Characterization and phylogenetic implications of the complete mitochondrial genome of Idiocerinae (Hemiptera: Cicadellidae)

The complete mitochondrial genome of Neuroctenus taiwanicus (Hemiptera: Aradidae)

Neuroctenus taiwanicus Kormilev, 1955 is a flat-bodied and enigmatic bug that was first discovered on the island of Taiwan, China. In this study, the whole mitochondrial genome of N. taiwanicus was sequenced and annotated for the first time, and its genomic data were uploaded to Genbank feedback number OR675057. The mitochondrial genome of N. taiwanicus is 15,340 bp in length, a typical circular DNA encoding 37 genes and a control region with 68.4% A + T content. The phylogeny reveals the taxonomic status of N. taiwanicus, which is most closely related to N. yunnanensis, and demonstrates the sister relationship among Neuroctenus, Mezira, and Brachyrhynchus. In addition, the results also confirm that Aradinae and Calisiinae are the earliest branching and more primitive in the family Aradidae, which is consistent with the analysis of the traditional classification.

Mitogenomic Analysis and Phylogenetic Implications for the Deltocephaline Tribe Chiasmini (Hemiptera: Cicadellidae: Deltocephalinae)

The grassland leafhopper tribe Chiasmini (Cicadellidae: Deltocephalinae) presently comprises 324 described species worldwide, with the highest species diversity occurring in the Nearctic region but a greater diversity of genera occurring in the Old World. In China, this tribe comprises 39 described species in 11 genera, but the fauna remains understudied. The complete mitogenomes of three species of this tribe have been sequenced previously. In order to better understand the phylogenetic position of Chiasmini within the subfamily Deltocephalinae and to investigate relationships among Chiasmini genera and species, we sequenced and analyzed the complete mitogenomes of 13 species belonging to seven genera from China. Comparison of the newly sequenced mitogenomes reveals a closed circular double-stranded structure containing 37 genes with a total length of 14,805 to 16,269 bp and a variable number of non-coding A + T-rich regions. The gene size, gene order, gene arrangement, base composition, codon usage, and secondary structure of tRNAs of the newly sequenced mitogenomes of these 13 species are highly conserved in Chiasmini. The ATN codon is commonly used as the start codon in protein-coding genes (PCGs), except for ND5 in Doratura sp. and ATP6 in Nephotettix nigropictus, which use the rare GTG start codon. Most protein-coding genes have TAA or TAG as the stop codon, but some genes have an incomplete T stop codon. Except for the tRNA for serine (trnS1(AGN)), the secondary structure of the other 21 tRNAs is a typical cloverleaf structure. In addition to the primary type of G-U mismatch, five other types of tRNA mismatches were observed: A-A, A-C, A-G, U-C, and U-U. Chiasmini mitochondrial genomes exhibit gene overlaps with three relatively stable regions: the overlapping sequence between trnW and trnC is AAGTCTTA, the overlapping sequence between ATP8 and ATP6 is generally ATGATTA, and the overlapping sequence between ND4 and ND4L is generally TTATCAT. The largest non-coding region is the control region, which exhibits significant length and compositional variation among species. Some Chiasmini have tandem repeat structures within their control regions. Unlike some other deltocephaline leafhoppers, the sequenced Chiasmini lack mitochondrial gene rearrangements. Phylogenetic analyses of different combinations of protein-coding and ribosomal genes using maximum likelihood and Bayesian methods under different models, using either amino acid or nucleotide sequences, are generally consistent and also agree with results of prior analyses of nuclear and partial mitochondrial gene sequence data, indicating that complete mitochondrial genomes are phylogenetically informative at different levels of divergence within Chiasmini and among leafhoppers in general. Apart from Athysanini and Opsiini, most of the deltocephaline tribes are recovered as monophyletic. The results of ML and BI analyses show that Chiasmini is a monophyletic group with seven monophyletic genera arranged as follows: ((Zahniserius + (Gurawa + (Doratura + Aconurella))) + (Leofa + (Exitianus + Nephotettix))).

Comparative analysis of codon usage patterns and phylogenetic implications of five mitochondrial genomes of the genus Japanagallia Ishihara, 1955 (Hemiptera, Cicadellidae, Megophthalminae)

Japanagallia is a genus of Cicadomorpha in the family of leafhoppers that are plant piercing-sucking insects, and it is difficult to distinguish by morphological characteristics. So far, only one complete mitochondrial genome data has been reported for the genus Japanagallia. Therefore, in order to better understand this group, we assembled and annotated the complete mitochondrial genomes of five Japanagallia species, and analyzed their codon usage patterns. Nucleotide composition analysis showed that AT content was higher than GC content, and the protein-coding sequences preferred to end with A/T at the third codon position. Relative synonymous codon usage analysis revealed most over-represented codon ends with A or T. Parity plot analysis revealed the codon usage bias of mitochondrial genes was influenced by both natural selection and mutation pressure. In the neutrality plot, the slopes of regression lines were < 0.5, suggesting that natural selection was playing a major role while mutation pressure was of minor importance. The effective number of codons showed that the codon usage bias between genes and genomes was low. Correspondence analysis revealed that the codon usage pattern differed among 13 protein-coding genes. Phylogenetic analyses based on three datasets using two methods (maximum likelihood and Bayesian inference), restored the Megophthalminae monophyly with high support values (bootstrap support values (BS) = 100, Bayesian posterior probability (PP) = 1). In the obtained topology, the seven Japanagallia species were clustered into a monophyletic group and formed a sister group with Durgade. In conclusion, our study can provide a reference for the future research on organism evolution, identification and phylogeny relationships of Japanagallia species.

Structural Characteristics and Phylogenetic Analysis of the Mitochondrial Genomes of Four Krisna Species (Hemiptera: Cicadellidae: Iassinae)

Krisna species are insects that have piercing-sucking mouthparts and belong to the Krisnini tribe in the Iassinae subfamily of leafhoppers in the Cicadellidae family. In this study, we sequenced and compared the mitochondrial genomes (mitogenomes) of four Krisna species. The results showed that all four mitogenomes were composed of cyclic double-stranded molecules and contained 13 protein-coding genes (PCGs) and 22 and 2 genes coding for tRNAs and rRNAs, respectively. Those mitogenomes exhibited similar base composition, gene size, and codon usage patterns for the protein-coding genes. The analysis of the nonsynonymous substitution rate (Ka)/synonymous substitution rate (Ks) showed that evolution occurred the fastest in ND4 and the slowest in COI. 13 PCGs that underwent purification selection were suitable for studying phylogenetic relationships within Krisna. ND2, ND6, and ATP6 had highly variable nucleotide diversity, whereas COI and ND1 exhibited the lowest diversity. Genes or gene regions with high nucleotide diversity can provide potential marker candidates for population genetics and species delimitation in Krisna. Analyses of parity and neutral plots showed that both natural selection and mutation pressure affected the codon usage bias. In the phylogenetic analysis, all subfamilies were restored to a monophyletic group; the Krisnini tribe is monophyletic, and the Krisna genus is paraphyletic. Our study provides novel insights into the significance of the background nucleotide composition and codon usage patterns in the CDSs of the 13 mitochondrial PCGs of the Krisna genome, which could enable the identification of a different gene organization and may be used for accurate phylogenetic analysis of Krisna species.

Comparative mitogenomics and phylogenetic analyses of the genus Menida (Hemiptera, Heteroptera, Pentatomidae)

In order to explore the genetic diversity and phylogenetic relationship of the genus Menida Motschulsky, 1861 and reveal the molecular evolution of the family Pentatomidae, subfamily Pentatominae, complete mitochondrial genomes of three species of Menida were sequenced, and the phylogenetic relationships of tribes within the subfamily Pentatominae were studied based on these results. The mitochondrial genomes of Menidamusiva (Jakovlev, 1876), M.lata Yang, 1934, and M.metallica Hsiao & Cheng, 1977 were 16,663 bp, 16,463 bp, and 16,418 bp, respectively, encoding 37 genes and including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes, and a control region. The mitochondrial genome characteristics of Menida were compared and analyzed, and the phylogenetic tree of the Pentatominae was constructed based on the mitochondrial genome datasets using Bayesian inference (BI) and maximum likelihood (MI) methods. The results showed that gene arrangements, nucleotide composition, codon preference, gene overlaps, and RNA secondary structures were highly conserved within the Menida and had more similar characteristics in Pentatominae. The phylogenetic analysis shows a highly consistent topological structure based on BI and ML methods, which supported that the genus Menida belongs to the Pentatominae and is closely related to Hoplistoderini. The examined East Asian species of Menida form a monophyletic group with the internal relationships: (M.musiva + (M.lata + (M.violacea + M.metallica))). In addition, these results support the monophyly of Eysarcorini and Strachiini. Placosternum and Cappaeini are stable sister groups in the evolutionary branch of Pentatominae. The results of this study enrich the mitochondrial genome databases of Pentatominae and have significance for further elucidation of the phylogenetic relationships within the Pentatominae.

Description of the whole mitochondrial genome of Bhatia longiradiata (Hemiptera, Cicadellidae, Deltocephalinae: Drabescini) and phylogenetic relationship

BACKGROUND

Mitochondrial genomes are extremely conserved in genetic processes and valuable molecular indications for phylogenetic and evolutionary examination, but the mitochondrial genome of Bhatia has not yet been reported.

OBJECTIVE

The target of this writing was to clarify the structural module of the mitochondrial genes of Bhatia longiradiata, verify the monophyletic of Drabescini, and explore the phylogenetic relationship between Drabescini with other leafhoppers.

METHODS

We performed sequencing and explanatory note of the mitochondrion of Bhatia longiradiata. The phylogeny relation was created by ML and Bayesian approaches using three dissimilar datasets (PCG12, PCG12rRNA, and AA), which were constructed to discuss the phylogenetic status of Bhatia longiradiata.

RESULTS

To report the architectural feature of the chondriosome of Bhatia longiradiata is a seal double-stranded annular molecule with 16,122 bp measurement and cover typically 37 genes. Several tandem repetitive units were observed in an AT enrichment area. The analysis showed that the branching relationships among the six trees were generally consistent, and each of the subfamilies was individually clustered into a monophyletic group within Cicadellidae. Bhatia longiradiata and other members of the Drabescini were aggregated into a clade that was situated within the Deltocephalinae.

CONCLUSION

The mitochondrial genome of Bhatia longiradiata covers 37 typical genes and a control region, which covers six tandem repeats. All species of Drabescini procedure a clade within Deltocephalinae. Drabescini and Scaphoideini form a branch and show a sister relationship with strong support. Therefore, we support the relegation of Selenocephalinae to a clan within Deltocephalinae.

Complete Mitogenome Analysis of Five Leafhopper Species of Idiocerini (Hemiptera: Cicadellidae)

Insect mitochondrial genomes (mitogenomes) are of great interest in exploring molecular evolution, phylogenetics, and biogeography. So far, only 12 mitogenomes of the leafhopper tribe Idiocerini have been released in GenBank, although the tribe comprises 488 known species including some agricultural, forestry, and horticultural pests. In order to compare and analyze the mitochondrial genome structure of Idiocerini and even the selective pressure of 13 protein-coding genes (PCGs) of the family Cicadellidae, the complete mitogenomes of five species including Nabicerus dentimus, Sahlbergotettix salicicola, Podulmorinus opacus, Podulmorinus consimilis, and a new species of a new genus were determined by next-generation sequencing. The size of the newly determined mitogenomes ranged from 14,733 bp to 15,044 bp, comprising the standard set of 13 PCGs, 22 transfer RNA genes, two ribosomal RNA genes, and a long non-coding control region (CR). The extent of purifying selection presented different pictures in the tribe and the family. The less pronounced genes (0.5 < dN/dS < 1) were nad5 and nad4l in Idiocerin, whereas in the family Cicadellidae including the sequences of Idiocerin, nad1-nad6 and cox1 genes were less pronounced. The codon encoding leucine was the most common in all species, and the codon encoding serine 1 was the most common in all species except for P. opacus. Interestingly, in P. opacus, another of the most common codons is that encoding serine 2. Among the 17 examined species of the Idiocerini, 14 species contained the tandem repeats, and 11 species of them contained the motif "TTATA". These findings will promote research on the structure and evolution of the mitochondrial genome and highlight the need for more mitogenomes in Cicadellidae.

Description and complete mitochondrial genome of Atkinsoniella zizhongi sp. nov. (Hemiptera: Cicadellidae: Cicadellinae) from China and its phylogenetic implications

A new species, Atkinsoniella zizhongi sp. nov. of the subfamily Cicadellinae, was described and illustrated from China. The new species is similar to A. nigrominiatula (Jacobi, 1944), A. limba Kuoh, 1991, A. dormana Li, 1992, A. peaka Yang, Meng et Li, 2017, and A. divaricata Yang, Meng et Li, 2017. But the characteristics of aedeagus and pygofer process can be used to distinguish them easily. The complete mitochondrial genome of the paratype was sequenced and assembled. The mitogenome of A. zizhongi sp. nov. was 16,483 bp in length, with an A+T content of 75.9%, containing 37 typical genes and a control region (CR). The gene order was consistent with the inferred insect ancestral mitochondrial genome. All of the PCGs were determined to have the typical stop codon TAA or TAG, while COX2 and ND5 ended with incomplete termination codons T and TA, respectively. In addition, phylogenetic trees were reconstructed based on PCGs and rRNAs using both the maximum likelihood (ML) and Bayesian inference (BI) methods. The results showed that the intergeneric and interspecific relationships within the subfamily Cicadellinae were completely consistent in all of the phylogenetic trees, except that the different interspecific relationships within the genus Bothrogonia were detected in the ML analysis based on the amino acid sequences. This study enriches the species diversity of Cicadellinae and further promotes research on its phylogeny.

Comparison of mitogenomes of three Petalocephala species (Hemiptera: Cicadellidae: Ledrinae) and their phylogenetic analysis

Ledrinae is a unique group of leafhoppers with a distinct appearance. Petalocephala is the largest Ledrinae genus that is difficult to identify except by dissecting the male genitals. To date, research on Ledrinae is relatively less compared with other leafhoppers. Therefore, to better understand this group, we sequenced and analyzed three complete Petalocephala mitochondrial genomes. We comparatively analyzed these general Petalocephala genomic features (including size, AT content, AT/GC skew, 13 protein-coding gene nucleotide compositions, etc.), and predicted 22 transfer RNA secondary structures. We obtained highly consistent phylogenetic results within Cicadellidae based on mitogenomic data using the maximum likelihood and Bayesian methods. Our results showed that all subfamilies were monophyletic and had a high node support rate, and there was a sister group relationship between Ledrinae and all other leafhopper groups. Furthermore, treehoppers were found to originate from leafhoppers and showed sister group relationships with Megophthalminae. Within Ledrinae, all phylogenetic trees supporting phylogenetic relationships were as follows: ([P. dicondylica + P. gongshanensis] + [Tituria pyramidata + [Ledra auditura + P. gongshanensis]]) Based on the complete mitogenome phylogenetic analysis and the comparison of morphological characteristics, we propose that Petalocephala is not monophyletic.

Comparative Analysis of Mitochondrial Genomes among Twelve Sibling Species of the Genus Atkinsoniella Distant, 1908 (Hemiptera: Cicadellidae: Cicadellinae) and Phylogenetic Analysis

Simple Summary

Atkinsoniella is a large genus of 98 species across the world and 88 species recorded in China within the globally distributed subfamily Cicadellinae, which is phytophagous, and some of which have been reported as important agricultural pests. Some Atkinsoniella species are very similar in morphological characteristics, making accurate identification at species level confusing. To provide further evidence toward understanding the relationships within the genus Atkinsoniella and subfamily Cicadellinae, mitogenomes of 12 Atkinsoniella sibling species were obtained and annotated. Their characteristics were comparatively analyzed. In addition, the comprehensive phylogenetic relationship within the subfamily Cicadellinae was determined based on three mitochondrial datasets using both the maximum-likelihood (ML) and Bayesian inference (BI) methods. The results suggested that the genus Atkinsoniella was recovered as a monophyletic group. The branches of the 12 newly sequenced species were clearly separated, with most nodes receiving strong support in all analyses, indicating that mitogenomics is an effective method for identifying closely related species and understanding their phylogenetic and evolutionary relationships.

Abstract

The herbivorous leafhopper genus Atkinsoniella Distant, 1908 (Hemiptera: Cicadellidae: Cicadellinae), a large genus of subfamily Cicadellinae, consists of 98 valid species worldwide and 88 species recorded in China. Some species of the genus are very similar in morphological characteristics, so they are difficult to identify accurately. In this study, 12 mitochondrial genomes of Atkinsoniella species with similar morphological characteristics were first obtained through high-throughput sequencing, which featured a typical circular molecule of 15,034–15,988 bp in length. The arrangement and orientation of 37 genes were identical to those of typical Cicadellidae mitogenomes. The phylogenetic relationship within the subfamily Cicadellinae was reconstructed using maximum-likelihood (ML) and Bayesian inference (BI) methods based on three concatenated datasets. The topological structures of the six obtained phylogenetic trees were highly consistent. The results suggested that Atkinsoniella was recovered as a monophyletic group and emerged as a sister group with the monophyletic clade of Bothrogonia, Paracrocampsa (part), and Draeculacephala (part). The branches of the 12 newly sequenced species were clearly separated, with most nodes receiving strong support in all analyses. In addition, the key to the 12 Atkinsoniella species was provided to identify species according to morphological characteristics. This study further promotes research on the classification, genetics, evolution, and phylogeny of the genus Atkinsoniella and subfamily Cicadellinae.

Novel gene rearrangement in the mitochondrial genome of Anastatus fulloi (Hymenoptera Chalcidoidea) and phylogenetic implications for Chalcidoidea

The genus Anastatus comprises a large group of parasitoids, including several biological control agents in agricultural and forest systems. The taxonomy and phylogeny of these species remain controversial. In this study, the mitogenome of A. fulloi Sheng and Wang was sequenced and characterized. The nearly full-length mitogenome of A. fulloi was 15,692 bp, compromising 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and a control region (CR). The total A + T contents were 83.83%, 82.18%, 87.58%, 87.27%, and 82.13% in the whole mitogenome, 13 PCGs, 22 tRNA genes, 2 rRNA genes, and CR, respectively. The mitogenome presented negative AT skews and positive GC skews, except for the CR. Most PCGs were encoded on the heavy strand, started with ATN codons, and ended with TAA codons. Among the 3736 amino acid-encoding codons, TTA (Leu1), CGA (Arg), TCA (Ser2), and TCT (Ser2) were predominant. Most tRNAs had cloverleaf secondary structures, except trnS1, with the absence of a dihydrouridine (DHU) arm. Compared with mitogenomes of the ancestral insect and another parasitoid within Eupelmidae, large-scale rearrangements were found in the mitogenome of A. fulloi, especially inversions and inverse transpositions of tRNA genes. The gene arrangements of parasitoid mitogenomes within Chalcidoidea were variable. A novel gene arrangement was presented in the mitogenome of A. fulloi. Phylogenetic analyses based on the 13 protein-coding genes of 20 parasitoids indicated that the phylogenetic relationship of 6 superfamilies could be presented as Mymaridae + (Eupelmidae + (Encyrtidae + (Trichogrammatidae + (Pteromalidae + Eulophidae)))). This study presents the first mitogenome of the Anastatus genus and offers insights into the identification, taxonomy, and phylogeny of these parasitoids.

Characterization, Comparison of Four New Mitogenomes of Centrotinae (Hemiptera: Membracidae) and Phylogenetic Implications Supports New Synonymy

To explore the phylogenetic relationships of the subfamily Centrotinae from the mitochondrial genome data, four complete mitogenomes (Anchon lineatus, Anchon yunnanensis, Gargara genistae and Tricentrus longivalvulatus) were sequenced and analyzed. All the newly sequenced mitogenomes contain 37 genes. Among the 13 protein-coding genes (PCGs) of the Centrotinae mitogenomes, a sliding window analysis and the ratio of Ka/Ks suggest that atp8 is a relatively fast evolving gene, while cox1 is the slowest. All PCGs start with ATN, except for nad5 (start with TTG), and stop with TAA or the incomplete stop codon T, except for nad2 and cytb (terminate with TAG). All tRNAs can fold into the typical cloverleaf secondary structure, except for trnS1, which lacks the dihydrouridine (DHU) arm. The BI and ML phylogenetic analyses of concatenated alignments of 13 mitochondrial PCGs among the major lineages produce a well-resolved framework. Phylogenetic analyses show that Membracoidea, Smiliinae and Centrotinae, together with tribes Centrotypini and Leptobelini are recovered as well-supported monophyletic groups. The tribe Gargarini (sensu Wallace et al.) and its monophyly are supported.

Complete Mitochondrial Genomes of Metcalfa pruinosa and Salurnis marginella (Hemiptera: Flatidae): Genomic Comparison and Phylogenetic Inference in Fulgoroidea

The complete mitochondrial genomes (mitogenomes) of two DNA barcode-defined haplotypes of Metcalfa pruinosa and one of Salurnis marginella (Hemiptera: Flatidae) were sequenced and compared to those of other Fulgoroidea species. Furthermore, the mitogenome sequences were used to reconstruct phylogenetic relationships among fulgoroid families. The three mitogenomes, including that of the available species of Flatidae, commonly possessed distinctive structures in the 1702-1836 bp A+T-rich region, such as two repeat regions at each end and a large centered nonrepeat region. All members of the superfamily Fulgoroidea, including the Flatidae, consistently possessed a motiflike sequence (TAGTA) at the ND1 and trnS₂ junction. The phylogenetic analyses consistently recovered the familial relationships of (((((Ricaniidae + Issidae) + Flatidae) + Fulgoridae) + Achilidae) + Derbidae) in the amino acid-based analysis, with the placement of Cixiidae and Delphacidae as the earliest-derived lineages of fulgoroid families, whereas the monophyly of Delphacidae was not congruent between tree-constructing algorithms.

The complete mitochondrial genome of leafhopper Koreocerus koreanus (Matsumura, 1915) (Hemiptera: Cicadellidae)

In this study, the complete mitochondrial genome (mitogenome) of Koreocerus koreanus (Mastsumura, 1915) was sequenced with 16,428 bp in length, which consisted of 37 genes including 22 transfer RNAs genes (tRNAs), 13 protein coding genes (PCGs) and 2 ribosomal RNAs genes (rRNAs). Except COX1 and ATP6 initiated with the TTG, other PCGs started with ATN. The COX1, ND4 and ND4L terminated with an incomplete T, while the remaining PCGs stopped with TAA. Excluding tRNA-Ser1 lacking a DHU arm, 21 tRNA genes with secondary structures were typical of cloverleaf structures. Phylogenetic analysis based on the complete mitochondrial sequences of 28 species (26 Cicadellidae and 2 outgroups) showed that Koreocerus koreanus was clustered into the subfamily Idiocerinae, the complete mitogenome of Koreocerus koreanus provides information for further study of Cicadellidae evolution.

Structural features of the mitogenome of the leafhopper genus Cladolidia (Hemiptera: Cicadellidae: Coelidiinae) and phylogenetic implications in Cicadellidae

The first two complete mitogenomes of the leafhopper genus Cladolidia (C. biungulata and C. robusta) were sequenced and annotated to further explore the phylogeny of Cladolidia. Both the newly sequenced mitogenomes have a typical circular structure, with lengths of 15,247 and 15,376 bp and A + T contents of 78.2% and 78%, respectively. We identified a highly conserved genome organization in the two Cladolidia spp. through comparative analysis that included the following assessments: genome content, gene order, nucleotide composition, codon usage, amino acid composition, and tRNA secondary structure. Moreover, we detected the base heterogeneity of Cicadellidae mitogenomic data and constructed phylogenetic trees using the nucleotide alignments of 12 subfamilies of 58 leafhopper species. We noted a weak heterogeneity in the base composition among the Cicadellidae mitogenomes. Phylogenetic analyses showed that the monophyly of each subfamily was generally well supported in the family Cicadellidae; the main topology was as follows: (Deltocephalinae + (Treehoppers + ((Megophthalminae + (Macropsinae + (Hylicinae + (Coelidiinae +Iassinae)) + (Idiocerinae + (Cicadellinae + (Typhlocybinae + (Mileewinae + (Evacanthinae +Ledrinae)))))))))). Within Coelidiinae, phylogenetic analyses revealed that C. biungulata and C. robusta belong to Coelidiinae and the monophyly of Cladolidia is well supported. In addition, on the basis of complete mitogenome phylogenetic analysis and the comparison of morphological characteristics, we further confirm the genus Olidiana as a paraphyletic group, suggesting that the genus may need taxonomic revisions.

Comparative Mitogenomics and Phylogenetic Analyses of Pentatomoidea (Hemiptera: Heteroptera)

Pentatomoidea is the largest superfamily of Pentatomomorpha; however, the phylogenetic relationships among pentatomoid families have been debated for a long time. In the present study, we gathered the mitogenomes of 55 species from eight common families (Acanthosomatidae, Cydnidae, Dinidoridae, Scutelleridae, Tessaratomidae, Plataspidae, Urostylididae and Pentatomidae), including 20 newly sequenced mitogenomes, and conducted comparative mitogenomic studies with an emphasis on the structures of non-coding regions. Heterogeneity in the base composition, and contrasting evolutionary rates were encountered among the mitogenomes in Pentatomoidea, especially in Urostylididae, which may lead to unstable phylogenetic topologies. When the family Urostylididae is excluded in taxa sampling or the third codon positions of protein coding genes are removed, phylogenetic analyses under site-homogenous models could provide more stable tree topologies. However, the relationships between families remained the same in all PhyloBayes analyses under the site-heterogeneous mixture model CAT + GTR with different datasets and were recovered as (Cydnidae + (((Tessaratomidae + Dinidoridae) + (Plataspidae + Scutelleridae)) + ((Acanthosomatidae + Urostylididae) + Pentatomidae)))). Our study showed that data optimizing strategies after heterogeneity assessments based on denser sampling and the use of site-heterogeneous mixture models are essential for further analysis of the phylogenetic relationships of Pentatomoidea.

Mitogenomics of five Olidiana leafhoppers (Hemiptera: Cicadellidae: Coelidiinae) and their phylogenetic implications

Similar morphological characteristics and limited molecular data of Olidiana resulted in their unknown phylogenetic statuses and equivocal relationships. To further understand the genus Olidiana, we sequenced and annotated five Olidiana complete mitochondrial genomes (mitogenomes). Our results show that Olidiana mitogenomes range from 15,205 bp to 15,993 bp in length and include 37 typical genes (13 protein-coding genes, 22 tRNAs, and 2 rRNAs) and a control region. Their nucleotide composition, codon usage, features of control region, and tRNA secondary structures are similar to other members of Cicadellidae. We constructed the phylogenetic tree of Cicadellidae using the maximum likelihood (ML) and Bayesian inference (BI) methods based on all valid mitogenome sequences. The most topological structure of the obtained phylogenetic tree is consistent. Our results support the monophyletic relationships among 10 subfamilies within Cicadellidae and confirm Iassinae and Coelidiinae to be sister groups with high approval ratings. Interestingly, Olidiana was inferred as a paraphyletic group with strong support via both ML and BI analyses. These complete mitogenomes of five Olidiana species could be useful in further studies for species diagnosis, evolution, and phylogeny research within Cicadellidae.

Structural features and phylogenetic implications of Cicadellidae subfamily and two new mitogenomes leafhoppers

Complete mitochondrial genome sequences facilitate species identification and analyses of phylogenetic relationships. However, the available data are limited to the diverse and widespread insect family Cicadellidae. This study analyzes and summarizes the complete mitochondrial genome structure characteristics of 11 leafhopper subfamilies and two newly sequenced Typhlocybinae species, Empoascanara wengangensis and E. gracilis. Moreover, using 13PCGs and rRNA data to analyze the nucleotide diversity, evolution rate, and the phylogenetic relationship between the subfamilies of 56 species, verifying the taxonomic status analysis of E. wengangensis and E. gracilis. The analysis results show that the genome structures of the subfamilies and the newly sequenced two species are very similar, and the size of the CR region is significantly related to the repeat unit. However, in the entire AT-skews and CG-skews, the AT-skews of other subfamilies are all positive, and CG-skews are negative, while Empoascini of Typhlocybinae and Ledrinae are the opposite. Furthermore, among 13PCGs, the AT-skews of 13 species are all negative while CG-skews are positive, which from Empoascini in Typhlocybinae, Idiocerinae, Cicadellinae, Ledrinae, and Evacanthinae. Phylogenetic analysis shows that ML and PB analysis produce almost consistent topologies between different data sets and models, and some relationships are highly supported and remain unchanged. Mileewinae is a monophyletic group and is a sister group with Typhlocybinae, and the sister group of Evacanthinae is Ledrinae + Cicadellinae. Phylogenetic analysis grouped the two newly sequenced species with other species of Typhlocybinae, which was separated from other subfamilies, and all Erythroneurini insects gathered together. However, E. gracilis grouped into a single group, not grouped with species of the same genus (Empoascanara). This result does not match the traditional classification, and other nuclear genes or transcriptome genes may be needed to verify the result. Nucleotide diversity analysis shows that nad4 and nad5 may be evaluated as potential DNA markers defining the Cicadellidae insect species.

Characterization of Two Complete Mitochondrial Genomes of Atkinsoniella (Hemiptera: Cicadellidae: Cicadellinae) and the Phylogenetic Implications

Simple Summary

Atkinsoniella is a large genus of almost 99 species across the world within the subfamily Cicadellinae, which is a large subfamily, comprising more than 2400 species of approximately 330 genera. Some of the Cicadellinae distributed worldwide are known as important agricultural pests. To better understand the mitogenomic characteristics of the genus Atkinsoniella and reveal phylogenetic relationships, the complete mitochondrial genomes of Atkinsoniella grahami and Atkinsoniella xanthonota were sequenced and comparatively analyzed in this study. The mitogenomes of these two Atkinsoniella species were found to be highly conserved, similarly to other Cicadellidae, except for the secondary structure of trnaS1, which formed a loop with the dihydrouridine (DHC) arm. This phenomenon has also been observed in other insect mitogenomes. Phylogenetic analyses, based on mitogenomes using both the maximum likelihood (ML) and Bayesian inference (BI) methods of three datasets, supported the monophyly of Cicadellinae, as well as the other subfamilies, and produced a well-resolved framework of Cicadellidae and valuable data for the phylogenetic study of Cicadellinae.

Abstract

The complete mitochondrial genomes of Atkinsoniella grahami and Atkinsoniella xanthonota were sequenced. The results showed that the mitogenomes of these two species are 15,621 and 15,895 bp in length, with A+T contents of 78.6% and 78.4%, respectively. Both mitogenomes contain 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and a control region (CR). For all PCGs, a standard start ATN codon (ATT, ATG, or ATA) was found at the initiation site, except for ATP8, for which translation is initiated with a TTG codon. All PCGs terminate with a complete TAA or TAG stop codon, except for COX2, which terminates with an incomplete stop codon T. All tRNAs have the typical cloverleaf secondary structure, except for trnS, which has a reduced dihydrouridine arm. Furthermore, these phylogenetic analyses were reconstructed based on 13 PCGs and two rRNA genes of 73 mitochondrial genome sequences, with both the maximum likelihood (ML) and Bayesian inference (BI) methods. The obtained mitogenome sequences in this study will promote research into the classification, population genetics, and evolution of Cicadellinae insects in the future.

Comparative analysis of mitochondrial genomes of Nirvanini and Evacanthini (Hemiptera: Cicadellidae) reveals an explicit evolutionary relationship

Mitogenomes of five leafhopper species, Chudania hellerina and Concaveplana rufolineata in Nirvanini, Carinata rufipenna, Evacanthus danmainus and E. heimianus representing Evacanthini, were sequenced. The lengths of these five mitogenomes range from 15,044 (C. hellerina) to 15,680 bp (E. heimianus). All five mitogenomes exhibit similar base composition, gene size and codon usage of protein-coding genes. All 22 tRNA genes have typical cloverleaf secondary structures, except for trnS1 (AGN) which appears to lack the dihydrouridine arm. The two included Nirvanini species employ the anticodon TCT instead of the commonly used GCT in trnS1 (AGN). Genes nad2, atp8 and nad6 were highly variable while cox1 and cob showed the lowest nucleotide diversity. Phylogenetic analyses of two concatenated nucleotide datasets, incorporating the newly sequenced taxa and other available membracoid mitogenomes, recovered each included leafhopper subfamily as monophyletic with evacanthine tribes Nirvanini and Evacanthini forming monophyletic sister clades. A relationship among Evacanthinae, Cicadellinae and Typhlocybinae received moderate branch support.

The Complete Mitochondrial Genome of Four Hylicinae (Hemiptera: Cicadellidae): Structural Features and Phylogenetic Implications

To reveal mtgenome characterizations and reconstruct phylogenetic relationships of Hylicinae, the complete mtgenomes of four hylicine species, including Nacolus tuberculatus, Hylica paradoxa, Balala fujiana, and Kalasha nativa, were sequenced and comparatively analyzed for the first time. We also carried out the richest (11) subfamily sampling of Cicadellidae to date, and reconstructed phylogenetic relationships of Membracoidea among 61 species based on three datasets using maximum likelihood and Bayesian inference analyses. All new sequenced mtgenomes are molecules ranging from 14,918 to 16,221 bp in length and are double stranded, circular in shape. The gene composition and arrangement of these mtgenomes are consistent with members of Membracoidea. Among 13 protein-coding genes, most show typical ATN start codons and TAR (TAA/TAG) or an incomplete stop codon T-, and several genes start by TTG/GTG. Results of the analysis for sliding window, nucleotide diversity, and nonsynonymous substitution/synonymous substitution indicate cox1 is a comparatively slower-evolving gene while atp8 is the fastest gene. In line with previous researches, phylogenetic results indicate that treehopper families are paraphyletic with respect to family Cicadellidae and also support the monophyly of all involved subfamilies including Hylicinae. Relationships among the four hylicine genera were recovered as (Hylica + (Nacolus + (Balala + Kalasha))).

Characterization of Two Complete Mitochondrial Genomes of Ledrinae (Hemiptera: Cicadellidae) and Phylogenetic Analysis

Mitochondrial genomes are widely used for investigations into phylogeny, phylogeography, and population genetics. More than 70 mitogenomes have been sequenced for the diverse hemipteran superfamily Membracoidea, but only one partial and two complete mtgenomes mitochondrial genomes have been sequenced for the included subfamily Ledrinae. Here, the complete mitochondrial genomes (mitogenomes) of two additional Ledrinae species are newly sequenced and comparatively analyzed. Results show both mitogenomes are circular, double-stranded molecules, with lengths of 14,927 bp (Tituria sagittata) and 14,918 bp (Petalocephala chlorophana). The gene order of these two newly sequenced Ledrinae is highly conserved and typical of members of Membracoidea. Similar tandem repeats in the control region were discovered in Ledrinae. Among 13 protein-coding genes (PCGs) of reported Ledrinae mitogenomes, analyses of the sliding window, nucleotide diversity, and nonsynonymous substitution (Ka)/synonymous substitution (Ks) indicate atp8 is a comparatively fast-evolving gene, while cox1 is the slowest. Phylogenetic relationships were also reconstructed for the superfamily Membracoidea based on expanded sampling and gene data from GenBank. This study shows that all subfamilies (sensu lato) are recovered as monophyletic. In agreement with previous studies, these results indicate that leafhoppers (Cicadellidae) are paraphyletic with respect to the two recognized families of treehoppers (Aetalionidae and Membracidae). Relationships within Ledrinae were recovered as (Ledra + (Petalocephala + Tituria)).

Characterization of the Complete Mitochondrial Genome of Drabescus ineffectus and Roxasellana stellata (Hemiptera: Cicadellidae: Deltocephalinae: Drabescini) and Their Phylogenetic Implications

To explore the mitogenome characteristics and shed light on the phylogenetic relationships and molecular evolution of Drabescini species, we sequenced and analyzed the complete mitochondrial genome of two species including Drabescus ineffectus and Roxasellana stellata. The complete mitogenomes of D. ineffectus and R. stellata are circular, closed and double-stranded molecules with a total length of 15744 bp and 15361 bp, respectively. These two newly sequenced mitogenomes contain the typical 37 genes. Most protein-coding genes (PCGs) began with the start codon ATN and terminated with the terminal codon TAA or TAG, with an exception of a special initiation codon of ND5, which started with TTG, and an incomplete stop codon T-- was found in the Cytb, COX2, ND1 and ND4. All tRNAs could be folded into the canonical cloverleaf secondary structure except for the trnS1, which lacks the DHU arm and is replaced by a simple loop. The multiple tandem repeat units were found in A + T-control region. The sliding window, Ka/Ks and genetic distance analyses indicated that the ATP8 presents a high variability and fast evolutionary rate compared to other PCGs. Phylogenetic analyses based on three different datasets (PCG123, PCG12R and AA) using both Bayesian inference (BI) and maximum likelihood (ML) methods showed strong support for the monophyly of Drabescini.

The Phylogenetic Implications of the Mitochondrial Genomes of Macropsis notata and Oncopsis nigrofasciata

Macropsinae are forest pests that feed on woody plants. They can damage the growth of trees and crops, and some species can also spread plant pathogens. Due to their widespread effects, these leafhoppers are of great economic significance, which is why there is a need to study their genomes. To fill the gap in the mitochondrial genomic data of the subfamily Macropsinae, we sequenced the complete mitochondrial genomes of Macropsis notata and Oncopsis nigrofasciata (which were 16,323 and 15,927 bp long, respectively). These two species are representative species of the leafhoppers group (Cicadellidae); the mitochondrial genomes of these species range from a length of 15,131 bp (Trocnadella arisana) to 16,811 bp (Parocerus laurifoliae). Both mitogenomes contained 37 typical insect mitochondrial genes and a control region; there were no long non-coding sequences. The genes within the mitogenome were very compact. The mitogenomes from both species contained two kinds of parallel repeat units in the control region. The whole mitogenomes of Macropsinae showed a heavy AT nucleotide bias (M. notata 76.8% and O. nigrofasciata 79.0%), a positive AT Skew (0.15 and 0.12), and a negative GC Skew (-0.14 and -0.08). Upon comparative ML and BI analysis, some clade relationships were consistent among the six trees. Most subfamilies were reconstructed into monophyletic groups with strong support in all analyses, with the exception of Evacanthinae and Cicadellinae. Unlike the results of previous research, it was shown that although all Deltocephalinae species are grouped into one clade, they were not the sister group to all other leafhoppers. Further, Cicadellinae and Evacanthinae were occasionally reconstructed as a polyphyletic and a paraphyletic group, respectively, possibly due to the limited numbers of samples and sequences. This mitogenome information for M. notata and O. nigrofasciata could facilitate future studies on the mitogenomic diversity and evolution of the related Membracoidea, and eventually help to control their effects on plants for the betterment of society at large.

The complete mitochondrial genome sequence of Scolopendra mutilans L. Koch, 1878 (Scolopendromorpha, Scolopendridae), with a comparative analysis of other centipede genomes

Scolopendramutilans L. Koch, 1878 is an important Chinese animal with thousands of years of medicinal history. However, the genomic information of this species is limited, which hinders its further application. Here, the complete mitochondrial genome (mitogenome) of S.mutilans was sequenced and assembled by next-generation sequencing. The genome is 15,011 bp in length, consisting of 13 protein-coding genes (PCGs), 14 tRNA genes, and two rRNA genes. Most PCGs start with the ATN initiation codon, and all PCGs have the conventional stop codons TAA and TAG. The S.mutilans mitogenome revealed nine simple sequence repeats (SSRs), and an obviously lower GC content compared with other seven centipede mitogenomes previously sequenced. After analysis of homologous regions between the eight centipede mitogenomes, the S.mutilans mitogenome further showed clear genomic rearrangements. The phylogenetic analysis of eight centipedes using 13 conserved PCG genes was finally performed. The phylogenetic reconstructions showed Scutigeromorpha as a separate group, and Scolopendromorpha in a sister-group relationship with Lithobiomorpha and Geophilomorpha. Collectively, the S.mutilans mitogenome provided new genomic resources, which will improve its medicinal research and applications in the future.

Comparative mitogenomes of six species in the subfamily Iassinae (Hemiptera: Cicadellidae) and phylogenetic analysis

For elucidating phylogenetic relationships among members of the family Cicadellidae, mitogenomes of six members of the subfamily Iassinae, including Batracomorphus lateprocessus, Iassus dorsalis, Krisna concava, Krisna rufimarginata, Gessius rufidorsus, and Trocnadella arisana, were sequenced. The mitogenomes are 14,724-15,356-bp long. Moreover, typical 37 genes in mitogenomes were identified; arrangement of these genes in the studied species was consistent with that in the inferred ancestral insects, except for tRNA genes, with a simple switch between the positions of trnI and trnQ in Trocnadella arisana. Most protein-coding genes in the Iassinae mitogenomes showed typical ATN start codons (ATA/ATT/ATC/ATG) and TAR (TAA/TAG) or an incomplete stop codon T--; ATP8 of all sequenced species showed the start codon TTG. The secondary structures of 16S rRNA and 12S rRNA were predicted. 16S rRNA comprised 6 domains with 43 helices, and 12S rRNA comprised 3 domains with 25 helices. All subfamilies, except Cicadellinae and Evacanthinae, were recovered as monophyletic. As reported previously, treehoppers originated from paraphyletic Cicadellidae. Iassinae and Coelidiinae, Megophthalminae and treehoppers, and Cicadellinae and Evacanthinae were sister groups with high nodal support.

Complete mitogenome of Olidiana ritcheriina (Hemiptera: Cicadellidae) and phylogeny of Cicadellidae

BACKGROUND

Coelidiinae, a relatively large subfamily within the family Cicadellidae, includes 129 genera and ∼1,300 species distributed worldwide. However, the mitogenomes of only two species (Olidiana sp. and Taharana fasciana) in the subfamily Coelidiinae have been assembled. Here, we report the first complete mitogenome assembly of the genus Olidiana.

METHODS

Specimens were collected from Wenxian County (Gansu Province, China) and identified on the basis of their morphology. Mitogenomes were sequenced by next-generation sequencing, following which an NGS template was generated, and this was confirmed using polymerase chain reaction and Sanger sequencing. Phylogenic trees were constructed using maximum likelihood and Bayesian analyses.

RESULTS

The mitogenome of O. ritcheriina was 15,166 bp long, with an A + T content of 78.0%. Compared with the mitogenome of other Cicadellidae sp., the gene order, gene content, gene size, base composition, and codon usage of protein-coding genes (PCGs) in O. ritcheriina were highly conserved. The standard start codon of all PCGs was ATN and stop codon was TAA or TAG; COII, COIII, and ND4L ended with a single T. All tRNA genes showed the typical cloverleaf secondary structure, except for trnSer, which did not have the dihydrouridine arm. Furthermore, the secondary structures of rRNAs (rrnL and rrnS) in O. ritcheriina were predicted. Overall, five domains and 42 helices were predicted for rrnL (domain III is absent in arthropods), and three structural domains and 27 helices were predicted for rrnS. Maximum likelihood and Bayesian analyses indicated that O. ritcheriina and other Coelidiinae members were clustered into a clade, indicating the relationships among their subfamilies; the main topology was as follows: (Deltocephalinae + ((Coelidiinae + Iassinae) + ((Typhlocybinae + Cicadellinae) + (Idiocerinae + (Treehopper + Megophthalminae))))). The phylogenetic relationships indicated that the molecular taxonomy of O. ritcheriina is consistent with the current morphological classification.

Structural and phylogenetic implications of the complete mitochondrial genome of Ledra auditura

We sequenced and annotated the first complete mitochondrial genome (mitogenome) of Ledra auditura (Hemiptera: Cicadellidae: Ledrinae) and reconstructed phylogenetic relationships among 47 species (including 2 outgroup species) on the basis of 3 datasets using maximum likelihood (ML) and Bayesian inference (BI) analyses. The complete L. auditura mitogenome (length, 16,094 bp) comprises 37 genes [13 protein-coding genes (PCGs), 22 tRNAs, and 2 rRNAs], 1 control region, and 2 long non-coding regions. The first long non-coding region (length, 211 bp) is located between tRNA-I and tRNA-Q and the second region (length, 994 bp) between tRNA-S2 and ND1. All PCGs show ATN (Met/Ile) as their start codon and TAR as their stop codon. Except tRNA-S1 (AGN), which lacks the dihydrouridine arm, all tRNAs can fold into the typical cloverleaf secondary structure. The complete L. auditura mitogenome shows a base composition bias of 76.3% A + T (A = 29.9%, T = 46.4%, G = 13.3%, and C = 10.5%), negative AT skew of -0.22, and positive GC skew of 0.12. In ML and BI analyses, L. auditura was clustered with Evacanthus heimianus (Hemiptera: Cicadellidae: Evacanthinae) with strong branch support.

Characterization of the Complete Mitochondrial Genome of Harpalus sinicus and Its Implications for Phylogenetic Analyses

In this study, we report the complete mitochondrial genome of Harpalus sinicus (occasionally named as the Chinese ground beetle) which is the first mitochondrial genome for Harpalus. The mitogenome is 16,521 bp in length, comprising 37 genes, and a control region. The A + T content of the mitogenome is as high as 80.6%. A mitochondrial origins of light-strand replication (OL)-like region is found firstly in the insect mitogenome, which can form a stem-loop hairpin structure. Thirteen protein-coding genes (PCGs) share high homology, and all of them are under purifying selection. All tRNA genes (tRNAs) can be folded into the classic cloverleaf secondary structures except tRNA-Ser (GCU), which lacks a dihydrouridine (DHU) stem. The secondary structure of two ribosomal RNA genes (rRNAs) is predicted based on previous insect models. Twelve types of tandem repeats and two stem-loop structures are detected in the control region, and two stem-loop structures may be involved in the initiation of replication and transcription. Additionally, phylogenetic analyses based on mitogenomes suggest that Harpalus is an independent lineage in Carabidae, and is closely related to four genera (Abax, Amara, Stomis, and Pterostichus). In general, this study provides meaningful genetic information for Harpalus sinicus and new insights into the phylogenetic relationships within the Carabidae.

Complete mitochondrial genomes of Bittacus strigosus and Panorpa debilis and genomic comparisons of Mecoptera

Mitochondrial genomes play a significant role in reconstructing phylogenetic relationships and revealing molecular evolution of insects. However, only four mitochondrial genomes were reported in Mecoptera to date. Here, we obtained two new complete mitochondrial genomes of the hangingfly Bittacus strigosus Hagen, 1861 and the scorpionfly Panorpa debilis Westwood, 1846. The results show that the complete mitogenome sequences of B. strigosus and P. debilis are 15,825 and 17,018 bp, respectively, both containing 37 genes and one control region. The mecopteran mitogenomes are highly similar in A + T bias, AT-skew, and GC-skew. Tandem repeats of the control region were discovered in Mecoptera for the first time. The sliding window, genetic distance, and Ka/Ks ratio analyses indicate the purifying selection of 13 protein-coding genes, the lowest evolutionary rate of cox1, and the highest sequence variability of atp8. Considering the sufficiently large size, fast evolution, and high ratio of Ka/Ks, nad4L and nad6 are regarded as potential markers for future phylogenetic analyses, population genetics, and species delimitations in Mecoptera. The phylogenetic relationships were reconstructed for four families of Mecoptera based on all six available mitogenomes using Bayesian inference and maximum likelihood methods. The phylogeny is presented as Boreidae + (Nannochoristidae + (Bittacidae + Panorpidae)).

Characterization and Phylogenetic Implications of the Complete Mitochondrial Genome of Syrphidae

In this study, the complete mitochondrial genomes (mitogenomes) of two hoverfly species of Korinchia angustiabdomena (Huo, Ren, and Zheng) and Volucella nigricans Coquillett (Diptera: Syrphidae) were determined and analyzed. The circular mitogenomes were 16,473 bp in K. angustiabdomena (GenBank No. MK870078) and 15,724 bp in V. nigricans (GenBank No. MK870079). Two newly sequenced mitogenomes both contained 37 genes, and the gene order was similar with other syrphine species. All the protein-coding genes (PCGs) were started with the standard ATN codons; and most of PCGs were terminated with a TAA stop codon, while ND1 in K. angustiabdomena ended with a TAG codon, and ND5 terminated with truncated T stop codons in both species. The phylogenetic relationship between K. angustiabdomena and V. nigricans with related lineages was reconstructed using Bayesian inference and Maximum-likelihood analyses. The monophyly of each family considered within Muscomorpha was confirmed by the clades in the phylogenetic tree, and superfamily of the Oestroidea (Calliphoridae, Sarcophagidae, and Oestridae) was unexpectedly found to be a paraphyletic group based on our selected data. This mitogenome information for K. angustiabdomena and V. nigricans could facilitate future studies of evolutionarily related insects.