Development Of E-chromosome Specific SCAR Markers For Thinopyrum Elongatum In Chinese Spring Wheat Background

A large portion of genomes are repeat sequence in Eukaryotes, such as the Triticeae, more than70percent of the genomic DNA is repeated sequence, and plenty of repeat DNA sequences are scattered in the genome. The copy number or insert position of repeat DNA sequence will change in the evolutionary process, compared with the highly conservativethe of single copy and low copy number DNA in different species, it can produce more genetic variation, so that can be species or chromosome specificity. These repeat DNA sequences can be very useful tools in species genome evolution, biodiversity research, genetic mapping and distant hybridization descendants of heterologous genetic material inspection. Diploid species of Thinopyrum elongatum is one of the valuable relatives for wheat quality and yielding improvement, the resistance of wheat scab attention by researchers especially. For better utilization of the genes or superior characters deposited in Thinopyrum elongatum species, wheat-Thinopyrum elongatum disomic additional and substitution lines have been obtained through cross between wheat and Thinopyrum elongatum. However, the markers for detection and tracking of alien genetic material of Thinopyrum elongatum were very limited and thus impeded us better to use these plant resources in wheat breeding. This study uses ISSR/IRAP/REMAP to screen E-chromosome specific DNA fragments of Thinopyrum elongatum, and then turn the DNA sequence into specific SCAR marks. These markers can be used to detect the Thinopyrum elongatum chromatin in wheat background, also can used for the wheat-Thinopyrum elongatum translocation line, provide fast and convenient new ways for detecting foreign genetic material in wheat breeding. The results were as follows:1. Development of E-chromosome specific SCAR markers for Thinopyrum elongatum11primers combined into35primer combinations were used to screen Triticum aestivum cv. Chinese Spring, Thinopyrum elongatum and Chinese Spring-Thinopyrum elongatum disomic additional lines for development of E-chromosome specific molecular markers of Thinopyrum elongatum. It was showed that45fragments which were specific for1E to7E except2E chromosome were obtained. The specific fragments distributed in1E,3E,4E,5E,6E and7E chromosomes were6,3,8,11,8and9. respectively, These specific fragments were cloned and sequenced, and then the sequencing results are blastxed with wheat in GenBank NCBI. Design PCR primers for those fragments without wheat homologous sequence, using Chinese spring, Thinopyrum elongatum and Chinese Spring-Thinopyrum elongatum disomic additional and substitutional lines for PCR reaction. Amplification fragments which numbers for Z34-1E200, Z8-4E374, Z17-6E199and Z31-7E215only appeared in Thinopyrum elongatum and Chinese Spring-Thinopyrum elongatum disomic additional and substitutional lines is consistent with the theoretical size. Which means the4E-chromosome specific segments that located in1E chromosome (Z34-1E200),4E chromosome (Z8-4E374),6E chromosome (Z17-6E199) and7E chromosome (Z31-7E215) can be converted to corresponding chromosomes specific SCAR marks. Then we used Z31-7E215to screen7ES and7EL ditelesomic additional lines, it only existed in7EL ditelesomic additional line. It is thought to Th. elongatum7EL chromosome specific SCAR marker. These molecular markers have good repeatability, amplification stability, easy and simple to handle, and cost effective, not only in different materials show superior stability, in between different generation also shows a good performance, provide excellent markers for molecular marker assisted breeding.2. Identified for wheat scabTwo consecutive years on the Chinese Spring-Agropyron elongatum disomic addition lines, Chinese Spring-Agropyron elongatum disomic substitution lines and hybrids of substitution lines and common wheat for wheat scab resistance identification. Using artificial single flower inoculation method, about25d investigation of disease vaccination, investigation records methods using records disease small panicles, calculation disease spikelet rate. Survey results showed that scab resistance genes may exist in Agropyron elongatum1E chromosome, consistent with previous reports.3The creation of wheat-Thinopyrum Scab translocation linesHybrid of common wheat and Chinese Spring-Agropyron elongatum7E substitution line, then hybrid the hybrids and Chinese Spring ph1b mutant. Molecular marker screening for ph1bph1b genotype from hybrid plants to create wheat-Thinopyrum Scab translocation lines.