Molecular evidence for the endosymbiont Wolbachia in a non-filaroid nematode, Angiostrongylus cantonensis

Abstract

Wolbachia harbored by most filarial parasites, is critical to both embryogenesis and microfilarial development, and may lead to inflammation and pathogenesis in infected hosts. Based on alignment of the sequences from the wsp, ftsZ, and 16S rRNA genes, Wolbachia was demonstrated to exist in Angiostrongylus cantonensis, a non-filaroid nematode. Although the wsp gene may not be the best candidate for evolutionary analysis of Wolbachia, this gene has been sequenced from a broader coverage of the host species, making it feasible to be used for phylogenetic analysis in this study. The results from both Neighbor-joining and Maximum parsimony methods showed that this novel Wolbachia does not belong to any of the known groups (C or D) of nematode-derived Wolbachia. In addition, the wsp gene sequence of this newly identified endosymbiont revealed a high degree of identity (98%) with that from Diaea circumlita c2, tentatively classified into the putative group G. This suggests that Wolbachia from A. cantonensis could represent a deeply branched lineage in Wolbachia evolution or the occurrence of horizontal transfer between infected hosts. In conclusion, the findings provide some insights into our understanding of the evolution of Wolbachia, particularly the isolate from A. cantonensis.

Endosymbiotic bacteria associated with nematodes, ticks and amoebae

“…Surveys of nonfilarial nematodes have failed to detect Wolbachia outside of this group (Bordenstein et al ., ), although some evidence for divergent Wolbachia ‐like sequences and structurally distinct bacteria has been reported in the plant parasitic Tylenchid nematode, Radopholus similis (Haegeman et al ., ). Reports of PCR amplification of Wolbachia sequence from the metastrongylid nematode Angiostrongylus cantonensis (Tsai et al ., ) have not been reproduced and appear to be because of laboratory contamination (Foster et al ., ). A more in‐depth survey of subfamilies of the Onchocercidae supports the view that Wolbachia arose late in the divergence of filarial nematodes.…”

Parasitism and Mutualism in Wolbachia: What the Phylogenomic Trees Can and Cannot Say

“…These taxa include supergroup E from primitively wingless insects, the springtails (Collembola) (Vandekerckhove et al 1999;Lo et al 2002;Czarnetzki and Tebbe 2004), supergroup F from termites, weevils, true bugs, and filarial nematodes (Casiraghi et al 2001;Lo et al 2002;Rasgon and Scott 2004), supergroup H from termites (Bordenstein and Rosengaus 2005), and three other divergent lineages that have not been labeled supergroups including those from the flea Ctenocephalides canis (Casiraghi et al 2005), the filarial nematode Dipetalonema gracile (Casiraghi et al 2005), and the pseudoscorpion Cordylochernes scorpioides (Zeh et al 2005;Zeh JA and Zeh DW 2006). One other supergroup, G, has been reported to occur in spiders (Rowley et al 2004) and a nonfilarial nematode (Tsai et al 2007); we have excluded this group from our analysis as it may represent an artificial clade due to recombination within the gene used for phylogenetic analysis (Baldo and Werren 2007).…”

Detection of Wolbachia Bacteria in Multiple Organs and Feces of the Triatomine Insect Rhodnius pallescens (Hemiptera, Reduviidae)

“…It also occurs in parasitic nematodes, such as Onchocerca volvulus, is responsible for the inflammatory reaction that induces blindness (22,24), and has been detected in Brugia malayi (34,36). Wolbachia has recently been found in Angiostrongylus cantonensis, a nematode that is not related to filarias (37).…”