Comparing the mitochondrial genomes of <it>Wolbachia</it>-dependent and independent filarial nematode species

<p>Abstract</p> <p>Background</p> <p>Many species of filarial nematodes depend on <it>Wolbachia</it> endobacteria to carry out their life cycle. Other species are naturally <it>Wolbachia</it>-free. The biological mechanisms underpinning <it>Wolbachia</it>-dependence and independence in filarial nematodes are not known. Previous studies have indicated that <it>Wolbachia</it> have an impact on mitochondrial gene expression, which may suggest a role in energy metabolism. If <it>Wolbachia</it> can supplement host energy metabolism, reduced mitochondrial function in infected filarial species may account for <it>Wolbachia</it>-dependence. <it>Wolbachia</it> also have a strong influence on mitochondrial evolution due to vertical co-transmission. This could drive alterations in mitochondrial genome sequence in infected species. Comparisons between the mitochondrial genome sequences of <it>Wolbachia</it>-dependent and independent filarial worms may reveal differences indicative of altered mitochondrial function.</p> <p>Results</p> <p>The mitochondrial genomes of 5 species of filarial nematodes, <it>Acanthocheilonema viteae, Chandlerella quiscali</it>, <it>Loa loa</it>, <it>Onchocerca flexuosa</it>, and <it>Wuchereria bancrofti</it>, were sequenced, annotated and compared with available mitochondrial genome sequences from <it>Brugia malayi, Dirofilaria immitis, Onchocerca volvulus</it> and <it>Setaria digitata</it>. <it>B. malayi</it>, <it>D. immitis, O. volvulus</it> and <it>W. bancrofti</it> are <it>Wolbachia</it>-dependent while <it>A. viteae, C. quiscali</it>, <it>L. loa, O. flexuosa</it> and <it>S. digitata</it> are <it>Wolbachia</it>-free. The 9 mitochondrial genomes were similar in size and AT content and encoded the same 12 protein-coding genes, 22 tRNAs and 2 rRNAs. Synteny was perfectly preserved in all species except <it>C. quiscali,</it> which had a different order for 5 tRNA genes. Protein-coding genes were expressed at the RNA level in all examined species. In phylogenetic trees based on mitochondrial protein-coding sequences, species did not cluster according to <it>Wolbachia</it> dependence.</p> <p>Conclusions</p> <p>Thus far, no discernable differences were detected between the mitochondrial genome sequences of <it>Wolbachia</it>-dependent and independent species. Additional research will be needed to determine whether mitochondria from <it>Wolbachia</it>-dependent filarial species show reduced function in comparison to the mitochondria of <it>Wolbachia</it>-independent species despite their sequence-level similarities.</p>

Abstract licence: CC BY-NC-ND

• FASconCAT-G: extensive functions for multiple sequence alignment preparations concerning phylogenetic studies · 2014

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.