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1.
BMC Evol Biol ; 20(1): 154, 2020 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-33213363

RESUMO

BACKGROUND: The white-backed planthopper (WBPH), Sogatella furcifera (Horváth) (Hemiptera, Delphacidae), is a migratory pest of rice in Asia. Shandong Province, in northern China, is located on the migration pathway of WBPH between southern and northeast China. The potential sources of WBPH in northern China are poorly understood. We studied the sources of WBPH in Shandong Province by determining the population genetic structure of WBPH in 18 sites distributed in Shandong and in six regions of the Greater Mekong Subregion (GMS). We used mitochondrial gene and single-nucleotide polymorphism (SNP) markers for analysis. RESULTS: All of the WBPH populations studied in the seven regions had low genetic diversity. Pairwise FST values based on mtDNA ranged from - 0.061 to 0.285, while FST based on SNP data ranged from - 0.007 to 0.009. These two molecular markers revealed that 4.40% (mtDNA) and 0.19% (SNP) genetic variation could be explained by the interpopulation variation, while the rest came from intrapopulation variation. The populations in the seven geographic regions comprised four hypothetical genetic clusters (K = 4) not associated with geographic location. Eighty-four of 129 individuals distributed across the given area were designated as recent migrants or of admixed ancestry. Although the substantial migration presented, a weak but significant correlation between genetic and geographic distances was found (r = 0.083, P = 0.004). CONCLUSION: The Greater Mekong Subregion was the main genetic source of WBPH in Shandong, while other source populations may also exist. The genetic structure of WBPH is shaped by both migration and geographic barriers. These results help clarify the migration route and the source of WBPH in northern China.


Assuntos
Migração Animal , DNA Mitocondrial/genética , Genética Populacional , Hemípteros , Polimorfismo de Nucleotídeo Único , Animais , Ásia , China , Hemípteros/genética , Oryza
2.
PLoS One ; 15(9): e0238549, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32903256

RESUMO

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a destructive pest that poses a significant threat to rice plants worldwide. To explore how BPHs adapt to the resistant rice variety, we analyzed proteomics profiles of two virulent N. lugens populations. We focused on Biotype Y, which can survive on the moderately resistant rice variety YHY15, and Biotype I, which can survive on the susceptible rice variety TN1. We performed protein quantitation using the isobaric tag for relative and absolute quantification (iTRAQ) and then compared the expression patterns between two virulent N. lugens populations and found 258 differentially expressed proteins (DEPs). We found that 151 of the DEPs were up-regulated, while 107 were down-regulated. We evaluated transcript levels of 8 expressed genes from the iTRAQ results by qRT-PCR, which revealed transcriptional changes that were consistent with the changes at the protein level. The determination of the protein changes in two virulent N. lugens populations would help to better understanding BPH adaptation to resistant rice varieties and facilitate the better design of new control strategies for host defense against BPH.


Assuntos
Hemípteros/genética , Proteínas de Insetos/genética , Oryza/parasitologia , Doenças das Plantas/parasitologia , Animais , Resistência à Doença , Regulação para Baixo , Perfilação da Expressão Gênica , Hemípteros/fisiologia , Interações Hospedeiro-Parasita , Proteômica , Transcriptoma , Regulação para Cima
3.
PLoS One ; 15(8): e0237744, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841246

RESUMO

Both the Mediterranean (MED) species of the Bemisia tabaci whitefly complex and the greenhouse whitefly (Trialeurodes vaporariorum, TV) are important agricultural pests. The two species of whiteflies differ in many aspects such as morphology, geographical distribution, host plant range, plant virus transmission, and resistance to insecticides. However, the molecular basis underlying their differences remains largely unknown. In this study, we analyzed the genetic divergences between the transcriptomes of MED and TV. In total, 2,944 pairs of orthologous genes were identified. The average identity of amino acid sequences between the two species is 93.6%. The average nonsynonymous (Ka) and synonymous (Ks) substitution rates and the ratio of Ka/Ks of the orthologous genes are 0.0389, 2.23 and 0.0204, respectively. The low average Ka/Ks ratio indicates that orthologous genes tend to be under strong purified selection. The most divergent gene classes are related to the metabolisms of xenobiotics, cofactors, vitamins and amino acids, and this divergence may underlie the different biological characteristics between the two species of whiteflies. Genes of differential expression between the two species are enriched in carbohydrate metabolism and regulation of autophagy. These findings provide molecular clues to uncover the biological and molecular differences between the two species of whiteflies.


Assuntos
Produção Agrícola , Genes de Insetos/genética , Especiação Genética , Hemípteros/genética , Proteínas de Insetos/genética , Sequência de Aminoácidos/genética , Substituição de Aminoácidos/genética , Aminoácidos/metabolismo , Animais , Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Região do Mediterrâneo , Anotação de Sequência Molecular , RNA-Seq , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Vitaminas/metabolismo , Xenobióticos/metabolismo
4.
PLoS Pathog ; 16(8): e1008710, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32817722

RESUMO

Rice stripe virus (RSV, genus Tenuivirus, family Phenuiviridae) is the causal agent of rice stripe disease transmitted by the small brown planthopper (SBPH, Laodelphax striatellus) in a persistent propagative manner. The midgut and salivary glands of SBPH are the first and last barriers to the viral circulation and transmission processes, respectively; however, the precise mechanisms used by RSV to cross these organs and transmit to rice plants have not been fully elucidated. We obtained the full-length cDNA sequence of L. striatellus α-tubulin 2 (LsTUB) and found that RSV infection increased the level of LsTUB in vivo. Furthermore, LsTUB was shown to co-localize with RSV nonstructural protein 3 (NS3) in vivo and bound NS3 at positions 74-76 and 80-82 in vitro. Transient gene silencing of LsTUB expression caused a significant reduction in detectable RSV loads and viral NS3 expression levels, but had no effect on NS3 silencing suppressor activity and viral replication in insect cells. However, suppression of LsTUB attenuated viral spread in the bodies of SBPHs and decreased RSV transmission rates to rice plants. Electrical penetration graphs (EPG) showed that LsTUB knockdown by RNAi did not impact SBPH feeding; therefore, the reduction in RSV transmission rates was likely caused by a decrease in viral loads inside the planthopper. These findings suggest that LsTUB mediates the passage of RSV through midgut and salivary glands and leads to successful horizontal transmission.


Assuntos
Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Insetos Vetores/metabolismo , Oryza/virologia , Doenças das Plantas/virologia , Tenuivirus/fisiologia , Tubulina (Proteína)/metabolismo , Animais , Sistema Digestório/metabolismo , Sistema Digestório/virologia , Hemípteros/genética , Hemípteros/virologia , Proteínas de Insetos/genética , Insetos Vetores/genética , Insetos Vetores/virologia , Glândulas Salivares/metabolismo , Glândulas Salivares/virologia , Tubulina (Proteína)/genética
5.
Sci Rep ; 10(1): 9418, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32523040

RESUMO

The Asian citrus psyllid (ACP; Diaphorina citri) is the vector of Candidatus Liberibacter asiaticus (CLas) that is associated with the devastating Huanglongbing (HLB; citrus greening disease). This pest of Asian origin has spread into the Americas and more recently into a few countries in East Africa. During recent surveys, suspect ACP adults and nymphs were recorded for the first time infesting citrus trees in southwest Nigeria. Morphological identification and DNA barcoding confirmed the samples to be D. citri. Analysis of the obtained sequences revealed that the ACP recorded in Nigeria clustered with other taxa in the previously identified B1 clade that consists of populations from different continents. The presence of the endosymbionts Ca. Carsonella ruddii and Ca. Profftella armatura in ACP from Nigeria was also confirmed by PCR and Sanger sequencing. The ACP individuals were assayed for the presence of CLaf, CLam and CLas by qPCR, but none of the insects tested positive for any of the Liberibacters. The prolific nature of ACP and the tropical climate prevailing in the citrus-producing areas of Nigeria and other West African countries may favor its rapid spread and population increase, thus posing a grave threat to the sustainability of citriculture in these countries.


Assuntos
Citrus/parasitologia , Hemípteros/genética , Espécies Introduzidas , Doenças das Plantas/parasitologia , África Oriental , África Ocidental , Animais , Insetos Vetores/genética , Nigéria , Ninfa/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Rhizobiaceae/genética
6.
Pest Manag Sci ; 76(11): 3857-3870, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32483911

RESUMO

BACKGROUND: The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a notorious pest that transmits the causal agent of huanglongbing (also called citrus greening disease). Resistance to insecticide in this destructive pest poses a serious threat to the citrus industry. To date, no systemic studies on genes coding for detoxification enzymes has been carried out on D. citri. RESULTS: Multiple transcriptomes were generated through deep sequencing of RNA libraries. Candidate genes potentially involved in detoxification including cytochrome P450 monooxygenases (CYPs), glutathione S-transferases (GSTs), and esterases (ESTs) were systematically identified by searching the transcriptomes and a draft genome assembly. A total of 49, 14 and 20 genes were found encoding CYPs, GSTs, and ESTs, respectively, in D. citri. The total numbers of candidate detoxification genes were much smaller than the counterparts reported in other insect species, which may reflect the strict oligophagy of this insect species. Developmental stage- and tissue-specific expression patterns of the identified genes as well as their responses to insecticide treatments identified a small set of genes that could participate in detoxifying plant secondary metabolites and insecticides. CONCLUSION: Our studies represent the most comprehensive investigation to date on identification, characterization and expression profiling of detoxification genes in D. citri. The information revealed in this study shall be useful in designing strategies to manage this important insect pest. © 2020 Society of Chemical Industry.


Assuntos
Citrus , Hemípteros , Animais , Perfilação da Expressão Gênica , Hemípteros/genética , Inseticidas , Transcriptoma
7.
Pest Manag Sci ; 76(11): 3649-3656, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32418333

RESUMO

BACKGROUND: Brown rice planthopper (BPH) is a devastating rice pest in Asia. Bph14 is the first cloned BPH-resistance gene in rice, inducing callose deposition while impeding BPH feeding. Nitrogen application affects plant growth and resistance. However, there is little evidence on the influence of nitrogen on the callose content or regulation of rice BPH resistance. In this study, Luoyou9348 (containing Bph14 and highly resistant to BPH) and Yangliangyou6 (without Bph14 and susceptible to BPH) were planted under varying nitrogen regimes (0 , 90, 180 kg ha-1 ) to determine their effects on the resistance levels of rice to BPH feeding. The experiments involved BPH performance, plant volatile profiling and BPH preferences in laboratory and field experiments. RESULTS: We found that BPH egg hatching rate, total number of eggs laid and BPH preference increased with increasing nitrogen application in both rice varieties. However, the expression of Bph14, callose content and BPH feeding significantly declined with an increase in nitrogen fertilization in Luoyou9348, compared with Yangliangyou6. Also, the emission of volatile terpene compounds increased with increasing nitrogen application, which resulted in an increase in BPH numbers on both varieties. Two-way analysis of variance indicated a significant interaction between rice variety and nitrogen in BPH feeding behavior. CONCLUSION: Our findings provide an insight for addressing problems involved in the incorporation of insecticidal genes into crop plants. The effects of nitrogen on insecticidal gene expression in rice plant defense are discussed. © 2020 Society of Chemical Industry.


Assuntos
Hemípteros , Animais , Ásia , Clonagem Molecular , Hemípteros/genética , Proteínas de Insetos , Nitrogênio , Oryza/genética
8.
PLoS One ; 15(5): e0232616, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32379806

RESUMO

Bemisia tabaci (sensu latu) is a group of >40 highly cryptic whitefly species that are of global agricultural importance, both as crop pests and plant-virus vectors. Two devastating cassava diseases in East and Central Africa are spread by abundant populations of one of these species termed Sub-Saharan Africa 1 (SSA1). There is a substantive risk that these whitefly-borne pandemics will continue to spread westwards and disrupt cassava production for millions of smallholder farmers in West Africa. We report here, therefore, the first comprehensive survey of cassava B. tabaci in eastern Nigeria, a West African region likely to be the first affected by the arrival of these whitefly-borne pandemics. We found one haplotype comprising 32 individuals with 100% identical mtCO1 sequence to the East African SSA1 populations (previously termed SSA1-SG1) and 19 mtCO1 haplotypes of Sub-Saharan Africa 3 (SSA3), the latter being the most prevalent and widely distributed B. tabaci species in eastern Nigeria. A more divergent SSA1 mtCO1 sequence (previously termed SSA1-SG5) was also identified in the region, as were mtCO1 sequences identifying the presence of the MED ASL B. tabaci species and Bemisia afer. Although B. tabaci SSA1 was found in eastern Nigeria, they were not present in the high abundances associated with the cassava mosaic (CMD) and cassava brown streak disease (CBSD) pandemics of East and Central Africa. Also, no severe CMD or any CBSD symptoms were found in the region.


Assuntos
Vetores de Doenças/classificação , Hemípteros/classificação , Doenças das Plantas , Animais , Haplótipos , Hemípteros/genética , Hemípteros/patogenicidade , Manihot/crescimento & desenvolvimento , Nigéria , Filogenia
9.
Proc Natl Acad Sci U S A ; 117(19): 10246-10253, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32327610

RESUMO

The evolution of insect resistance to pesticides poses a continuing threat to agriculture and human health. While much is known about the proximate molecular and biochemical mechanisms that confer resistance, far less is known about the regulation of the specific genes/gene families involved, particularly by trans-acting factors such as signal-regulated transcription factors. Here we resolve in fine detail the trans-regulation of CYP6CM1, a cytochrome P450 that confers resistance to neonicotinoid insecticides in the whitefly Bemisia tabaci, by the mitogen-activated protein kinase (MAPK)-directed activation of the transcription factor cAMP-response element binding protein (CREB). Reporter gene assays were used to identify the putative promoter of CYP6CM1, but no consistent polymorphisms were observed in the promoter of a resistant strain of B. tabaci (imidacloprid-resistant, IMR), which overexpresses this gene, compared to a susceptible strain (imidacloprid-susceptible, IMS). Investigation of potential trans-acting factors using in vitro and in vivo assays demonstrated that the bZIP transcription factor CREB directly regulates CYP6CM1 expression by binding to a cAMP-response element (CRE)-like site in the promoter of this gene. CREB is overexpressed in the IMR strain, and inhibitor, luciferase, and RNA interference assays revealed that a signaling pathway of MAPKs mediates the activation of CREB, and thus the increased expression of CYP6CM1, by phosphorylation-mediated signal transduction. Collectively, these results provide mechanistic insights into the regulation of xenobiotic responses in insects and implicate both the MAPK-signaling pathway and a transcription factor in the development of pesticide resistance.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Resistência a Medicamentos/genética , Regulação da Expressão Gênica , Hemípteros/crescimento & desenvolvimento , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Sistema Enzimático do Citocromo P-450/genética , Hemípteros/efeitos dos fármacos , Hemípteros/genética , Hemípteros/metabolismo , Inseticidas/farmacologia , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação , Fosforilação , Regiões Promotoras Genéticas
10.
Biol Lett ; 16(4): 20190940, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32343935

RESUMO

Geomagnetic field (GMF) intensity can be used by some animals to determine their position during migration. However, its role, if any, in mediating other migration-related phenotypes remains largely unknown. Here, we simulated variation in GMF intensity between two locations along the migration route of a nocturnal insect migrant, the brown planthopper Nilaparvata lugens, that varied by approximately 5 µT in field intensity. After one generation of exposure, we tested for changes in key morphological, behavioural and physiological traits related to migratory performance, including wing dimorphism, flight capacity and positive phototaxis. Our results showed that all three morphological and behavioural phenotypes responded to a small difference in magnetic field intensity. Consistent magnetic responses in the expression of the phototaxis-related Drosophila-like cryptochrome 1 (Cry1) gene and levels of two primary energy substrates used during flight, triglyceride and trehalose, were also found. Our findings indicate changes in GMF intensity can alter the expression of phenotypes critical for insect migration and highlight the unique role of magnetoreception as a trait that may help migratory insects express potentially beneficial phenotypes in geographically variable environments.


Assuntos
Hemípteros , Animais , Hemípteros/genética , Proteínas de Insetos/genética , Campos Magnéticos , Fenótipo , Asas de Animais
11.
Artigo em Inglês | MEDLINE | ID: mdl-32148145

RESUMO

The Cicadellidae (Auchenorrhyncha: Hemiptera) are important agricultural, horticultural and ornamental pests. But it is very difficult to define nymphs and female adults using morphological characteristics. This research was aimed at understanding the variety of leafhoppers species and defining the prospective cause of the aster-yellow disease in China Aster, Marigold and Chrysanthemum. Two surveys were conducted in and around Pune, Maharashtra and Bengaluru, Karnataka between November 2016 and February 2017. The mitochondrial cytochrome oxidase subunit I (mtCOI) region marker was used in the species diagnosis and genetic diversity research. Through the use of mtCOI molecular marker eight different leafhoppers species were identified as Sogatella furcifera, Homalodisca insolita, Amrasca biguttula, Balclutha incise and Balclutha abdominalis and Japanagallia trifurcate. Whereas at genus level identified as Toya, Empoasca, Perkinsiella, Hishimonus, Tambocerus, Phaconeura, Curena, Psammotettix and Graphocophala species. These results are strongly corroborated with morphological identification. On the basis of multiple sequence alignment of the mtCOI gene, a species phylogenetic tree with the highest likelihood was drawn. All the leafhopper species clustered together in accordance with the species data collected from the database of the different geographic regions from the NCBI GenBank and Barcode of Life (BOLD). Such results suggest that it is important to use both molecular and morphological methods to ensure accurate identification of organisms. To conclude, this research contributes valuable knowledge to molecular biology and recognizes leafhopper species that serve as major phytoplasma vectors.


Assuntos
Calendula/genética , Chrysanthemum/genética , Código de Barras de DNA Taxonômico , Hemípteros/genética , Doenças das Plantas/genética , Animais , China , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Genoma Mitocondrial/genética , Filogenia
12.
J Chem Ecol ; 46(4): 363-377, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32125582

RESUMO

Insects have evolved highly sensitive olfactory sensory systems to detect plant hosts and mates, with plant volatiles playing an important role in informing insect behavior. Chemosensory proteins (CSPs) are thought to play a key role in this process, but in this respect, there is limited information on brown planthopper Nilaparvata lugens, one of the most destructive pests of rice. To expand our understanding of CSP function in N. lugens we explored expression profiles and binding characteristics of NlugCSP3. The ligands with higher binding affinity were also validated by molecular docking and behavioral assays. NlugCSP3 mRNA was expressed at relatively higher levels in antennae and abdomen of 3-day-old unmated macropterous males as well as in antennae of 3-day mated macropterous and brachypterous females. Fluorescence competitive binding assays revealed that 5 out of 25 candidate volatiles are strong binders (Ki < 10 µM). Behavioral assays revealed that nonadecane and 2-tridecanone, which have high binding affinities in fluorescence competition-binding assays, displayed strong attractiveness to N. lugens. Pursuing this further, molecular docking analysis identified key amino acid residues involved in binding volatile compounds. Overall, our data provide a base for further investigation of the potential physiological functions of CSP3 in Nilaparvata lugens, and extend the function of NlugCSP3 in chemoreception of N. lugens.


Assuntos
Expressão Gênica , Hemípteros/genética , Proteínas de Insetos/genética , Compostos Orgânicos Voláteis/metabolismo , Fatores Etários , Aminoácidos/metabolismo , Animais , Antenas de Artrópodes/metabolismo , Feminino , Perfilação da Expressão Gênica , Hemípteros/química , Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Ligantes , Masculino , Simulação de Acoplamento Molecular , Reprodução , Fatores Sexuais , Asas de Animais/anatomia & histologia
13.
PLoS One ; 15(3): e0230741, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32214353

RESUMO

The accurate and rapid identification of insect pests is an important step in the prevention and control of outbreaks in areas that are otherwise pest free. The potato-tomato psyllid Bactericera cockerelli (Sulc, 1909) is the main vector of 'Candidatus Liberibacter solanacearum' on potato and tomato crops in North America and New Zealand; and is considered a threat for introduction in Europe and other pest-free regions. This study describes the design and validation of the first species-specific TaqMan probe-based real-time PCR assay, targeting the ITS2 gene region of B. cockerelli. The assay detected B. cockerelli genomic DNA from adults, immatures, and eggs, with 100% accuracy. This assay also detected DNA from cloned plasmids containing the ITS2 region of B. cockerelli with 100% accuracy. The assay showed 0% false positives when tested on genomic and cloned DNA from 73 other psyllid species collected from across Europe, New Zealand, Mexico and the USA. This included 8 other species in the Bactericera genus and the main vectors of 'Candidatus Liberibacter solanacearum' worldwide. The limit of detection for this assay at optimum conditions was 0.000001ng DNA (~200 copies) of ITS2 DNA which equates to around a 1:10000 dilution of DNA from one single adult specimen. This assay is the first real-time PCR based method for accurate, robust, sensitive and specific identification of B. cockerelli from all life stages. It can be used as a surveillance and monitoring tool to further study this important crop pest and to aid the prevention of outbreaks, or to prevent their spread after establishment in new areas.


Assuntos
Código de Barras de DNA Taxonômico , Bases de Dados Genéticas , Hemípteros/classificação , Hemípteros/genética , Lycopersicon esculentum , Reação em Cadeia da Polimerase em Tempo Real/métodos , Animais , Biologia Computacional , Hemípteros/fisiologia , Análise de Sequência de DNA , Fatores de Tempo
14.
Virology ; 542: 54-62, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32056668

RESUMO

Intergenic region of begomovirus genome is vital to virus replication and viral gene transcription in plants. Previous studies have reported that Tomato yellow leaf curl China virus (TYLCCNV), a begomovirus, is able to accumulate and transcribe in its whitefly vector. However, the viral and host components that participate in begomovirus transcription in whiteflies are hitherto unknown. Using a yeast one-hybrid system, we identified >50 whitefly proteins that interacted with TYLCCNV intergenic region. Dual luciferase analysis revealed that one of the identified proteins, the hairy and enhancer of split homolog-1 (HES1), specifically bound to CACGTG motif in TYLCCNV intergenic region. Silencing HES1 decreased viral transcription, accumulation and transmission. These results demonstrate that the interactions between whitefly proteins and the intergenic region of TYLCCNV may contribute to viral transcription in the whitefly vector. Our findings offer valuable clues for the research and development of novel strategies to interfere with begomovirus transmission.


Assuntos
Begomovirus/genética , Hemípteros/metabolismo , Hemípteros/virologia , Proteínas de Insetos/metabolismo , Fatores de Transcrição HES-1/metabolismo , Animais , Begomovirus/patogenicidade , Begomovirus/fisiologia , DNA Intergênico , Técnicas de Silenciamento de Genes , Genoma Viral , Hemípteros/genética , Interações entre Hospedeiro e Microrganismos/genética , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/genética , Insetos Vetores/genética , Insetos Vetores/metabolismo , Insetos Vetores/virologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Ligação Proteica , Tabaco/virologia , Fatores de Transcrição HES-1/antagonistas & inibidores , Fatores de Transcrição HES-1/genética , Transcrição Genética , Técnicas do Sistema de Duplo-Híbrido
15.
Insect Biochem Mol Biol ; 120: 103337, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32109588

RESUMO

As the counterparts of noradrenaline and adrenaline in vertebrates, octopamine (OA) regulates multiple physiological and behavioral processes in invertebrate. OA mediates its effects via binding to specific octopamine receptors (OARs). Functional and pharmacological characterization of OARs have been reported in several insects. However, little work was documented in hemipteran insects. We cloned a ß-adrenergic-like OAR (NcOA2B2) from Nephotettix cincticeps. NcOA2B2 shares high similarity with members of the OA2B2 receptor class. Transcript level of NcOA2B2 varied in various tissues and was highly expressed in the leg. After heterologous expression in CHO-K1 cells, NcOA2B2 was dose-dependently activated by OA (EC50 = 2.56 nM) and tyramine (TA) (EC50 = 149 nM). Besides putative octopaminergic agonists, dopaminergic agonists and amitraz and DPMF potently activated NcOA2B2 in a dose-dependent manner. Receptor activity was blocked by potential antagonists and was most efficiently antagonized by asenapine. Phentolamine showed both antagonist and agonist effects on NcOA2B2. Our results offer the important information about molecular and pharmacological characterization of an OAR from N. cincticeps that will provide the basis for forthcoming studies on its roles in physiological processes and behaviors, and facilitate the design of novel insecticides for pest control.


Assuntos
Regulação da Expressão Gênica , Hemípteros/genética , Proteínas de Insetos/genética , Receptores de Amina Biogênica/genética , Sequência de Aminoácidos , Animais , AMP Cíclico/metabolismo , Dopamina/metabolismo , Hemípteros/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Octopamina/metabolismo , Filogenia , Receptores de Amina Biogênica/química , Receptores de Amina Biogênica/metabolismo , Alinhamento de Sequência , Tiramina/metabolismo
16.
Bull Entomol Res ; 110(4): 521-534, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32037992

RESUMO

Pear psyllids (Hemiptera: Psylloidea: Psyllidae: Cacopsylla spp.) belong to the most serious pests of pear (Pyrus spp.). They damage pear trees by excessive removal of phloem sap, by soiling the fruits with honeydew which, in turn, provides a substrate for sooty mould, and by transmission of Candidatus Phytoplasma spp., the causal agents of the pear decline disease. The morphological similarity, the presence of seasonal dimorphism that affects adult colour, size and wing morphology and uncritical use of species names, led to much confusion in the taxonomy of pear psyllids. As a result, pear psyllids have been frequently misidentified. Many of the entries attributed to Cacopsylla pyricola and other species in the GenBank are misidentifications which led to additional, unnecessary confusion. Here we analysed DNA barcodes of 11 pear psyllid species from eastern Asia, Europe and Iran using four mitochondrial gene fragments (COI 658 bp, COI 403 bp, COI-tRNAleu-COII 580 bp and 16S rDNA 452 bp). The efficiency of identification was notably high and considerable barcoding gaps were observed in all markers. Our results confirm the synonymies of the seasonal forms of Cacopsylla jukyungi ( = C. cinereosignata, winter form) and C. maculatili ( = C. qiuzili, summer form) previously suggested based on morphology. Some previous misidentifications (C. chinensis from China, Japan and Korea = misidentification of C. jukyungi; C. pyricola and C. pyrisuga from East Asia = misidentification of C. jukyungi and C. burckhardti, respectively; C. pyricola from Iran = misidentification of C. bidens, C. pyri and Cacopsylla sp.) are also corrected. There is no evidence for the presence of European pear psyllid species in East Asia.


Assuntos
Hemípteros/química , Hemípteros/genética , Animais , Código de Barras de DNA Taxonômico/métodos , Genes de Insetos , Genes Mitocondriais , Especificidade da Espécie
17.
Bull Entomol Res ; 110(4): 512-520, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32046801

RESUMO

Insecticide resistance is an increasing problem in citrus production. The Asian citrus psyllid, Diaphornia citri Kuwayama, is recognized as one of the most important citrus pests worldwide and it has developed resistance in areas where insecticides have been overused. The development of insecticide resistance is often associated with fitness costs that only become apparent in the absence of selection pressure. Here, the fitness costs associated with resistance to thiamethoxam and imidacloprid were investigated in three agricultural populations of D. citri as compared with susceptible laboratory colonies. Results showed that all field populations had greater resistance than laboratory susceptible colonies. For both thiamethoxam and imidacloprid, a Candidatus Liberibacter asiaticus-positive (CLas+) colony was more susceptible than the CLas- colony. Resistance ratios ranged from 7.65-16.11 for imidacloprid and 26.79-49.09 for thiamethoxam in field populations as compared with a susceptible, CLas- laboratory strain. Among three resistant field populations, a significantly reduced net reproductive rate and finite rate of population increase were observed in a population from Lake Wales, FL as compared to both susceptible strains. The fecundity of field populations from Lake Wales, FL was statistically lower than both laboratory susceptible populations. Certain changes in morphological characteristics were observed among resistant, as compared, with susceptible strains. Our data suggest fitness disadvantages associated with insecticide resistance in D. citri are related to both development and reproduction. The lower fitness of D. citri populations that exhibit resistance to neonicotinoid insecticides should promote recovery of sensitivity when those populations are no longer exposed to thiamethoxam and/or imidacloprid in the field. The results are congruent with a strategy of insecticide rotation for resistance management.


Assuntos
Hemípteros/genética , Hemípteros/fisiologia , Resistência a Inseticidas/genética , Rhizobiaceae , Animais , Citrus , Florida , Inseticidas , Neonicotinoides , Nitrocompostos , Doenças das Plantas/microbiologia , Crescimento Demográfico , Reprodução/fisiologia , Tiametoxam
18.
ISME J ; 14(6): 1384-1395, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32076126

RESUMO

Auchenorrhynchan insects (Hemiptera) generally depend on two bacterial symbionts for nutrition. These bacteria experience extreme genome reduction and loss of essential cell functions that require direct host support, or the replacement of failing symbionts with more capable ones. However, it remains unclear how hosts adapt to integrate symbionts into their systems, particularly when they are replaced. Here, we comparatively investigated the evolution of host-support mechanisms in the glassy-winged sharpshooter, Homalodisca vitripennis (GWSS), and the aster leafhopper, Macrosteles quadrilineatus (ALF). ALF harbors the ancestral co-symbionts of the Auchenorrhyncha that have tiny genomes, Sulcia (190 kb) and Nasuia (112 kb). In GWSS, Sulcia retains an expanded genome (245 kb), but Nasuia was replaced by the more capable Baumannia (686 kb). To support their symbionts, GWSS and ALF have evolved novel mechanisms via horizontal gene transfer, gene duplication, and co-option of mitochondrial support genes. However, GWSS has fewer support systems targeting essential bacterial processes. In particular, although both hosts use ancestral mechanisms to support Sulcia, GWSS does not encode all of the same support genes required to sustain Sulcia-ALF or Nasuia. Moreover, GWSS support of Baumannia is far more limited and tailored to its expanded capabilities. Our results demonstrate how symbiont replacements shape host genomes and the co-evolutionary process.


Assuntos
Fenômenos Fisiológicos Bacterianos , Evolução Biológica , Hemípteros/microbiologia , Simbiose , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Transferência Genética Horizontal , Genoma Bacteriano , Hemípteros/genética , Filogenia
19.
PLoS One ; 15(2): e0228631, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32017800

RESUMO

With the objective of assisting in the understanding of the chromosome evolution of Pentatomomorpha and in the quest to understand how the genome organizes/reorganizes for the chromosomal position of the 45S rDNA in this infraorder, we analyzed 15 species (it has being 12 never studied before by FISH) of Pentatomomorpha with the probe of 18S rDNA. The mapping of the 45S gene in the Coreidae family demonstrated that the species presented markings on the autosomes, with the exception of Acanthocephala parensis and Leptoglossus gonagra that showed markers on m-chromosomes. Most species of the Pentatomidae family showed marking in the autosomes, except for two species that had 45S rDNA on X sex chromosome (Odmalea sp. and Graphosoma lineatum) and two that showed marking on the X and Y sex chromosomes. Species of the Pyrrhocoridae family showed 18S rDNA markers in autosomes, X chromosome as well as in Neo X. The Largidae and Scutelleridae families were represented by only one species that showed marking on the X sex chromosome and on a pair of autosomes, respectively. Based on this, we characterized the arrangement of 45S DNAr in the chromosomes of 12 new species of Heteroptera and discussed the main evolutionary events related to the genomic reorganization of these species during the events of chromosome and karyotype evolution in Pentatomomorpha infraorder.


Assuntos
Cromossomos de Insetos/genética , Evolução Molecular , Heterópteros/genética , Animais , Mapeamento Cromossômico , DNA Ribossômico/genética , Hemípteros/genética , Hibridização in Situ Fluorescente , Filogenia , Ribossomos/genética , Cromossomo X , Cromossomo Y
20.
Gene ; 737: 144446, 2020 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-32035241

RESUMO

The homeotic complex (Hox) gene Ultrabithorax (Ubx) plays pivotal roles in modifying specific morphological differences among the second (T2), the third thoracic (T3), and the first abdomen (A1) segment in several insects. Whether Ubx regulates wing dimorphism and other morphological traits in the delphacid family (order Hemiptera) remains elusive. In this study, we cloned a full-length Ubx ortholog (NlUbx) from the wing-dimorphic planthopper Nilaparvata lugens, and identified two NlUbx isoforms. RNA-interference (RNAi)-mediated silencing of NlUbx in short-winged BPH nymphs significantly induced the development of wing-like appendages from T3 wingbuds, and this effect is likely mediated by the insulin/insulin-like signaling pathway. RNAi knockdown of NlUbx in long-winged BPH nymphs led to a transformation from hindwings to forewings. Additionally, silencing of NlUbx not only dramatically changed the T3 morphology, but also led to jumping defect of T3 legs. First-instar nymphs derived from parental RNAi had an additional leg-like appendages on A1. These results suggest that Ubx plays a role in determining some morphological traits in delphacid planthoppers, and thus help in understanding evolution of morphological characteristics in arthropods.


Assuntos
Hemípteros/genética , Proteínas de Insetos/genética , Asas de Animais/metabolismo , Sequência de Aminoácidos , Animais , Clonagem Molecular , Feminino , Técnicas de Silenciamento de Genes , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/química , Masculino , Alinhamento de Sequência , Asas de Animais/crescimento & desenvolvimento
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