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Thierry Candresse - One of the best experts on this subject based on the ideXlab platform.
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Datamining, genetic diversity analyses, and phylogeographic reconstructions redefine the worldwide evolutionary history of grapevine Pinot gris virus and grapevine berry inner necrosis virus
Phytobiomes Journal, 2020Co-Authors: Jean-michel Hily, Thierry Candresse, Nils Poulicard, Emmanuelle Vigne, Monique Beuve, Lauriane Renault, Amandine Velt, Anne-sophie Spilmont, Olivier LemaireAbstract:The recently described member of the genus Trichovirus grapevine Pinot gris virus (GPGV) has now been detected in most grape-growing countries. While it has been associated with severe mottling and deformation symptoms under some circumstances, it has generally been detected in asymptomatic infections. The cause(s) underlying this variable association with symptoms remain(s) subject to speculations. GPGV genetic diversity has been studied using short genomic regions amplified by RT-PCR but not so far at the pan-genomic level. In an attempt to gain insight into GPGV diversity and evolutionary history, a systematic datamining effort was performed on our own high-throughput sequencing (HTS) data as well as on publicly available sequence read archive files. One hundred new complete or near complete GPGV genomic sequences were thus obtained, together with 69 new complete genomes for the other grapevine-infecting Trichovirus, grapevine berry inner necrosis virus (GINV). Phylogenetic and diversity analyses revealed that both viruses likely have their origin in Asia and that China is the most probable country of origin of GPGV. However, despite their common taxonomy, origin, and host, these two Trichoviruses display very distinct genetic features and evolutionary traits. GINV shows an important overall genetic diversity, and is likely evolving under a balancing selection in a very restricted region of the world. On the contrary, GPGV shows a worldwide distribution with a modest genetic diversity and presents a strong selective sweep pattern. Taken together, these results show how two closely related Trichoviruses differ drastically in their evolutionary history and epidemiological success. Possible causes for these differences are discussed. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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First Report of Grapevine Pinot gris virus (GPGV) in grapevine in France.
Plant disease, 2015Co-Authors: Monique Beuve, Thierry Candresse, M. Tannières, Olivier LemaireAbstract:Grapevine Pinot gris virus (GPGV), belonging to the genus Trichovirus of the family Betaflexiviridae, was first identified by siRNA sequencing in northern Italy in 2012, in the grapevine varieties Pinot gris, Traminer, and Pinot Noir, which exhibited mottling and leaf deformation (1), and in asymptomatic vines, with a lower frequency. Since 2012, this virus has also been reported in South Korea, Slovenia, Greece (3), Czech Republic (2), Slovakia (2), and southern Italy (4). In 2014, GPGV was identified by Illumina sequencing of total RNAs extracted from leaves of the Merlot variety (Vitis vinifera) grafted onto Gravesac rootstock originated from a vineyard in the Bordeaux region of France. This Merlot plant exhibited fanleaf-like degeneration symptoms associated with Tomato black ring virus (TBRV) infection. Cuttings were collected in 2010 and maintained thereafter in a greenhouse. The full-length genome was assembled either de novo or by mapping of the Illumina reads on a reference GPGV genome (GenBank F...
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First Report of Apricot pseudo-chlorotic leaf spot virus Infecting Plum (Prunus domestica) in the Czech Republic
Plant Disease, 2012Co-Authors: Dana Šafářová, Chantal Faure, Milan Navrátil, Thierry Candresse, Armelle MaraisAbstract:Apricot pseudo-chlorotic leaf spot virus (APCLSV) is a novel, still poorly known Trichovirus in the family Betaflexiviridae. It is most closely related to Apple chlorotic leaf spot virus (ACLSV) (2,4) and infects stone fruit trees of the Prunus genus. Its presence has so far been detected in apricot, plum, Japanese plum, and peach trees in Italy, Spain, France, Hungary, Turkey, Jordan, and Australia (1,2,4). During the summers of 2008 and 2010, leaf samples of old Czech local plum cultivars were obtained from the Holovousy collection and assessed for the presence of viruses belonging to the Capillovirus, Trichovirus, and Foveavirus genera using the polyvalent degenerate oligonucleotides (PDO) nested reverse transcription (RT)-PCR test (3). Following amplification from total RNAs extracts, the amplicons were cloned and several clones were sequenced for each plant sample. In plum (Prunus domestica) cv. Babce, a mixture of amplicons was observed and BlastN and BlastX analyses of the obtained sequences reveal...
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Strategies to facilitate the development of uncloned or cloned infectious full-length viral cDNAs : Apple chlorotic leaf spot virus as a case study
Virology Journal, 2011Co-Authors: Fater Youssef, Armelle Marais, Pascal Gentit, Chantal Faure, Thierry CandresseAbstract:Background Approaches to simplify and streamline the construction of full-length infectious cDNA clones (FL-cDNAs) are needed. Among desirable improvements are the ability to use total nucleic acids (TNA) extracts from infected hosts (to bypass viral purification limitations) for the direct one-step amplification of large FL-cDNAs, the possibility to inoculate plants with uncloned FL-cDNAs and the simplified cloning of these large molecules. Results Using the 7.55 kb genome of Apple chlorotic leaf spot Trichovirus (ACLSV) approaches allowing the rapid generation from TNA extracts of FL-cDNAs under the control of the T7 promoter and the successful inoculation of plants using in vitro transcripts obtained from these uncloned amplification products have been developed. We also show that the yeast homologous recombination system permits efficient cloning of FL-cDNAs and the simultaneous one-step tailoring of a ternary Yeast-Escherichia coli-Agrobacterium tumefaciens shuttle vector allowing efficient inoculation of both herbaceous and woody host plants by agroinfiltration. Conclusions The fast and efficient strategies described here should have broad applications, in particular for the study "difficult" plant viruses, such as those infecting woody hosts, and potentially for other, non plant-infecting viral agents.
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First report of Apple chlorotic leaf spot virus in quince in Greece
Plant Disease, 2007Co-Authors: M.m. Mathioudakis, Thierry Candresse, N.i. KatisAbstract:The sanitary status of pome fruit trees was evaluated in central and northern Greece during a survey in the autumn of 2004 and spring of 2005. Twenty-six leaf samples were collected from five symptomless and 21 symptomatic quince trees showing fruit deformation (FD) symptoms and diffuse chlorotic leaf spots. All samples were tested for the presence of Apple chlorotic leaf spot virus (ACLSV), a member of the Trichovirus genus, initially by ELISA and then by a specific reverse transcription (RT)-PCR assay reported previously (1). ACLSV has a broad host range that includes most, if not all, Prunoidae (peach, apricot, plum, and cherry) and Maloidae (apple, pear, and quince) fruit tree species. Although it has been tentatively linked with fruit, leaf, bark, and growth retardation symptoms in quince (2,3), its geographic distribution and association with specific symptoms is still poorly determined. ACLSV was initially detected by serology in two plants, one symptomless and one showing FD symptoms. ACLSV presence in these two samples and in an additional symptomless plant was confirmed by the ACLSV-specific RT-PCR assay. Sequencing of the RT-PCR amplicon from the symptomatic isolate (EMBL Accession No. AM292923), which was positive in both assays, confirmed the identification of ACLSV. The obtained sequence shows 93% nucleotide identity with an apple isolate of ACLSV (EMBL Accession No. AY677103). To our knowledge, these findings represent the first report of the presence of ACLSV in quince in Greece. They further indicate that at least for some host-cultivar/virus isolate combinations, ACLSV may be asymptomatic in quince and that the symptoms observed in the plants sampled are unrelated to ACLSV infection.
Henryk Czosnek - One of the best experts on this subject based on the ideXlab platform.
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Expressing a whitefly GroEL protein in Nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus A or tobacco mosaic virus
Archives of Virology, 2009Co-Authors: Dagan Edelbaum, Rena Gorovits, Sonoko Sasaki, Masato Ikegami, Henryk CzosnekAbstract:Transgenesis offers many ways to obtain virus-resistant plants. However, in most cases resistance is against a single virus or viral strain. We have taken a novel approach based on the ability of a whitefly endosymbiotic GroEL to bind viruses belonging to several genera, in vivo and in vitro. We have expressed the GroEL gene in Nicotiana benthamiana plants, postulating that upon virus inoculation, GroEL will bind to virions, thereby interfering with pathogenesis. The transgenic plants were inoculated with the begomovirus tomato yellow leaf curl virus (TYLCV) and the cucumovirus cucumber mosaic virus (CMV), both of which interacted with GroEL in vitro, and with the Trichovirus grapevine virus A (GVA) and the tobamovirus tobacco mosaic virus (TMV), which did not. While the transgenic plants inoculated with TYLCV and CMV presented a high level of tolerance, those inoculated with GVA and TMV were susceptible. The amounts of virus in tolerant transgenic plants was lower by three orders of magnitude than those in non-transgenic plants; in comparison, the amounts of virus in susceptible transgenic plants were similar to those in non-transgenic plants. Leaf extracts of the tolerant plants contained GroEL-virus complexes. Hence, tolerance was correlated with trapping of viruses in planta. This study demonstrated that multiple resistances to viruses belonging to several different taxonomic genera could be achieved. Moreover, it might be hypothesized that plants expressing GroEL will be tolerant to those viruses that bind to GroEL in vitro, such as members of the genera Begomovirus, Cucumovirus, Ilarvirus, Luteovirus, and Tospovirus.
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Expressing a whitefly GroEL protein in Nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus A or tobacco mosaic virus
Archives of virology, 2009Co-Authors: Dagan Edelbaum, Rena Gorovits, Sonoko Sasaki, Masato Ikegami, Henryk CzosnekAbstract:Transgenesis offers many ways to obtain virus-resistant plants. However, in most cases resistance is against a single virus or viral strain. We have taken a novel approach based on the ability of a whitefly endosymbiotic GroEL to bind viruses belonging to several genera, in vivo and in vitro. We have expressed the GroEL gene in Nicotiana benthamiana plants, postulating that upon virus inoculation, GroEL will bind to virions, thereby interfering with pathogenesis. The transgenic plants were inoculated with the begomovirus tomato yellow leaf curl virus (TYLCV) and the cucumovirus cucumber mosaic virus (CMV), both of which interacted with GroEL in vitro, and with the Trichovirus grapevine virus A (GVA) and the tobamovirus tobacco mosaic virus (TMV), which did not. While the transgenic plants inoculated with TYLCV and CMV presented a high level of tolerance, those inoculated with GVA and TMV were susceptible. The amounts of virus in tolerant transgenic plants was lower by three orders of magnitude than those in non-transgenic plants; in comparison, the amounts of virus in susceptible transgenic plants were similar to those in non-transgenic plants. Leaf extracts of the tolerant plants contained GroEL-virus complexes. Hence, tolerance was correlated with trapping of viruses in planta. This study demonstrated that multiple resistances to viruses belonging to several different taxonomic genera could be achieved. Moreover, it might be hypothesized that plants expressing GroEL will be tolerant to those viruses that bind to GroEL in vitro, such as members of the genera Begomovirus, Cucumovirus, Ilarvirus, Luteovirus, and Tospovirus.
G. P. Martelli - One of the best experts on this subject based on the ideXlab platform.
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Non-radioactive molecular probes for the detection of three filamentous viruses of the grapevine
Vitis: Journal of Grapevine Research, 2015Co-Authors: Pasquale Saldarelli, H. Guglielmi Montano, G. P. MartelliAbstract:Digoxigenin-labelled riboprobes (DIG-RNA) were developed for the detection in infected tissue extracts of grapevine Trichovirus A (GVA), grapevine Trichovirus B (GVB) and grapevine leafroll-associated closterovirus III (GLRaV III). The probes were virus-specific and could be used for the identification of the respective viruses in sap expressed from infected Nicotiana species (GVA and GVB) and in total nucleic acid extracts from infected grapevines (GVA, GVB and GLRaV III). The efficiency of detection was the same as (GLRaV III), or slightly less than (GVA), with ELISA. No difference was found in detection efficiency between DIG-RNA and cDNA radioactive probes.
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Some properties of a hitherto undescribed filamentous virus of the grapevine
Vitis: Journal of Grapevine Research, 2015Co-Authors: E. Choueiri, Donato Boscia, M. A. Castellano, Michele Digiaro, G. P. MartelliAbstract:An apparently new, non mechanically-transmissible clostero-like virus, for which the name ''grapevine leafroll-associated virus 7('') (GLRaV-7) is proposed, was found in Albanian grapevine accessions. Virus particles were filamentous, had conspicuous cross banding and a length of 1500-1700 nm. Virions had coat protein subunits with an estimated M(r) of ca. 37 kDa and a ssRNA genome with size of ca. 19.5 kb as deduced from the estimate of dsRNA (ca. 19.5 kbp) extracted from grapevine tissues. A virus-specific antiserum was raised, which decorated virions at a dilution of 1:1000. This antiserum did not recognize particles of any of the six grapevine leafroll-associated clostero-like viruses (GLRaV-1 to -6) known to date, nor of grapevine Trichovirus A (GVA) and B (GVB). Grapevine indicators graft-inoculated with material from accessions containing GLRaV-7 reacted with mild leafroll-like symptoms. In a survey in which 2226 vines from 30 different countries were examined by ELISA, GLRaV-7 was found in 141 plants from Albania, Greece, Hungary, Egypt, and Italy.
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Worldwide diffusion of Fig latent virus 1 in fig accessions and its detection by serological and molecular tools
Julius-Kühn-Archiv, 2010Co-Authors: G. Gattoni, Donato Boscia, A. Minafra, M. A. Castellano, A. De Stradis, Toufic Elbeaino, Michele Digiaro, G. P. MartelliAbstract:A virus with filamentous particles ca. 700 nm long, denoted Fig latent virus 1 (FLV-1) is widespread in Apulian (southern Italy) fig orchards, in trees showing or not mosaic symptoms and in symptomless seedlings. The virus was transmitted by sap inoculation to a very restricted range of herbaceous hosts without inducing apparent symptoms and was transmitted through fig seeds to a very high percentage (80 to 100 %). It was successfully purified from root tissues of infected figs. A virus-specific antiserum raised in rabbits, proved useful for its detection in fig leaf dips by immunosorbent electron microscopy (ISEM), Western Blot, dot immuno-binding (DIBA), ELISA. The viral genome structure resembles that of members of the genus Trichovirus in the family Flexiviridae . Keywords : fig latent virus, Trichovirus , serology, ISEM, Western blot, DIBA, ELISA
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SEED TRANSMISSION OF FIG LATENT VIRUS 1
Journal of Plant Pathology, 2009Co-Authors: M. A. Castellano, Donato Boscia, A. De Stradis, A. Minafra, G. P. MartelliAbstract:SUMMARY The transmission through seeds of Fig latent virus 1 (FLV-1), a putative member of the genus Trichovirus, was investigated. Batches of seedlings of different age (1-yearold and 4-weeks-old) and geographical origin (Italy, Greece and Turkey) were analyzed by immunosorbent electron microscopy (ISEM) using a virus-specific antiserum. FLV-1 was detected in all groups of seedlings, the great majority of which were symptomless. Infection rate ranged from 73 to 100% (average 92%). Bundles of virus particles were observed in the cytoplasm of mesophyll cells of symptomless seedlings and positive RT-PCR responses were obtained in a few random assays using FLV1-specific primers. The high transmission rate differentiates FLV-1 from most of the other seed-transmitted plant viruses which, in general, have a lower transmission frequency, and from the extant Trichoviruses, none of which is apparently transmitted though seeds.
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grapevine virus a nucleotide sequence genome organization and relationship in the Trichovirus genus
Archives of Virology, 1997Co-Authors: A. Minafra, P. Saldarelli, G. P. MartelliAbstract:The 5′ terminal region of the genomic RNA of grapevine virus A (GVA), a tentative member of the Trichovirus genus, encompassing 5 466 nucleotides, was sequenced. Evidence was obtained that the RNA is capped. Two putative open reading frames (ORF) were identified: ORF 1 that codes for a 194 kDa polypeptide with conserved motifs of replication-related proteins of positive-strand RNA viruses, and ORF 2 that encodes a 19 kDa polypeptide with no significant homology with protein sequences from databases. This polypeptide, however, showed 44% similarity with the product expressed by a comparable ORF present in grapevine virus B (GVB). GVA genome had the same size and structural organization as that of GVB. It also had the same size of the genome of apple chlorotic leaf spot virus (ACLSV), the type species of the Trichovirus genus, but differed substantially in the number (5 versus 3), size, and order of genes. Differences existed also in the degree of sequence homology between polymerases, which did not cluster together in phylogenetic trees. Definitive (ACLSV, PVT) and tentative (GVA, GVB) Trichovirus species differ molecularly, biologically and epidemiologically to an extent that warrants the taxonomic revision of the genus.
Dagan Edelbaum - One of the best experts on this subject based on the ideXlab platform.
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Expressing a whitefly GroEL protein in Nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus A or tobacco mosaic virus
Archives of Virology, 2009Co-Authors: Dagan Edelbaum, Rena Gorovits, Sonoko Sasaki, Masato Ikegami, Henryk CzosnekAbstract:Transgenesis offers many ways to obtain virus-resistant plants. However, in most cases resistance is against a single virus or viral strain. We have taken a novel approach based on the ability of a whitefly endosymbiotic GroEL to bind viruses belonging to several genera, in vivo and in vitro. We have expressed the GroEL gene in Nicotiana benthamiana plants, postulating that upon virus inoculation, GroEL will bind to virions, thereby interfering with pathogenesis. The transgenic plants were inoculated with the begomovirus tomato yellow leaf curl virus (TYLCV) and the cucumovirus cucumber mosaic virus (CMV), both of which interacted with GroEL in vitro, and with the Trichovirus grapevine virus A (GVA) and the tobamovirus tobacco mosaic virus (TMV), which did not. While the transgenic plants inoculated with TYLCV and CMV presented a high level of tolerance, those inoculated with GVA and TMV were susceptible. The amounts of virus in tolerant transgenic plants was lower by three orders of magnitude than those in non-transgenic plants; in comparison, the amounts of virus in susceptible transgenic plants were similar to those in non-transgenic plants. Leaf extracts of the tolerant plants contained GroEL-virus complexes. Hence, tolerance was correlated with trapping of viruses in planta. This study demonstrated that multiple resistances to viruses belonging to several different taxonomic genera could be achieved. Moreover, it might be hypothesized that plants expressing GroEL will be tolerant to those viruses that bind to GroEL in vitro, such as members of the genera Begomovirus, Cucumovirus, Ilarvirus, Luteovirus, and Tospovirus.
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Expressing a whitefly GroEL protein in Nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus A or tobacco mosaic virus
Archives of virology, 2009Co-Authors: Dagan Edelbaum, Rena Gorovits, Sonoko Sasaki, Masato Ikegami, Henryk CzosnekAbstract:Transgenesis offers many ways to obtain virus-resistant plants. However, in most cases resistance is against a single virus or viral strain. We have taken a novel approach based on the ability of a whitefly endosymbiotic GroEL to bind viruses belonging to several genera, in vivo and in vitro. We have expressed the GroEL gene in Nicotiana benthamiana plants, postulating that upon virus inoculation, GroEL will bind to virions, thereby interfering with pathogenesis. The transgenic plants were inoculated with the begomovirus tomato yellow leaf curl virus (TYLCV) and the cucumovirus cucumber mosaic virus (CMV), both of which interacted with GroEL in vitro, and with the Trichovirus grapevine virus A (GVA) and the tobamovirus tobacco mosaic virus (TMV), which did not. While the transgenic plants inoculated with TYLCV and CMV presented a high level of tolerance, those inoculated with GVA and TMV were susceptible. The amounts of virus in tolerant transgenic plants was lower by three orders of magnitude than those in non-transgenic plants; in comparison, the amounts of virus in susceptible transgenic plants were similar to those in non-transgenic plants. Leaf extracts of the tolerant plants contained GroEL-virus complexes. Hence, tolerance was correlated with trapping of viruses in planta. This study demonstrated that multiple resistances to viruses belonging to several different taxonomic genera could be achieved. Moreover, it might be hypothesized that plants expressing GroEL will be tolerant to those viruses that bind to GroEL in vitro, such as members of the genera Begomovirus, Cucumovirus, Ilarvirus, Luteovirus, and Tospovirus.
G. P. Martelli - One of the best experts on this subject based on the ideXlab platform.
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SOME PROPERTIES OF FIG LATENT VIRUS 1, A NEW MEMBER OF THE FAMILY FLEXIVIRIDAE
Journal of Plant Pathology, 2009Co-Authors: G. Gattoni, Donato Boscia, M. A. Castellano, A. De Stradis, Toufic Elbeaino, Michele Digiaro, A. Minafra, G. P. MartelliAbstract:A virus with filamentous particles ca. 700 nm long, denoted Fig latent virus 1 (FLV-1) is widespread in Apulian (southern Italy) fig orchards, in trees showing or not mosaic symptoms and in symptomless seedlings. This virus was transmitted by sap inoculation to a very restricted range of herbaceous hosts without inducing apparent symptoms. It was successfully purified from root tissues of infected figs. A virus-specific antiserum raised in rabbits, proved useful for its detection in fig leaf dips by immunosorbent electron microscopy. The cytology of infected cells was little affected. Bundles of filamentous particles were observed in the cytoplasma of parenchyma cells of infected fig trees and seedlings. The viral genome is a single-stranded positive-sense RNA with an estimated size of ca. 8,000 nt, 6,620 of which have been sequenced, starting from the polyadenylated 3’ terminus. Genomic RNA consists of four open reading frames encoding, in the 5’?3’ direction, the replication-associated proteins (ORF 1), a 43 kDa putative movement protein (ORF 2), the 46 kDa coat protein (ORF 3), and a 12 kDa protein with nucleic acid binding properties. The viral genome structure and organization resembles that of members of the genus Trichovirus, family Flexiviridae and, indeed, FLV- 1 clusters with Trichoviruses in phylogenetic trees constructed with coat protein sequences. However, a distinct difference with all members of the genus rests with the size of the coat protein subunits (46 versus 22-27 kDa) and the presence of ORF 4, which is present only in three tentative species of this genus.
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Family Flexiviridae: a case study in virion and genome plasticity.
Annual Review of Phytopathology, 2007Co-Authors: G. P. Martelli, M J Adams, Jan Kreuze, Valerian V. DoljaAbstract: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...
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Family Flexiviridae: a case study in virion and genome plasticity.
Annual review of phytopathology, 2007Co-Authors: G. P. Martelli, Michael J. Adams, Jan Kreuze, Valerian V. DoljaAbstract:The 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 recombination and gene loss would then have generated a very diverse group of plant and fungal viruses.
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Family Flexiviridae: A Case Study in Virion and
2007Co-Authors: G. P. Martelli, Michael J. Adams, Jan Kreuze, Valerian V. DoljaAbstract:The 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 recombination and gene loss would then have generated a very diverse group of plant and fungal viruses.
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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.
