Fine Mapping Of The Tomato Yellow Leaf Curl Resistance Gene Ty-5 And The Application Of Linkage Marker

Tomato(Solanum lycopersicum)belongs to the Solanaceae family.Tomato becomes one of the most important and favorite cultivated vegetables in the world due to its adaptability,easy cultivation,high yield,and high nutritional value.Tomato yellow leaf curl disease(TYLCD)restricts the yield and quality of tomato.Tomato yellow leaf curl virus(TYLCV)is one of the important pathogen of TYLCD.TYLCV spread fast and widely,disease management for TYLCV is difficult,physical control,chemical control and biological control methods can reduce the occurrence of disease in a certain degree,but these preventions are not complete and even harm to the environment.These practices are also uneconomical and laborious.Therefore,Marker assisted selection has become an effective method for tomato resistant breeding.Breeding TYLCV-resistant tomato cultivars offers an attractive method to control these diseases and can fundamentally solve the devastation of TYLCV.Thus far,seven TYLCV resistance genes have been identified,the genes including Ty-1,Ty-2,Ty-3,Ty-3a,Ty-4,Ty-6 and recessive gene ty-5,they from wild tomato species.Ty-1 and Ty-3 were cloned,resistant tomato varieties were main include Ty-1,Ty-2,Ty-3 and Ty-3a resistance genes.The ty-5 gene was a newly discovered resisant TYLCV gene in recent years and the material containing the gene has high resistantance to TYLCV.The ty-5 gene was mapped to chromosome 4,which is a main QTL,can explain 46.6%phenotypic variation.Therefore,ty-5 resistance gene was fine maped and cloned has important significance for tomato breeding and function research.In this study,Resistant line AVT01227 and susceptible line moneymaker as parents to construct the segregating population.Segregating population F2 plants as the main material to construct a R-pool and a S-pool.Combine with the BSA method and the re-sequencing technique,comparing and analyzing the results of BSA-seq and tomato genome.Initially set to the candidate interval of ty-5 gene was 970kb and include 129 candidate genes.The InDel markers and SNP markers of the ty-5 gene were designed and developed in the candidate region.Then select recombinant plants of the F2 plants using theses markers.Narrowing the region of the candidate genes and fine mapping the ty-5 gene.Finally ty-5 gene was fined map in 14.5kb region between the ty5-25 marker and the ty5-29 marker.In this region only one gene is pelota gene.Pelota is determined the candidate gene for ty-5.And then ty-5 gene was sequence compared and expression analysis,the result can conclude,ty-5 gene resistance was due to the nucleotide difference in the transcriptional region of the sequence.In order to speed up the application of ty-5 gene and establishment the multi-resistance polymerization breeding system,in this study the multiplex PCR system of ty-5 and Ty-2 gene was established.No commercial varieties with ty-5 gene are available,the genetic linkage map of the gene was constructed and fine mapping can be used to molecular marker-assisted selection and creation tomato material which containing ty-5 gene,that can rich varieties of resistant materials,provide the basis for the application of the gene in the variety and also provide the theoretical basis for clarifying the resistance mechanism of ty-5 resistance-related genes.