Haynaldia villosa is a wild relative of wheat and a valuable gene resource for wheat improvement.Owing to the limited number of probes available for fluorescence in situ hybridization(FISH),the resolution at which the karyotype of H.villosa can be characterized is poor,hampering accurate characterization of small segmental alien introgressions.We designed ten oligonucleotide probes using tandem repeats in DNA sequences derived from the short arm of H.villosa chromosome 6 V(6 VS).FISH with seven of them resulted in clear signals on H.villosa chromosomes.Using these,we constructed FISH karyotypes for H.villosa using oligo-6 VS-1 and oligo-6 VS-35 oligonucleotides and characterized the distribution of the two probes in five different H.villosa accessions.The new FISH probes can efficiently characterize H.villosa introgressions into wheat.
Haynaldia villosa(L.)Schur(syn.Dasypyrum villosum(L.)Candargy)(2n=14,genome VV),a wild relative of wheat,is an important gene pool for improving wheat quality and disease resistance.Several genes found in H.villosa have been transferred into wheat to improve wheat resistance by the development of alien translocation lines.The seed storage protein loci on chromosome
EST-PCR based molecular markers specific for alien chromosomes are not only useful for the detection of the introgressed alien chromatin in the wheat background,but also provide evidence of the syntenic relationship between homoeologous chromosomes.In the present study,in order to develop high density and evenly distributed molecular markers on chromosome4V of Haynaldia villosa,a total of 607 primer pairs were designed according to the EST sequences,which were previously located in 23 different bins of wheat chromosomes 4A,4B and 4D.By using the Triticum durum-H.villosa amphiploid and T.aestivum-H.villosa alien chromosome lines involving chromosome 4V,it was found that 9.23%of the tested primers could amplify specific bands for chromosome 4V.Thirty and twenty-six specific markers could be assigned to chromosome arms4VS and 4VL,respectively.These 4V specific markers provided efficient tools for the characterization of structural variation involving the chromosome 4V as well as for the selection of useful genes located on chromosome 4V in breeding programs.
Expressed sequence tags-derived polymerase chain reaction(EST-PCR) molecular markers specific for alien chromosomes can be used to not only monitor the introgressed alien chromatin in wheat background, but also provide the evidence of the syntenic relationship between homoeologous chromosomes. In the present study, in order to develop high density and evenly distributed molecular markers specific for chromosome 6 VL of Dasypyrum villosum, 297 primer pairs were designed based on the expressed sequence tags(EST) sequences, which were previously mapped in different bins of the long arms of wheat homoeologous 6 AL, 6 BL, and 6 DL. By using the Triticum aestivum, D. villosum, T. durum-D. villosum amphiploid, and T. aestivum-D. villosum alien chromosome lines involving chromosome 6 V, it was found that 32(10.77%) primers could amplify specific bands for chromosome 6 V, and 31 could be allocated to chromosome arm 6 VL. These 6 VL specific markers provided efficient tools for the characterization of structural variation involving the chromosome 6 VL in common wheat background as well as for the selection of useful genes located on 6 VL in breeding programs.
