AT-rich Region Research Articles

The complete mitochondrial genome sequence of Aulacophora indica

Aulacophora indica has been intensively studied since it can cause serious damage to cucurbits. Here, we reported the complete mitochondrial genome of A. indica for the first time. The mitochondrial genome is 15,730 bp in length and contained 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs, and an AT-rich control region. Phylogenetic tree indicated that A. indica is more closely related to Aulacophora lewisii than other Galerucinae beetles.

The mitochondrial genome of the Spanish honey bee, Apis mellifera iberiensis (Insecta: Hymenoptera: Apidae), from Portugal

The Spanish honey bee Apis mellifera iberiensis, had a mitochondrial genome of 16,560 bp. It consisted of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and an AT-rich control region. The sample was from Portugal and its mitogenome resembled those of the African (A)-lineage honey bee subspecies. It was most closely related to other North African honey bees, namely A. m. sahariensis and A. m. intermissa.

Phylogenetic Relationships of Russian Far-East Apis cerana with Other North Asian Populations

Abstract Apis cerana Fabricius, 1793 is the eastern honeybee species distributed throughout Asia from the tropical climate in the southern part to the temperate climate in the northern part. We sequenced and annotated the complete mitochondrial DNA (mtDNA) of A. cerana from Vladivostok, Primorsky Krai of the Russian Far East and uploaded it to the database GenBank (AP018450). MtDNA sequence has 15,919 bp length, AT-content 84% and GC-content 16% and contains 22 tRNA genes, 13 protein-coding genes, two ribosomal RNA genes, one AT-rich region and four non-coding intergenic regions (NC1-4). All proteincoding genes start with ATT and ATG codons, except for ATC, the start codon of the ATP8 gene, which and stop with the common stop codons TAA and TAG. A comparative analysis of complete mtDNA of A. cerana from China, Indonesia, Korea, Malaysia, Russia, Taiwan, Thailand, Vietnam, and Japan found that the Russian Far East Apis cerana differed from others on the subspecies level. Based on the comparative analysis of complete mtDNA (~16,000 bp), nuclear DNA (nDNA) gene Vitellogenin (VG) (~4,100 bp) and morphological measurements (six parameters), we assumed that the Russian Far-East A. cerana can be a distinct northern Asia population and can be described as a separate unique subspecies of A. c. ussuriensis subsp. nov. A. c. koreana subsp. nov. is also validated and described as a new subspecies.

Characteristics of a Colistin-Resistant Escherichia coli ST695 Harboring the Chromosomally-Encoded mcr-1 Gene.

Enterobacteriaceae having chromosomally-encoded mcr-1 is rarely reported. In this study, we recovered a chromosomal mcr-1 carrying Escherichia coli, designated HeN100, from the feces of a diarrheal pig in China. Antimicrobial susceptibility testing showed that HeN100 was resistant to three aminoglycosides, twelve β-lactams including three carbapenems, one phenicol, two tetracyclines, two fluoroquinolones, nitrofurantoin, and colistin tested. Oxford Nanopore MinION sequencing revealed that the complete genomes of the multidrug resistant (MDR) HeN100 consisted of a single circular chromosome and five circular plasmids. Bioinformatical analysis determined HeN100 as ST695 and it contained many acquired resistance genes responsible for its MDR phenotypes, including colistin resistance mcr-1 and the carbapenem resistance blaNDM-1, and most of these genes were located on plasmids. However, the mcr-1 was found on the chromosome, and it was located between an IS30-like element ISApl1 and a PAP2-like encoding gene. These three genes consisted of an “ISApl1-mcr-1-orf” segment and inserted in high AT-rich regions. Finally, we found the blaNDM-1 was carried on an IncFII type conjugative plasmid. The conjugation frequency of this plasmid was 7.61 ± 2.11 × 10−5 per recipient, and its conjugation conferred resistance to carbapenems and other β-lactams, as well as aminoglycosides. The spread of this mcr-1/blaNDM-1-carrying E. coli ST695 represents a great concern of public health.

Conjugating a groove binder analogue to a styryl-quinolinium scaffold for the light-up detection of duplex and G-Quadruplex DNA with different binding modes.

The rational design of novel small molecules, which can target specific DNA sequences or secondary structural DNAs, is one of the most important goals in medicinal chemistry. Also the studies of DNA binding potency which can give fundamental insight into binding mechanisms and specificity are essential. In this paper, a N-methylated quinolinium probe NSQ functionalized with a G-Quadruplex DNA groove binder analogue was designed and synthesized. NSQ was found to express selective and sensitive for "light-up" detection of both G-Quadruplex and duplex DNAs over RNA and other biomolecules. The characteristics of NSQ and its interactions with DNAs were comprehensively evaluated by means of fluorescence, UV-Vis, circular dichroism, FID assay, DFT calculation and molecular docking. NSQ exhibited higher binding affinity to G-Quadruplex than to duplex DNA. Binding mechanism analysis indicated NSQ interacted with G-Quadruplex DNA mainly through end-stacking mode, while bound with duplex DNA into the minor groove of AT-rich regions. Further, NSQ exhibited potent invitro anti-tumor activity, and to elucidate the cellular applications, confocal cell imaging was carried out and validated its mainly nuclear localization.

Unveiling introgression in bumblebee (Bombus terrestris) populations through mitogenome-based markers.

The bumblebee, Bombus terrestris, is an important pollinator commercially used on a global scale. The exported subspecies B.t.terrestris has colonised diverse environments, in some cases displacing wild pollinators to the verge of local extinction. In this sense, the native Iberian subspecies B.t.lusitanicus may be threatened by the subspecies B.t.terrestris, naturally distributed from the Pyrenees to Central Europe but also observed in southern Spain due to escapes from commercial nests. Mitochondrial genomes have a low recombination rate and a small effective population size owing to their maternal inheritance, thus providing an accurate approach to study hybridisation events between populations. Therefore, we present the sequences of the mitogenomes of both subspecies as a molecular framework to select suitable markers to detect possible introgression events between them. We used metagenomics to obtain approximately 17 kbp of the mitogenome from both subspecies. Their mitogenomes differed in 358 bp (excluding the AT-rich region). Four mitogenomic fragments were selected to be tested as subspecific diagnostic markers. A RFLP detected in the gene nad2 (NADH dehydrogenase subunit 2) has proven to be an efficient, quick and cost-effective tool to assess the dispersion of the non-endemic subspecies into Iberian native populations. Subspecific haplotypes were observed in both morphological subspecies, suggesting introgression events in the northern natural contact area and in the new human-mediated contact area in the south of the Iberian Peninsula.

Plastome phylogenomics of Poaceae: alternate topologies depend on alignment gaps

AbstractIn Poaceae there is an evolutionary radiation of c. 5000 species called the ‘PACMAD’ grasses. Two hypotheses explain deep PACMAD relationships: the ‘aristidoid sister’ and the ‘panicoid sister’ hypotheses. In each case, the named subfamily is sister to all other taxa. These hypotheses were investigated with data partitions from plastid genomes (plastomes) of 169 grasses including five newly sequenced aristidoids. Plastomes were analysed 40 times with successive addition of more gapped positions introduced by sequence alignment, until all such positions were included. Alignment gaps include low complexity, AT-rich regions. Without gaps, the panicoid sister hypothesis (P(ACMAD)) was moderately supported, but as gaps were gradually added into the input matrix, the topology and support values fluctuated through a transition zone with stripping thresholds from 2–11% until a weakly supported aristidoid sister topology was retrieved. Support values for the aristidoid sister topology then rose and plateaued for remaining analyses until all gaps were allowed. The fact that the aristidoid sister hypothesis was retrieved largely when gapped positions were included suggests that this result might be artefactual. Knowledge of the deep PACMAD topology explicitly impacts our understanding of the radiation of PACMAD grasses into open habitats.

Comparative in silico study of congocidine congeners as potential inhibitors of African swine fever virus.

African swine fever virus (ASFV) infection is fatal in domesticated pigs, with a mortality rate approaching 100%. This may result in economic losses and threats to food security. Currently, there are no approved vaccines or antiviral therapies for ASFV. Therefore, in this study, we evaluated congocidine congeners and a tris-benzimidazole as potential inhibitors of ASFV transcription using an in silico approach. We applied redocking of congocidine and docking of its congeners and a tris-benzimidazole to a receptor containing B-DNA with AT-motifs as a target to mimic conserved ASFV late gene promoters. Subsequently, the binding scores of DNA-ligand docked complexes were evaluated and their binding affinity was estimated. Molecular dynamics (MD) simulation was then used to assess ligand behavior within the minor groove. From our results, it is evident the less toxic congocidine congeners and tris-benzimidazole could dock to AT-rich regions significantly. Additionally, the predicted binding affinities had suitable values comparable to other experimentally determined minor groove binders, MD simulation of the docked DNA-ligand complexes and subsequent molecular trajectory visualization further showed that the ligands remained embedded in the minor groove during the time course of simulation, indicating that these ligands may have potential applications in abrogating ASFV transcription.

Complete mitochondrial genome of two Thitarodes species (Lepidoptera, Hepialidae), the host moths of Ophiocordyceps sinensis and phylogenetic implications

Thitarodes (Lepidoptera, Hepialidae) is the only genus that hosts to the Ophiocordyceps sinensis, a traditional Chinese medicine considered as a powerful medicinal supplement. In this study, the complete mitochondrial genomes (mitogenomes) of two species, T. damxungensis and T. pui, have been sequenced, which are 15,928 bp and 15,362 bp in size respectively, and both contain 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs and an AT-rich region. Like other hepialoids, the gene arrangement of the mitogenomes of T. damxungensis and T. pui is identical to the ancestral arrangement but differs from those of other lepidopteran species on account of the different arrangements of trnM, trnI, and trnQ. The size of AT-rich region is 545 bp in T. damxungensis and 1030 bp in T. pui. Tandem repetition in the AT-rich region is responsible for the length difference of the A + T-rich region in both species. In Hepialidae, the phylogenetic study based on the dataset of the sequences that combined the protein-coding genes and RNA genes suggested that the species T. yunnanensis should still belong to the genus Thitarodes rather than Ahamns, which is different from the results based on the traditional phylogeny.

Description of soybean aphid (Aphis glycines Matsumura) mitochondrial genome and comparative mitogenomics of Aphididae (Hemiptera: Sternorrhyncha)

The complete mitochondrial genome of the soybean aphid (Aphis glycines Matsumura), a major agricultural pest in the world, is described for the first time, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, as well as a large repeat region between tRNA-Glu and tRNA-Phe, and an AT-rich control region. The 17,954 bp mtgenome is the largest reported from the family Aphididae, and its gene order follows the ancestral insect mtgenome except for the repeat region, which contains a 195 bp unit repeated 11.9 times, representing the highest reported repeats among the known aphid mtgenomes to date. A new molecular phylogeny of Aphidae is reconstructed based on all available aphid mtgenomes, and it is shown that the mtgenome data can robustly resolve relationships at the subfamily level, but do not have sufficient phylogenetic information to resolve deep relationships. A phylogeny-based comparative analysis of mtgenomes has been performed to investigate the evolution of the repeat region between tRNA-Glu and tRNA-Phe. So far, among aphids, 13 species are known to have this repeat region of variable lengths, and a phylogenetic analysis of the repeat region shows that a large proportion of the sequences are conserved across the phylogeny, suggesting that the repeat region evolved in the most recent common ancestor of Aphidinae and Eriosomatinae, and that it has gone through numerous episodes of lineage-specific losses and expansions. Combined together, this study provides novel insights into how the repeat regions have evolved within aphids.

Structural features and phylogenetic implications of four new mitogenomes of Centrotinae (Hemiptera: Membracidae)

To explore the variation and phylogenetic utility of mitogenomes among lineages of the diverse hemipteran superfamily Membracoidea, we sequenced four new mitogenomes of four treehopper species of the subfamily Centrotinae (Membracidae): Hypsauchenia hardwichii, Leptocentrus albolineatus, Maurya qinlingensis, and Tricentrus brunneus. The mitogenomes are 15,508 to 16,467 bp in size, and comprise the typical set of 37 mitochondrial genes and a large non-coding region (AT-rich region). Gene organization, nucleotide composition and codon usage of protein-coding genes (PCGs) are similar to those of most other sequenced Membracidae mitogenomes. All PCGs start with a typical ATN or TTG and end with TAA/G or the incomplete stop codon (a single T). All transfer RNA genes can be folded into typical clover-leaf secondary structures, except for trnS1. The location, length and AT content of the rrnS and rrnL genes are highly conserved in the Membracidae mitogenomes. In contrast, the AT-rich control region is highly variable in length and in numbers of tandem repeats present. Phylogenetic analyses based on the nucleotide and amino acid sequence data of 13 PCGs from 59 species of Membracoidea and four outgroups (Cercopoidea and Cicadoidea species) recovered Membracoidea as monophyletic with strong support, and Cicadellidae as paraphyletic with respect to Aetalionidae + Membracidae, in agreement with previous analyses. Relationships among membracoid subfamilies were also in general agreement with results from prior studies. The monophyly of Centrotinae is strongly supported, with relationships among tribes recovered as ((Centrotini+ (Tricentrini + Antialcidini)) + ((Leptobelini + Hypsauchenini) + Leptocentrini).

Mitogenome of Anterastes babadaghi (Orthoptera: Tettigoniinae; Platycleidini):Frequent conserved overlapping regions within Tettigoniinae.

Development of next generation sequencing rapidly increased the number of total mitogenome in data bases. However, the documented number of total mitogenome from species of Tettigoniinae is still limited and a comparison at subfamily level has not been made sufficiently. This paper aims to describe total mitogenome of A. babadaghi (Orthoptera, Tettigoniidae) by comparing to the known mitogenomes of other Tettigoniinae. The total mitogenome of A. babadaghi is 15882-15883 bp, AT skewed with 70.2% AT percentage, and consists of 13 protein coding genes (PCG), 22 tRNA genes, two rRNA genes and an AT rich control region. The genes are ordered as in pancrustacean. The comparative description of mitogenomes in Tettigoniinae showed that total length varies between 15766-16788 bp, the start codon for protein coding genes almost always fits to the ATN pattern, the stop codons are incomplete T-- / TA- and rarely complete TAA, intergenic spacers (IGS) and overlapping regions (OR) in species of the subfamily are similar in number, location, length and nucleotide sequence. We arrived to following conclusion from comparative data: (i) A. babadaghi has a typical orthopteran mitogenome by general features; (ii) this generalisation seems valid for Tettigoniinae as gene content, gene location, gene order, average AT content, anticodons and secondary structure of the tRNA genes, the start and stop codons of the protein coding genes, and several IGSs/ORs are similar to other orthopteran and hexapopods, (iii) variation range in total mitogenome length is narrow in Tettigoniinae and mainly determined by the lengths of control region and total IGSs, (iv) mitogenome of the subfamily exhibits conserved patterns especially in overlapping regions, but conserved features are mostly plesiomorphic.

Population Genome Sequencing of the Scab Fungal Species Venturia inaequalis, Venturia pirina, Venturia aucupariae and Venturia asperata.

The Venturia genus comprises fungal species that are pathogens on Rosaceae host plants, including V. inaequalis and V. asperata on apple, V. aucupariae on sorbus and V. pirina on pear. Although the genetic structure of V. inaequalis populations has been investigated in detail, genomic features underlying these subdivisions remain poorly understood. Here, we report whole genome sequencing of 87 Venturia strains that represent each species and each population within V. inaequalis. We present a PacBio genome assembly for the V. inaequalis EU-B04 reference isolate. The size of selected genomes was determined by flow cytometry, and varied from 45 to 93 Mb. Genome assemblies of V. inaequalis and V. aucupariae contain a high content of transposable elements (TEs), most of which belong to the Gypsy or Copia LTR superfamilies and have been inactivated by Repeat-Induced Point mutations. The reference assembly of V. inaequalis presents a mosaic structure of GC-equilibrated regions that mainly contain predicted genes and AT-rich regions, mainly composed of TEs. Six pairs of strains were identified as clones. Single-Nucleotide Polymorphism (SNP) analysis between these clones revealed a high number of SNPs that are mostly located in AT-rich regions due to misalignments and allowed determining a false discovery rate. The availability of these genome sequences is expected to stimulate genetics and population genomics research of Venturia pathogens. Especially, it will help understanding the evolutionary history of Venturia species that are pathogenic on different hosts, a history that has probably been substantially influenced by TEs.

Affinities of Terminal Inverted Repeats to DNA Binding Domain of Transposase Affect the Transposition Activity of Bamboo Ppmar2 Mariner-Like Element.

Mariner-like elements (MLE) are a super-family of DNA transposons widespread in animal and plant genomes. Based on their transposition characteristics, such as random insertions and high-frequency heterogeneous transpositions, several MLEs have been developed to be used as tools in gene tagging and gene therapy. Two active MLEs, Ppmar1 and Ppmar2, have previously been identified in moso bamboo (Phyllostachys edulis). Both of these have a preferential insertion affinity to AT-rich region and their insertion sites are close to random in the host genome. In Ppmar2 element, we studied the affinities of terminal inverted repeats (TIRs) to DNA binding domain (DBD) and their influence on the transposition activity. We could identify two putative boxes in the TIRs which play a significant role in defining the TIR’s affinities to the DBD. Seven mutated TIRs were constructed, differing in affinities based on similarities with those of other plant MLEs. Gel mobility shift assays showed that the TIR mutants with mutation sites G669A-C671A had significantly higher affinities than the mutants with mutation sites C657T-A660T. The high-affinity TIRs indicated that their transposition frequency was 1.5–2.0 times higher than that of the wild type TIRs in yeast transposition assays. The MLE mutants with low-affinity TIRs had relatively lower transposition frequency from that of wild types. We conclude that TIR affinity to DBD significantly affects the transposition activity of Ppmar2. The mutant MLEs highly active TIRs constructed in this study can be used as a tool for bamboo genetic studies.

The complete mitochondrial genome sequence and phylogenetic analysis of Lycocerus asperipennis (Coleoptera, Cantharidae)

The complete mitochondrial genome of a common Chinese soldier beetle was sequenced, Lycocerus asperipennis (Coleoptera, Cantharidae, Cantharinae). The mitogenome is a double-stranded circular molecule, and the obtained sequence with 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA subunits, and an AT-rich region, as in other insects. Total length of this mitogenome is 16162 bp and the composition of each base is A (41.5%), T (37.7%), C (12.4%), G (8.4%), respectively. The phylogenetic tree analysis using 16 species of Elateriformia shows that L. asperipennis is closest to Chauliognathus opacus, which belongs to the subfamily Chauliognathinae of Cantharidae.

The complete mitochondrial genome sequences of two insect-tea producers in Pyralidae (Lepidoptera) from South China: Pyralis farinalis and Orthopygia glaucinalis

Complete mitochondrial genomes of Pyralis farinalis and Orthopygia glaucinalis were sequenced, respectively. Both contains 13 protein-coding genes (PCGs), 22 tRNA, two rRNA genes, and one AT-rich region. Pyralis farinlis mitogenome was 15,204 bp, with 11,234 bp coding 3732 aa. The rRNA had 1004 bp LSU and 802 bp SSU. Mitogenome of O. glaucinalis was 15,032 bp, with 11,038 bp coding 3668 aa. The rRNA contained 1406 bp LSU and 814 bp SSU. All PCGs used TAN as stop codon, except for both ND4 and ND5 of O. glaucinalis. Phylogenetic relationship of both species was also shown with 13 references.

The complete mitochondrial genome of Sarcophaga brevicornis (Diptera: Sarcophagidae)

Sarcophaga brevicornis (Diptera: Sarcophagidae) was of utmost forensic importance due to their wide distribution, ubiquitous, and synanthropic nature. The complete mitochondrial genome (mitogenome) of S. brevicornis was first sequenced and assembled in this study. The length of circular mitogenome was 15,152 bp, which showed in a typical arthropod genome, including 13 protein-coding genes (13 PCGs), two ribosomal RNA (two rRNA) genes, 22 transfer RNA (22 tRNA) genes, and an AT-rich region. Its nucleotide composition was A 39.0%, C 12.7%, G 10.6%, and T 37.7%. Furthermore, phylogenetic relationships of S. brevicornis and the published sarcophagid species were evaluated based on 13 PCGs. The results indicated that S. brevicornis was clearly separated from the other sarcophagid species, but it was closed to the species of Sarcophaga similis. This study provided a significant database reference for genetic structure and phylogenetic analysis of Sarcophagidae.

The complete mitochondrial genome of Gibbovalva kobusi (Lepidoptera: Gracillariidae)

In this study, the complete mitochondrial genome (mitogenome) of Gibbovalva kobusi was at first sequenced by high-throughput sequencing. As a circular DNA molecule, the complete mitogenome is 15,717 bp in length (GeneBank accession number: MK956103) and consists of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and an AT-rich region. The nucleotide composition is A (41.0%), C (11.6%), G (7.9%), and T (39.5%). Based on the sequences of complete mitogenome from 11 species as ingroups and 3 superfamily Tineoidea species as outgroups, the phylogenetic trees were constructed. The family Gracilariidae as a monophyletic clade is strongly supported by the bootstrap value of 100%.

The complete mitochondrial genome of Sarcophaga pterygota (Diptera: Sarcophagidae)

Sarcophaga pterygota (Diptera: Sarcophagidae) plays a crucial role in medical and veterinary management. The complete mitochondrial genome (mitogenome) of S. pterygota was first sequenced and annotated. The circle DNA is composed of 13 protein-coding genes (13 PCGs), 2 ribosomal RNA (2 rRNAs), 22 transfer RNA (22 tRNAs) and a AT-rich region. It shows that arrangement of the genes is similar with the classical metazoan. The size of mitogenome is 15,236 bp containing A (40.0%), G (9.3%), T (36.6%), and C (14.1%). Moreover, phylogenetic analysis reveals that the branch of S. pterygota is clustered separately. This study enriches the mitogenome database of flesh flies and represents progress for analyzing of phylogenetic relationships.

The complete mitochondrial genome of the freshwater crab Sinolapotamon patellifer (Decapoda: Brachyura: Potamoidea)

We report the complete mitochondrial genome of Sinolapotamon patellifer for the first time, which is found to be 16,547 base pairs in length, and contains 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA), and one non-coding AT-rich region known as the D-loop. In addition, the mitogenome has 17 intergenic regions ranging from 1 to 1512 bp in length. The mitochondrial genome of S. patellifer is the first mitochondrial genome under the genus Sinolapamon, providing DNA data for species identification, enriching the species diversity of Brachyura, and providing a basis for further studies on population genetics and phylogenetics.