Characterization Of Wolbachia Infection In Laodelphax Striatellus And Their Phylogenetic Analysis

Wolbachia is a group of intracellular inherited bacteria that infect a wide range of arthropods. The prevalence of Wolbachia infection in insects is about 16%. They are associated with a number of different reproductive phenotypes in their hosts, such as cytoplasmic incompatibility, parthenogenesis and feminization. More and more researches on Wolbachia are developed in recent years. Rice stripe virus (RSV) is an important virus on rice,which caused great losses to local rice production. As the major vector of RSV, Laodelphax striatellus is an important pest on rice. So Laodelphax striatellus, RSV and Wolbachia were chosen as the object of this research, to investigate the characterization of the prevalence of Wolbachia infection in Laodelphax striatellus, its relation with RSV infection, and the phylogeny of Wolbachia and its host Laodelphax striatellus, while providing the research basis for Vector-Insect-Symbiont Technology (VIST).RSV and Wolbachia infection in Laodelphax striatellus were detected by DIBA and PCR method respectively. Results showed that: 1.There was widespread prevalence of Wolbachia infection in Laodelphax striatellus. The prevalence of Wolbachia in Laodelphax striatellus was very high, some even to 88.89%. 2. Ther prevalence of the female group and male group in planthopper (nonviruliferous populations,viruliferous populations) was compared, and the result showed that the prevalence of male group was higher than female group. 3. No mutualistic relationships were found between RSV infection and Wolbachia infection through ovum; Wolbachia can transmitted vertically through ovum, but not all offsprings infected by Wolbachia. Detection to the F1 generation of the female parent which both infected by RSV and Wolbachia in order to study the transmission relationships between RSV and Wolbachia through ovum. There were many nymphae which infected by RSV but no Wolbachia infection detected.Wsp gene of Laodelphax striatellus and Sogatella furcifera from different geographical areas were cloned and sequenced. Phylogenetic analysis showed that: 1.They shared highly identity with each other, which indicated that Wolbachia could transmit between their host Laodelphax striatellus from different geographical ares, which also indicate that Laodelphax striatellus may migrate from different geographical areas. 2. Phylogeny of planthoppers and a parasitic wasp of Laodelphax striatellus was analysed, and the results indicated that Wolbachia could transmit horizontally between planthoppers and the parasitic wasp; Wolbchia in Nilaparvata lugens shared low identity with the Wolbchia in Laodelphax striatellus and Sogatella furcifera. 3. Phylogenetic analysis of Wolbachia in Laodelphax striatellus and other insects showed that Wolbachia infecting Laodelphax striatellus all belong to strain wStri in subgroup Con of supergroup B.CoII gene sequences were cloned and sequenced. Phylogenetic analysis showed that: 1.CoII gene of the 9 Laodelphax striatellus populations shared the identity of 99%-100%, which indicated there was no geographical differentiation between these 9 Laodelphax striatellus populations, or CoII gene was not suitable for differentiation of Laodelphax striatellus populations from different geographical ares. 2. Laodelphax striatellus and Sogatella furcifera shared the identity of about 80%, which indicated CoII gene was suitable for interspecific classification.