Hemipteran mitochondrial genomes: features, structures and implications for phylogeny.

The study of Hemipteran mitochondrial genomes (mitogenomes) began with the Chagas disease vector, Triatoma dimidiata, in 2001. At present, 90 complete Hemipteran mitogenomes have been sequenced and annotated. This review examines the history of Hemipteran mitogenomes research and summarizes the main features of them including genome organization, nucleotide composition, protein-coding genes, tRNAs and rRNAs, and non-coding regions. Special attention is given to the comparative analysis of repeat regions. Gene rearrangements are an additional data type for a few families, and most mitogenomes are arranged in the same order to the proposed ancestral insect. We also discuss and provide insights on the phylogenetic analyses of a variety of taxonomic levels. This review is expected to further expand our understanding of research in this field and serve as a valuable reference resource.

The Complete Mitochondrial Genome of Mindarus keteleerifoliae (Insecta: Hemiptera: Aphididae) and Comparison with Other Aphididae Insects.

The mitogenome of Mindarus keteleerifoliae Zhang (Hemiptera: Aphididae) is a 15,199 bp circular molecule. The gene order and orientation of M. keteleerifoliae is similarly arranged to that of the ancestral insect of other aphid mitogenomes, and, a tRNA isomerism event maybe identified in the mitogenome of M. keteleerifoliae. The tRNA-Trp gene is coded in the J-strand and the same sequence in the N-strand codes for the tRNA-Ser gene. A similar phenomenon was also found in the mitogenome of Eriosoma lanigerum. However, whether tRNA isomers in aphids exist requires further study. Phylogenetic analyses, using all available protein-coding genes, support Mindarinae as the basal position of Aphididae. Two tribes of Aphidinae were recovered with high statistical significance. Characteristics of the M. keteleerifoliae mitogenome revealed distinct mitogenome structures and provided abundant phylogenetic signals, thus advancing our understanding of insect mitogenomic architecture and evolution. But, because only eight complete aphid mitogenomes, including M. keteleerifoliae, were published, future studies with larger taxon sampling sizes are necessary.

A total-evidence phylogenetic analysis of Hormaphidinae (Hemiptera: Aphididae), with comments on the evolution of galls.

A phylogenetic analysis of Hormaphidinae is presented based on a total-evidence approach. Four genes (two mitochondrial, COI and CytB, and two nuclear, EF-1α and LWO) are combined with 65 morphological and seven biological characters. Sixty-three hormaphidine species representing three tribes and 36 genera as well as nine outgroups are included. Parsimony and model-based approaches are used, and several support values and implied weighting schemes are explored to assess clade stability. The monophyly of Hormaphidinae and Nipponaphidini is supported, but Cerataphidini and Hormaphidini are not recovered as monophyletic. Based on the parsimony hypothesis from the total-evidence analysis, the phylogenetic relationships within Hormaphidinae are discussed. Cerataphidini is re-delimited to exclude Doraphis and Tsugaphis, and Hormaphidini is redefined to include Doraphis. Ceratocallis Qiao & Zhang is established as a junior synonym of Ceratoglyphina van der Goot, syn. nov. Lithoaphis quercisucta Qiao, Guo & Zhang is transferred to the genus Neohormaphis Noordam as Neohormaphis quercisucta (Qiao, Guo & Zhang) comb. nov. Galls have evolved independently within three tribes of Hormaphidinae. In Cerataphidini, pseudogalls are ancestral, both single-cavity and multiple-cavity galls have evolved once, and galls appear to have evolved towards greater complexity. Galling on secondary hosts has evolved twice in hormaphidines.

The fern-feeder aphids (Hemiptera: Aphididae) from China: a generic account, descriptions of one new genus, one new species, one new subspecies, and keys.

Fern-feeder aphids (Hemiptera: Aphididae) in China are represented by 13 species in 10 genera, including a new genus, Vietaphis gen nov., a new species, Vietaphis aliquantus sp nov., from Guizhou and Tibet on Plagiogyria japonicum, and a new subspecies, Amphorophora scabripes galba ssp nov., from Guizhou on Pentarhizidium intermedium. Two genera, Amphorophora Buckton and Idiopterus Davis, and four species or subspecies, Amphorophora ampullate ben-galensis Hille Ris Lambers and Basu, Idiopterus nephrelepidis Davis, Micromyzodium polypodii Takahashi, and Myzus filicis Basu, are reported for the first time in China. Apterae and alatae of Myzus filicis are redescribed herein, and with host plant notes. The fern-feeder aphid genus Ne-omacromyzus Lee is considered a junior synonym of Idiopterus. Furthermore, Neomacromyzus cyrtomicola Lee is transferred to the genus Idiopterus, as Idiopterus cyrtomicola (Lee), comb nov., which is herein considered a junior synonym of Idiopterus nephrelepidis Davis. Keys to Chinese fern-feeder species are provided. Morphological figures and biometrical data of Vietaphis aliquantus sp nov., Amphorophora scabripes galba ssp nov., and Myzus filicis are presented.

An integrative strategy used by the aphid Uroleucon formosanum to counter host sesquiterpene lactone defense: Insights from combined genomic and transcriptomic analysis.

Insect herbivores adapt and develop strategies to counteract plant chemical defenses. The aphid Uroleucon formosanum is a serious sap-sucking pest that infests lettuces containing toxic sesquiterpene lactones (STLs). Herein, we employed a combination of genome sequencing and RNA-seq transcriptome profiling to understand the mechanisms underlying phytotoxin tolerance in U. formosanum. We generated the first chromosome-level genome assembly for U. formosanum, with a total size of 453.26 Mb and a scaffold N50 of 33.22 Mb. Comparative genomic analyses revealed an enrichment of signals for positive selection and gene family expansion in immune-related pathways. Specifically, the expanded set of heat shock protein 70 (HSP70) genes showed upregulation after treatment with lactucin, suggesting that they may play a role in the immune response against STLs. The expression of takeout-like genes and cuticle-associated genes was also significantly increased in the lactucin-treated samples. Additionally, 53 cytochrome P450 monooxygenase, 30 carboxylesterase, 19 glutathione S-transferase, 32 uridine diphosphate glycosyltransferase and 63 ATP-binding cassette (ABC) transporter genes were identified in the U. formosanum genome. CYP4C1, CYP6A13 and 7 ABC genes were strongly upregulated in response to lactucin treatment, indicating the involvement of detoxifying enzymes in the tolerance of U. formosanum to STLs. Our findings suggest that the cuticle barrier, immune response and enzyme-mediated metabolic detoxification jointly enhance the tolerance of U. formosanum to phytotoxins and promote its adaptation to host plants. This study presents a valuable genomic resource and provides insights into insect adaptation to plant chemical challenges and future technological developments for pest management.

[The molecular epidemiology characteristics of norovirus in environment and clinical samples in Guangzhou from 2009 to 2011].

OBJECTIVE: To investigate the molecular epidemiological characteristics of norovirus in Guangzhou from 2009 to 2011. METHODS: A total of 183 water samples, 1162 seafood samples and 1066 diarrhea stool specimens were collected from January 2010 to May 2011, June 2009 to June 2011 and July 2009 to December 2010 respectively in Guangzhou. Norovirus was detected by real time reverse transcript-PCR (qRT-PCR). The partial polymerase gene was amplified from norovirus positive samples, then sequenced and compared with the sequences of norovirus in GenBank. The phylogenetic tree was created. RESULTS: The positive rate was 19.67% (36/183), 8.26% (96/1162) and 37.05% (395/1066) in water samples, seafood and diarrhea patients respectively. Noroviruses from positive samples could be divided into 10 representative strains, in which 7 representative strains of genotype of 208 samples was type G2-4. The sequences from water, seafood and stool specimens were highly homologous with the similarity of 94% - 100%. CONCLUSION: In Guangzhou, the predominant Norovirus genotype was G2-4 and the positive rate of samples was high.

Two new species of Sinolachnus Hille Ris Lambers (Hemiptera, Aphididae, Lachninae) from China.

Two new Sinolachnus species from China, Sinolachnusrubusis Qiao & Li, sp. nov. feeding on Rubus sp. from Shaanxi and Sichuan Provinces, and Sinolachnusyunnanensis Qiao & Li, sp. nov. feeding on Elaeagnus sp. from Yunnan Province, are described and illustrated. Keys to Sinolachnus species distributed in China are presented. All examined specimens are deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

Cavariella Del Guercio (Hemiptera, Aphidinae, Macrosiphini) in China, with a new species, new synonymies, and first country records.

The genus Cavariella is distinguished from other Macrosiphini genera (Aphididae, Aphidinae) because it has a supra-caudal process on abdominal tergite VIII which possesses two setae distally. It is Holarctic in distribution, and half of its species are Asian. The Chinese fauna of this genus, 17 species, have been restudied, morphologically and through DNA barcodes. As a result: Cavariellahidaensis Takahashi is transferred to Elatobium; Cavariellasculptura Qiao & Xu, sp. nov. is described from specimens collected on Torilis and Cryptotaenia (Apiaceae); Cavariellacessana Zhang, Chen, Zhong & Li, syn. nov. and Cavariellalargispiracula Zhang, Chen, Zhong & Li, syn. nov. are respectively junior synonyms of Cavariellaaquatica (Gillette & Bragg) and Cavariellasapporoensis Takahashi; Cavariellagilgiana Zhang, Chen, Zhong & Li and Cavariellalhasana Zhang are confirmed as valid species and complete descriptions are provided; Cavariellabhutanensis Chakrabarti & Das, Cavariellanigra Basu, Cavariellapastinacae (Linnaeus), and Cavariellapustula Essig are recorded for the first time from China. Additionally, keys for species of Cavariella known in China are provided and modifications to the key by Blackman and Eastop of aphid species on Angelica (Aphids on World's Plants) are presented.

Six new species of Aspidophorodon Verma, 1967 (Hemiptera, Aphididae, Aphidinae) from China.

The genus Aspidophorodon Verma is presented including six new species from China namely Aspidophorodoncapitatum Qiao & Xu, sp. nov. Aspidophorodonlongicornutum Qiao & Xu, sp. nov. Aspidophorodonreticulatum Qiao & Xu, sp. nov. Aspidophorodonfurcatum Qiao & Xu, sp. nov. Aspidophorodonlongirostre Qiao & Xu, sp. nov. and Aspidophorodonobtusirostre Qiao & Xu, sp. nov. Aspidophorodoncornuatum Qiao 2015, is considered as a junior synonym of Aspidophorodonlongituberculatum (Zhang Zhong & Zhang 1992), syn. nov. Two species Aspidophorodonharvense Verma and Aspidophorodonindicum (David Rajasingh & Narayanan) are recorded for the first time in China. The genus is mainly distributed in East Asia and is represented by 15 species in the world of which 12 are found in China. Keys to the species of Aspidophorodon are given.

Diversity of bacteria associated with Hormaphidinae aphids (Hemiptera: Aphididae).

Bacteria are ubiquitous inhabitants of animals. Hormaphidinae is a particular aphid group exhibiting very diverse life history traits. However, the microbiota in this group is poorly known. In the present study, using high-throughput sequencing of bacterial 16S ribosomal RNA gene amplicons, we surveyed the bacterial flora in hormaphidine aphids and explored whether the aphid tribe, host plant and geographical distribution are associated with the distribution of secondary symbionts. The most dominant bacteria detected in hormaphidine species are heritable symbionts. As expected, the primary endosymbiont Buchnera aphidicola is the most abundant symbiont across all species and has cospeciated with its host aphids. Six secondary symbionts were detected in Hormaphidinae. Arsenophonus is widespread in Hormaphidinae species, suggesting the possibility of ancient acquisition of this symbiont. Ordination analyses and statistical tests show that the symbiont composition does not seem to relate to any of the aphid tribes, host plants or geographical distributions, which indicate that horizontal transfers might occur for these symbionts in Hormaphidinae. Correlation analysis exhibits negative interference between Buchnera and coexisting secondary symbionts, while the interactions between different secondary symbionts are complicated. These findings display a comprehensive picture of the microbiota in Hormaphidinae and may be helpful in understanding the symbiont diversity within a group of aphids.

 Neothelaxespileata, a new species from China (Hemiptera, Sternorrhyncha, Aphididae, Thelaxinae).

Neothelaxespileata Qiao sp. nov., found on Pileamartinii (Urticaceae) in China, is described and illustrated. Neothelaxes Chakrabarti & Quednau is also a new generic record for China.

Review of Mesocallis Matsumura from China (Hemiptera, Aphididae), with one new species.

The aphid genus Mesocallis Matsumura in China is reviewed. A total of seven species are recognised using morphological characteristics, including six known species, Mesocallis (Mesocallis) alnicola Ghosh, M. (Paratinocallis) corylicola (Higuchi), M. (M.) pteleae Matsumura, M. (M.) sawashibae (Matsumura), M. (P.) yunnanensis (Zhang) and M. (M.) taoi Quednau, and one new species, M. (M.) platycaryae Qiao, sp. nov. The new species, collected on Platycarya strobilacea (Juglandaceae) in Anhui Province, China, is described and illustrated. A key to Mesocallis species from China is presented.

Host Plants Influence the Symbiont Diversity of Eriosomatinae (Hemiptera: Aphididae).

Eriosomatinae is a particular aphid group with typically heteroecious holocyclic life cycle, exhibiting strong primary host plant specialization and inducing galls on primary host plants. Aphids are frequently associated with bacterial symbionts, which can play fundamental roles in the ecology and evolution of their host aphids. However, the bacterial communities in Eriosomatinae are poorly known. In the present study, using high-throughput sequencing of the bacterial 16S ribosomal RNA gene, we surveyed the bacterial flora of eriosomatines and explored the associations between symbiont diversity and aphid relatedness, aphid host plant and geographical distribution. The microbiota of Eriosomatinae is dominated by the heritable primary endosymbiont Buchnera and several facultative symbionts. The primary endosymbiont Buchnera is expectedly the most abundant symbiont across all species. Six facultative symbionts were identified. Regiella was the most commonly identified facultative symbiont, and multiple infections of facultative symbionts were detected in the majority of the samples. Ordination analyses and statistical tests show that the symbiont community of aphids feeding on plants from the family Ulmaceae were distinguishable from aphids feeding on other host plants. Species in Eriosomatinae feeding on different plants are likely to carry different symbiont compositions. The symbiont distributions seem to be not related to taxonomic distance and geographical distance. Our findings suggest that host plants can affect symbiont maintenance, and will improve our understanding of the interactions between aphids, their symbionts and ecological conditions.

[Risk assessment of H5N1 human infection after an outbreak of avian influenza in water fowl].

OBJECTIVE: To evaluate the risk of human infection after the outbreak of avian influenza H5N1 in animals, and probe the possibility for virus transmission. METHODS: By means of field epidemiological study, molecular epidemiology, serology and emergency surveillance, persons who had ever closely contacted with sick or dead poultry were observed. While, the RT-PCR and gene sequencing method were used to detect H5 nucleic acid from environmental swabs from 4 epidemic spots, and hemagglutination inhibition assay was also used to detect H5 antibody. RESULTS: Of 22 environmental swabs detected from 4 epidemic spots, one was positive for H5 nucleic acid, and the homogeneity was 95.9% as compared with H5N1 virus A/China/GD01/2006 (H5N1) found in Guangzhou in 2006 by gene sequence analysis. 62 environmental swabs from live poultry stalls of food markets near epidemic spot were detected negative. Six of 68 blood samples of contacts were positive for H9 antibody, and all were negative for H5 antibody. 68 throat swabs of contacts were detected negative for H5 nucleic acid. No close contact was found abnormal after 7 days medical observation. 337 influenza-like cases were reported in emergency surveillance, and no suspicious case was found. CONCLUSION: The current outbreak of H5N1 avian influenza in water fowls has not yet caused further transmission, and human avian influenza case has not been observed. It indicates that the ability of H5N1 virus to transmit to human is not strong yet, and the risk of human infection for H5N1 is still low.

The mitochondrial genome of Greenidea psidii van der Goot (Hemiptera: Aphididae: Greenideinae) and comparisons with other Aphididae aphids.

The complete mitochondrial genome of Greenidea psidii was sequenced and compared with the genomes of other aphid species. The G. psidii mitogenome is 16,202 bp long with an A + T content of 85.4%, comprising 37 genes arranged in the same order as the inferred insect ancestral arrangement, a control region and a special repeat region between trnE and trnF. G. psidii is the first representative possessing such a repeat region from the subfamily Greenideinae. These repeat motifs found in Aphidinae, Eriosomatinae and Greenideinae are species-specific, differing in nucleotide composition, length and copy number across different species. All reported complete aphid mitogenomes are A- and C-skewed in the whole genomes and show opposite skewness for C and G between the majority and minority strands. The ratios of nonsynonymous to synonymous substitution rates indicated that the evolution of the aphid mitogenomes has been dominated by purifying selection. Based on whole mitogenome sequences, the phylogenetic relationships among all aphid species with complete mitogenomes were investigated. G. psidii was robustly clustered with Cervaphis quercus, confirming its affiliation with the subfamily Greenideinae.

The genes expression difference between winged and wingless bird cherry-oat aphid Rhopalosiphum padi based on transcriptomic data.

Aphids produce wing and wingless morphs, depending on the environmental conditions during their complex life cycles. Wing and wingless variations play an important role in migration and host alternation, affecting the migration and host alternation processes. Several transcriptional studies have concentrated on aphids and sought to determine how an organism perceives environmental cues and responds in a plastic manner, but the underlying mechanisms have remained unclear. Therefore, to better understand the molecular mechanisms underlying the wing polyphenism of this fascinating phenomenon, we provide the first report concerning the wing development of aphids in bird cherry-oat aphid Rhopalosiphum padi with comparative transcriptional analysis of all the developmental stages by RNA-Seq. We identified several candidate genes related to biogenic amines and hormones that may be specifically involved in wing development. Moreover, we found that the third instar stage might be a critical stage for visibility of alternative morphs as well as changes in the expression of thirty-three genes associated with wing development. Several genes, i.e., Wnt2, Fng, Uba1, Hh, Foxo, Dpp, Brk, Ap, Dll, Hth, Tsh, Nub, Scr, Antp, Ubx, Asc, Srf and Fl, had different expression levels in different developmental stages and may play important roles in regulating wing polyphenism.

Insect-bacteria parallel evolution in multiple-co-obligate-aphid association: a case in Lachninae (Hemiptera: Aphididae).

Parallel phylogenies between aphid and its obligate symbiont Buchnera are hot topics which always focused on aphid lower taxonomic levels. Symbionts in the subfamily Lachninae are special. Buchnera in many lachnine species has undergone functional and genome size reduction that was replaced by other co-obligate symbionts. In this study, we constructed the phylogenetic relationships of Lachninae with a combined dataset of five genes sequenced from Buchnera to estimate the effects of a dual symbiotic system in the aphid-Buchnera cospeciation association. The phylogeny of Buchnera in Lachninae was well-resolved in the combined dataset. Each of the genera formed strongly supported monophyletic groups, with the exception of the genus Cinara. The phylogeny based on sequences from Buchnera was divided into five tribes according to the clades of the Lachninae hosts tree, with the phylogenies of Buchnera and Lachninae being generally congruent. These results first provided evidence of parallel evolution at the aphid subfamily level comprehensively and supported the view that topological congruence between the phylogenies of Buchnera and Lachninae would not be interfered with the other co-obligate symbionts, such as Sarretia, in aphid-entosymbiont association. These results also provided new insight in understanding host-plant coevolution in lachnine lineages.

DNA barcoding and species delimitation of Chaitophorinae (Hemiptera, Aphididae).

Chaitophorinae aphids are widespread across Eurasia and North America, and include some important agricultural and horticultural pests. So, accurate rapid species identification is very important. Here, we used three mitochondrial genes and one endosymbiont gene to calculate and analyze the genetic distances within different datasets. For species delimitation, two distance-based methods were employed, threshold with NJ (neighbor-joining) and ABGD (Automatic Barcode Gap Discovery), and two tree-based approaches, GMYC (General Mixed Yule Coalescent) and PTP (Poisson Tree Process). The genetic interspecific divergence was clearly larger than the intraspecific divergence for four molecular markers. COI and COII genes were found to be more suitable for Chaitophorinae DNA barcoding. For species delimitation, at least one distance-based method combined with one tree-based method would be preferable. Based on the data for Chaitophorus saliniger and Laingia psammae, DNA barcoding may also reveal geographical variation.

The dengue preface to endemic in mainland China: the historical largest outbreak by Aedes albopictus in Guangzhou, 2014.

BACKGROUND: Dengue was regarded as a mild epidemic in mainland China transmitted by Aedes albopictus. However, the 2014 record-breaking outbreak in Guangzhou could change the situation. In order to provide an early warning of epidemic trends and provide evidence for prevention and control strategies, we seek to characterize the 2014 outbreak through application of detailed cases and entomological data, as well as phylogenetic analysis of viral envelope (E) gene. METHODS: We used case survey data identified through the Notifiable Infectious Disease Report System, entomological surveillance and population serosurvey, along with laboratory testing for IgM/IgG, NS1, and isolation of viral samples followed by E gene sequencing and phylogenetic analysis to examine the epidemiological and molecular characteristics of the outbreak. RESULTS: The 2014 dengue outbreak in Guangzhou accounted for nearly 80% of total reported cases that year in mainland China; a total of 37,376 cases including 37,340 indigenous cases with incidence rate 2908.3 per million and 36 imported cases were reported in Guangzhou, with 14,055 hospitalized and 5 deaths. The epidemic lasted for 193 days from June 11 to December 21, with the highest incidence observed in domestic workers, the unemployed and retirees. The inapparent infection rate was 18.00% (135/750). In total, 96 dengue virus 1 (DENV-1) and 11 dengue virus 2 (DENV-2) strains were isolated. Phylogenetic analysis indicated that the DENV-1 strains were divided into genotype I and V, similar to the strains isolated in Guangzhou and Dongguan in 2013. The DENV-2 strains isolated were similar to those imported from Thailand on May 11 in 2014 and that imported from Indonesia in 2012. CONCLUSIONS: The 2014 dengue epidemic was confirmed to be the first co-circulation of DENV-1 and DENV-2 in Guangzhou. The DENV-1 strain was endemic, while the DENV-2 strain was imported, being efficiently transmitted by the Aedes albopictus vector species at levels as high as Aedes aegypti.

Yamatochaitophorus yichunensis, a new species of aphid (Aphididae: Chaitophorinae) from northeast China.

Yamatochaitophorus yichunensis sp. n. is described from specimens collected in northeast China on Acer tegmentosum (Aceraceae). Yamatochaitophorus is also a new generic record for China. Type specimens are deposited in the National Zoological Museum of China, Institute of Zoology, Chinese Academy of Sciences, Beijing, China (NZMC) and the Natural History Museum, London, UK (BMNH).