The Bacterial Composition And Diversity In Natural Populations Of Cinara Tujafilina

Aphids are the important agricultural and forestry pests, which mainly feed on plant phloem sap by sucking mouthparts, causing plants growing weak or even death.The symbiotic bacteria are widespread within the body of aphid, and they provide the necessary nutrient for the growth and development of host aphid and play the important roles in the defence of enemies and tissue immunity. There are many factors that affect microorganisms in the Aphid,such as aphid host species, geographical isolation, temperature, and environment. In order to compare the endosymbionts composition and difference between Cinara tujafilina and C.pinitabulaeformis which grow in same site,and the endosymbionts composition and difference among the different populations of C. tujafilina, the bacterial communities associated with C.tujafilina and C. pinitabulaeformis were analyzed by 16 S r RNA-RFLP(PCR- Restriction Fragment Length Polymorphism(RFLP) method,and the bacterial communities within the different populations of C. tujafilina(Yangling, Jiangzhang, Mazhao and Qianling) were analyzed by T-RFLP(terminal restriction fragment length polymorphism). The results are as follows:1. Results of bacteria associated with Cinara tujafilina and C. pinitabulaeformis using16 S rRNA-RFLP method showed that: the bacteria in two aphid species consist of primary endosymbiont Buchnera aphidicola and secondary endosymbiont Candidatus Serratia symbiotica, but their percentage were different in each clone library. In the clone library of C.tujafilina, B. aphidicola and Ca. Serratia symbiotica accounted for 37% and 56%, respectively,and a small amount of Enterobacter hormaechei accounted for 7%. In the library of C.pinitabulaeformis, B. aphidicola and Ca. Serratia symbiotica accounted for 66.7%, and 33.3%,respectively. The results indicate that the bacterial compositions of two aphid species are simple and similar, and they have the same kinds of endosymbiosis.2. The results of the bacterial communities within bodies of C. tujafilina among the different populations(Yangling, Jiangzhang, Mazhao and Qianling) using T-RFLP method showed that the number of T-RFs digested by Alu I enzyme is the most clear profile compared to the results of Hha I and Afa I. Therefore, Alu I enzyme was chosed to analysis the all samples.3. According to the T-RFs bands and peak values, the similarity coefficient of the bacterial communities between individuals in Jiangzhang populations is very low,dissimilarity account for 39.9%. The similarity among individuals in other three population are high, and they are middle similarity.4. Diversity analysis showed that the diversity index in Qianling population was lowest(Shannon index=1.62) and highest in Jiangzhang population(Shannon index=2.50). The dominance index was highest in Jiangzhang population(Simpson index=0.88), and the dominance index among other populations were similar. The abundance index was highest in Yangling population(Margalef index=1.13), followed by Jiangzhang populations(Margalef index=1.09). The evenness index was highest in Mazhao population(Pielou index=0.58). In short, compared to the other three populations, there are higher diversity index, dominance index, richness index and lower evenness index in Jiangzhang population.5. According to the T-RFs fragment abundance in four populations, 22 kinds, 32 kinds,28 kinds, 60 kinds of T-RFs fragment were found in Qianling population,Yangling population,Mazhao population and Jiangzhang population respectively. The dominant bacteria in Qianling population, Mazhao population and Yangling population were obvious, but the predominant bacteria-T-RFs fragment length were different.There is no clear T-RFs fragment in 16 individuals of Jiangzhang population. the 285 bp T-RF was dominant in all populations.