant materials were scored in six grades with Roelfs＇s system at the 14th day after inoculation. Twenty-two pairs of SSR and EST-SSR primer on wheat chromosome 3D were used to tag the resistance gene Lr24. One of the four polymorphism pdrners co-segregated with Lr24 was acquired after testing with 468 F2 individuals. Sequence analysis showed that Xcweml7 was 223 bp, in which from the 7th to 220th bp （coding 71 amino acid residues） showed 36% identity to a poly-protein gene of rice chromosome 5. The marker Xcweml7 was further converted into a STS marker, and tested together with a reported SCAR marker in the same population. The results showed that they both co-segregated with Lr24, and could amplify a single 310-bp （SCAR marker） or 180-bp （STS marker） band only in TcLr24 and Taishan 1 （a landrace carried Lr24）. It suggests that the STS marker developed in the study can be used in MAS directly.