The complete mitochondrial genome of click beetle Chiagosnius sulcicollis (Coleoptera: Elateridae) and phylogenetic analysis

Abstract

In this study, we determined the complete mitochondrial genome sequence of click beetle Chiagosnius sulcicollis (Candeze, 1878) (GenBank accession no. MK792747) using next-generation sequencing (NGS) method. The mitogenome is 15,848 bp in length, consisting of 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes, and 1 non-coding control region. The overall nucleotide composition was 41.6% A, 31.5% T, 16.6% C, and 10.3% G, with 73.1% AT, respectively. The gene arrangement is consistent with the typical insect mitochondrial genome. Phylogenetic analysis revealed that C. sulcicollis clustered into a clade with Melanotus villosus with high bootstrap support.

Keywords:

• Insecta
• molecular phylogeny
• mitochondrial DNA
• genetic diversity

Elateridae commonly known as click beetles due to a unique and well-known startling defence mechanism named ‘clicking’ contains approximately 10,000 species (Johnson 2002). Chiagosnius sulcicollis, with yellowish-brown vertical stripe in the middle of the fore wing, mainly distributed in southern China and Southeast Asia (Jiang and Wang 1999). Here, we determined the complete mitochondrial genome of C. sulcicollis, which is the first mitochondrial genome sequenced to date in the genus of Chiagosnius.

The sampled specimen was collected from Jianfengling National Nature Reserve, Hainan, China (18°44′ N, 108°54′ E) in May, 2018. The specimen was stored in the Entomological specimen room of Shangluo University. The complete mitochondrial DNA sequence was determined by Illumina HiSeq 2500 Sequencing System (Illumina, San Diego, CA). In total, 5.2 Gb raw reads were obtained, quality-trimmed, and assembled using MITObim v1.7 (Hahn et al. 2013).

The complete mitochondrial genome of C. sulcicollis was 15,848 bp in total length and deposited in GenBank database with an accession number MK792747. The overall base composition was 41.6% A, 31.5% T, 16.6% C, and 10.3% G, with an A + T ratio of 73.1%. The full mitochondrial genome contains 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and a putative control region (CR). The gene arrangement of C. sulcicollis is found to be similar to most insect mitochondrial genomes (Wolstenholme 1992). Most PCGs of C. sulcicollis have the conventional start codon for invertebrate mitochondrial PCGs (ATN), with the exception of nad1 (TTG) and cox1 (AAT), as the asparagine (AAT or AAC) are proposed to be the start codon for cox1 in suborder Polyphaga (Sheffield et al. 2008). Most of the PCGs terminate with the stop codon TAA or TAG, whereas cox2, cox3 and nad5 end with the incomplete codon T. Nine protein-coding genes are encoded on the majority strand (J-strand) and four (nad5, nad4, nad4L, and nad1) on the minority strand (N-strand). All 22 tRNA genes can be folded into the typical cloverleaf structure except for trnS1, in which the dihydrouridine (DHU) arm cannot form a stable stem-loop structure but a simple loop. Two rRNA genes (rrnL and rrnS) locate at trnL1/trnV and trnV/control regions, respectively, and both rRNA genes are encoded on the N-strand. The lengths of the two rRNA genes (rrnL and rrnS) in C. sulcicollis are about 1283 and 738 bp, with the A + T contents of 78.1 and 75.9%, respectively. The length of the control region is 1235 bp, with the AT content of this region being ∼81.3%.

The phylogenetic tree was constructed using the maximum-likelihood method through raxmlGUI 1.5 (Silvestro and Michalak 2012). Results showed that the family Elateridae is monophyletic and C. sulcicollis is sister to Melanotus villosus (Figure 1), which was consistent with the previous studies (Douglas 2011; Lin et al. 2018; Meng et al. 2018). In conclusion, we obtained and described the complete mitochondrial genome of C. sulcicollis, which constitute a valuable and useful resource for population genetic study and identification efforts on this species.

Figure 1. Phylogenetic relationships based on the 13 mitochondrial protein-coding genes sequences inferred from RaxML. Numbers on branches are Bootstrap values (BV).

Disclosure statement

All authors have read and approved the final manuscript. No conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by grants from the Scientific Innovation Team of Shangluo [SK2018-03-03], the Opening Foundation of Key Laboratory of Resource Biology and Biotechnology in Western China, Northwest University, the Ministry of Education [ZSK2017005].