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M J Adams – One of the best experts on this subject based on the ideXlab platform.

  • Family Flexiviridae: a case study in virion and genome plasticity.
    Annual Review of Phytopathology, 2007
    Co-Authors: Giovanni P. Martelli, M J Adams, Jan Kreuze, Valerian V. Dolja

    Abstract:

    AbstractThe plant virus family Flexiviridae includes the definitive genera Potexvirus, Mandarivirus, Allexivirus, Carlavirus, Foveavirus, Capillovirus, Vitivirus, Trichovirus, the putative genus Citrivirus, and some unassigned species. Its establishment was based on similarities in virion morphology, common features in genome type and organization, and strong phylogenetic relationships between replicational and structural proteins. In this review, we provide a brief account of the main biological and molecular properties of the members of the family, with special emphasis on the relationships within and among the genera. In phylogenetic analyses the potexvirus-like replicases were more closely related to tymoviruses than to carlaviruses. We postulate a common evolutionary ancestor for the family Tymoviridae and the two distinct evolutionary clusters of the Flexiviridae, i.e., a plant virus with a polyadenylated genome, filamentous virions, and a triple gene block of movement proteins. Subsequent recombina…

  • The new plant virus family Flexiviridae and assessment of molecular criteria for species demarcation
    Archives of Virology, 2004
    Co-Authors: M J Adams, John F. Antoniw, M. Joseph, A. A. Brunt, Thierry Candresse, G. D. Foster, R. G. Milne, Giovanni P. Martelli, Claude M Fauquet

    Abstract:

    Summary. The new plant virus family Flexiviridae is described. The family is named because its members have flexuous virions and it includes the existing genera Allexivirus, Capillovirus,Carlavirus,Foveavirus,Potexvirus,Trichovirus andVitivirus, plus the new genus Mandarivirus together with some related viruses not assigned to any genus. The family is justified from phylogenetic analyses of the polymerase and coat protein (CP) sequences. To help to define suitable molecular criteria for demarcation of species, a complete set of pairwise comparisons was made using the nucleotide (nt) and amino acid (aa) sequences of each fullysequenced gene from every available accession in the family. Based on the distributions and on inspection of the data, it was concluded that, as a general rule, distinct species have less than ca. 72% identical nt or 80% identical aa between their entire CP or replication protein genes.

  • Virology Division News: The new plant virus family Flexiviridae and assessment of molecular criteria for species demarcation

    Archives of Virology, 2004
    Co-Authors: M J Adams, G. P. Martelli, John F. Antoniw, M. Joseph, A. A. Brunt, Thierry Candresse, G. D. Foster, R. G. Milne, Claude M Fauquet

    Abstract:

    The new plant virus family Flexiviridae is described. The family is named because its members have flexuous virions and it includes the existing genera Allexivirus , Capillovirus , Carlavirus , Foveavirus , Potexvirus , Trichovirus and Vitivirus , plus the new genus Mandarivirus together with some related viruses not assigned to any genus. The family is justified from phylogenetic analyses of the polymerase and coat protein (CP) sequences. To help to define suitable molecular criteria for demarcation of species, a complete set of pairwise comparisons was made using the nucleotide (nt) and amino acid (aa) sequences of each fully-sequenced gene from every available accession in the family. Based on the distributions and on inspection of the data, it was concluded that, as a general rule, distinct species have less than ca. 72% identical nt or 80% identical aa between their entire CP or replication protein genes.

Milena Leite Oliveira – One of the best experts on this subject based on the ideXlab platform.

  • Survey of viruses belonging to different genera and species in noble garlic in Brazil
    Scientia Agricola, 2015
    Co-Authors: Tatiana Mituti, Milena Leite Oliveira, Monika Fecury Moura, Renate Krause Sakate, Julio Massaharu Marubayashi, Vitor Massami Imaizumi, Marcelo Agenor Pavan

    Abstract:

    Garlic (Allium sativumL.) is a host to several viruses, most commonly those belonging to theAllexivirus,Carlavirus, orPotyvirusgenera. Nine species distributed among these three genera have been reported in Brazil: two species within carlaviruses, two within potyviruses, and five within Allexiviruses. To quantify the prevalence of these viruses, young leaves from 520 plants (plants either symptomatic or asymptomatic) were collected from commercial fields grown in four Brazilian states and analyzed using universal and species-specific primers via the reverse transcription polymerase chain reaction (RT-PCR). Potyvirus presence was positive in 306 samples (81 %), 151 of them (38 %) in mixed infections with other viruses. The most frequent potyviruses wereOnion yellow dwarf virus(OYDV, 56 %) andLeek yellow stripe virus(LYSV, 55 %). 187 samples (49 %) were positive for Allexivirus, with 33 (9 %) showing single infections and 154 (41 %) showing mixed infections withGarlic virus A (GarV-A),Garlic virus B(GarV-B),Garlic virus C(GarV-C),Garlic virus D(GarV-D), and species belonging to theCarlavirus andPotyvirusgenera. The predominant species in which Allexiviruses were found were GarV-A and GarV-D. Only 15 samples (4 %) were infected solely by a carlavirus, and 63 (17 %) showed mixed infections with viruses from different genera. The dominant species of carlavirus wasGarlic commom latent virus(GarCLV). Carlaviruses and Allexiviruses are frequently associated with mixed infections with potyviruses, whereas mixed infections with carlaviruses and Allexiviruses are rare. About 70 % of the plants collected were positive for at least one species of virus.

  • Análise da presença de vírus em alho semente da segunda e quarta gerações, produzidos por termoterapia e cultura de tecido
    Grupo Paulista de Fitopatologia, 2014
    Co-Authors: Milena Leite Oliveira, Mituti Tatiana, Pavan, Marcelo Agenor, Nardini, João Paulo Calore, Bruno Rossito De ,marchi, Bampi Daiana, Krause-sakate Renate

    Abstract:

    The garlic (Allium sativum L.) can be naturally infected by a complex of filamentous viruses belonging to the genera Potyvirus, Carlavirus and Allexivirus. Accumulation of these viruses occurs especially by vegetative propagation through cloves. As the cultivated garlic plant does not produce true seed worldwide, virus-free plants can only be obtained by tissue culture of stem apices and thermotherapy. Using these techniques, garlic seeds were produced at the School of Agricultural Sciences – UNESP, Botucatu, and evaluated by RT-PCR for the presence of potyvirus, carlavirus and Allexivirus. In the second generation of microcloves propagated in a greenhouse, 6.6% infection was detected, only by Allexivirus. In the fourth generation, however, there was 60% incidence by Allexivirus, 35% by potyvirus and all negative by carlavirus. The high rate of infection by Allexivirus may be related to the greater difficulty of removing the species of viruses belonging to this genus, as observed by other authors, and also based on the infection and transmission of the virus by the mite, Aceria tulipae, during the storage of bulbs from one year to the other. The garlic at the fourth generation corresponds to cloves weighed less than 1 gram and not selected for commercial multiplication. Selection for the size of cloves has a positive effect on the choice of cloves with lower rates of viral infection, as the technique of thermotherapy and tissue culture do not eliminate the virus completely. Results also emphasize the need of fumigation for the garlic seed stored from one year to the other in order to prevent the transmission of Allexivirus during storage.O alho (Allium sativum L.) pode estar naturalmente infectado por um complexo de vírus filamentosos pertencentes aos gêneros Potyvirus, Carlavirus e Allexivirus. O acúmulo destes vírus se dá, principalmente, pela sua propagação vegetativa através dos bulbilhos. Como a planta de alho cultivada não produz semente verdadeira em todo o mundo, a única forma de se obter plantas livres de vírus se dá pela cultura de tecidos dos ápices caulinares e termoterapia. Utilizando estas técnicas, alhos sementes foram produzidos na FCA- UNESP de Botucatu e avaliados via RT-PCR para a presença de potyvirus, carlavirus e Allexivirus. Na segunda geração dos microbulbilhos propagados em casa de vegetação, 6,6% de infecção foi verificada por Allexivirus. Já na quarta geração foi observada incidência de 60% com Allexivirus, 35% com potyvirus e todas foram negativas para carlavirus. A alta taxa de infecção por Allexivirus pode estar relacionada à maior dificuldade de remoção de espécies de vírus pertencentes a este gênero, como também já observado por outros autores, pela infecção e transmissão de vírus pelo ácaro, Aceriatulipae, durante o armazenamento dos bulbos de um ano a outro. O alho na quarta geração corresponde a bulbilhos com peso inferior a 1 grama e que não haviam sido selecionados para multiplicação comercial. A seleção para tamanho do bulbilho tem efeito positivo na escolha de bulbilhos com menores taxas de infecção por vírus, já que a técnica de termoterapia e cultura de tecidos não elimina totalmente os vírus. Os resultados também enfatizam a necessidade de se realizar fumigação no alho semente armazenado de um ano a outro a fim de evitar a transmissão de Allexivirus durante o armazenamento

  • Bulbilhos aéreos de alho, provenientes de escapes florais, são infectados por vírus
    Grupo Paulista de Fitopatologia, 2014
    Co-Authors: Tatiana Mituti, Milena Leite Oliveira, João Paulo Calore Nardini, Monika Fecury Moura, Maria Isabel Motta Hoffmann, Leysimar Ribeiro Pitzr Guimarães, Renate Krause Sakate, Marcelo Agenor Pavan

    Abstract:

    Em campos de produção comercial de alho é comum observar plantas naturalmente infectadas por vírus dos gêneros Allexivirus, Carlavirus e Potyvirus. Os bulbilhos aéreos podem ser uma alternativa para a propagação de plantas de alho livres de vírus. Desta forma, o objetivo deste trabalho foi analisar a taxa de perpetuação dos vírus de plantas infectadas para os bulbilhos aéreos. Os bulbilhos aéreos obtidos de plantas infectadas foram analisados por RT-PCR utilizando oligonucleotídeos universais para os gêneros Allexivirus, Carlavirus e Potyvirus. A taxa de perpetuação foi de 65% para allexivírus, 20% para carlavírus e 82,22% para potyvírus. Os resultados demonstraram que a perpetuação dos diferentes vírus do bulbo para os bulbilhos aéreos é elevada, inviabilizando a utilização direta dos bulbilhos aéreos provenientes de plantas matrizes infectadas por vírus. Esta metodologia deve ser utilizada somente a partir de plantas isentas de vírus

Marcelo Agenor Pavan – One of the best experts on this subject based on the ideXlab platform.

  • Survey of viruses belonging to different genera and species in noble garlic in Brazil
    Scientia Agricola, 2015
    Co-Authors: Tatiana Mituti, Milena Leite Oliveira, Monika Fecury Moura, Renate Krause Sakate, Julio Massaharu Marubayashi, Vitor Massami Imaizumi, Marcelo Agenor Pavan

    Abstract:

    Garlic (Allium sativumL.) is a host to several viruses, most commonly those belonging to theAllexivirus,Carlavirus, orPotyvirusgenera. Nine species distributed among these three genera have been reported in Brazil: two species within carlaviruses, two within potyviruses, and five within Allexiviruses. To quantify the prevalence of these viruses, young leaves from 520 plants (plants either symptomatic or asymptomatic) were collected from commercial fields grown in four Brazilian states and analyzed using universal and species-specific primers via the reverse transcription polymerase chain reaction (RT-PCR). Potyvirus presence was positive in 306 samples (81 %), 151 of them (38 %) in mixed infections with other viruses. The most frequent potyviruses wereOnion yellow dwarf virus(OYDV, 56 %) andLeek yellow stripe virus(LYSV, 55 %). 187 samples (49 %) were positive for Allexivirus, with 33 (9 %) showing single infections and 154 (41 %) showing mixed infections withGarlic virus A (GarV-A),Garlic virus B(GarV-B),Garlic virus C(GarV-C),Garlic virus D(GarV-D), and species belonging to theCarlavirus andPotyvirusgenera. The predominant species in which Allexiviruses were found were GarV-A and GarV-D. Only 15 samples (4 %) were infected solely by a carlavirus, and 63 (17 %) showed mixed infections with viruses from different genera. The dominant species of carlavirus wasGarlic commom latent virus(GarCLV). Carlaviruses and Allexiviruses are frequently associated with mixed infections with potyviruses, whereas mixed infections with carlaviruses and Allexiviruses are rare. About 70 % of the plants collected were positive for at least one species of virus.

  • Bulbilhos aéreos de alho, provenientes de escapes florais, são infectados por vírus
    Grupo Paulista de Fitopatologia, 2014
    Co-Authors: Tatiana Mituti, Milena Leite Oliveira, João Paulo Calore Nardini, Monika Fecury Moura, Maria Isabel Motta Hoffmann, Leysimar Ribeiro Pitzr Guimarães, Renate Krause Sakate, Marcelo Agenor Pavan

    Abstract:

    Em campos de produção comercial de alho é comum observar plantas naturalmente infectadas por vírus dos gêneros Allexivirus, Carlavirus e Potyvirus. Os bulbilhos aéreos podem ser uma alternativa para a propagação de plantas de alho livres de vírus. Desta forma, o objetivo deste trabalho foi analisar a taxa de perpetuação dos vírus de plantas infectadas para os bulbilhos aéreos. Os bulbilhos aéreos obtidos de plantas infectadas foram analisados por RT-PCR utilizando oligonucleotídeos universais para os gêneros Allexivirus, Carlavirus e Potyvirus. A taxa de perpetuação foi de 65% para allexivírus, 20% para carlavírus e 82,22% para potyvírus. Os resultados demonstraram que a perpetuação dos diferentes vírus do bulbo para os bulbilhos aéreos é elevada, inviabilizando a utilização direta dos bulbilhos aéreos provenientes de plantas matrizes infectadas por vírus. Esta metodologia deve ser utilizada somente a partir de plantas isentas de vírus

  • Análise da presença de vírus em alho semente da segunda e quarta gerações, produzidos por termoterapia e cultura de tecido
    Grupo Paulista de Fitopatologia, 2014
    Co-Authors: Milena Leite Oliveira, Tatiana Mituti, Marcelo Agenor Pavan, João Paulo Calore Nardini, Bruno Rossito De ,marchi, Daiana Bampi, Renate Krause-sakate

    Abstract:

    O alho (Allium sativum L.) pode estar naturalmente infectado por um complexo de vírus filamentosos pertencentes aos gêneros Potyvirus, Carlavirus e Allexivirus. O acúmulo destes vírus se dá, principalmente, pela sua propagação vegetativa através dos bulbilhos. Como a planta de alho cultivada não produz semente verdadeira em todo o mundo, a única forma de se obter plantas livres de vírus se dá pela cultura de tecidos dos ápices caulinares e termoterapia. Utilizando estas técnicas, alhos sementes foram produzidos na FCA- UNESP de Botucatu e avaliados via RT-PCR para a presença de potyvirus, carlavirus e Allexivirus. Na segunda geração dos microbulbilhos propagados em casa de vegetação, 6,6% de infecção foi verificada por Allexivirus. Já na quarta geração foi observada incidência de 60% com Allexivirus, 35% com potyvirus e todas foram negativas para carlavirus. A alta taxa de infecção por Allexivirus pode estar relacionada à maior dificuldade de remoção de espécies de vírus pertencentes a este gênero, como também já observado por outros autores, pela infecção e transmissão de vírus pelo ácaro, Aceriatulipae, durante o armazenamento dos bulbos de um ano a outro. O alho na quarta geração corresponde a bulbilhos com peso inferior a 1 grama e que não haviam sido selecionados para multiplicação comercial. A seleção para tamanho do bulbilho tem efeito positivo na escolha de bulbilhos com menores taxas de infecção por vírus, já que a técnica de termoterapia e cultura de tecidos não elimina totalmente os vírus. Os resultados também enfatizam a necessidade de se realizar fumigação no alho semente armazenado de um ano a outro a fim de evitar a transmissão de Allexivirus durante o armazenamento