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1.
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
2.
Insect Mol Biol ; 29(1): 38-47, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31260146

RESUMO

The chitin biosynthesis pathway is an important physiology process in arthropods. However, few microRNAs (miRNAs) involved in the regulation of the chitin biosynthesis pathway in insects have been reported until now. In this study, four groups of samples that either upregulated or downregulated the chitin biosynthesis pathway were collected for deep sequencing, and a total of 15 unique mature miRNAs with significantly different expression levels were found, including 11 known miRNAs and four novel miRNAs. Subsequently, we showed that miR-2703 and its new target gene chitin synthase 1a are important for ecdysone-induced chitin biosynthesis in Nilaparvata lugens, a serious insect pest of rice. The nymphs showed an obvious moulting defect phenotype, lower survival rate and significantly reduced chitin content after miR-2703 feeding or injection. Furthermore, we found that the transcription level of miR-2703 was not repressed by 20-hydroxyecdysone signalling after Broad-Complex (BR-C) double-stranded RNA (dsRNA) injection compared with the repressed levels after green fluorescent protein dsRNA injection, suggesting that the involvement of miR-2703 in the 20-hydroxyecdysone pathway contributes to BR-C activity. miR-2703 regulates the chitin biosynthesis pathway by targeting chitin synthase 1a in response to 20-hydroxyecdysone signalling.


Assuntos
Quitina Sintase/genética , Quitina/biossíntese , Hemípteros/genética , MicroRNAs , Animais , Quitina/genética , Ecdisterona , Hemípteros/enzimologia , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Muda/genética , Ninfa/crescimento & desenvolvimento , Interferência de RNA , RNA de Cadeia Dupla , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
3.
J Agric Food Chem ; 68(1): 117-127, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31820963

RESUMO

Six new quassinoids, named kumulactone F (1), kumulactone G (2), kumulactone H (4), kumulactone I (5), kumulactone J (6), and kumulactone K (7), a pair of undescribed epimers α- and ß-nigakihemiacetal G (3), 15 known quassinoids (8-22), and a mixture of the known compounds α- and ß-neoquassin (23) were separated from the dried stems of the medical plants Picrasma quassioides. The chemical structures of all of the new compounds were established by spectroscopic data analyses (HR-ESI-MS, 1D and 2D NMR spectroscopy, and electronic circular dichroism (ECD)). Biologically, compounds 9 and 21 showed toxicity toward the Asian citrus psyllid Diaphorina citri Kuwayama with potent activity even equal to that of the positive control (Abamectin), compound 11 exhibited an excellent neuroprotective effect against SH-SY5Y cells which were pretreated by H2O2 with potent activity equal to that of the positive control (Trolox), and none of them showed cytotoxic activity toward the HeLa or A549 cell lines (IC50 > 100 µM).


Assuntos
Hemípteros/efeitos dos fármacos , Inseticidas/farmacologia , Fármacos Neuroprotetores/farmacologia , Picrasma/química , Extratos Vegetais/farmacologia , Quassinas/farmacologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Hemípteros/crescimento & desenvolvimento , Humanos , Peróxido de Hidrogênio/toxicidade , Inseticidas/química , Neurônios/citologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/química , Extratos Vegetais/química , Quassinas/química
4.
Insect Sci ; 27(1): 58-68, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29676854

RESUMO

"Candidatus Liberibacter solanacearum" (Lso) are phloem-restricted and unculturable Gram-negative bacteria. Presently five haplotypes have been identified worldwide; but only haplotypes A and B are associated with the vector Bactericera cockerelli (Sulc.) in the Americas. Previous studies showed that Lso-infection reduces B. cockerelli reproductive output and that Lso haplotype B is more pathogenic than Lso haplotype A. To understand the interaction of Lso haplotype B and B. cockerelli, the fitness of Lso-free and Lso B-infected insects, and the expression of vitellogenin (BcVg1-like), a gene involved directly in the insect reproduction were analyzed. Statistical differences in the number of eggs oviposited, and the total number of progeny nymphs and adults were found among crosses of insects with or without Lso. Significant differences in sex proportions were found between Lso B-infected and Lso-free crosses: a higher proportion of F1 adult females were obtained from Lso B-infected mothers. A significant reduction of BcVg1-like was observed in crosses performed with Lso B-infected females compared to the Lso-free insects. In female cohorts of different age, a significant reduction of BcVg1-like expression was measured in 7-d-old Lso B-infected females (virgin and mated) compared with 7-d-old Lso-free females (virgin and mated), respectively. The reduction of BcVg1-like transcript was associated with a lower number of developing oocytes observed in female's reproductive systems. Overall, this study represents the first step to understand the interaction of Lso B with B. cockerelli, highlighting the effect of Lso B infection on egg production, BcVg1-like expression, and oocyte development.


Assuntos
Aptidão Genética , Hemípteros/fisiologia , Rhizobiaceae/fisiologia , Vitelogênese , Animais , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Hemípteros/microbiologia , Lycopersicon esculentum/microbiologia , Lycopersicon esculentum/fisiologia , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Ninfa/fisiologia , Doenças das Plantas/microbiologia
5.
J Insect Sci ; 19(6)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31830272

RESUMO

The sycamore lace bug, Corythucha ciliata (Say) is an invasive pest infesting trees of the genus Platanus. Both adults and nymphs damage the foliage of sycamore trees. Nymphs cannot survive in low temperatures; however, the sycamore lace bug overwinters as adults. In this study, we analyzed the metabolite profiles of this pest to determine significantly regulated metabolites during paurometabolous development from nymphs to adults. The identification of metabolites is essential to convert analytical data into meaningful biological knowledge. A total of 62 metabolites were identified using GC-MS. Among them, 29 different metabolites showed differences in content among nymphs, adult females (AF), and adult males (AM). Five of the 29 metabolites, including caffeic acid, D-glucose, D-mannose, glycerol and aminooxyacetic acid, were significantly increased and nine of them were significantly decreased during the developmental stages from nymph to adult. In addition, we identified three novel aldo-keto reductase (AKR) genes that may play a significant role in the control of glycerol biosynthesis. Moreover, the characteristics and expression levels of these genes were analyzed. This study will provide us with the necessary information to improve our understanding of the changes in metabolites in C. ciliata during paurometabolous development.


Assuntos
Aldo-Ceto Redutases/metabolismo , Hemípteros/metabolismo , Metamorfose Biológica , Animais , Feminino , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Masculino , Filogenia
6.
PLoS One ; 14(12): e0226995, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31877184

RESUMO

External structures of insects contribute to the ability of herbivores to select and feed on their host plants. The invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) is an economically important and polyphagous insect pest in the eastern US. The lanternfly causes substantial damage to many woody plants by sucking phloem sap, reducing photosynthesis, causing weeping wounds, and creating conditions for sooty mold. Lanternfly nymphs switch host plants during their development. However, little is known about relationship between the lanternfly and its plant hosts, and particularly about morphological adaptations of the lanternfly to host plant usage at each developmental stage of the pest. In this study, we focused on assessing changes in morphology of (a) the lanternfly mouthparts (stylets and labium), and (b) the lanternfly tarsal tips (arolia and tarsal claws) at each developmental stage. Our study revealed several developmental patterns among which the presence of the indentations on mandibular stylets in late instars and adults, as well as the exponential growth of the labium and stylet length, and the tarsal claw dispersal during the lanternfly development. Our findings are critical for investigating and predicting the lanternfly host range, and the lanternfly dispersal to new host trees at each developmental stage.


Assuntos
Hemípteros/anatomia & histologia , Hemípteros/crescimento & desenvolvimento , Herbivoria , Animais , Feminino , Hemípteros/ultraestrutura , Masculino , Microscopia Eletrônica de Varredura , Árvores/fisiologia
7.
J Insect Sci ; 19(6)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31745557

RESUMO

Juvenile hormone (JH) is responsible for repressing larval metamorphosis and inducing vitellogenesis and egg production in insects. Methoprene-tolerant (Met) is known to be an intracellular receptor and transducer of JH. We examined the role of Met in ovarian development in the rice pest Sogatella furcifera (Horváth). We first cloned and sequenced S. furcifera Met (SfMet). The SfMet protein belongs to the basic helix-loop-helix/Per-Arnt-Sim (bHLH-PAS) family with a bHLH domain and two PAS domains (PAS-A and PAS-B). SfMet was expressed in all developmental stages and tissues but was most highly expressed in the ovaries of adult females. Furthermore, RNA interference (RNAi) mediated silencing of SfMet substantially reduced the expression of SfVg, decreased yolk protein deposition and blocked oocyte maturation and ovarian development. These results demonstrate that SfMet plays a key role in female reproduction in S. furcifera and suggest that targeting this gene could be an effective way of controlling this pest.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Hemípteros/genética , Proteínas de Insetos/genética , Sequência de Aminoácidos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Drosophila , Feminino , Técnicas de Silenciamento de Genes , Hemípteros/crescimento & desenvolvimento , Hemípteros/metabolismo , Controle de Insetos , Proteínas de Insetos/metabolismo , Ovário/crescimento & desenvolvimento , Ovário/metabolismo
8.
Cienc. tecnol. salud ; 6(2): 98-106, jul dic 2019. ^c27 cmilus
Artigo em Espanhol | LILACS | ID: biblio-1095831

RESUMO

El complejo de mosca blanca (Hemiptera: Aleyrodidae) incluye algunas de las principales plagas del ejote francés (Phaseolus vulgaris L.). Dentro de las cuales, Bemisia tabaci es vector del virus del mosaico dorado que afecta la calidad y rendimiento del cultivo, con pérdidas hasta del 100% y un control difícil debido a la resistencia adquirida por las plagas hacia algunos agroquímicos. El ejote francés ocupa el segundo lugar entre de los productos no tradicionales de exportación de Guatemala. Su manejo agronómico ha sido principalmente a través del control químico, el cual afecta insectos y otros organismos que no son el objetivo del control, tales como: polinizadores, insectos benéficos, humanos y fauna silvestre. Los objetivos del estudio fueron: determinar la presencia de enemigos naturales nativos de la mosca blanca e identificar las especies de mosca blanca presentes en el cultivo del ejote francés en Chimaltenango. Para el estudio se establecieron cuatro parcelas de 300 m², se realizaron muestreos semanales durante dos ciclos del cultivo. En cada parcela se muestrearon cinco sitios y en cada sitio cinco plantas. Las especies de parasitoides nativos encontrados fueron: Encarsia Formosa Gahan, Eretmocerus eremicus Rose y Zolnerowuch y Amitus fuscipennis MacGown y Nebeker, la especie más abundante fue A. fuscipennis. Los depredadores identificados fueron Chrysoperla carnea (Stephens) e Hippodamia convergens Guerin-Meneville. La especie más abundante fue H. convergens. Estas especies podrían ser herramientas valiosas para ser empleadas en programas de control biológico, producciones orgánicas o en programas de manejo integrado de plagas.


The whitefly complex (Hemiptera: Aleyrodidae) includes some of the main pests of the French green bean (Phaseolus vulgaris L.). Among which, Bemisia tabaci is a vector of the golden mosaic virus that affects the quality and yield of the crop, with losses up to 100% and difficult control due to the resistance acquired by pests towards some agrochemicals. The French green bean ranks second among the non-traditional export products of Guatemala. Its agronomic management has been mainly through chemical control, which affects insects and other organisms that are not the objective of the control, such as: pollinators, beneficial insects, humans and wildlife. The objectives of the study were: to determine the presence of natural enemies native to the whitefly and identify the species of whitefly present in the cultivation of the French bean in Chimaltenango. For the study, four 300 m² plots were established, weekly sampling was carried out during two crop cycles. Five sites were sampled on each plot and five plants on each site. The native parasitoid species found were: Encarsia Formosa Gahan, Eretmocerus eremicus Rose and Zolnerowuch and Amitus fuscipennis MacGown and Nebeker, the most abundant species was A. fuscipennis. The predators identified were Chrysoperla carnea (Stephens) and Hippodamia convergens Guerin-Meneville. The most abundant species was H. convergens. These species could be valuable tools to be used in biological control programs, organic productions or in integrated pest management programs.


Assuntos
Animais , Phaseolus/crescimento & desenvolvimento , Phaseolus/parasitologia , Hemípteros/crescimento & desenvolvimento , Hemípteros/parasitologia , Controle Biológico de Vetores/métodos , Vírus do Mosaico
9.
J Insect Sci ; 19(5)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31612946

RESUMO

Insect hormones regulate metamorphosis including that leading to sexual dimorphism. Using RNA-Seq, we discovered that the second-instar male larva (SM) of the white wax insect, Ericerus pela, have 5,968 and 8,620 differentially expressed transcripts compared with the second-instar female larva (SF) and the first-instar male larva (FM), respectively. The expression levels of genes involved in the apoptosis of old tissues and the reconstruction of new ones in the SM significantly enhanced, while the SF mainly has enhanced expression levels of anabolic genes such as chitin. We predicted that the second-instar larvae are the developmental origin of sexual dimorphic metamorphosis. Meanwhile, in the juvenile hormone (JH) metabolic pathway, CYP15A1 and JH esterase (JHE) are differentially expressed; and in the 20-hydroxyecdysone (20E) metabolic pathway, CYP307A1, CYP314A1, and CYP18A1 are differentially expressed. In the SM, the expression levels of CYP307A1 and CYP314A1 are significantly increased, whereas the expression level of CYP18A1 is significantly decreased; in the SF, the expression levels of the above genes are opposite to that of the SM. Expression trends of RNA-seq is consistent with the expression level of qRT-PCR, and seven of them are highly correlated (R ≥ 0.610) and four are moderately correlated (0.588 ≥ R ≥ 0.542).


Assuntos
Regulação da Expressão Gênica/fisiologia , Hemípteros/genética , Proteínas de Insetos/genética , Hormônios Juvenis/genética , Metamorfose Biológica/genética , Animais , Feminino , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/metabolismo , Hormônios Juvenis/metabolismo , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento
10.
Insect Biochem Mol Biol ; 115: 103246, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31618682

RESUMO

The brown planthopper (BPH) Nilaparvata lugens contains two insulin receptor homologues, designated NlInR1 and NlInR2. NlInR1 is strikingly homologous to the typical InR in insects and vertebrates, containing a ligand-activated intracellular tyrosine kinase catalytic domain. Herein, we report an optimized CRISPR/Cas9 system to induce mutations in the NlInR1 locus in BPH, consisting of a Cas9 plasmid that is specifically expressed in the germline via the Nlvasa promoter and versatile sgRNA expression plasmids under the control of the U6 promoter. We systematically evaluated the efficiency of injection mix compositions and demonstrated an appropriate combination of Cas9/sgRNA to target essential genes. Furthermore, we showed that homozygous mutants for the NlInR1 gene are early embryonic lethal, whereas heterozygous mutants grow more slowly, exhibit a severe reduction in body weight and wing size and live longer than the wild type. Interestingly, the severity of the mutant phenotype was different when targeting distinct important domains of the NlInR1 locus. The severity of the mutant phenotype is similar to that of insulin/insulin-like growth factor (IGF) signaling pathway deficiencies in vertebrates, suggesting a conserved function of NlInR1 in the regulation of development and longevity. Global expression profiling suggests that NlInR1 regulates many cellular processes in BPH, including insulin resistance, phototransduction, metabolism, endocytosis, longevity, biosynthesis and protein processing. Our results also pave the way for understanding the precise molecular mechanism of insulin signaling in wing polyphenism in insects.


Assuntos
Hemípteros/crescimento & desenvolvimento , Receptor de Insulina/genética , Animais , Sistemas CRISPR-Cas , Feminino , Haploinsuficiência , Hemípteros/genética , Longevidade/genética , Masculino
11.
Int J Mol Sci ; 20(15)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31370145

RESUMO

Chitin synthase is a critical enzyme that catalyzes N-acetylglucosamine to form chitin, which plays an important role in the growth and development of insects. In this study, we identified a chitin synthase gene (CHS) with a complete open reading frame (ORF) of 3180 bp from the genome database of Diaphorina citri, encoding a protein of 1059 amino acid residues with the appropriate signature motifs (EDR and QRRRW). Reverse transcription-quantitative PCR (RT-qPCR) analysis suggested that D. citri CHS (DcCHS) was expressed throughout all developmental stages and all tissues. DcCHS had the highest expression level in the integument and fifth-instar nymph stage. Furthermore, the effects of diflubenzuron (DFB) on D. citri mortality and DcCHS expression level were investigated using fifth-instar nymph through leaf dip bioassay, and the results revealed that the nymph exposed to DFB had the highest mortality compared with control group (Triton-100). Silencing of DcCHS by RNA interference resulted in malformed phenotypes and increased mortality with decreased molting rate. In addition, transmission electron microscopy (TEM) and fluorescence in situ hybridization (FISH) also revealed corresponding ultrastructural defects. Our results suggest that DcCHS might play an important role in the development of D. citri and can be used as a potential target for psyllid control.


Assuntos
Quitina Sintase/genética , Genoma de Inseto , Hemípteros/genética , Proteínas de Insetos/genética , Ninfa/genética , Interferência de RNA , Sequência de Aminoácidos , Animais , Quitina Sintase/antagonistas & inibidores , Quitina Sintase/metabolismo , Citrus/parasitologia , Diflubenzuron/farmacologia , Frutas/parasitologia , Regulação da Expressão Gênica no Desenvolvimento , Hemípteros/efeitos dos fármacos , Hemípteros/enzimologia , Hemípteros/crescimento & desenvolvimento , Controle de Insetos , Proteínas de Insetos/antagonistas & inibidores , Proteínas de Insetos/metabolismo , Muda/efeitos dos fármacos , Muda/genética , Ninfa/efeitos dos fármacos , Ninfa/crescimento & desenvolvimento , Ninfa/metabolismo , Fases de Leitura Aberta , Filogenia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos
12.
Insect Biochem Mol Biol ; 113: 103215, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31449847

RESUMO

In this study, two novel antibacterial peptide genes, termed lugensin A and B were identified and characterized from a rice sap-sucking hemipteran insect pest, the brown planthopper, Nilaparvata lugens. Lugensin gene expression was significantly induced by Gram-negative and Gram-positive bacterial stains under the regulation of a signal receptor, the long peptidoglycan recognition protein (PGRP-LC) in the IMD pathway. Knockdown of PGRP-LC by RNAi eliminated bacterium induced Lugensin gene expression. Lugensins had the apparent antibacterial activities against Escherichia coli K12, Bacillus subtilis and the rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) strain RS-1. Lugensins inhibited bacterial proliferation by disrupting the integrity of the bacterial membranes. Scanning electron microscopy revealed abnormal membrane morphology of the recombinant Lugensin-treated bacteria. Lugensins induced complete cell disruption of E. coli K12 and B. subtilis strains while formed the holes on the cell surface of Aaa RS-1 strain. Immunofluorescence showed that Lugensins localized in the cell membrane of E. coli K12 while accumulated in the cytosol of B. subtilis. Differently, Lugensins remained in both the cell membrane and the cytosol of Aaa RS-1 strain, suggesting different action modes of Lugensins to different microbes. This is the first report of the novel antibacterial peptides found in the rice sap-sucking hemipteran insect species.


Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Regulação da Expressão Gênica , Hemípteros/genética , Proteínas de Insetos/genética , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Comamonadaceae/efeitos dos fármacos , Escherichia coli K12/efeitos dos fármacos , Feminino , Hemípteros/crescimento & desenvolvimento , Hemípteros/metabolismo , Proteínas de Insetos/metabolismo , Proteínas de Insetos/farmacologia , Masculino , Ninfa/genética , Ninfa/metabolismo , Oócitos/metabolismo , Interferência de RNA
13.
Insect Biochem Mol Biol ; 113: 103211, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31425852

RESUMO

Wolbachia are intracellular bacteria that manipulate host reproduction by several mechanisms including cytoplasmic incompatibility (CI). However, the underlying mechanisms of Wolbachia-induced CI are not entirely clear. Here, we monitored the Wolbachia distribution in the male gonads of the small brown planthopper (Laodelphax striatellus, SBPH) at different development stages, and investigated the influence of Wolbachia on male gonads by a quantitative proteomic analysis. A total of 276 differentially expressed proteins were identified, with the majority of them participating in metabolism, modification, and reproduction. Knocking down the expression of outer dense fiber protein (ODFP) and venom allergen 5-like (VA5L) showed decreased egg reproduction, and these two genes might be responsible for Wolbachia improved fecundity in infected L. striatellus; whereas knocking down the expression of cytosol amino-peptidase-like (CAL) significantly decreased the egg hatch rate in Wolbachia-uninfected L. striatellus, but not in the Wolbachia-infected one. Considering that the mRNA/protein level of CAL was downregulated by Wolbachia infection and dsCAL treatment closely mimicked Wolbachia-induced CI, we presumed that CAL might be one of the factors determining the CI phenotype.


Assuntos
Hemípteros/fisiologia , Proteínas de Insetos/genética , Wolbachia/fisiologia , Animais , Gônadas/crescimento & desenvolvimento , Gônadas/microbiologia , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/metabolismo , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Proteoma , Proteômica , Reprodução
14.
J Insect Sci ; 19(3)2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31225879

RESUMO

As water for agriculture becomes less available in the semi-arid western United States, alternative irrigation strategies such as deficit irrigation may be necessary for continued crop production. Alternative irrigation practices in cotton (Gossypium spp. [Malvales: Valvaceae]) can result in episodic drought stress that alters temperature profiles within the crop canopy. These altered temperatures may influence populations of important pests such as Lygus hesperus Knight. Field studies often associate lower population densities of L. hesperus with limited irrigation. Recent studies of the thermal ecology of L. hesperus egg and nymphal development have demonstrated only subtle effects of the high, variable temperatures typical of moderate drought stress in cotton. However, influences of these conditions on L. hesperus adult reproductive development have not been studied. The reproductive development of L. hesperus adults was examined under constant (±0.2°C) and variable (±8°C) regimes at a low (15°C), moderate (22°C), and high (29°C) daily mean temperatures. No developmental differences were demonstrated between temperature regimes under moderate or high temperatures. At the low temperature, only the times to the occurrence of eggs, filled medial accessory glands, and filling seminal vesicles were shorter under variable regime, compared with the constant temperature. These results suggest that temporary, episodic increases in crop canopy temperatures caused by moderate drought stress are unlikely to impact L. hesperus population growth, and may only promote short-term displacement of adults into adjacent crops with preferable conditions.


Assuntos
Hemípteros/crescimento & desenvolvimento , Maturidade Sexual , Animais , Feminino , Masculino , Temperatura
15.
PLoS Genet ; 15(6): e1008235, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31242182

RESUMO

Polyphenism is a successful strategy adopted by organisms to adapt to environmental changes. Brown planthoppers (BPH, Nilaparvata lugens) develop two wing phenotypes, including long-winged (LW) and short-winged (SW) morphs. Though insulin receptor (InR) and juvenile hormone (JH) have been known to regulate wing polyphenism in BPH, the interaction between these regulators remains largely elusive. Here, we discovered that a conserved microRNA, miR-34, modulates a positive autoregulatory feedback loop of JH and insulin/IGF signaling (IIS) pathway to control wing polyphenism in BPH. Nlu-miR-34 is abundant in SW BPHs and suppresses NlInR1 by targeting at two binding sites in the 3'UTR of NlInR1. Overexpressing miR-34 in LW BPHs by injecting agomir-34 induces the development towards SW BPHs, whereas knocking down miR-34 in SW BPHs by injecting antagomir-34 induces more LW BPHs when another NlInR1 suppressor, NlInR2, is also suppressed simultaneously. A cis-response element of Broad Complex (Br-C) is found in the promoter region of Nlu-miR-34, suggesting that 20-hydroxyecdysone (20E) might be involved in wing polyphenism regulation. Topic application of 20E downregulates miR-34 expression but does not change wing morphs. On the other hand, JH application upregulates miR-34 expression and induces more SW BPHs. Moreover, knocking down genes in IIS pathway changes JH titers and miR-34 abundance. In all, we showed that miRNA mediates the cross talk between JH, 20E and IIS pathway by forming a positive feedback loop, uncovering a comprehensive regulation mechanism which integrates almost all known regulators controlling wing polyphenism in insects.


Assuntos
Hemípteros/genética , MicroRNAs/genética , Receptor de Insulina/genética , Asas de Animais/crescimento & desenvolvimento , Animais , Antagomirs/genética , Ecdisterona/genética , Regulação da Expressão Gênica/genética , Hemípteros/crescimento & desenvolvimento , Hormônios Juvenis/genética , Fenótipo , Regiões Promotoras Genéticas/genética , Asas de Animais/metabolismo
16.
Insect Mol Biol ; 28(6): 828-836, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31069883

RESUMO

S-Adenosyl-l-methionine-dependent methyltransferases (SAMMTases) modulate important cellular and metabolic activities in both prokaryotes and eukaryotes. Here, we functionally characterized an SAMMTase gene (MTase15) in the migratory brown planthopper (BPH), Nilaparvata lugens, which is the most notorious rice pest in Asia. The cDNA sequence of MTase15 is 2764 nt in length with an open reading frame of 1218 nt encoding 405 amino acid residues. Quantitative real-time PCR analysis showed that MTase15 was readily detected from egg to adult stages and extensively distributed in various body parts of adult females and males, with slightly high levels in ovary and testis, respectively. In addition, MTase15 was transcriptionally regulated by the insulin signalling pathway in BPH. RNA-interference-mediated knockdown of MTase15 (dsMtase15) resulted in deficiencies in vitellogenin synthesis and oogenesis, and female infertility. Males with Mtase15 knockdown retained the capability of producing sperms with normal viability, but less sperm was transferred to wild-type (wt) females during copulation, and eggs laid by these wt females arrested embryogenesis. These findings not only assign a functional role to MTase15, but also provide a link between the insulin signalling pathway and epigenetic regulation in BPH reproduction.


Assuntos
Regulação da Expressão Gênica , Hemípteros/fisiologia , Proteínas de Insetos/genética , Metiltransferases/genética , Animais , Feminino , Perfilação da Expressão Gênica , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/metabolismo , Masculino , Metiltransferases/metabolismo , Ninfa/genética , Ninfa/metabolismo , Óvulo/metabolismo , Reprodução/genética
17.
J Insect Physiol ; 116: 90-99, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31063731

RESUMO

Using the mass spectrometry analysis of cuticle casts of brown planthopper (BPH, Nilaparvata lugens) and transcriptome analysis of BPH tissues, we identified a gigantic gene (50,922 bp, 16,973 aa) tentatively called Nlegf-like. Multiple transcripts were found. Nlegf-like encodes an integral membrane protein of 16,973 amino acid residues with 260 EGF-like repeats and 16 Ca2+-binding EGF repeats type (cbEGFs) in the extracellular portion. Nlegf-like was highly expressed in the integument and tended to peak at the middle stage or late stage of each nymph instar. Phylogenetic analysis showed this gene is conserved in many other insects. Different double-stranded RNA-mediated RNA interference targeting eight different regions of the Nlegf-like gene resulted in abnormal cuticle formation or molting and lethal phenotypes. Transmission electron microscopy revealed that the newly formed endocuticle was significantly thinner for RNAi-treated BPHs with phenotype of contracted abdomen, or the old cuticle could not be digested sufficiently for those with phenotype of slender body shape or died with molting difficulty when compared with the control group. We suggest that the Nlegf-like is crucial for metabolism of the cuticle in BPH molting.


Assuntos
Fator de Crescimento Epidérmico/genética , Hemípteros/genética , Proteínas de Insetos/genética , Muda/genética , Sequência de Aminoácidos , Animais , Fator de Crescimento Epidérmico/química , Fator de Crescimento Epidérmico/metabolismo , Feminino , Hemípteros/crescimento & desenvolvimento , Hemípteros/metabolismo , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Ninfa/metabolismo , Filogenia , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , Alinhamento de Sequência
18.
Pest Manag Sci ; 75(11): 2882-2891, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31038255

RESUMO

BACKGROUND: Microbial surfactants are multifunctional surface-active molecules that have been overlooked in formulating microbial biopesticides. We report a novel approach using the biosurfactant rhamnolipid (RML) against the destructive cosmopolitan insect pest Bemisia tabaci, as well as the combined action of RML with aerial conidia of two entomopathogenic fungi, Cordyceps javanica and Beauveria bassiana. RML was also tested as a suspension agent to improve the recovery rate of conidia from solid substrate for fungal preparations. RESULTS: The recovery rate of conidia increased dramatically (two to five times) with RML compared with a standard surfactant (Tween 80). Spraying solutions of 0.075% and 0.1% (w/v) RML on B. tabaci third instar nymphs induced 100% mortality within 4 days. Conidial suspensions at 5 × 106 conidia/mL amended with RML at 0.01% or 0.05% markedly increased nymphal mortalities and considerably reduced LC50 . Conidial suspensions of B. bassiana with 0.05% RML added were more effective against whitefly nymphs (87.3% mortality) than C. javanica + RML (51.4% mortality). CONCLUSION: Our results show that this bacterium-based RML improved the recovery rate of hydrophobic conidia, and that mixtures of RML with fungal spore suspensions increased their insecticidal activity. © 2019 Society of Chemical Industry.


Assuntos
Beauveria/fisiologia , Cordyceps/fisiologia , Glicolipídeos/farmacologia , Hemípteros , Inseticidas/farmacologia , Controle Biológico de Vetores/métodos , Tensoativos/farmacologia , Animais , Hemípteros/efeitos dos fármacos , Hemípteros/crescimento & desenvolvimento , Hemípteros/microbiologia , Ninfa/efeitos dos fármacos , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Esporos Fúngicos/fisiologia
19.
Arch Insect Biochem Physiol ; 101(3): e21555, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31038785

RESUMO

RNAi-based pest control strategies are emerging as environment friendly and species-specific alternatives for the use of conventional pesticides. Because N-glycosylation is important for many biological processes, such as growth and development, the early steps of protein N-glycosylation are promising targets for an RNAi-based pest control strategy. Through injection of dsRNAs, the expression of the catalytic subunits of the oligosaccharyl transferase complex was efficiently silenced in nymphs of the notorious rice pest insect Nilaparvata lugens. Silencing of both STT3 isoforms resulted in a high mortality of the N. lugens nymphs. However, our data reveals the occurrence of a functional redundancy between the two isoforms when silencing only one of the isoforms. These observations confirm the potential to use the early genes in the N-glycosylation pathway as targets for an RNAi-based pest control strategy. In addition, the existence of a functional redundancy between the two STT3 isoforms presents a factor which one must take into account when designing RNAi-based approaches.


Assuntos
Hemípteros/genética , Controle de Insetos/métodos , Interferência de RNA , Animais , Hemípteros/crescimento & desenvolvimento , Ninfa/genética , Ninfa/crescimento & desenvolvimento
20.
Pest Manag Sci ; 75(12): 3371-3380, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31095875

RESUMO

BACKGROUND: Empoasca onukii, the tea green leafhopper, is a key pest of tea whose control often requires the extensive use of insecticides. As a predator of the tea green leafhopper, the mite Anystis baccarum is a potential biological control agent worldwide, though little is known about how intercropping cover crops can impact its suppressing effect on E. onukii. Therefore, we conducted a field experiment to investigate how the relationship of the abundance of the predatory mite and its leafhopper prey is influenced by two different cover crops and a manually weeded inter-row treatment as a contrast to naturally growing vegetation in a tea plantation in China. RESULTS: The abundance of A. baccarum was significantly higher in tea canopies of intercropped treatments than in canopies over natural ground cover. Litter samples showed higher abundances of A. baccarum when tea was intercropped with Paspalum notatum than with natural ground cover in the first year of treatment. The abundance of E. onukii in tea canopies was higher over the bare ground treatment in the first year but the opposite was observed in the second year. CONCLUSIONS: Results suggest that the abundance of A. baccarum in a tea plantation is influenced by intercropping and it can affect its leafhopper prey, albeit with varying levels of suppression. For informing biological control and suppression of pests, long-term experiments are needed to investigate the interactions of both pest and predator with cover crop treatments. © 2019 Society of Chemical Industry.


Assuntos
Produção Agrícola/métodos , Cadeia Alimentar , Hemípteros/fisiologia , Ácaros/fisiologia , Controle Biológico de Vetores , Animais , Camellia sinensis , China , Hemípteros/crescimento & desenvolvimento , Ninfa/crescimento & desenvolvimento , Ninfa/fisiologia , Comportamento Predatório
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