Studies On Molecular Maker Of Cucumber Mosaic Virus Resistance-Related Gene In Cucumber (Cucumis Sativus L.)

Cucumber is cultivated widely and liked by worldwide people because of its good taste and rich nutrition. The occurrence of virus disease has caused tremendous effect and economic loss on the production of Cucumber. CMV (Cucumber mosaic virus) is one of the major pathogens of virus disease in Cucumber, which is introduced into plant cell during aphid probing or feeding. The application of the pesticides to prevent the spread of CMV is less effective. Breeding the disease-resistant varieties is the economic and effective method to control virus spread. During the transfer of disease-resistance gene by traditional breeding, it needs inoculation to identify the resistance, that is time consuming and labor intensity. And there are some problems such as the loss of objective traits and the low efficiency during the gene transferring. The development of MAS Maker-Assisted Selection) provides a rapid and effective way for the plant disease-resistance breeding.In this study, the parent F-3, which is a CMV-resistant inbred line in Cucumber, and the other parent HZL04-1 ,which is a CMV-susceptible inbred line, were crossed to generate the F₁,F₂ population. The parents and each individual in F₁,F₂ population were inoculated with CMV, a major pathogen in Cucumber. According to the result of disease-resistance assay, five CMV-resistant and five CMV-susceptible individual in F₂ population were chosen to construct two groups of resistant and susceptible respectively by using the method of BSA (bulked segregation analysis), in order to find the molecular maker linked with the CMV-resistant gene with AFLP,SRAP and SSR in Cucumber. The main results were as follows:1. In the versatile environmental test chamber, the seedlings were inoculated with CMV artificially and assayed. It showed that the resistance inheritance of cucumber CMV was controlled by nucleus , by a single recessive gene and not by cytoplasm in the test of materials used in this research.2. 298 polymorphic primer combinations between the two parents were found from 1024 AFLP primer combinations, 122 polymorphic primer combinations between the two parents were found from 221 SRAP primer combinations, 18 polymorphic primer combinations between the two parents were found from 140 SSR primer combinations. 3. A dominant AFLP marker linked to cucumber CMV gene is discovered. By checking the polymorphism between the five resistant plants and the five susceptible plants, a dominant marker, E22/M88-204bp, is found. Population analysis indicated that among 140 F2 plants, 28 resistant didn't appear the fragment which were in accordance with their resistant parents, while the 100 susceptible plants possessed one fragment which were in accordance with their susceptible parent. There were 3 resistant plants possessed one fragment and 9 susceptible plants didn't appear the fragment at that locus. Linkage analysis indicated that the AFLP marker was linked to cucumber CMV susceptible gene, and the genetic distance was 8.57cM.4. The AFLP maker E22/M88-204bp was retrieved,sequenced,designed a pair of suitable primer and transformed a SCAR maker. 13 susceptible varieties were tested by the SCAR maker, and the fit ratio is 84.6%. It showed that the SCAR maker was applied in MAS on Cucumber.