| Wheat yellow dwarf disease (WYD) is one of the most serious diseases of cereals worldwide.It is caused by barley yellow dwarf virus, which was spreaded by aphids and often causes serious yield loss. Thinopyrum intermedium, a wheatgrass, shows a high level of resistance to BYDV The wheatgrass possesses three resistance genes which locate on the 7St. 7E and 2Ai-2 chromosomes in Thirropyrum intermedium. A resistance gene from 7St chromosome was designated as Bdv2. Researchers crossed the wheatgrass to wheat to obtain a series of virus-resistant wheat translocation lines which carries Bdv2, for example, HW642. In order to detection and trackingWild-hybridization t introgression into wheat bankgroud alive chromosome, used disomic addition/ translocation lines and the parental materials which contain alive chromosome as template, On the basis of the BLAST information on 90 wESTs mapped on the bin 7DL3-0.82-1.00,development of the specific EST-PCR markers for alive wheat chromosome , To effectively tracking and detection of homologous with wheat seventh linked to the yellow dwarf marker genes, in this study we designed 75 pairs of EST primers which derived from ESTs allocated on wheat group 7 chromosomes. 75 wheat EST sequences located in the distal region of 7DL were explored to identify specific PCR markers for the Bdv2 region on the basis of the homoeologous relationship between wheat chromosome 7D and Th.intermedium chromosome7Ai#1.These markers show polymorphism in 3 levels: AGE-PAGE-SSCP and could be classified into 2 types: simple polymorphism and Acomplex polymorphism. amplified successfully and 14 (with a yield rate18.7%)7XL specific EST-PCR markers. These EST-PCR markers could distinguish Bdv2 from another BYDV-resistance gene located on Th.intermedium chromosome 2Ai-2. These specific bands for the Bdv2 region were further cloned and sequenced. The sequencing analysis indicated that the specific sequences for the Bdv2 region were highly homologous with the original wheat EST sequences that were used to design primers, and encode respectively a protein kinase, P450, centrin, transducin, and a hypothetical protein.However, the results showed that the alien Bdv2 region segment could not recombine with the homoeologous wheat chromosome segment in the F2 population and all the EST-PCR markers co-segregated with the Bdv2 region, it is necessary for genetic mapping of Bdv2 to develop an idea mapping population, in which some recombinants can occur. This test method is obtained by using two kinds of induced mutations in this paper , one kinds is EMS was used as chemical mutagen to build the mutant library with wheat translocation lines HW642 Another kind of 60Co-γradiation mutagenesis HW642 wheat before flowering period female gamete (2 ~ 3 days) after radiation with common wheat hybrid, Aphids infected with the BYDV-GAV serotype were used to inoculate the wheat M2 generation.mutant seedlings in the field, Biological characters and agronomic investigated in M2 generation. Some of susceptible mutants identified from M2 plants will be validated , The rate of EMS M2 phenotype mutation was 13.7%,on the molecular level , The rate of M2 detection mutation was 7.3%, thus ,the rate of 60Co-γM2 phenotype mutation was 10.7%,on the molecular level , The rate of M2 detection mutation was 58.3%。The two libraries of induced with EMS and 60Co-γare ideal mutant library and it will be efficiently used in wheat functional genomic research and wheat improvement.
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