Construction Of The High-resolution Genetic Map Of R10 Gene Conferring Resistance To Late Blight In Potato

Potato (Solanum tuberosum L.) is the fourth most important crop in the world and the acreage is only inferior to paddy rice, wheat and corn. Simultaneously,It is also the vegetable, forage, processes and industrial crop. It holds the important status in the agricultural production and the lives of the people. Late blight, caused by Phytophthora infestans, is one of the most devastating diseases in cultivated potato. It's hazardous and the prevention difficulties have surpassed rice blast and wheat rust that was regard as the international first big crop's diseases. Cloning of the resistance gene, resistance gene polymorphism in the field is considered the most promising strategy for blight control in the future. The R10 gene conferring resistance to potato late blight has broad resistance spectrum and was used widely in breeding programs.In this study, the late blight differential 3681ad (MaR10) which contain R10 and the susceptible cultivar Katahdin and their F1 were used to contruct genetic mapping. The plant clones were inoculation with the P.infestans isolate 89148-9, and their DNA were extracted. Comparative genomics facilitated the mapping of the R10 gene, and BSA in combination with the CAPS and AFLP technique is a powerful tool for markers development and enrichment. The high-resolution genetic map of the R10 locus was constructed.The experiment achieved the following results:1. A single dominant gene is identified in the R10 differential with P. infestans isolate 89148-9. A segregating population of 195 genotypes was inoculated and analysied. The results show that 92 clones were resistant, 100 clones were susceptible, and the middle index of disease was only one clone. The numbers of plants which disease index 1 and 5 accord with ratio of 1:1(χ2 = 0.26; p≥0.5).2. Based on sequence analysis for resistant genes known in MLB, it's indicated that these haplotypes have conserved domains and belong to R3a gene family. So the conserved primers were designed based on the conserved sequences of R3a gene and its horologes derived from MLB were used to identify resistance gene analogs (RGA) closely linked to the R10 gene. The RGA-CAPS marker RGA -600 and RGA-1000 linked 0.36 cM to the R10 gene, were developed and made base for the cloning of R10 gene.3. Construction for the high-resolution genetic map of R10. 6 PCR markers and 9 AFLP markers linked to R10 are developed using a combined strategy of comparative genomics and bulked segregant analysis. R10 gene resides between the two PCR markers 1001T and 656T that define a genetic interval of 0.26 cM. The genetic map gives a base for molecular isolation the R10 gene via positional cloning and comparative genomics...