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Thierry Candresse - One of the best experts on this subject based on the ideXlab platform.
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first report of cherry virus a in prunus mume in china
Plant Disease, 2008Co-Authors: Armelle Marais, L Svanelladumas, Chantal Faure, Thierry CandresseAbstract:Natural infections of Cherry virus A (CVA) have been reported in sweet (Prunus avium) and sour cherry (P. cerasus) from a number of European countries, North America, and Japan. CVA has been detected occasionally in other Prunus hosts such as peach, plum, and apricot (1). In the spring of 2007, samples from four Japanese apricot (Prunus mume) trees from the Jiangsu Province of China were analyzed by a polyvalent reverse transcriptase-PCR assay that amplifies a short region of the polymerase gene of viruses from several genera in the family Flexiviridae (2). Sequencing of the amplified products identified CVA in three samples. Two isolates (GenBank Accession Nos. EU730949 and EU730950) were closely related and highly homologous (97.5 to 99.3% identity) to noncherry isolates of CVA (GenBank Accession Nos AY792509 and DQ445275 to DQ445292). The third isolate (GenBank Accession No. EU730951) was approximately 90% identical to the other P. mume isolates and showed the highest identity (92.3%) to a cherry isolate (GenBank Accession No AF413923). CVA infection of the P. mume samples was confirmed by two CVA-specific primer pairs targeting genomic regions corresponding to the movement or coat protein genes. Since the samples showed mixed infections with Plum pox virus (PPV) or Asian Prunus virus 1 (APV1), potential CVA symptomatology could not be evaluated. To our knowledge, these results are the first identification of CVA in China and in P. mume, extending the geographical distribution and natural host range of this virus. Additional work is needed to evaluate whether CVA poses a threat to P. mume production or whether, as in other identified hosts, CVA is largely latent. References: (1) M. Barone et al. Plant Dis. 90:1459, 2006. (2) X. Foissac et al. Phytopathology 95:617, 2005.
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Asian prunus viruses: New related members of the family Flexiviridae in Prunus germplasm of Asian origin.
Virus research, 2006Co-Authors: Armelle Marais, Laurence Svanella-dumas, Pascal Gentit, Xavier Foissac, Thierry CandresseAbstract:Serological reactivity to Plum pox virus (PPV) antisera has been described in several Prunus sources of Asian origin that are free of PPV infection. Using polyvalent or specific PCR assays, the presence of three closely related agents in two of these sources, Prunus mume cv. Bungo and P. persica cv. Ku Chu'a Hung, was demonstrated. Similarities in genome organization and sequence comparisons indicate that these agents should be regarded as members of the genus Foveavirus, their only singular trait being a very large (>800 nt) 3' non-coding region (NCR), as compared to the ca. 130-180 nt 3' NCR observed in other Foveaviruses. The three agents are very divergent from known Foveaviruses but are also significantly removed one from the others, with overall nucleotide sequence identity levels in the sequenced region of ca. 74-76% and of only 60.8-67.5% in their complete CP gene (61.9-71.3% amino acid sequence identity). Given the species discrimination criteria in the family Flexiviridae, these three agents should be regarded as three related yet distinct new viruses belonging to the Foveavirus genus, for which the names Asian prunus virus 1, 2 and 3 are proposed. Evidence is provided for the presence of variants of these new viruses in other Prunus germplasm of Asian origin.
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banana virus x bvx a novel flexivirus harbouring defective rnas definies a new genus within the Flexiviridae family
Microbes in a changing world = XIIIth International Congress of Virology San Fransisco (USA) July 23-28 2005, 2005Co-Authors: Pierreyves Teycheney, Armelle Marais, L Svanelladumas, Thierry CandresseAbstract:Background: Banana and plantain (Musa spp) are an essential staple food and account for one of the most widely exported fruits in the world. This crop is susceptible to numerous pests and pathogens, including five reported and characterized viruses which are severe constraints to exchanges of Musa germplasm. A study of the molecular variability of Banana mild mosaic virus (BanMMV) isolates infecting banana in Guadeloupe lead to the identification of a short nucleotide sequence belonging to a distinct viral species. Methods: The partial nucleotide sequence of the RNA genome of this agent was determined from double stranded RNA following 3' RACE amplification. Results: Five open reading frames were identified from the analysis of the last 2917 nucleotides of RACE-amplified sequence. They correspond, from 5' to 3', to a truncated ORF encoding replication-associated protein, three ORFs encoding a movement-associated triple gene block (TGB) and a capsid protein (CP) gene. This deduced genome organization is similar to that of some members of the Flexiviridae family such as Potexviruses and Foveaviruses. Sequence comparisons suggest that this virus is a new virus species in the Flexiviridae family, for which the name Banana virus X (BVX) is proposed. Sequence comparisons also showed that BVX is only distantly related to other members of the Flexiviridae family, in which it does not appear to belong to any existing genus. There is currently no evidence that infection by BVX can cause any visible symptoms in Musa sp. Furthermore, it was shown that BVX produces defective RNAs derived from its genomic RNA by non-homologous recombination. Three distinct pairs of donor/acceptor recombination sites involving short direct nucleotide repeats were characterized. Contrary to the situation encountered for the Potexviruses, these recombination sites are located within the TGB1 and CP genes and the recombination event results in a truncated TGB1 protein. A small scale study of the molecular variability of BVX was performed on Musa samples collected in different locations in Guadeloupe. It showed that BVX is reasonably distributed in Musa plants in Guadeloupe and displays a very low level of molecular variability, which is in marked contrast to the situation encountered for BanMMV, another member of the Flexiviridae family infecting Musa spp. (Resume d'auteur)
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The new plant virus family Flexiviridae and assessment of molecular criteria for species demarcation
Archives of Virology, 2004Co-Authors: M J Adams, John F. Antoniw, G. D. Foster, R. G. Milne, G. P. Martelli, A. A. Brunt, M. Joseph, Thierry Candresse, Claude M FauquetAbstract: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.
Menghsiao Meng - One of the best experts on this subject based on the ideXlab platform.
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suppression of bamboo mosaic virus accumulation by a putative methyltransferase in nicotiana benthamiana
Journal of Virology, 2009Co-Authors: Chunwei Cheng, Yauheiu Hsu, Chinghsiu Tsai, Chengcheng Lee, Jaoshien Chen, Yiyuong Hsiao, Chimau Chuang, Menghsiao MengAbstract:Bamboo mosaic virus (BaMV) is a flexuous-rod positive-sense RNA virus belonging to the genus Potexvirus of the family Flexiviridae. The 6.4-kb genome contains five open reading frames (ORFs), with a 5′ methyl cap and a 3′ poly(A) tail (27). Two major subgenomic RNAs of 2 and 1 kb are produced upon viral infection in host cells. The protein product of ORF1, translated from the genomic RNA, is a 155-kDa viral replicase comprising an N-terminal capping enzyme domain (23), a helicase-like domain harboring nucleoside triphosphatase/RNA 5′-triphosphatase activities (24), and a C-terminal RNA-dependent RNA polymerase (RdRp) (22). The capping enzyme domain exhibits an S-adenosyl-l-methionine (AdoMet)-dependent guanylyltransferase activity, which is characteristic of the capping enzyme in members of alphavirus superfamily (2, 3, 17, 28). Following the 5′-γ-phosphate-removed activity of the viral nucleoside triphosphatase/RNA 5′-triphosphatase, the capping enzyme domain is responsible for cap structure formation at the 5′-diphosphate end of the viral RNAs (11), while the viral RdRp domain plays a central role in viral replication and transcription. Viruses encode limited number of proteins, and hence they need to recruit host proteins to aid in the various steps of the viral infection, including entry, gene expression, replication, virion assembly, and release. Elucidating the interactions between viruses and their hosts is thus a necessary task toward understanding the complete life cycle of the viruses. In regard to the replication of positive-strand RNA viruses, cellular factors of the host RNA-processing and translational machinery are often recruited for use in the viral replication complex (1, 20). For example, translation elongation factors Ts, Tu, and ribosomal protein S1 are components of the replicase complex of RNA bacteriophage Qβ (5), while EF-1α (functionally homologous to bacterial Tu), EF-1β, and EF-1γ (homologous to bacterial Ts) bind tightly to the viral RNA polymerase of Vesicular stomatitis virus (8). Poly(A)-binding protein, the other component of host translational machinery, was also found in association with RdRp of Zucchini yellow mosaic potyvirus (32). Moreover, eIF1A was found to bind the RNAs of Tobacco mosaic virus (TMV) (34, 37), Turnip yellow mosaic virus (12), West Nile virus (4), and Dengue virus (9). Recently, genome-wide screens have identified a wide variety of cellular factors capable of affecting the replication of Brome mosaic virus and Tomato bushy stunt virus in yeast (18, 29). These factors are diverse, and many of them are involved in the metabolism of proteins, nucleic acids, and lipids. With respect to BaMV, binding of the chloroplast phosphoglycerate kinase to the 3′ untranslated region was found to be required for efficient accumulation of BaMV coat protein in Nicotiana benthamiana (26). A yeast two-hybrid screen was used to identify cellular factors from a leaf cDNA library of N. benthamiana by using the RdRp domain of BaMV as bait in this study. A putative methyltransferase was discovered, and its involvement in the accumulation of BaMV was investigated.
Nikolaos I. Katis - One of the best experts on this subject based on the ideXlab platform.
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first report of pepino mosaic virus infecting greenhouse cherry tomatoes in greece
Plant Disease, 2011Co-Authors: K Efthimiou, A P Gatsios, K C Aretakis, L C Papayiannis, Nikolaos I. KatisAbstract:Pepino mosaic virus (PepMV) (genus Potexvirus, family Flexiviridae) is a mechanically transmitted virus that has emerged as a significant problem of greenhouse tomato crops in Europe and around the world during the past 10 years (1). In spring of 2010, mosaic symptoms were observed on leaves of cherry tomato (Lycopersicon esculentum var. cerasiforme) greenhouse crops (hybrids Shiren, Tomito, and Rubino top) in the areas of Drymos and Vonitsa, located at Aitoloakarnania Prefecture, in Greece. A total of 63 tomato samples (55 from symptomatic and 8 from asymptomatic plants) were collected from 11 greenhouses where disease incidence ranged from 10 to 20%. All samples were tested by double-antibody sandwich (DAS)-ELISA using polyclonal antibodies from BIOREBA, AG (Reinach, Switzerland) for the presence of PepMV, Cucumber mosaic virus (CMV), and Tomato mosaic virus (ToMV). Leaf tissue from PepMV-, CMV-, and ToMV-infected samples and virus-free tomato plants were included in all tests as positive and negative c...
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Elimination of a new ampelovirus (GLRaV-Pr) and Grapevine rupestris stem pitting associated virus (GRSPaV) from two Vitis vinifera cultivars combining in vitro thermotherapy with shoot tip culture
Scientia Horticulturae, 2009Co-Authors: Varvara I. Maliogka, F.g. Skiada, Eleftherios P. Eleftheriou, Nikolaos I. KatisAbstract:A new virus species designated as Grapevine leafroll associated virus-Pr (GLRaV-Pr), which is classified in a distinct phylogenetic group of the genus Ampelovirus (Closteroviridae), was recently characterized from Greek grapevine cultivars. Elimination studies of GLRaV-Pr were carried out in two grapevine cultivars, ‘Mantilaria’ and ‘Prevezaniko’, co-infected with Grapevine rupestris stem pitting associated virus (GRSPaV, Flexiviridae). Both viruses were detected by nested RT-PCR assays. Virus elimination was achieved by combining in vitro thermotherapy with meristem (0.2 mm) or shoot tip culture (0.5 cm). The survival and regeneration rate of meristems was very low. On the other hand, high survival rates were observed in the cultured shoot tips accompanied with high elimination rates for both viruses. Data obtained in this study indicate that virus elimination depends on the genotype of grapevine. The results confirmed that sanitation is easier for species of the Closteroviridae family than for GRSPaV, whereas it seems that eradication of GLRaV-Pr and GRSPaV is feasible even with larger plant tissue parts if combined with an appropriate thermotherapy profile in vitro.
Denis Leclerc - One of the best experts on this subject based on the ideXlab platform.
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Nucleotide sequence and phylogenetic analysis of a new potexvirus: Malva Mosaic Virus
Infection Genetics and Evolution, 2007Co-Authors: Fabien Côté, Christine Paré, Nathalie Majeau, Marilène Bolduc, Éric Leblanc, Michael G Bernardy, Michel G. Bergeron, Denis LeclercAbstract:Abstract A filamentous virus isolated from Malva neglecta Wallr. (common mallow) and propagated in Chenopodium quinoa was grown, cloned and the complete nucleotide sequence was determined (GenBank accession # DQ660333 ). The genomic RNA is 6858 nt in length and contains five major open reading frames (ORFs). The genomic organization is similar to members and the viral encoded proteins shared homology with the group of the Potexvirus genus in the Flexiviridae family. Phylogenetic analysis revealed a close relationship with narcissus mosaic virus (NMV), scallion virus X (ScaVX) and, to a lesser extent, to Alstroemeria virus X (AlsVX) and pepino mosaic virus (PepMV). A novel putative pseudoknot structure is predicted in the 3′-UTR of a subgroup of potexviruses, including this newly described virus. The consensus GAAAA sequence is detected at the 5′-end of the genomic RNA and experimental data strongly suggest that this motif could be a distinctive hallmark of this genus. The name Malva mosaic virus is proposed.
Chunwei Cheng - One of the best experts on this subject based on the ideXlab platform.
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suppression of bamboo mosaic virus accumulation by a putative methyltransferase in nicotiana benthamiana
Journal of Virology, 2009Co-Authors: Chunwei Cheng, Yauheiu Hsu, Chinghsiu Tsai, Chengcheng Lee, Jaoshien Chen, Yiyuong Hsiao, Chimau Chuang, Menghsiao MengAbstract:Bamboo mosaic virus (BaMV) is a flexuous-rod positive-sense RNA virus belonging to the genus Potexvirus of the family Flexiviridae. The 6.4-kb genome contains five open reading frames (ORFs), with a 5′ methyl cap and a 3′ poly(A) tail (27). Two major subgenomic RNAs of 2 and 1 kb are produced upon viral infection in host cells. The protein product of ORF1, translated from the genomic RNA, is a 155-kDa viral replicase comprising an N-terminal capping enzyme domain (23), a helicase-like domain harboring nucleoside triphosphatase/RNA 5′-triphosphatase activities (24), and a C-terminal RNA-dependent RNA polymerase (RdRp) (22). The capping enzyme domain exhibits an S-adenosyl-l-methionine (AdoMet)-dependent guanylyltransferase activity, which is characteristic of the capping enzyme in members of alphavirus superfamily (2, 3, 17, 28). Following the 5′-γ-phosphate-removed activity of the viral nucleoside triphosphatase/RNA 5′-triphosphatase, the capping enzyme domain is responsible for cap structure formation at the 5′-diphosphate end of the viral RNAs (11), while the viral RdRp domain plays a central role in viral replication and transcription. Viruses encode limited number of proteins, and hence they need to recruit host proteins to aid in the various steps of the viral infection, including entry, gene expression, replication, virion assembly, and release. Elucidating the interactions between viruses and their hosts is thus a necessary task toward understanding the complete life cycle of the viruses. In regard to the replication of positive-strand RNA viruses, cellular factors of the host RNA-processing and translational machinery are often recruited for use in the viral replication complex (1, 20). For example, translation elongation factors Ts, Tu, and ribosomal protein S1 are components of the replicase complex of RNA bacteriophage Qβ (5), while EF-1α (functionally homologous to bacterial Tu), EF-1β, and EF-1γ (homologous to bacterial Ts) bind tightly to the viral RNA polymerase of Vesicular stomatitis virus (8). Poly(A)-binding protein, the other component of host translational machinery, was also found in association with RdRp of Zucchini yellow mosaic potyvirus (32). Moreover, eIF1A was found to bind the RNAs of Tobacco mosaic virus (TMV) (34, 37), Turnip yellow mosaic virus (12), West Nile virus (4), and Dengue virus (9). Recently, genome-wide screens have identified a wide variety of cellular factors capable of affecting the replication of Brome mosaic virus and Tomato bushy stunt virus in yeast (18, 29). These factors are diverse, and many of them are involved in the metabolism of proteins, nucleic acids, and lipids. With respect to BaMV, binding of the chloroplast phosphoglycerate kinase to the 3′ untranslated region was found to be required for efficient accumulation of BaMV coat protein in Nicotiana benthamiana (26). A yeast two-hybrid screen was used to identify cellular factors from a leaf cDNA library of N. benthamiana by using the RdRp domain of BaMV as bait in this study. A putative methyltransferase was discovered, and its involvement in the accumulation of BaMV was investigated.