Breakdown of coevolution between symbiotic bacteriaWolbachiaand their filarial hosts

Abstract

Wolbachia is an alpha-proteobacterial symbiont widely distributed in arthropods. Since the identification of Wolbachia in certain animal-parasitic nematodes (the Onchocercidae or filariae), the relationship between arthropod and nematode Wolbachia has attracted great interest. The obligate symbiosis in filariae, which renders infected species susceptible to antibiotic chemotherapy, was held to be distinct from the Wolbachia-arthropod relationship, typified by reproductive parasitism. While co-evolutionary signatures in Wolbachia-arthropod symbioses are generally weak, reflecting horizontal transmission events, strict co-evolution between filariae and Wolbachia has been reported previously. However, the absence of close outgroups for phylogenetic studies prevented the determination of which host group originally acquired Wolbachia. Here, we present the largest co-phylogenetic analysis of Wolbachia in filariae performed to date including: (i) a screening and an updated phylogeny of Wolbachia; (ii) a co-phylogenetic analysis; and (iii) a hypothesis on the acquisition of Wolbachia infection. First, our results show a general overestimation of Wolbachia occurrence and support the hypothesis of an ancestral absence of infection in the nematode phylum. The accuracy of supergroup J is also underlined. Second, although a global pattern of coevolution remains, the signal is derived predominantly from filarial clades associated with Wolbachia in supergroups C and J. In other filarial clades, harbouring Wolbachia supergroups D and F, horizontal acquisitions and secondary losses are common. Finally, our results suggest that supergroup C is the basal Wolbachia clade within the Ecdysozoa. This hypothesis on the origin of Wolbachia would change drastically our understanding of Wolbachia evolution.

Dermatitis caused by autochthonous Cercopithifilaria bainae from a dog in Florida, USA: clinical, histological and parasitological diagnosis and treatment

“…The authors elected to withhold melarsomine as the therapeutic:toxic ratio was perceived to be poor because the dog did not have any evidence of systemic disease. In addition, because C. bainae nematodes have not been found to harbour Wolbachia spp., doxycycline was not recommended . Treatment with a macrocyclic lactone (ML ‐ moxidectin topically) and an anti‐inflammatory dose of corticosteroid (prednisone) was selected.…”

“…In addition, because C. bainae nematodes have not been found to harbour Wolbachia spp., doxycycline was not recommended . Treatment with a macrocyclic lactone (ML ‐ moxidectin topically) and an anti‐inflammatory dose of corticosteroid (prednisone) was selected. The frequency of moxidectin application was increased to two weeks due to the short prepatent period in which production of microfilariae susceptible to ML may develop more rapidly than microfilariae of Dirofilaria immitis .…”

Revisiting the phylogeny ofWolbachiain Collembola

“…In our unrooted MLST tree, supergroup E is sister to the A + H clade; however, the sister‐group relationship between A and H is not well supported (Figure 1). As supergroup H was considered the sister‐group of supergroup E in most of the previous studies (Bordenstein et al., 2009; Lefoulon et al., 2016; Lo et al., 2007), the relationship between A, H, and E would be better illustrated when more MLST sequences are available, especially for supergroup H. The phylogenetic inferences based on 16S rRNA and ftsZ genes indicate that supergroups K and L might also be close to supergroup E (Fig. S7A).…”

“…Robust characterization of supergroups is necessary to understand the origin and radiation of Wolbachia and to elucidate the nature of the interaction between Wolbachia and its hosts (Ros, Fleming, Feil, & Breeuwer, 2009). Thus far, 17 supergroups have been reported for Wolbachia, designated A-Q (Augustinos et al, 2011;Bandi, Anderson, Genchi, & Blaxter, 1998;Bing et al, 2014;Bordenstein & Rosengaus, 2005;Glowska, Dragun-Damian, Dabert, & Gerth, 2015;Haegeman et al, 2009;Lefoulon et al, 2016;Lo, Casiraghi, Salati, Bazzocchi, & Bandi, 2002;Ros et al, 2009;Rowley, Raven, & McGraw, 2004;Vandekerckhove et al, 1999;Werren et al, 1995). However, the proposed supergroup G, based on wsp genes only, has been proved to be a wsp recombinant clade, instead of a valid supergroup (Baldo & Werren, 2007).…”

Complete Genome Sequence of the Wolbachia wAlbB Endosymbiont of Aedes albopictus

“…Maternally 63 transmitted infections are widespread, occurring in an estimated 40-65% of insect species 64 (Hilgenboecker et al 2008;Werren et al 2008) including 28% of mosquito species (Kittayapong 65 et al 2000). Wolbachia infections are not limited to arthropods as nematodes, including several 66 major human pathogens, also harbor the endosymbiont (Fenn et al 2006; Lefoulon et al 2016). 67…”