New Insights into the Evolution of Wolbachia Infections in Filarial Nematodes Inferred from a Large Range of Screened Species

摘要: Background Wolbachia are intriguing symbiotic endobacteria with a peculiar host range that includes arthropods and single nematode family, the Onchocercidae encompassing agents of filariases. This raises question origin infection in filariae. Wolbachia infect female germline hypodermis. Some evidences lead to theory act as mutualist coevolved filariae from one event: their removal sterilizes filariae; all specimens positive species infected; vertically inherited; few lost symbiont. However, most data on filaria relationships derive studies Onchocercinae Dirofilariinae, mammals. Methodology/Principal Findings We investigated distribution testing 35 filarial species, including 28 7 genera and/or subgenera newly screened, using PCR, immunohistochemical staining, whole mount fluorescent analysis, cocladogenesis analysis. (i) Among screened mammals eight harbour but for some them, bacteria absent hypodermis, or variable density. (ii) not detected pathological model Monanema martini 8, upon 9, Cercopithifilaria. (iii) Supergroup F is identified two Mansonella Cercopithifilaria japonica. (iv) Type intestinal cells somatic genital tract. (v) Oswaldofilariinae, Waltonellinae Splendidofilariinae, saurian, anuran bird respectively, detected. Conclusions/Significance The absence 63% onchocercids, notably ancestral Oswaldofilariinae estimated 140 mya old, diverse tissues distribution, recent lateral transfer supergroup Wolbachia, modify current view role evolution endosymbiont hosts. Further genomic analyses sampled welcomed decipher open questions.