Characterization of the complete mitochondrial genome of Formica selysi (Insecta: Hymenoptera: Formicidae: Formicinae)

Characterization and Phylogenetic Implication of Complete Mitochondrial Genome of the Medicinal Ant Formica sinae (Hymenoptera: Formicidae): Genomic Comparisons in Formicidae

Ants (Hymenoptera: Formicidae) are among the largest and most widespread families of terrestrial insects and are valuable to medical and ecological investigations. The mitochondrial genome has been widely used as a reliable genetic marker for species identification and phylogenetic analyses. To further understand the mitogenome-level characteristics of the congeneric Formicidae species, the complete mitogenome of Formica sinae (Hymenoptera: Formicidae) was sequenced, annotated, and compared with other 48 Formicidae species. The results showed that gene composition, content, and codon usage were conserved. The complete mitochondrial genome of F. sinae was 17,432 bp, including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and one control region located between rrnS and trnM, which was 1,256 bp long, the longest of all sequenced species. Gene rearrangement was not detected in Formica species (Hymenoptera: Formicidae). All PCGs of F. sinae were initiated with ATN codons and terminated with the TAA codon. The overall nucleotide composition of F. sinae was AT-biased (83.51%), being 80.58% in PCGs, 86.68% in tRNAs, 87.10% in rRNAs, and 88.70% in the control region. Phylogenetic analyses indicated that each subfamily formed a strongly monophyletic group. Furthermore, F. sinae clustered with Formica fusca (Hymenoptera: Formicidae) and Formica selysi (Hymenoptera: Formicidae). This work enhances the genetic data of Formicidae and contributes to our understanding of their phylogenic relationship, evolution, and utilization.

Complete Nucleotide Sequence of the Mitogenome of Tapinoma ibericum (Hymenoptera: Formicidae: Dolichoderinae), Gene Organization and Phylogenetics Implications for the Dolichoderinae Subfamily

The ant Tapinoma ibericum Santschi, 1925 is native to the Iberian Peninsula. This species, as well as other species from the Tapinoma nigerrimum complex, could form supercolonies that make these species potentially invasive and could give rise to pests. Recently a mature colony from this species has been found in the Isle of Wight (United Kingdom). Mitogenomes have been used to study the taxonomy, biogeography and genetics of species, improving the development of strategies against pest invasion. However, the number of available mitogenomes from the subfamily Dolichoderinae is still scarce and only two of these mitogenomes belong to Tapinoma species. Herein, the complete mitogenome of T. ibericum is presented in order to increase the molecular information of the genus. The T. ibericum mitogenome, retrieved by Next-Generation Sequencing data, is 15,715 bp in length. It contains the typical set of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNAs and the A + T-rich control region. Comparisons of the T. ibericum mitogenome with other dolichoderine mitogenomes revealed the existence of four gene rearrangements in relation with the ancestral insect mitogenome. One of these rearrangements, involving the tRNA-Ile, tRNA-Gln and tRNA-Met genes, was found in most of the analyzed ant mitogenomes. Probably this rearrangement was an ancestral or plesiomorphic character in Formicidae. Interestingly, another rearrangement that affects to tRNA-Trp, tRNA-Cys and tRNA-Tyr genes was found only in Tapinoma species. This change could be a synapomorphic character for the genus Tapinoma, and could be used as a phylogenetic marker. Additionally, a phylogenetic analysis was performed using the protein-coding gene sequences from available Dolichoderinae mitogenomes, as well as mitogenomes from representative species from other Formicidae subfamilies. Results support the monophyletic nature of the genus Tapinoma placing it within the same clade as the rest of Dolichoderinae species.

A New Mitochondrial Genome of Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) and Mitogenome-Wide Investigation on Polymorphisms

Simple Summary

We completed one mitogenome of white-backed planthopper (WBPH), Sogatella furcifera (Horváth), with finding heteroplasmy phenomenon confirmed by PCR reaction and Sanger sequencing method. This heteroplasmy was not observed in WBPHs (n = 24) collected from the fields, suggesting that it may be uncommon in fields. We also analyzed single nucleotide polymorphisms, insertion and deletions, and simple sequence repeats among three currently available WBPH mitogenomes of Korea and China, suggesting that identified intraspecific variations could be potential candidates for developing markers to distinguish geographical populations of WBPH including Korean and Chinese. Phylogenetic analysis of 32 mitogenomes of Delphacidae including the three WBPH mitogenomes suggested that Delphacinae seems to be monophyletic and Sogatella species including WBPH are clearly formed as one clade.

Abstract

White-backed planthopper (WBPH), Sogatella furcifera (Horváth), is one of the major sap-sucking rice pests in East Asia. We have determined a new complete mitochondrial genome of WBPH collected in the Korean peninsula using NGS technology. Its length and GC percentages are 16,613 bp and 23.8%, respectively. We observed one polymorphic site, a non-synonymous change, in the COX3 gene with confirmation heteroplasmy phenomenon within individuals of WBPH by PCR amplification and Sanger sequencing, the first report in this species. In addition, this heteroplasmy was not observed in wild WBPH populations, suggesting that it may be uncommon in fields. We analyzed single nucleotide polymorphisms, insertion, and deletions, and simple sequence repeats among the three WBPH mitogenomes from Korea and China and found diverse intraspecific variations, which could be potential candidates for developing markers to distinguish geographical populations. Phylogenetic analysis of 32 mitogenomes of Delphacidae including the three WBPH mitogenomes suggested that Delphacinae seems to be monophyletic and Sogatella species including WBPH are clearly formed as one clade. In the future, it is expected that complete mitogenomes of individuals of geographically dispersed WBPH populations will be used for further population genetic studies to understand the migration pathway of WBPH.

Complete mitochondrial genome sequence of Tapinoma melanocephalum (Hymenoptera: Formicidae)

Tapinoma melanocephalum is a ubiquitous invasive species and widely distributed in subtropical and tropical regions around the world. Here, we sequenced and annotated the complete mitochondrial genome (mitogenome) of T. melanocephalum. This mitogenome was 15,499 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and 2 ribosomal RNA unit genes (rRNAs). Compared to other Formicidae species, gene order of T. melanocephalum was not conserved and one tRNA cluster trnW-trnC-trnY converted to trnW-trnY-trnC. The whole mitogenome exhibited heavy AT nucleotide bias (79.5%). All PCGs started with the standard ATN codons. Except for cox1 and nad5 end with the incomplete codon T-, all PCGs terminated with the stop codon TAA. Phylogenetic analysis showed that T. melanocephalum got together with three same subfamily Dolichoderinae species and one Dorylinae species, indicating the close relationship of Dolichoderinae and Dorylinae.

Accessible molecular phylogenomics at no cost: obtaining 14 new mitogenomes for the ant subfamily Pseudomyrmecinae from public data

The advent of Next Generation Sequencing has reduced sequencing costs and increased genomic projects from a huge amount of organismal taxa, generating an unprecedented amount of genomic datasets publicly available. Often, only a tiny fraction of outstanding relevance of the genomic data produced by researchers is used in their works. This fact allows the data generated to be recycled in further projects worldwide. The assembly of complete mitogenomes is frequently overlooked though it is useful to understand evolutionary relationships among taxa, especially those presenting poor mtDNA sampling at the level of genera and families. This is exactly the case for ants (Hymenoptera:Formicidae) and more specifically for the subfamily Pseudomyrmecinae, a group of arboreal ants with several cases of convergent coevolution without any complete mitochondrial sequence available. In this work, we assembled, annotated and performed comparative genomics analyses of 14 new complete mitochondria from Pseudomyrmecinae species relying solely on public datasets available from the Sequence Read Archive (SRA). We used all complete mitogenomes available for ants to study the gene order conservation and also to generate two phylogenetic trees using both (i) concatenated set of 13 mitochondrial genes and (ii) the whole mitochondrial sequences. Even though the tree topologies diverged subtly from each other (and from previous studies), our results confirm several known relationships and generate new evidences for sister clade classification inside Pseudomyrmecinae clade. We also performed a synteny analysis for Formicidae and identified possible sites in which nucleotidic insertions happened in mitogenomes of pseudomyrmecine ants. Using a data mining/bioinformatics approach, the current work increased the number of complete mitochondrial genomes available for ants from 15 to 29, demonstrating the unique potential of public databases for mitogenomics studies. The wide applications of mitogenomes in research and presence of mitochondrial data in different public dataset types makes the "no budget mitogenomics" approach ideal for comprehensive molecular studies, especially for subsampled taxa.

The complete mitochondrial genome of Orancistrocerusaterrimusaterrimus and comparative analysis in the family Vespidae (Hymenoptera, Vespidae, Eumeninae)

To date, only one mitochondrial genome (mitogenome) in the Eumeninae has been reported in the world and this is the first report in China. The mitogenome of O.a.aterrimus is 17 972 bp long, and contains 38 genes, including 13 protein coding genes (PCGs), 23 tRNA genes, two rRNA genes, a long non-coding region (NCR), and a control region (CR). The mitogenome has 79.43% A + T content, its 13 PCGs use ATN as the initiation codon except for cox1 using TTG, and nine genes used complete translation termination TAA and four genes have incomplete stop codon T (cox2, cox3, nad4, and cytb). Twenty-two of 23 tRNAs can form the typical cloverleaf secondary structure except for trnS1. The CR is 1 078 bp long with 84.69% A+T content, comprising 28 bp tandem repeat sequences and 13 bp T-strech. There are two gene rearrangements which are an extra trnM2 located between trnQ and nad2 and the trnL2 in the upstream of nad1. Within all rearrangements of these mitogenomes reported in the family Vespidae, the translocation between trnS1 and trnE genes only appears in Vespinae, and the translocation of trnY in Polistinae and Vespinae. The absent codons of 13 PCGs in Polistinae are more than those both in Vespinae and Eumeninae in the family Vespidae. The study reports the complete mitogenome of O.a.aterrimus, compares the characteristics and construct phylogenetic relationships of the mitogenomes in the family Vespidae.

The complete mitochondrial genome of yellow crazy ant, Anoplolepis gracilipes (Hymenoptera: Formicidae)

The yellow crazy ant Anoplolepis gracilipes is an invasive species that threatens biodiversity in introduced ecosystems. We sequenced the A. gracilipes mitogenome using next-generation sequencing methods. The circular mitogenome of A. gracilipes was 16,943 bp included 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNAs, and a single large non-coding region of 893 bp. The base composition was AT-biased (72%). Three genomic rearrangements compared to ancestral insects were found. Phylogenetic analysis based on the concatenated nucleotide sequences of the 13 protein-coding genes supports A. gracilipes belonging to the Formicinae subfamily. We announce the A. gracilipes mitogenome as a DNA reference for further population genetic, phylogenetic, and evolutionary analyses.

Next-Generation Sequencing of Two Mitochondrial Genomes from Family Pompilidae (Hymenoptera: Vespoidea) Reveal Novel Patterns of Gene Arrangement

Animal mitochondrial genomes have provided large and diverse datasets for evolutionary studies. Here, the first two representative mitochondrial genomes from the family Pompilidae (Hymenoptera: Vespoidea) were determined using next-generation sequencing. The sequenced region of these two mitochondrial genomes from the species Auplopus sp. and Agenioideus sp. was 16,746 bp long with an A + T content of 83.12% and 16,596 bp long with an A + T content of 78.64%, respectively. In both species, all of the 37 typical mitochondrial genes were determined. The secondary structure of tRNA genes and rRNA genes were predicted and compared with those of other insects. Atypical trnS1 using abnormal anticodons TCT and lacking D-stem pairings was identified. There were 49 helices belonging to six domains in rrnL and 30 helices belonging to three domains in rrns present. Compared with the ancestral organization, four and two tRNA genes were rearranged in mitochondrial genomes of Auplopus and Agenioideus, respectively. In both species, trnM was shuffled upstream of the trnI-trnQ-trnM cluster, and trnA was translocated from the cluster trnA-trnR-trnN-trnS1-trnE-trnF to the region between nad1 and trnL1, which is novel to the Vespoidea. In Auplopus, the tRNA cluster trnW-trnC-trnY was shuffled to trnW-trnY-trnC. Phylogenetic analysis within Vespoidea revealed that Pompilidae and Mutillidae formed a sister lineage, and then sistered Formicidae. The genomes presented in this study have enriched the knowledge base of molecular markers, which is valuable in respect to studies about the gene rearrangement mechanism, genomic evolutionary processes and phylogeny of Hymenoptera.

Complete mitochondrial genome of Camponotus atrox (Hymenoptera: Formicidae): a new tRNA arrangement in Hymenoptera

We sequenced the complete mitochondrial (mt) genome of Camponotus atrox (Hymenoptera: Formicidae), which is only distributed in Korea. The genome was 16 540 bp in size and contained typical sets of genes (13 protein-coding genes, 22 tRNAs, and 2 rRNAs). The C. atrox A+T-rich region, at 1402 bp, was the longest of all sequenced ant genomes and was composed of an identical tandem repeat consisting of six 100-bp copies and one 96-bp copy. A total of 315 bp of intergenic spacer sequence was spread over 23 regions. An alignment of the spacer sequences in ants was largely feasible among congeneric species, and there was substantial sequence divergence, indicating their potential use as molecular markers for congeneric species. The A/T contents at the first and second codon positions of protein-coding genes (PCGs) were similar for ant species, including C. atrox (73.9% vs. 72.3%, on average). With increased taxon sampling among hymenopteran superfamilies, differences in the divergence rates (i.e., the non-synonymous substitution rates) between the suborders Symphyta and Apocrita were detected, consistent with previous results. The C. atrox mt genome had a unique gene arrangement, trnI-trnM-trnQ, at the A+T-rich region and ND2 junction (underline indicates inverted gene). This may have originated from a tandem duplication of trnM-trnI, resulting in trnM-trnI-trnM-trnI-trnQ, and the subsequent loss of the first trnM and second trnI, resulting in trnI-trnM-trnQ.