Diversity of endosymbiont bacteria associated with a non-filarial nematode group

Abstract

There is a significant knowledge gap with regard to non-filarial nematodes and their relationships, if any, with intracellular bacteria, with only sporadic reports in the literature. An intracellular bacteriaXiphinematobacter, belonging to subdivision 2 of the Verrucomicrobia, was previously reported in the ovaries of three species of the non-filarialXiphinema americanum-group of nematodes. We explored the diversity ofXiphinematobacterin 22 populations ofX. americanumsourced from six continents and conservatively have identified nine phylotypes, six of which have not previously been reported. A geographic basis to the phylotypes was noted with phylotypes A and B only found in Europe, whereas phylotypes F, G, H and I were mainly found in North America. Phylotypes C, D and E showed greater geographical variation. Sequences ofXiphinematobacterfrom this study help to inform the taxonomy of Verrucomicrobia such that the status and composition of Verrucomicrobia subdivision 2 potentially requires reflection.

Molecular diversity of bacterial endosymbionts associated with dagger nematodes of the genus Xiphinema (Nematoda: Longidoridae) reveals a high degree of phylogenetic congruence with their host

“…; Lazarova et al . ). Our study has been performed using a combination of integrative identification techniques (such as barcoding and morphology) because of the difficulty of species identification in this group (Palomares‐Rius et al .…”

“…This procedure of nematode host identification is unknown from other studies of endosymbionts that have published sequences and deposited them in GenBank (Lazarova et al . ).…”

“…This finding is partially inconsistent with the results of Lazarova et al . (), who found that bacterial endosymbionts were geographically associated with their hosts. However, as mentioned previously, the hosts of these bacterial endosymbionts were not clearly identified with measurements or molecular markers in their study.…”

“…This study recovered nine phylotypes, which were grouped based on geographic origin of the nematode population (Lazarova et al . ).…”

“…In male specimens, bacterial endosymbionts also populate the gut epithelium but not the ripe testes (Vandekerckhove et al 2002). Recently, the diversity of Candidatus Xiphinematobacter has been studied using 22 populations from the X. americanum group (Lazarova et al 2016). This study recovered nine phylotypes, which were grouped based on geographic origin of the nematode population (Lazarova et al 2016).…”