Abstract
The complete mitochondrial genome (mitogenome) of Conwentzia sinica Yang, 1974 was sequenced and analyzed. The sequenced mitogenome is 15,153 bp in size, including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and one control region. Thirteen PCGs use ATN as the start codon. Most of PCGs terminate with TAA codons but ND5, ND4 with a single T residue, and ND3 terminates with TAG. The lrRNA gene is 1290 bp. The measured length of srRNA gene is 782 bp. Twenty-two tRNA genes possess the typical clover-leaf secondary structure except for tRNASer(AGN). The phylogenetic result supports the monophyly of the family Coniopterygidae and a closer relationship between Conwentzia and Coniopteryx.
Keywords: Coniopterygidae, Conwentzia sinica, mitochondrial genome
Conwentzia Enderlein, 1905 belongs to family Coniopterygidae, which is the smallest and most special group in the order Neuroptera (Wang and Liu 2007). Conwentzia sinica Yang, 1974 is an important predatory natural enemy of Oligonychus perditus Pritchard and Baker, 1955 (Xu et al. 2007). However, the phylogenetic relationship within the family Coniopterygidae from the perspective of molecular biology is still almost blank (Wang and Liu 2007). In this study, the complete mitochondrial genome (mitogenome) of C. sinica was reported and the phylogenetic relationship was reconstructed combining the current mitogenome data of other two Coniopterygidae species and other six families of Neuroptera.
In this study, the specimen was obtained from Penglai Park in Shanghai, China. Voucher specimen (No. CAU-Cwen-SH2) was deposited at the Entomological Museum of China Agricultural University (CAU). The mitogenome was sequenced by next-generation sequencing method with Illumina Hiseq 2500 (Sangon Biotech, Beijing) and the sequence was deposited in GenBank under the MN200022.
The sequenced mitogenome is 15,153 bp in length, including 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and one control region. The base composition is: A, 40.6%; T, 38.3%; C, 12.1%; G, 9.0%. It showed that the nucleotide composition of the mitochondrial genome is significantly biased towards A + T (78.9%) with the negative AT-skew 0.028) and negative GC-skew (−0.149). The gene arrangement is consistent with the putative ancestor of insects and also other two Coniopterygidae species, e.g. Semidalis aleyrodiformis and Coniopteryx sp. (Wang et al. 2017). All PCGs start with ATT codon except for COII, ND3, ND5, ND1 (ATA), ATP6, COIII, ND4, CytB (ATG). All of the PCGs terminate with the complete stop codon (TAA for ND2, COI, ATP8, ATP6, COIII, ND4L, ND6, ND3, CytB, ND1; TAG for ND3) except ND4 and ND5 with a single T residue as the termination codon. The lrRNA is 1290 bp in length with an A + T content of 84.2% and the srRNA is 782 bp in length with an A + T content of 83.7%. The control region located between the srRNA and tRNAIle is 416 bp with A + T content of 90.2%. The length of 22 tRNA genes measured ranged from 56 bp to 71 bp. All tRNA genes possess the typical clover-leaf secondary structure except for tRNASer(AGN), which lacks a dihydroxyuridine (DHU) arm.
The phylogenetic tree was constructed based on the sequences of 13 protein-coding genes from 10 neuropteran species by using Phylobayes MPI on XSEDE (1.5a) (Lartillot et al. 2009) with method under the GTR + CAT model (Song et al. 2016; Li et al. 2017; Liu et al. 2018). The result supports the monophyly of the family Coniopterygidae and shows Coniopteryx has a closer relationship with Conwentzia than with Semidalis. This result about the relationship of the three genera is different from the morphological classification in Coniopterygidae, therefore, further research is needed (Figure 1).
Figure 1.
Phylogenetic tree inferred from analysis of the nucleotide of the 13 PCGs. The nodal numbers indicate the Bayesian posterior probability. GenBank accession numbers for the sequences are indicated next to the species names. The newly sequenced mitogenome is indicated by the asterisk.
Disclosure statement
All authors have read and approved the final manuscript. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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