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1.
Viruses ; 13(2)2021 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-33525612

RESUMO

Broad bean wilt virus 2 (BBWV-2), which belongs to the genus Fabavirus of the family Secoviridae, is an important pathogen that causes damage to broad bean, pepper, yam, spinach and other economically important ornamental and horticultural crops worldwide. Previously, only limited reports have shown the genetic variation of BBWV2. Meanwhile, the detailed evolutionary changes, synonymous codon usage bias and host adaptation of this virus are largely unclear. Here, we performed comprehensive analyses of the phylodynamics, reassortment, composition bias and codon usage pattern of BBWV2 using forty-two complete genome sequences of BBWV-2 isolates together with two other full-length RNA1 sequences and six full-length RNA2 sequences. Both recombination and reassortment had a significant influence on the genomic evolution of BBWV2. Through phylogenetic analysis we detected three and four lineages based on the ORF1 and ORF2 nonrecombinant sequences, respectively. The evolutionary rates of the two BBWV2 ORF coding sequences were 8.895 × 10-4 and 4.560 × 10-4 subs/site/year, respectively. We found a relatively conserved and stable genomic composition with a lower codon usage choice in the two BBWV2 protein coding sequences. ENC-plot and neutrality plot analyses showed that natural selection is the key factor shaping the codon usage pattern of BBWV2. Strong correlations between BBWV2 and broad bean and pepper were observed from similarity index (SiD), codon adaptation index (CAI) and relative codon deoptimization index (RCDI) analyses. Our study is the first to evaluate the phylodynamics, codon usage patterns and adaptive evolution of a fabavirus, and our results may be useful for the understanding of the origin of this virus.


Assuntos
Uso do Códon , Fabavirus/genética , Genoma Viral , Plantas/virologia , Adaptação Fisiológica , Códon , Evolução Molecular , Fabavirus/fisiologia , Interações Hospedeiro-Patógeno , Fases de Leitura Aberta , Filogenia , Doenças das Plantas/virologia , Fenômenos Fisiológicos Vegetais , Recombinação Genética , Seleção Genética
2.
Mol Plant Pathol ; 21(11): 1421-1435, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32936537

RESUMO

Broad bean wilt virus 1 (BBWV-1, genus Fabavirus, family Secoviridae) is a bipartite, single-stranded positive-sense RNA virus infecting many horticultural and ornamental crops worldwide. RNA1 encodes proteins involved in viral replication whereas RNA2 encodes two coat proteins (the large and small coat proteins) and two putative movement proteins (MPs) of different sizes with overlapping C-terminal regions. In this work, we determined the role played by the small putative BBWV-1 MP (VP37) on virus pathogenicity, host specificity, and suppression of post-transcriptional gene silencing (PTGS). We engineered a BBWV-1 35S-driven full-length cDNA infectious clone corresponding to BBWV-1 RNA1 and RNA2 (pBBWV1-Wt) and generated a mutant knocking out VP37 (pBBWV1-G492C). Agroinfiltration assays showed that pBBWV1-Wt, as the original BBWV-1 isolate, infected broad bean, tomato, pepper, and Nicotiana benthamiana, whereas pBBWV1-G492C did not infect pepper and tomato systemically. Also, pBBWV1-G492C induced milder symptoms in broad bean and N. benthamiana than pBBWV1-Wt. Differential retrotranscription and amplification of the (+) and (-) strands showed that pBBWV1-G492C replicated in the agroinfiltrated leaves of pepper but not in tomato. All this suggests that VP37 is a determinant of pathogenicity and host specificity. Transient expression of VP37 through a potato virus X (PVX) vector enhanced PVX symptoms and induced systemic necrosis associated with programmed cell death in N. benthamiana plants. Finally, VP37 was identified as a viral suppressor of RNA silencing by transient expression in N. benthamiana 16c plants and movement complementation of a viral construct based on turnip crinkle virus (pTCV-GFP).


Assuntos
Fabavirus/patogenicidade , Especificidade de Hospedeiro/genética , Doenças das Plantas/virologia , Interferência de RNA , Vicia faba/virologia , Proteínas Virais/metabolismo , Capsicum/virologia , Fabavirus/genética , Expressão Gênica , Lycopersicon esculentum/virologia , RNA Viral/genética , Tabaco/virologia , Proteínas Virais/genética , Virulência
3.
Arch Virol ; 165(9): 2073-2078, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32621153

RESUMO

Complete RNA1 and RNA2 sequences of two and nearly complete genome sequences of six new variants of grapevine fabavirus found in Japan were compared to those of previously reported variants. Negative selection pressure was suggested, and no recombination events were detected in either RNA1 or RNA2. The first 18 nucleotides in both RNAs were predicted to form a stem-loop structure. The variants could be genetically divided into four groups based on RNA1 and two based on RNA2. A broad-spectrum reverse transcription polymerase chain reaction assay using a primer pair designed based on an RNA2 consensus sequence was able to detect all of the known variants.


Assuntos
Fabavirus/isolamento & purificação , Variação Genética , Doenças das Plantas/virologia , Vitis/virologia , Fabavirus/classificação , Fabavirus/genética , Genoma Viral , Filogenia , RNA Viral/genética
4.
Viruses ; 11(4)2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30970658

RESUMO

As an invasive weed, Mikania micrantha Kunth has caused serious damage to natural forest ecosystems in South China in recent years. Mikania micrantha wilt virus (MMWV), an isolate of the Gentian mosaic virus (GeMV), is transmitted by Myzus persicae (Sulzer) in a non-persistent manner and can effectively inhibit the growth of M. micrantha. To explore the MMWV-M. micrantha-M. persicae interaction and its impact on the invasion of M. micrantha, volatile compounds (VOCs) emitted from healthy, mock-inoculated, and MMWV-infected plants were collected, and effects on host preference of the apterous and alate aphids were assessed with Y-shaped olfactometers. Gas chromatography-mass spectrometry (GC-MS) analysis indicated that MMWV infection changed the VOC profiles, rendering plants more attractive to aphids. Clip-cages were used to document the population growth rate of M. persicae fed on healthy, mock-inoculated, or MMWV-infected plants. Compared to those reared on healthy plants, the population growth of M. persicae drastically decreased on the MMWV-infected plants. Plant host choice tests based on visual and contact cues were also conducted using alate M. persicae. Interestingly, the initial attractiveness of MMWV-infected plants diminished, and more alate M. persicae moved to healthy plants. Taken together, MMWV appeared to be able to manipulate its plant host to first attract insect vectors to infected plants but then repel viruliferous vectors to promote its own dispersal. Its potential application for invasive weed management is discussed.


Assuntos
Afídeos/fisiologia , Fabavirus/crescimento & desenvolvimento , Comportamento Alimentar/efeitos dos fármacos , Interações entre Hospedeiro e Microrganismos , Especificidade de Hospedeiro/efeitos dos fármacos , Mikania/virologia , Feromônios/metabolismo , Animais , Afídeos/efeitos dos fármacos , China , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/fisiologia , Doenças das Plantas/virologia , Compostos Orgânicos Voláteis/metabolismo
5.
Viruses ; 10(4)2018 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-29670059

RESUMO

During their lifetime, perennial woody plants are expected to face multiple infection events. Furthermore, multiple genotypes of individual virus species may co-infect the same host. This may eventually lead to a situation where plants harbor complex communities of viral species/strains. Using high-throughput sequencing, we describe co-infection of sweet and sour cherry trees with diverse genomic variants of two closely related viruses, namely prunus virus F (PrVF) and cherry virus F (CVF). Both viruses are most homologous to members of the Fabavirus genus (Secoviridae family). The comparison of CVF and PrVF RNA2 genomic sequences suggests that the two viruses may significantly differ in their expression strategy. Indeed, similar to comoviruses, the smaller genomic segment of PrVF, RNA2, may be translated in two collinear proteins while CVF likely expresses only the shorter of these two proteins. Linked with the observation that identity levels between the coat proteins of these two viruses are significantly below the family species demarcation cut-off, these findings support the idea that CVF and PrVF represent two separate Fabavirus species.


Assuntos
Fabavirus/genética , Variação Genética , Doenças das Plantas/virologia , Prunus/virologia , Perfilação da Expressão Gênica , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala
6.
Virus Res ; 242: 141-145, 2017 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-28970056

RESUMO

Broad bean wilt virus 2 (BBWV2, genus Fabavirus, family Secoviridae) has a wide host range and infects many economically important crops. Various isolates of BBWV2 have been identified from diverse host plants, and their molecular and biological characteristics have been investigated. In our previous study, we demonstrated that BBWV2 RNA2 contains a symptom determinant(s) capable of enhancing symptom severity by utilizing infectious full-length cDNA clones of two distinct strains of BBWV2, pBBWV2-PAP1 (a severe strain) and pBBWV2-RP1 (a mild strain). In the present study, to identify the symptom determinant(s) of BBWV2, we exploited disease responses of pBBWV2-PAP1- and pBBWV2-RP1-derived chimeric viruses and amino acid substitution mutant viruses in Nicotiana benthamiana and pepper (Capsicum annuum Quarri) and demonstrated that the movement protein (MP) encoded in BBWV RNA2 is the determinant of disease symptom severity in both plants. A single amino acid substitution in the MP was sufficient for changing symptom severity of BBWV2. Our finding provides a role for the MP as a symptom determinant in BBWV2 and increases the understanding of the basis of molecular interactions between host plants and BBWV2.


Assuntos
Capsicum/virologia , Fabavirus/patogenicidade , Interações Hospedeiro-Patógeno , Doenças das Plantas/virologia , Proteínas do Movimento Viral em Plantas/metabolismo , Fatores de Virulência/metabolismo , Mutação , Recombinação Genética , Genética Reversa , Tabaco/virologia
7.
Sci Rep ; 7(1): 11329, 2017 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-28900201

RESUMO

A disease causing smaller and cracked fruit affects peach [Prunus persica (L.) Batsch], resulting in significant decreases in yield and quality. In this study, peach tree leaves showing typical symptoms were subjected to deep sequencing of small RNAs for a complete survey of presumed causal viral pathogens. The results revealed two known viroids (Hop stunt viroid and Peach latent mosaic viroid), two known viruses (Apple chlorotic leaf spot trichovirus and Plum bark necrosis stem pitting-associated virus) and a novel virus provisionally named Peach leaf pitting-associated virus (PLPaV). Phylogenetic analysis based on RNA-dependent RNA polymerase placed PLPaV into a separate cluster under the genus Fabavirus in the family Secoviridae. The genome consists of two positive-sense single-stranded RNAs, i.e., RNA1 [6,357 nt, with a 48-nt poly(A) tail] and RNA2 [3,862 nt, with a 25-nt poly(A) containing two cytosines]. Biological tests of GF305 peach indicator seedlings indicated a leaf-pitting symptom rather than the smaller and cracked fruit symptoms related to virus and viroid infection. To our knowledge, this is the first report of a fabavirus infecting peach. PLPaV presents several new molecular and biological features that are absent in other fabaviruses, contributing to an overall better understanding of fabaviruses.


Assuntos
Fabavirus/genética , Genoma Viral , Sequenciamento de Nucleotídeos em Larga Escala , Doenças das Plantas/virologia , Prunus persica/virologia , Sequência de Bases , Fabavirus/classificação , Genômica/métodos , Especificidade de Hospedeiro , Conformação de Ácido Nucleico , Fenótipo , Filogenia , Dobramento de RNA , RNA Viral/química , RNA Viral/genética
8.
Arch Virol ; 162(3): 811-816, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27815695

RESUMO

The genus Fabavirus currently consists of five species represented by viruses that infect a wide range of hosts but none reported from temperate climate fruit trees. A virus with genomic features resembling fabaviruses (tentatively named Prunus virus F, PrVF) was revealed by high throughput sequencing of extracts from a sweet cherry tree (Prunus avium). PrVF was subsequently shown to be graft transmissible and further identified in three other non-symptomatic Prunus spp. from different geographical locations. Two genetic variants of RNA1 and RNA2 coexisted in the same samples. RNA1 consisted of 6,165 and 6,163 nucleotides, and RNA2 consisted of 3,622 and 3,468 nucleotides.


Assuntos
Fabavirus/genética , Fabavirus/isolamento & purificação , Doenças das Plantas/virologia , Prunus avium/virologia , Fabavirus/classificação , Frutas/virologia , Genoma Viral , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Análise de Sequência de DNA
9.
Virus Res ; 217: 71-5, 2016 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-26951858

RESUMO

Broad bean wilt virus 1 (BBWV-1), genus Fabavirus, has a genome composed of two single-stranded positive-sense RNAs of ∼5.8 (RNA1) and 3.4kb (RNA2). Full-length cDNA clones of both genomic RNAs (pBenR1 and pBenR2) from BBWV-1 isolate Ben were constructed under the control of the T7 promoter. In vitro derived capped transcripts were infectious in Nicotiana benthamiana, Chenopodium quinoa and Vicia faba plants. The biological activity of viral transcripts was not affected by extra bases at the 5'-terminus introduced during in vitro transcription. Virions derived from the infectious cDNA clones displayed similar viral infectivity and accumulation, as well as symptom induction as the wild-type BBWV-1 isolate.


Assuntos
DNA Complementar , DNA Viral , Fabavirus/patogenicidade , Fabavirus/genética , Doenças das Plantas/virologia , RNA Viral , Tabaco/virologia , Vicia faba/virologia , Vírion/genética , Vírion/patogenicidade
10.
Sci Rep ; 6: 21552, 2016 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-26903400

RESUMO

The movement protein VP37 of broad bean wilt virus 2 (BBWV 2) forms tubules in the plasmodesmata (PD) for the transport of virions between cells. This paper reports a mutual association between the BBWV 2 VP37-tubule complex and PD at the cytological level as determined by transmission electron microscopy. The generation of VP37-tubules within different PD leads to a different occurrence frequency as well as different morphology lines of virus-like particles. In addition, the frequency of VP37-tubules was different between PD found at different cellular interfaces, as well as between single-lined PD and branched PD. VP37-tubule generation also induced structural alterations of PD as well as modifications to the cell wall (CW) in the vicinity of the PD. A structural comparison using three-dimensional (3D) electron tomography (ET), determined that desmotubule structures found in the center of normal PD were absent in PD containing VP37-tubules. Using gold labeling, modification of the CW by callose deposition and cellulose reduction was observable on PD containing VP37-tubule. These cytological observations provide evidence of a mutual association of MP-derived tubules and PD in a natural host, improving our fundamental understanding of interactions between viral MP and PD that result in intercellular movement of virus particles.


Assuntos
Chenopodium quinoa/virologia , Fabavirus/ultraestrutura , Folhas de Planta/virologia , Plasmodesmos/virologia , Vírion/ultraestrutura , Parede Celular/ultraestrutura , Parede Celular/virologia , Chenopodium quinoa/ultraestrutura , Fabavirus/metabolismo , Interações Hospedeiro-Patógeno , Microscopia Eletrônica de Transmissão , Folhas de Planta/ultraestrutura , Plasmodesmos/ultraestrutura , Transporte Proteico , Proteínas Virais/metabolismo , Vírion/metabolismo
11.
Virus Res ; 211: 25-8, 2016 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-26428303

RESUMO

Broad bean wilt virus 2 (BBWV2), which belongs to the genus Fabavirus, is a destructive pathogen of many economically important horticultural and ornamental crops. In this study, we constructed infectious full-length cDNA clones of two distinct isolates of BBWV2 under control of the cauliflower mosaic virus 35S promoter. BBWV2-PAP1 isolated from paprika (Capsicum annuum var. gulosum) induces severe disease symptoms in various pepper varieties, whereas BBWV2-RP1 isolated from red pepper (Capsicum annuum L.) causes mild symptoms. Agrobacterium-mediated inoculation of the infectious cDNA clones of BBWV2-PAP1 and RP1 resulted in the same symptoms as the original virus isolates. The infectious cDNA clones of BBWV2-PAP1 and RP1 were used to examine the symptoms induced by pseudorecombinants between the two isolates to localize in which of the two genomic RNAs are the symptom severity determinants in BBWV2. The pseudorecombinant of RP1-RNA1 and PAP1-RNA2 induced severe symptoms, similar to those caused by the parental isolate PAP1, whereas the pseudorecombinant of PAP1-RNA1 and RP1-RNA2 induced mild symptoms, similar to those caused by the parental isolate RP1. Our results suggest that BBWV2 RNA2 contains a symptom determinant(s) capable of enhancing symptom severity.


Assuntos
Fabavirus/genética , Fabavirus/patogenicidade , Doenças das Plantas/virologia , RNA Viral/genética , Capsicum/virologia , Fabavirus/fisiologia , Proteínas Associadas a Pancreatite , RNA Viral/metabolismo , Tabaco/virologia , Virulência
12.
Bing Du Xue Bao ; 31(1): 58-64, 2015 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-25997332

RESUMO

To identity the pathogen that causes the mosaic and yellowing symptoms on Atractylodes macrocephala Koidz in Jiangxian, Shanxi province, biological inoculation, sequence-independent amplification (SIA),RT-PCR and other identification methods were used. The results showed that the chlorotic and necrosis symptoms occurred in the indicator plant Chenopodium quinoa after it was infected with the pathogen,and the same symptoms appeared after the reinoculation of healthy Atractylodes macrocephala Koidz; this reflected that the disease was likely to be caused by a virus. The results of SIA and sequencing showed that Broad bean wilt virus 2 (BBWV2) was present in severely mosaic Atractylodes macrocephala Koidz leaves. To further characterize the BBWV2 isolate from Atractylodes macrocephala (BBWV2-Am), the polyprotein partial gene encoded by BBWV2-Am RNA2 was cloned and sequenced. Sequence alignments showed that the nucleotide sequence identity of BBWV2-Am SCP and LCP genes ranged from 79.3% to 87.2% and from 80.1% to 89.2% compared to other BBWV2 strains,respectively; the deduced amino acid sequence similarities of the two gene products ranged from 91.2% to 95.7% and from 89.44 to 95.5%, respectively,compared to those of other BBWV2 strains. Phylogenetic comparisons showed that BBWV2-Am was most likely to be related to BBWV2-Rg,but formed an independent branch. This is the first report of BBWV2 in Atractylodes macrocephala Koidz.


Assuntos
Atractylodes/virologia , Fabavirus/genética , Fabavirus/isolamento & purificação , Doenças das Plantas/virologia , Sequência de Aminoácidos , Fabavirus/química , Fabavirus/classificação , Dados de Sequência Molecular , Filogenia , Análise de Sequência , Proteínas Virais/química , Proteínas Virais/genética
13.
Virus Res ; 192: 62-73, 2014 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-25173697

RESUMO

Viruses encode RNA silencing suppressors to counteract host RNA silencing-mediated defense responses. In this study, we demonstrate that VP53, VP37 and LCP encoded by RNA2 of broad bean wilt virus 2 (BBWV-2), a member of the genus Fabavirus, are strong suppressors of RNA silencing triggered by single-stranded sense RNA. They, however, had no effect on suppression of RNA silencing induced by double-stranded RNA. We provide evidence that these three suppressors can significantly limit the accumulation of small interfering RNAs (siRNAs) in tissues where the GFP gene has been silenced, and prevent the long distance spread of the induced silencing signal. Gel mobility shift assays showed that all three suppressors could bind ssRNA in a size-specific manner. Interestingly, VP37 and LCP, but not VP53, could reverse the silencing of a GFP gene in leaf tissue. Furthermore, these three proteins are capable of enhancing pathogenicity of potato virus X. Collectively, our findings indicate that viruses employ a more sophisticated strategy to overcome the host defense response mediated through suppression of RNA silencing during virus infection. As far as we are aware, this is the first report of RNA silencing suppressors encoded by a virus in the genus Fabavirus.


Assuntos
Fabavirus/imunologia , Fabavirus/fisiologia , Interações Hospedeiro-Patógeno , Interferência de RNA , Tabaco/imunologia , Tabaco/virologia , Proteínas Virais/metabolismo , Ensaio de Desvio de Mobilidade Eletroforética , Evasão da Resposta Imune , Ligação Proteica , RNA Interferente Pequeno/metabolismo
14.
Arch Virol ; 159(4): 779-84, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24122109

RESUMO

Analysis of four genomic regions from 37 geographically diverse isolates of broad bean wilt virus 1 (BBWV-1) showed high genetic diversity in comparison to most plant viruses. Comparison of synonymous and nonsynonymous substitutions of the small coat protein gene (SCP) revealed negative selection for most amino acid positions. Phylogenetic analysis of SCP showed that some BBWV-1 isolates from distant geographical areas were genetically close, suggesting long-distance migration. Analysis of genetic differentiation revealed high gene flow between Spanish and Near Eastern subpopulations, which were separated from North-Central and South-Eastern European subpopulations. Finally, putative recombinant and reassortant genomes were also identified.


Assuntos
Evolução Molecular , Fabavirus/classificação , Fabavirus/genética , Fluxo Gênico , Recombinação Genética , Seleção Genética , Análise por Conglomerados , Europa (Continente) , Fabaceae/virologia , Fabavirus/isolamento & purificação , Variação Genética , Oriente Médio , Dados de Sequência Molecular , Filogeografia , Doenças das Plantas/virologia , Análise de Sequência de DNA
15.
J Virol Methods ; 197: 77-82, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24361876

RESUMO

The genus Fabavirus of the family Secoviridae comprises a group of poorly characterized viruses. To date, only five species have been described: Broad bean wilt virus 1 (BBWV-1), Broad bean wilt virus 2 (BBWV-2), Lamium mild mosaic virus (LMMV), Gentian mosaic virus (GeMV) and Cucurbit mild mosaic virus (CuMMV). The development is described of two RT-PCR procedures for the detection and identification of Fabavirus species: a one-step RT-PCR using a single pair of conserved primers for the detection of all fabaviruses, and a one-step multiplex RT-PCR using species-specific primers for the simultaneous detection and identification of the above-mentioned species of the genus Fabavirus. These methods were applied successfully to field samples and the results were compared with those obtained by molecular hybridization and ELISA. The combination of the two techniques enables rapid, sensitive and reliable identification of the five known fabavirus species, as well as the possibility of discovering new species of this genus.


Assuntos
Fabavirus/classificação , Fabavirus/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Primers do DNA/genética , Fabavirus/genética , Doenças das Plantas/virologia , RNA Viral/genética , Sensibilidade e Especificidade , Fatores de Tempo
16.
Arch Virol ; 158(11): 2405-8, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23680926

RESUMO

Lamium mild mosaic virus (LMMV) is the only one of the five members of the genus Fabavirus for which there are no nucleotide sequence data. In this study, the complete genome sequence of LMMV was determined and compared with the available complete genome sequences of other members of the genus Fabavirus. The genome was the largest of the genus but maintained the typical organization, with RNA 1 of 6080 nucleotides (nt), RNA 2 of 4065 nt, and an unusually long 3' untranslated region in RNA 2 of 603 nt. Phylogenetic analysis of the amino acid sequences of the protease-polymerase (Pro-Pol) region and the two coat proteins confirmed that LMMV belongs to a distinct species within the genus Fabavirus.


Assuntos
Fabavirus/genética , Genoma Viral/genética , Lamiaceae/virologia , Vírus do Mosaico/genética , Doenças das Plantas/virologia , Análise de Sequência de DNA , Sequência de Bases , Proteínas do Capsídeo/genética , RNA Polimerases Dirigidas por DNA/genética , Fabavirus/classificação , Fabavirus/fisiologia , Dados de Sequência Molecular , Vírus do Mosaico/classificação , Vírus do Mosaico/fisiologia , Peptídeo Hidrolases/genética , Filogenia , RNA Viral/genética , Especificidade da Espécie , Tabaco/virologia , Proteínas Virais/genética
17.
Arch Virol ; 158(7): 1549-54, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23404460

RESUMO

We determined the complete nucleotide sequence of a broad bean wilt virus 2 (BBWV-2) isolate from gentian in Japan. The full-length RNA1 and RNA2 sequences, excluding poly(A) tails, were 5955 and 3600 nucleotides long, respectively. Analysis indicated that, in contrast to other BBWV-2 isolates, the 5' end of both RNA1 and RNA2 starts with a GUU sequence. We successfully inoculated Nicotiana benthamiana with BBWV-2 by infiltrating a mixed suspension of two Agrobacterium tumefaciens clones carrying binary vectors with the full-length RNA1 and RNA2 sequences. This is the first report on the efficient, easy and high-throughput use of agroinoculation for generating BBWV-2 infections.


Assuntos
Agrobacterium tumefaciens/genética , Fabavirus/genética , Técnicas de Transferência de Genes , Vetores Genéticos , Gentiana/virologia , Transformação Genética , Fabavirus/isolamento & purificação , Genoma Viral , Japão , Dados de Sequência Molecular , RNA Viral/genética , Análise de Sequência de DNA , Tabaco/virologia
18.
Arch Virol ; 157(3): 597-600, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22187104

RESUMO

The complete genome sequence of a cucurbit-infecting fabavirus was determined. Sequence analysis revealed that it had a genomic organization typical of fabaviruses, with genome segment sizes of 5870 nt (RNA-1) and 3294 nt (RNA-2). It shared CP and Pro-Pol amino acid sequence identities of 52.0-58.9% with those of reported fabaviruses. ELISA and western blots gave no cross-reactions between this cucurbit virus and broad bean wilt viruses 1 and 2. Based on molecular and serological criteria for species demarcation in the genus Fabavirus, the virus represents a distinct species, for which the species name Cucurbit mild mosaic virus (CuMMV) is proposed.


Assuntos
Cucurbita/virologia , Fabavirus/genética , Fabavirus/isolamento & purificação , Genoma Viral , RNA Viral/genética , Análise de Sequência de DNA , Anticorpos Antivirais/imunologia , Western Blotting , China , Análise por Conglomerados , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Fabavirus/classificação , Fabavirus/imunologia , Dados de Sequência Molecular , Filogenia , Homologia de Sequência de Aminoácidos
19.
J Virol Methods ; 177(2): 202-5, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21855578

RESUMO

Broad bean wilt virus 1 (BBWV-1) and BBWV-2 are the two most significant viruses in the genus Fabavirus, causing damage to many economically important agricultural crops worldwide. A quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) procedure using two TaqMan(®)MGB probes was developed for sensitive and specific detection and quantitation of BBWV-1 and BBWV-2. Primers and probes were designed from conserved sequence stretches to detect all isolates of each virus. Standard curves using RNA transcripts identical to both TaqMan(®)MGB probes enabled absolute quantitation, with a wide dynamic range and high sensitivity (10(3)-10(10) RNA molecules). RT-qPCR was assayed with genetically divergent BBWV-1 and BBWV-2 isolates from different plant hosts and countries, and was used to evaluate the temporal accumulation of BBWV-1 RNA in two plant hosts.


Assuntos
Chenopodium quinoa/virologia , Fabavirus/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Vicia faba/virologia , Sequência de Bases , Sequência Conservada , Primers do DNA/genética , Fabavirus/classificação , Fabavirus/genética , Dados de Sequência Molecular , Sondas de Ácido Nucleico/genética , Doenças das Plantas/virologia , RNA Viral/genética , RNA Viral/isolamento & purificação , Sensibilidade e Especificidade , Alinhamento de Sequência
20.
Virus Res ; 159(2): 206-14, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21549771

RESUMO

Biological control has the potential to limit the population growth of arthropod vectors and consequently may be expected to reduce plant virus spread in a crop. However, reduction of vector abundance is not the only effect of biological control. Natural enemies might induce antipredator behaviour that affects feeding and dispersal of vectors, and therefore virus spread. Here we test the effect of two natural enemies on dispersal of the aphid vector Myzus persicae and transmission of Broad bean wilt virus 1 (BBWV-1), genus Fabavirus, which is non-persistently transmitted by aphids. One of the predators tested, the syrphid Sphaerophoria rueppellii, is considered to induce low disturbance in aphid colonies, whereas the other, the coccinellid Adalia bipunctata, is assumed to induce high disturbance. Natural enemies enhanced aphid dispersal, but not virus transmission as compared to the control treatment without predators. However, transmission efficiency of BBWV-1 was higher in the presence of coccinellid adults than with syrphids. The behavioural observations of predators and the reactions of aphids to their presence indicate that a stronger antipredator behaviour is induced by coccinellid adults than by syrphids. The different antipredator behaviour displayed by aphids towards coccinellid adults and syrphids might explain the differences found in the rate of virus spread in their presence.


Assuntos
Afídeos/crescimento & desenvolvimento , Afídeos/virologia , Besouros/fisiologia , Dípteros/fisiologia , Fabavirus/isolamento & purificação , Doenças das Plantas/virologia , Comportamento Predatório , Animais , Vetores de Doenças
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