Abstract
In this study, the first complete mitochondrial genome of genus Euconocephalus (Euconocephalus nasutus) was determined. The mitochondrial genome is 14,999 bp in length, including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes, and an A + T-rich region. Phylogenetic analysis highly supported that E. nasutus showed a close relationship with Ruspolia dubia. The complete mitochondrial genome sequence of E. nasutus will provide fundamental data for the phylogenetic and biogeographic studies of the Tettigoniidae.
Keywords: Euconocephalus nasutus, mitogenome, phylogeny
Euconocephalus nasutus belongs to family Tettigoniidae. In China, it is mainly distributed in the southwest region. Euconocephalus nasutus can be used for food and medicine (Wang 2012). Complete mitochondrial genome has been considered as a useful tool for population genetic and phylogenetic studies (Cameron 2014). Here, we report the complete mitochondrial genome sequence of E. nasutus, which is the first for the genus Euconocephalus. The annotated mitochondrial DNA sequence has been submitted to GenBank under accession number MN183101.
Adult specimens of E. nasutus were collected from Wanli (28.72 N, 115.74 E), Nanchang City, Jiangxi Province, China, on 18 April 2016. The sample was deposited at Tianjin State Key Laboratory of Modern Chinese Medicine (voucher number: bycm-1).
The mitochondrial genome of E. nasutus is 14,999 bp in length. The composition of the whole genome is 36.5% A, 34.7% T, 17.8% C, and 11.0% G. E. nasutus contains 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes, and an A + T-rich region. It is similar to the mitochondrial genome of same subfamily species Ruspolia dubia (Zhou et al. 2007).
The longest gene within this molecule is ND5 containing 1732 bp and the shortest is ATP8 gene which is 162 bp. Three PCGs initiation codons are ATT, six PCGs initiation codons are ATG, three PCGs initiation codons are ATA, except that COI starts with TCA. Correspondingly, most PCGs end with TAA, while COIII, ND5, CytB stop with T-TrnaLys, T-TrnaPhe, TAG, respectively. MITOS Web Server and tRNAscan-SE (Lowe and Chan 2016) Search Server were employed to verify tRNAs based on their cloverleaf secondary structure.
To help us understand the phylogenetic position of E. nasutus in family Tettigoniidae, E. nasutus and other 11 published complete mitochondrial genome sequences in Tettigoniidae were used to reconstruct the maximum-likelihood (ML) phylogenetic tree (Figure 1). Ommexecha virens was served as outgroup. As expected, E. nasutus showed a close relationship with Ruspolia dubia, and further confirmed that E. nasutus belongs to the subfamily Conocephalinae. Moreover, the complete mitochondrial genome of E. nasutus can be used for further phylogenetic study within Tettigoniidae.
Figure 1.
ML phylogenetic tree of Euconocephalus nasutus with 12 species was constructed by complete mitochondrial sequences. The numbers at each node indicate bootstrap support. GenBank accession numbers are given in brackets. Subfamilies of the sampled taxa are shown on the right. Ommexecha virens was selected as outgroup.
Disclosure statement
No potential conflict of interest was reported by the authors.
References
- Cameron SL. 2014. Insect mitochondrial genomics: implications for evolution and phylogeny. Annu Rev Entomol. 59(1):95–117. [DOI] [PubMed] [Google Scholar]
- Lowe TM, Chan PP. 2016. tRNAscan-SE on-line: integrating search and context for analysis of transfer RNA genes. Nucleic Acids Res. 44(W1):W54–57. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wang H. 2012. Analysis and evaluation of the nutritional composition of Euconocephalus nasutus Thunberg. 49(5):1304–1308. [Google Scholar]
- Zhou Z, Huang Y, Shi F. 2007. The mitochondrial genome of Ruspolia dubia (Orthoptera: Conocephalidae) contains a short A + T-rich region of 70 bp in length. Genome. 50(9):855–866. [DOI] [PubMed] [Google Scholar]