WO Phage Discovery And The Relationship With Wolbachia

WO phage discovery and the relationship with WolbachiaBacteriophage is the virus which infecting bacteria,it is specific in host,and makes a significant force in bacterial genome evolution.Bacteriophage is also notable catalysts of horizontal transferring and can shuttle through large portions of unique DNA into recipient host genomes.However,in the obligate intracellular parasitic symbiotic bacteria, bacteriophage is rarely found.In 1999,Masui ect.reported that they seperated a kind of insertion sequence from Wolbachia of wTai.Shinjit and Masui first discovered the bateriophage genetic of Wolbachia genome in Teleogryllus taiwanemma,and denominated it as WO phage.It had been shown that the bacteriophage WO can be either lysogenicly intergrated into the Wolbachia chromosome,or lytic and free in the cytopoasm.It may take important genes in the form of phage inserted in the genom of Wolbachia and take part in the process of Wolbachia regulating the host's reproductive mode.Through encoding the orf7 gene of WO phage'capsid protein,and PCR amplification, found the WO phage infecting Wolbachia.Then the granule of WO phage was distilled and observed through electron microscopic observation.Showed that WO phage was infected by WO phage,and the phage was activity.The infection relationship between Wolbachia and WO phage was studied,as well as the exist stablility of WO phage in different generations and geographical population of Corcyra cephalonica and Drosophila melanogaster.The result showed that WO phage was not freely existed in the parasitic insect,but was special virus infecting Wolbachia,Wolbachia and WO phage was stable existing in different generations and geographical population of Corcyra cephalonica and Drosophila melanogaste.It was presumed that WO phage and Wolbachia may have a long and stable coevolution.On the other hand the results also confirmed the G+ C content of WO phage and Wolbachia genome was very similar.It was surveyed that the infection situation of WO phage in twelfth hosts which carried Wolbachia.After investigation,8 of the hosts carried WO phage,the other four hosts were different strain of trichogram matids.The result showed that WO phage distributing abroad, and had strong infecting ability to the host of Wolbachia.It would has correlation to induce the phenotype of cytoplasm not affinity.WO phage was first time discovered existing in the seven insect hosts reported by this study.The gene of orf7 of WO phage in Wolbachia infecting in the five insects (Echinochemus squameusbillerg,Drosophila melanogaster,Sarcophaga spp,Bracon hebetor Say,ec) were cloned and sequenced,six clones and forteen sequences were got,and registered in Genebank.Then the topological structure of WO phage was found different with its host of Wolbachia.This showed the correlation between WO phage and Wolbachia was not evidence. The gene had horizontal transfered between Wolbachia in different hosts during the long term process of evolution and evolvement.If this inference was right,WO phage probably was the only gene outflow carrier,and took part in the process of promoting the heredity evolution of Wolbachia as the phage of self bacteria.The expression of wsp gene from Wolbachia and the orf7 gene from phage WO were studied in eggs,larvae,pupae,female and male of Corcyra cephalonica through the technical of RT-PCR.The express volumes of two genes were comparatively analysised.The results showed that in pupae,larvae and the female body of Corcyra cephalonica,the transcription of wsp and orf7 genes were basically the same.They were Clearly expressed and the expression volume were very high.But the two genes were not expressed in eggs and male body.And existed in the form of WO phage.This showed that the expression of WO phage in males and female bodies of Corcyra cephalonica was different.WO phage and its host of Wolbachia were both maternally inherited.Adopted the method of SYBR Green I fluorescent dyes chimeric,after the Real-Time PCR detection of Wolbachia's wsp and WO's phage in Corcyra cephalonica,Bracon hebetor Say and Drosophila melanogaster,the deduced expression ammout of WO phage in Wolbachia was studied.The results showed that the expression ammount of wsp and orf7 were different in the three insects.During them,the different expression amounts between the wsp were slight,but between orf7 were large.