Página 1 dos resultados de 68 itens digitais encontrados em 0.016 segundos

Vector within-host feeding preference mediates transmission of a heterogeneously distributed pathogen

DAUGHERTY, Matthew P.; LOPES, Joao; ALMEIDA, Rodrigo P. P.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.38%
2. We documented the within-host distribution of two vector species that differ in transmission efficiency, the leafhoppers Draeculacephala minerva and Graphocephala atropunctata, and which are free to move throughout entirely caged alfalfa plants. The more efficient vector D. minerva fed preferentially at the base of the plant near the soil surface, whereas the less efficient G. atropunctata preferred overwhelming the top of the plant. 3. Next we documented X. fastidiosa heterogeneity in mechanically inoculated plants. Infection rates were up to 50% higher and mean bacterial population densities were 100-fold higher near the plant base than at the top or in the taproot. 4. Finally, we estimated transmission efficiency of the two leafhoppers when they were confined at either the base or top of inoculated alfalfa plants. Both vectors were inefficient when confined at the top of infected plants and were 20-60% more efficient when confined at the plant base. 5. These results show that vector transmission efficiency is determined by the interaction between leafhopper within-plant feeding behaviour and pathogen within-plant distribution. Fine-scale vector and pathogen overlap is likely to be a requirement generally for efficient transmission of vector-borne pathogens.; USDA; California Department of Food and Agriculture; CAPES/Brazil

Weedy Hosts and Prevalence of Potential Leafhopper Vectors (Hemiptera: Cicadellidae) of a Phytoplasma (16SrIX group) Associated With Huanglongbing Symptoms in Citrus Groves

Marques, R. N.; Teixeira, D. C.; Yamamoto, Pedro Takao; Lopes, Joao Roberto Spotti
Fonte: ENTOMOLOGICAL SOC AMER; LANHAM Publicador: ENTOMOLOGICAL SOC AMER; LANHAM
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
26.58%
Huanglongbing (HLB) is a severe citrus (Citrus spp.) disease associated with the bacteria genus Candidatus Liberibacter, detected in Brazil in 2004. Another bacterium was found in association with HLB symptoms and characterized as a phytoplasma belonging to the 16SrIX group. The objectives of this study were to identify potential leafhopper vectors of the HLB-associated phytoplasma and their host plants. Leafhoppers were sampled every other week for 12 mo with sticky yellow cards placed at two heights (0.3 and 1.5 m) in the citrus tree canopy and by using a sweep net in the ground vegetation of two sweet orange, Citrus sinensis (L.) Osbeck, groves infected by the HLB-phytoplasma in Sao Paulo state. Faunistic analyses indicated one Agalliinae (Agallia albidula Uhler) and three Deltocephalinae [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stal), and Scaphytopius (Convelinus) marginelineatus (Stal)] species, as the most abundant and frequent leafhoppers (Hemiptera: Cicadellidae). Visual observations indicated an association of leafhopper species with some weeds and the influence of weed species composition on leafhopper abundance in low-lying vegetation. S. marginelineatus and P. flavicosta were more frequent on Sida rhombifolia L. and Althernantera tenella Colla...

Effect of contact and systemic insecticides on the sharpshooter Bucephalogonia xanthophis (Hemiptera: cicadellidae), a vector of Xylella fastidiosa in citrus

Bezerra-Silva, Gerane Celly Dias; Silva, Márcio Alves; Miranda, Marcelo Pedreira de; Lopes, Joao Roberto Spotti
Fonte: FLORIDA ENTOMOLOGICAL SOC; LUTZ Publicador: FLORIDA ENTOMOLOGICAL SOC; LUTZ
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.33%
The knockdown and toxic effects of insecticides of different chemical groups and modes of action registered for citrus in Brazil were investigated for effective control of Bucephalogonia xanthophis, a sharpshooter vector of Xylella fastidiosa in citrus. The active ingredients dimethoate (1.2 mL/1.2L), imidacloprid (0.24 mL/1.2L) and lambda-cyhalothrin (0.24 mL/1.2L), as well as a control (water), were sprayed onto branches of potted-citrus nursery trees to evaluate the effect of residual contact. The insects were confined on sprayed branches by using sleeve cages, in groups of 10 per branch (5 branches/treatment). Lambdacyhalothrin showed a knockdown effect on B. xanthophis (>70% mortality within 2 h of exposure), and the residues were effective for approximately one wk. Imidacloprid, lambdacyhalothrin and dimethoate suppressed the vector populations for up to 3 wk after application, when the insects were exposed to sprayed plants for at least 24 h. In another experiment, 2 neonicotinoid insecticides (thiamethoxam and imidacloprid) were applied by soil drench to potted nursery trees, in order to study their systemic effect, i.e., mortality by ingestion on sharpshooter adults. Thiamethoxam and imidacloprid effectively controlled the vectors at all concentrations tested...

Potenciais hospedeiros alternativos para o fitoplasma e o espiroplasma, agentes do enfezamento do milho, e alterações bioquímicas em plantas infectadas pelo espiroplasma; Potencial hosts for maize mollicutes, agent of corn stunt, and biochemical changes in plants infected by the spiroplasma

Haas, Isolda Cristina Ruschel
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 16/04/2010 Português
Relevância na Pesquisa
36.54%
Os enfezamentos vermelho e pálido são importantes doenças do milho, causadas, respectivamente, por um fitoplasma e por um espiroplasma (Spiroplasma kunkelii). As duas formas de enfezamento foram relatadas no Brasil no início da década de 70 e se tornaram economicamente relevantes no início dos anos 80, com a introdução de novas técnicas de cultivo no milho. Apesar de ser um patossistema conhecido e estudado, ainda há certos pontos em relação à doença que permanecem desconhecidos. Um deles é em relação à sobrevivência do vetor (Dalbulus maidis) e do patógeno durante a entressafra. Outro, diz respeito às alterações bioquímicas envolvidas na relação hospedeiro-patógeno. O presente trabalho visou avaliar algumas gramíneas, usadas na formação de pastagens, e ervas-daninhas, que ocorrem nas áreas cultivadas com milho, como possíveis hospedeiros alternativos destes patógenos; ainda, buscouse estudar algumas alterações bioquímicas que ocorrem nas plantas de milho quando infectadas por espiroplasma. Para isto, o trabalho foi desenvolvido em três etapas. Na primeira, onze espécies de capins e ervas daninhas foram experimentalmente inoculadas com o espiroplasma através do vetor. As avaliações foram realizadas com base na observação de sintomas...

Cigarrinhas (Hemiptera: Cicadellidae) potenciais vetoras de um fitoplasma (grupo 16SrlX) associado a sintomas de Huanglongbing dos citros, suas plantas hospedeiras e quantificação do patógeno; Potential leafhopper vectors (Hemiptera: Cicadellidae) of a phytoplasma (16SrIX group) associated with citrus huanglongbing symptoms, host plants and pathogen quantification

Marques, Rodrigo Neves
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/04/2011 Português
Relevância na Pesquisa
26.77%
O Huanglongbing (HLB) é uma das mais temidas doenças da citricultura mundial, associada a bactérias do gênero Candidatus Liberibacter, que foram detectadas no Brasil em 2004. Em 2008, detectou-se outra bactéria associada a sintomas de HLB no Estado de São Paulo, que foi caracterizada como sendo um fitoplasma do grupo 16 SrIX. Fitoplasmas são molicutes fitopatógenos restritos ao floema de plantas, disseminados por insetos vetores. O presente trabalho buscou identificar cigarrinhas potencialmente vetoras do fitoplasma associado ao HLB e plantas hospedeiras desses insetos, bem como desenvolver uma técnica de quantificação de DNA desse patógeno em insetos e plantas. Amostragens de cigarrinhas foram realizadas quinzenalmente por 12 meses em dois pomares de laranja com histórico de ocorrência do fitoplasma 16SrIX na região norte do Estado de São Paulo, usando-se armadilhas adesivas amarelas em duas alturas (0,3 e 1,5 m) da copa de árvores cítricas, e rede de varredura na vegetação espontânea. Dados faunísticos identificaram uma espécie de Agalliinae (Agallia albidula Uhler) e três de Deltocephalinae, [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stål) e Scaphytopius (Convelinus) marginelineatus (Stål)], como os cicadelídeos (Hemiptera: Cicadellidae) mais abundantes e frequentes nas áreas estudadas. Essas espécies predominaram na amostragem com rede de varredura e na menor altura de coleta com armadilhas adesivas...

First record of Eudorylas schreiteri (Shannon) (Diptera: Pipunculidae) as a parasitoid of the corn leafhopper (Hemiptera: Cicadellidae) in Argentina, with a table of pipunculid-host associations in the neotropical region

Virla,Eduardo G; Moya-Raygoza,Gustavo; Rafael,José A
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2009 Português
Relevância na Pesquisa
36.35%
The big-headed fly Eudorylas schreiteri (Shannon) is recorded for the first time as an endoparasitoid of the corn leafhopper Dalbulus maidis (DeLong & Wolcott) in Northern Argentina. A table of known Neotropical pipunculid-host associations is presented.

First host record for Anteon pilicorne (Ogloblin) (Hymenoptera: Dryinidae), a parasitoid of Cicadellidae, including the corn leafhopper (Hemiptera: Cicadellidae)

Virla,EG; Espinosa,MS; Moya-Raygoza,G
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2011 Português
Relevância na Pesquisa
36.35%
For the first time the dryinid wasp Anteon pilicorne (Ogloblin) is recorded as a parasitoid of two Macrostelini leafhoppers: Balclutha rosea (Scott) and the corn leafhopper Dalbulus maidis (DeLong & Wolcott). New distributional records are presented.

Spiralin Is Not Essential for Helicity, Motility, or Pathogenicity but Is Required for Efficient Transmission of Spiroplasma citri by Its Leafhopper Vector Circulifer haematoceps

Duret, Sybille; Berho, Nathalie; Danet, Jean-Luc; Garnier, Monique; Renaudin, Joël
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/2003 Português
Relevância na Pesquisa
46.61%
Spiralin is the most abundant protein at the surface of the plant pathogenic mollicute Spiroplasma citri and hence might play a role in the interactions of the spiroplasma with its host plant and/or its insect vector. To study spiralin function, mutants were produced by inactivating the spiralin gene through homologous recombination. A spiralin-green fluorescent protein (GFP) translational fusion was engineered and introduced into S. citri by using an oriC-based targeting vector. According to the strategy used, integration of the plasmid by a single-crossover recombination at the spiralin gene resulted in the expression of the spiralin-GFP fusion protein. Two distinct mutants were isolated. Western and colony immunoblot analyses showed that one mutant (GII3-9a5) did produce the spiralin-GFP fusion protein, which was found not to fluoresce, whereas the other (GII3-9a2) produced neither the fusion protein nor the wild-type spiralin. Both mutants displayed helical morphology and motility, similarly to the wild-type strain GII-3. Genomic DNA analyses revealed that GII3-9a5 was unstable and that GII3-9a2 was probably derived from GII3-9a5 by a double-crossover recombination between plasmid sequences integrated into the GII3-9a5 chromosome and free plasmid. When injected into the leafhopper vector Circulifer haematoceps...

Regulation of expression of the wound tumor virus genome in persistently infected vector cells is related to change in translational activity of viral transcripts.

Peterson, A J; Nuss, D L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1986 Português
Relevância na Pesquisa
36.3%
The interaction between a plant virus and its insect vector was studied at the molecular level by examining wound tumor virus (WTV) gene expression in cultured cells derived from its leafhopper vector. Infection of vector cells by WTV is noncytopathic and results in an acute phase (through day 5), followed by persistence beginning with the first cell passage. Viral-specific polypeptide synthesis and viral genome RNA accumulation increased to a maximum level during the first 5 days following inoculation and then decreased as infected cells were passaged (to 5 to 20% of the level observed during the acute phase by passages 10 to 15). In contrast, viral-specific mRNAs were present at approximately the same level in the acute phase and in the early stage (passage 10) of the persistent phase of infection. Although viral transcripts isolated at different times after inoculation exhibited identical electrophoretic migration patterns, they had different functional activities in cell-free translation systems. Transcripts isolated from persistently infected cells were inefficiently translated in vitro, reflecting the situation in infected cells. These results indicate that the decline in the level of viral polypeptide synthesis associated with the persistent phase of WTV infection is related to a change in the translational activity of viral transcripts.

Disruption of a Gene Predicted To Encode a Solute Binding Protein of an ABC Transporter Reduces Transmission of Spiroplasma citri by the Leafhopper Circulifer haematoceps

Boutareaud, A.; Danet, J. L.; Garnier, M.; Saillard, C.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2004 Português
Relevância na Pesquisa
36.71%
Spiroplasma citri is transmitted from plant to plant by phloem-feeding leafhoppers. In an attempt to identify mechanisms involved in transmission, mutants of S. citri affected in their transmission must be available. For this purpose, transposon (Tn4001) mutagenesis was used to produce mutants which have been screened for their ability to be transmitted by the leafhopper vector Circulifer haematoceps to periwinkle plants. With one mutant (G76) which multiplied in leafhoppers as efficiently as S. citri wild-type (wt) strain GII-3, the plants showed symptoms 4 to 5 weeks later than those infected with wt GII-3. Thirty to fifty percent of plants exposed to leafhoppers injected with G76 remained symptomless, whereas for wt GII-3, all plants exposed to the transmission showed severe symptoms. This suggests that the mutant G76 was injected into plants by the leafhoppers less efficiently than wt GII-3. To check this possibility, the number of spiroplasma cells injected by a leafhopper through a Parafilm membrane into SP4 medium was determined. Thirty times less mutant G76 than wt GII-3 was transmitted through the membrane. These results suggest that mutant G76 was affected either in its capacity to penetrate the salivary glands and/or to multiply within them. In mutant G76...

Entry of Spiroplasma citri into Circulifer haematoceps Cells Involves Interaction between Spiroplasma Phosphoglycerate Kinase and Leafhopper Actin▿

Labroussaa, Fabien; Arricau-Bouvery, Nathalie; Dubrana, Marie-Pierre; Saillard, Colette
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.71%
Transmission of the phytopathogenic mollicutes, spiroplasmas, and phytoplasmas by their insect vectors mainly depends on their ability to pass through gut cells, to multiply in various tissues, and to traverse the salivary gland cells. The passage of these different barriers suggests molecular interactions between the plant mollicute and the insect vector that regulate transmission. In the present study, we focused on the interaction between Spiroplasma citri and its leafhopper vector, Circulifer haematoceps. An in vitro protein overlay assay identified five significant binding activities between S. citri proteins and insect host proteins from salivary glands. One insect protein involved in one binding activity was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) as actin. Confocal microscopy observations of infected salivary glands revealed that spiroplasmas colocated with the host actin filaments. An S. citri actin-binding protein of 44 kDa was isolated by affinity chromatography and identified by LC-MS/MS as phosphoglycerate kinase (PGK). To investigate the role of the PGK-actin interaction, we performed competitive binding and internalization assays on leafhopper cultured cell lines (Ciha-1) in which His6-tagged PGK from S. citri or purified PGK from Saccharomyces cerevisiae was added prior to the addition of S. citri inoculum. The results suggested that exogenous PGK has no effect on spiroplasmal attachment to leafhopper cell surfaces but inhibits S. citri internalization...

Sequences Essential for Transmission of Spiroplasma citri by Its Leafhopper Vector, Circulifer haematoceps, Revealed by Plasmid Curing and Replacement Based on Incompatibility▿ †

Breton, Marc; Duret, Sybille; Danet, Jean-Luc; Dubrana, Marie-Pierre; Renaudin, Joël
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.68%
Spiroplasma citri GII3 contains highly related low-copy-number plasmids pSci1 to -6. Despite the strong similarities between their replication regions, these plasmids coexist in the spiroplasma cells, indicating that they are mutually compatible. The pSci1 to -6 plasmids encode the membrane proteins known as S. citri adhesion-related proteins (ScARPs) (pSci1 to -5) and the hydrophilic protein P32 (pSci6), which had been tentatively associated with insect transmission, as they were not detected in non-insect-transmissible strains. With the aim of further investigating the role of plasmid-encoded determinants in insect transmission, we have constructed S. citri mutant strains that differ in their plasmid contents by developing a plasmid curing/replacement strategy based on the incompatibility of plasmids having identical replication regions. Experimental transmission of these S. citri plasmid mutants through injection into the leafhopper vector Circulifer haematoceps revealed that pSci6, more precisely, the pSci6_06 coding sequence, encoding a protein of unknown function, was essential for transmission. In contrast, ScARPs and P32 were dispensable for both acquisition and transmission of the spiroplasmas by the leafhopper vector, even though S. citri mutants lacking pSci1 to -5 (encoding ScARPs) were acquired and transmitted at lower efficiencies than the wild-type strain GII3.

The Repetitive Domain of ScARP3d Triggers Entry of Spiroplasma citri into Cultured Cells of the Vector Circulifer haematoceps

Béven, Laure; Duret, Sybille; Batailler, Brigitte; Dubrana, Marie-Pierre; Saillard, Colette; Renaudin, Joël; Arricau-Bouvery, Nathalie
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 31/10/2012 Português
Relevância na Pesquisa
36.62%
Spiroplasma citri is a plant pathogenic mollicute transmitted by the leafhopper vector Circulifer haematoceps. Successful transmission requires the spiroplasmas to cross the intestinal epithelium and salivary gland barriers through endocytosis mediated by receptor-ligand interactions. To characterize these interactions we studied the adhesion and invasion capabilities of a S. citri mutant using the Ciha-1 leafhopper cell line. S. citri GII3 wild-type contains 7 plasmids, 5 of which (pSci1 to 5) encode 8 related adhesins (ScARPs). As compared to the wild-type strain GII3, the S. citri mutant G/6 lacking pSci1 to 5 was affected in its ability to adhere and enter into the Ciha-1 cells. Proteolysis analyses, Triton X-114 partitioning and agglutination assays showed that the N-terminal part of ScARP3d, consisting of repeated sequences, was exposed to the spiroplasma surface whereas the C-terminal part was anchored into the membrane. Latex beads cytadherence assays showed the ScARP3d repeat domain (Rep3d) to be involved, and internalization of the Rep3d-coated beads to be actin-dependent. These data suggested that ScARP3d, via its Rep3d domain, was implicated in adhesion of S. citri GII3 to insect cells. Inhibition tests using anti-Rep3d antibodies and competitive assays with recombinant Rep3d both resulted in a decrease of insect cells invasion by the spiroplasmas. Unexpectedly...

Tubular Structure Induced by a Plant Virus Facilitates Viral Spread in Its Vector Insect

Chen, Qian; Chen, Hongyan; Mao, Qianzhuo; Liu, Qifei; Shimizu, Takumi; Uehara-Ichiki, Tamaki; Wu, Zujian; Xie, Lianhui; Omura, Toshihiro; Wei, Taiyun
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.88%
Rice dwarf virus (RDV) replicates in and is transmitted by a leafhopper vector in a persistent-propagative manner. Previous cytopathologic and genetic data revealed that tubular structures, constructed by the nonstructural viral protein Pns10, contain viral particles and are directly involved in the intercellular spread of RDV among cultured leafhopper cells. Here, we demonstrated that RDV exploited these virus-containing tubules to move along actin-based microvilli of the epithelial cells and muscle fibers of visceral muscle tissues in the alimentary canal, facilitating the spread of virus in the body of its insect vector leafhoppers. In cultured leafhopper cells, the knockdown of Pns10 expression due to RNA interference (RNAi) induced by synthesized dsRNA from Pns10 gene strongly inhibited tubule formation and prevented the spread of virus among insect vector cells. RNAi induced after ingestion of dsRNA from Pns10 gene strongly inhibited formation of tubules, preventing intercellular spread and transmission of the virus by the leafhopper. All these results, for the first time, show that a persistent-propagative virus exploits virus-containing tubules composed of a nonstructural viral protein to traffic along actin-based cellular protrusions...

Novel Rickettsiella Bacterium in the Leafhopper Orosius albicinctus (Hemiptera: Cicadellidae)

Iasur-Kruh, Lilach; Weintraub, Phyllis G.; Mozes-Daube, Netta; Robinson, Wyatt E.; Perlman, Steve J.; Zchori-Fein, Einat
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2013 Português
Relevância na Pesquisa
26.71%
Bacteria in the genus Rickettsiella (Coxiellaceae), which are mainly known as arthropod pathogens, are emerging as excellent models to study transitions between mutualism and pathogenicity. The current report characterizes a novel Rickettsiella found in the leafhopper Orosius albicinctus (Hemiptera: Cicadellidae), a major vector of phytoplasma diseases in Europe and Asia. Denaturing gradient gel electrophoresis (DGGE) and pyrosequencing were used to survey the main symbionts of O. albicinctus, revealing the obligate symbionts Sulcia and Nasuia, and the facultative symbionts Arsenophonus and Wolbachia, in addition to Rickettsiella. The leafhopper Rickettsiella is allied with bacteria found in ticks. Screening O. albicinctus from the field showed that Rickettsiella is highly prevalent, with over 60% of individuals infected. A stable Rickettsiella infection was maintained in a leafhopper laboratory colony for at least 10 generations, and fluorescence microscopy localized bacteria to accessory glands of the female reproductive tract, suggesting that the bacterium is vertically transmitted. Future studies will be needed to examine how Rickettsiella affects host fitess and its ability to vector phytopathogens.

Rice gall dwarf virus exploits tubules to facilitate viral spread among cultured insect vector cells derived from leafhopper Recilia dorsalis

Chen, Hongyan; Zheng, Limin; Jia, Dongsheng; Zhang, Peng; Chen, Qian; Liu, Qifei; Wei, Taiyun
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 23/07/2013 Português
Relevância na Pesquisa
36.9%
Rice gall dwarf virus (RGDV), a member of the family Reoviridae, causes repeated epidemics in rice fields in southern China. An RGDV isolate collected from Guangdong Province (southern China) is mainly transmitted by leafhopper vector Recilia dorsalis in a persistent-propagative manner. The infection by RGDV induces the formation of virus-containing tubules in the plant host and insect vector. In this study, we established continuous cell cultures of the leafhopper R. dorsalis to investigate the functional role of these tubules within the insect vector. Cytopathologic studies revealed that the tubules, which comprised viral non-structural protein Pns11 and contained viral particles, were able to protrude from the surface of cultured leafhopper cells. Tubule-like structures formed in non-host insect cells after the expression of Pns11 in a baculovirus system, suggesting that Pns11 was the minimal viral factor required for the formation of the tubules induced by RGDV infection. In cultured leafhopper cells, knockdown of Pns11 expression from RNA interference, induced by synthesized dsRNA from the Pns11 gene, abolished the formation of such tubules, preventing the direct cell-to-cell spread of RGDV without significant effects on viral multiplication. All these results show that RGDV exploits virus-containing tubules to facilitate viral spread among its insect vector cells.

Semipersistent Transmission of Leafhopper-Borne Maize Chlorotic Dwarf Virus

Nault, L. R.; Styer, W. E.; Knoke, J. K.; Pitre, H. N.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
Português
Relevância na Pesquisa
36.62%
Maize chlorotic dwarf virus (MCDV), an isometric virus associated with a stunting disease of maize, has a semipersistent relationship with its leafhopper vector, Graminella nigrifrons (Forbes). Leafhopper’s lose their ability to transmit MCDV within 48 h after virus is acquired. Leafhoppers given a 96-h virus-acquisition access period (AAP) were more efficient vectors than leafhoppers given a 24-h AAP. The leafhoppers can transmit MCDV following a 2-h AAP and a 2-h inculation period. None of 100 nymphs which previously fed on infected corn and then molted transmitted MCDV, whereas 25 of 100 nonmolted nymphs transmitted virus. Both adult males and females transmit MCDV. The leafhopper Deltocephalus sonorus Ball also is a vector of MCDV, although it is inefficient when compared to G. nigrifrons. The leafhoppers, Dalbulus elimatus (Ball), D. maidis DeLong and Wolcott, and Macrosteles fasifrons (Stål), failed to transmit MCDV.

Análise faunística de cigarrinhas (Hemiptera: Cicadellidae) na cultura da videira no Rio Grande do Sul; Faunistic analysis of leafhopper (Hemiptera: Cicadellidae) species in vineyards of Rio Grande do Sul state, Brazil

RINGENBERG, Rudiney; LOPES, João R S; BOTTON, Marcos; AZEVEDO-FILHO, Wilson S de; CAVICHIOLI, Rodney R
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.49%
In some American countries, grapevines are affected by Pierce's disease (PD), which is caused by a particular strain of Xylella fastidiosa not yet reported in Brazil. In order to investigate the potential for PD spread in Brazil in case of pathogen introduction, we conducted a faunistic analysis of leafhoppers (Hemiptera: Cicadellidae) associated to vineyards in the State of Rio Grande do Sul, with emphasis in the subfamily Cicadellinae (sharpshooters), which includes the main potential vectors of X. fastidiosa. Leafhopper samplings were carried out fortnightly during two years (9/2004-9/2006) in four Vitis vinifera vineyards in the municipalities of Bento Gonçalves and Farroupilha (RS). Thirtyfour leafhopper and six spittlebug species were collected, but most (98.4%) of the 3,893 specimens trapped were leafhoppers, distributed in the subfamilies Cicadellinae (60.2%), Gyponinae (34.1%), Deltocephalinae (3.8%) and Coelidinae (0.3%). The sharpshooter specimens were divided in the tribes Cicadellini (68.5%; 12 species) and Proconiini (31.5%; 11 species). Based on the faunistic indices, five species of Cicadellini, Bucephalogonia xanthophis (Berg), Dilobopterus dispar (Germar), Macugonalia cavifrons Stal, Sibovia sagata (Signoret) and Spinagonalia rubrovittata Cavichioli...

Egg parasitoids of the corn leafhopper, Dalbulus maidis, in the southernmost area of its distribution range

Virla, Eduardo Gabriel; Moya Raygoza, Gustavo; Luft Albarracin, Erica Beatriz
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Português
Relevância na Pesquisa
36.62%
Egg parasitoids of the corn leafhopper, Dalbulus maidis (DeLong and Wolcott) (Hemiptera: Cicadellidae), were surveyed exposing sentinel eggs of the leafhopper along a latitudinal transect of 600 km in Argentina, the southernmost area of its distribution range. Four parasitoid species were obtained: the mymarids Anagrus breviphragma Soyka (Hymenoptera: Mymaridae), Anagrus flaveolus Waterhouse, and Polynema sp., and the trichogrammatid Pseudoligosita longifrangiata (Viggiani) (Hymenoptera: Trichogrammatidae). The low parasitism rate, low species richness, and high proportion of generalist egg parasitoids were quite clear in the southern distribution limit of the vector, in contrast to regions where corn crops are available all year round and there are continuous and overlapping generations of the pest. Further studies need to be done in order to determine the native host of the above egg parasitoids, the seasonal abundance, and the possible occurrence of other species affecting D. maidis populations in the studied area.; Los parasitoides de huevos de la chicharrita del maíz, Dalbulus maidis (DeLong and Wolcott), fueron estudiados exponiendo huevos trampas a lo largo de una transecta de 600 Km en Argentina, en su rango de distribución más austral. Cuatro especies de parasitoides fueron obtenidos: los mimaridos Anagrus breviphragma Soyka...

Dryinidae (Hymenoptera: Chrysidoidea) parasitoids of the corn leafhopper, Dalbulus maidis (Delong & Wolcott) (Hemiptera: Cicadellidae), in Argentina, with description of the male of Gonatopus moyaraygozai Olmi

Virla,Eduardo G; Olmi,Massimo
Fonte: ASOCIACIÓN INTERCIENCIA Publicador: ASOCIACIÓN INTERCIENCIA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2007 Português
Relevância na Pesquisa
36.58%
The parasitoids of the Corn Leafhopper, Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Auchenorrhyncha) were studied in Tucumán Province, Argentina. Leafhoppers parasitized by Dryinidae (Hymenoptera: Chrysidoidea) were collected in cornfields from Dec 2003 to Apr 2005. Dryinid adults belonging to three species, Gonatopus caraibicus (Olmi), Gonatopus contortus Olmi, and G. moyaraygozai Olmi, were obtained. G. moyaraygozai is quoted for the first time in Argentina, and the male is described for the first time. This contribution presents the first field host-association record for G. caraibicus and D. maidis; in addition, G. contortus, and G. moyaraygozai are cited for the first time attacking Corn Leafhopper populations. Data on the parasitization rate by G. moyaraygozai are given.