Complete mitochondrial genome of the giant liver fluke Fascioloides magna (Digenea: Fasciolidae) and its comparison with selected trematodes

Abstract

BackgroundRepresentatives of the trematode family Fasciolidae are responsible for major socio-economic losses worldwide. Fascioloides magna is an important pathogenic liver fluke of wild and domestic ungulates. To date, only a limited number of studies concerning the molecular biology of F. magna exist. Therefore, the objective of the present study was to determine the complete mitochondrial (mt) genome sequence of F. magna, and assess the phylogenetic relationships of this fluke with other trematodes based on the mtDNA dataset.FindingsThe complete F. magna mt genome sequence is 14,047 bp. The gene content and arrangement of the F. magna mt genome is similar to those of Fasciola spp., except that trnE is located between trnG and the only non-coding region in F. magna mt genome. Phylogenetic relationships of F. magna with selected trematodes using Bayesian inference (BI) was reconstructed based on the concatenated amino acid sequences for 12 protein-coding genes, which confirmed that the genus Fascioloides is closely related to the genus Fasciola; the intergeneric differences of amino acid composition between the genera Fascioloides and Fasciola ranged 17.97–18.24 %.ConclusionsThe determination of F. magna mt genome sequence provides a valuable resource for further investigations of the phylogeny of the family Fasciolidae and other trematodes, and represents a useful platform for designing appropriate molecular markers.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1699-7) contains supplementary material, which is available to authorized users.

Mitochondrial DNA Evidence Supports the Hypothesis that Triodontophorus Species Belong to Cyathostominae

“…There are also several pairs of repeats in the long non-coding regions of the three nematodes in this study with 12 bp for direct repeats and 12–14 bp for inverted repeats. This phenomenon was also found in the long non-coding regions of other helminthes, such as Strongyloides stercoralis, W. bancrofti, Fascioloides magna, Taenia multiceps, T. hydatigena , and T. pisiformis , but the lengths of those repeat sequences were longer than those in the three worms in the present study (Hu et al, 2003 ; Jia et al, 2010 ; Ramesh et al, 2012 ; Ma et al, 2016 ). Nevertheless, the functions of these regions remain unclear.…”

Fasciolopsis buski (Digenea: Fasciolidae) from China and India may represent distinct taxa based on mitochondrial and nuclear ribosomal DNA sequences

“…1 ), and contains 36 genes, including 12 protein-coding genes ( atp 6, cyt b, cox 1–3, nad 1–6 and nad 4L), 22 tRNA genes and two rRNA genes ( rrn L and rrn S) (Table 1 ). The gene content and organization of F. buski mt genome is consistent with other fasciolid flukes [ 22 ]. There is only one NCR in F. buski mt genome, which is located between trn E (13,458–13,519) and cox 3 (1–645) (Table 1 ), which is consistent with Fas.…”

“…magna and Fa. hepatica (7.04% in ITS-1, 13.8% in ITS-2) [ 22 ]. The results of these comparative sequence analyses suggest that F. buski isolates from China and India may represent distinct fluke species.…”

“…Meanwhile, as the complete mitochondrial (mt) genome sequence of F. buski from India has been decoded [ 21 ], we have noticed that the sequence difference in the nicotinamide dehydrogenase subunit 1 ( nad 1) gene between the F. buski isolates from India and Vietnam is 17.7%, which is higher than that between Fascioloides magna and Fa. hepatica (15%) [ 22 ]. Still, no information exists to illustrate the relationships between isolates of F. buski from India, Vietnam and mainland China, and none of the publications have explained the sequence discrepancies among these F. buski isolates.…”

Mitochondrial genomic comparison of Clonorchis sinensis from South Korea with other isolates of this species

“…Clonorchis sinensis (Cs-k2) Jinju-si, Gyeongsangnam-do Province, South Korea KY564177 Present study C. sinensis (Cs-k1) Korea JF729304.1 (Cai et al, 2012) C. sinensis (Cs-c1) China JF729303.1 (Cai et al, 2012) C. sinensis (Cs-r1) Khabarovsk, Khabarovskiy Krai, Russia FJ381664.2 (Shekhovtsov et al, 2010) Dicrocoelium chinensis Gansu, China NC_025279.1 (Liu et al, 2014b) D. dendriticum Gansu, China NC_025280.1 (Liu et al, 2014b) Fasciola gigantica Guangxi, China NC_024025.1 (Liu et al, 2014a) F. hepatica Victoria, Australia NC_002546.1 (Le et al, 2001) Fasciola sp. ('intermediate form' Heilongjiang, China KF543343.1 (Liu et al, 2014a) Fascioloides magna Czech Republic NC_029481.1 (Ma et al, 2016) Opisthorchis felineus Novosibirsk Oblast, Russia NC_011127.2 (Shekhovtsov et al, 2010) O. viverrini Laos JF739555.1 (Cai et al, 2012) Table 4 Pairwise comparison of levels of sequence variation (%) in the mitochondrial gene or inferred amino acid sequences derived from mitochondrial genomes representing Clonorchis sinensis from Korea (Cs-k1 and Cs-k2), China (Cs-c1) and Russia (Cs-r1) (cf. Table 1).…”