RAPD Analysis Of The Striped Flea Beetle (Phyllotreta Striolata) From Different Sites In Fujian Province

The striped flea beetle [Phyllotreta striolata (Fab.), SFB] is a significant pest of cruciferous crops. SFB spreads widely across China and the problem of its continuous damages to the vegetables by SFB is becoming more serious, from which a heavy economic loss results every year. Thus the control and management of SFB has become the focus of some studies and researches.As a type of molecular marker, RAPD is widely applied on the analysis of genetic differentiation and genetic variety of ecological populations of many insects. In order to study the genetic variety and provide the control and management of SFB with necessary theories, in this paper, the genomic DNAs of SFB from ten different sites in Fujian province were isolated and RAPD reaction system was established to detect the polymorphism of DNAs. During the DNA isolation, three different types of SFB sample were used and the results were compared. Also, three different methods for extraction of DNA from SFB were applied and different results were showed. With L46, the optimal reaction system for RAPD-PCR amplification were optimized and thus established.This paper showed that during the extraction of DNA, among all the 3 different samples used, fresh and cold stored samples were almost equal in the quality and concentration of DNA, and thus cold stored sample could be used for DNA extraction. And the first and classical method for DNA extraction showed the best result, while the results of other two different methods using DNAzol genomic DNA isolation reagent and Genomic DNA isolation kit were less ideal. With L46 and after the optimization for RAPD, the optimal reaction conditions were also obtained.Among all the 50 random primers, twenty primers could amplify clear and repeating bands. One hundred and twenty-seven fragments were obtained and thenumber of the variable bands was 34. There was not a single polymorphic band which could tell one population from others, but the combination of polymorphic bands could reach that goal.From the analysis of genetic similarity coefficient, genetic distance and the neighbor-joining tree of ten populations, the populations of Fuzhou, Sanming, Pinghe, Nanping and Shaxian showed some genetic similarity and were included in one group, while those of Xianyou, Zhaoan and Tongan were included in another group. The populations of Lianchen and Jianou were not included in either group. And from some calculations and comparisons of genetic distances and ecological distances, another conclusion was that the geographical distance between populations may not be a key factor to judge their genetic similarity and genetic distance.This paper applied the technique of RAPD on the study of geographical populations of SFB for the first time and laid some experimental foundation and provided theoretic demonstrations for analysis of genetic differentiation and genetic variety of different geographical populations of SFB.