Discovery Of TYLCV Susceptible Gene And Application Of Disease Resistance Functional Marker Of Ty-5 In Tomato

Tomato(Solarium lycopersicum)is an annual or perennial plant belonging to the Solanaceae family.It has high nutritional value and are loved by consumers.Tomatoyellow leaf curl virus(TYLCV)is a single-stranded circular DNA virus belongs to the genus Begomovirus within the family Geminiviridae.This virus were transmitted by the whitefly,Bemisia tabaci.TYLCV is one of the most serious virus in tomato.Tomatoes that are infected with TYLCV display leaf curling,yellowing,and stunting of plant growth.Severe damage due to TYLCV result in plant death and subsequently no crop yield.At present,there have identified six TYLCV resistance genes,including Ty-1,Ty-2,Ty-3,Ty-4,ty-5,and Ty-6.Ty-1,Ty-2 and Ty-3 have been introgressed into hybrid tomato cultivars in China.However,long-term use of these three genes,rapidly mutation of virus,and compound infection of different viruses can lead to compromise of the resistance.Introgression of other resistance genes into hybrid cultivars is necessary.This study focuses on the mechanism of ty-5 gene and its breeding application.It is known that the resistance of ty-5 gene to TYLCV is due to the loss of susceptibility function of its allele Ty-5,but the mechanism is not clear.In this study,RNA-seq and virus-induced gene silencing technology were used to screen and verify the differentially expressed genes involved in the pathogenic process.In addition,we have also developed and applied HRM markers for ty-5.In general,the main findings are as follows:1.RNA sequencing technology was used to analyze Moneymaker and Moneymaker-Ty-5 that were inoculated with TYLCV.According to GO annotation,KEGG pathway enrichment and differential expression gene analysis,12 candidate genes were screened which may involved in the pathogenic infection process.2.The VIGS vectors of 11 candidate genes we constructed and silenced in Moneymaker.After that,these plants were inoculated with TYLCV The function of candidate genes were confirmed by the phenotypic identification and qRT-PCR.Solyc01g007280,Solyc04g077340 and Solyc12g100030 were further identified as the key genes.This finding provide a foundation for the subsequent research on the molecular mechanism of Ty-5 and the application of related genes in resistance breeding.3.A HRM marker was developed according to the base replacement in the coding region of the allele TY-5/ty-5 in AVTO1227 and Moneymaker,which provide technical support for the application of ty-5 gene in molecular marker-assisted breeding.