The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
Piero Roggero - One of the best experts on this subject based on the ideXlab platform.
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Detection of Varicosavirus and Ophiovirus in lettuce associated with lettuce big-vein symptoms in Brazil
Fitopatologia Brasileira, 2005Co-Authors: Addolorata Colariccio, Alexandre L. R. Chaves, Marcelo Eiras, C. M. Chagas, Piero RoggeroAbstract:Em levantamentos realizados entre 1998 e 2003, nas principais regioes produtoras de alface (Lactuca sativa) e escarola (Cichorium endivia) no cinturao verde de Sao Paulo, foram observados sintomas de espessamento de nervuras foliares, clorose, crescimento irregular e ausencia de formacao da cabeca. Por meio de testes biologicos, DAS-Enzyme linked immunosorbent assay (Elisa) e microscopia eletronica de transmissao constatou-se a presenca do Lettuce big-vein associated virus e Mirafiori lettuce virus, responsaveis pela sindrome do espessamento clorotico das nervuras da alface ("lettuce big-vein").
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Transmission by Olpidium brassicae of Mirafiori lettuce virus and Lettuce big-vein virus, and Their Roles in Lettuce Big-Vein Etiology
Phytopathology®, 2002Co-Authors: Hervé Lot, Robert N. Campbell, Sylvie Souche, Robert G. Milne, Piero RoggeroAbstract:Lot, H., Campbell, R. N., Souche, S., Milne, R. G., and Roggero, P. 2002. Transmission by Olpidium brassicae of Mirafiori lettuce virus and Lettuce big-vein virus, and their roles in lettuce big-vein etiology. Phytopathology 92:288-293. Big-vein disease occurs on lettuce worldwide in temperate conditions; the causal agent has been presumed to be Lettuce big-vein virus (LBVV), genus Varicosavirus, vectored by the soilborne fungus Olpidium brassicae. Recently, the role of LBVV in the etiology of big-vein disease has been questioned because a second soilborne virus, Mirafiori lettuce virus (MiLV), genus Ophiovirus, has been found frequently in big-veinaffected lettuce. LBVV and MiLV, detectable and distinguishable by enzyme-linked immunosorbent assay using specific antisera, were tested for their ability to be transmitted from lettuce to lettuce by mechanical inoculation of sap extracts, or by zoospores of O. brassicae, and to cause big-vein disease. Both viruses were mechanically transmissible from lettuce to herbaceous hosts and to lettuce, but very erratically. LBVV was transmitted by O. brassicae but lettuce infected with only this virus never showed symptoms. MiLV was transmitted in the same manner, and lettuce infected with this virus alone consistently developed big-vein symptoms regardless of the presence or absence of LBVV. With repeated mechanical transmission, isolates of both viruses appeared to lose the ability to be vectored, and MiLV appeared to lose the ability to cause bigvein symptoms. The recovery of MiLV (Mendocino isolate, from California) from stored O. brassicae resting spores puts the earliest directly demonstrable existence of MiLV at 1990.
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Transmission by Olpidium brassicae of mirafiori lettuce virus and lettuce big-vein virus, and their roles in lettuce big-vein etiology
Phytopathology, 2002Co-Authors: Hervé Lot, Robert N. Campbell, Sylvie Souche, Robert G. Milne, Piero RoggeroAbstract:Big-vein disease occurs on lettuce worldwide in temperate conditions; the causal agent has been presumed to be Lettuce big-vein virus (LBVV), genus Varicosavirus, vectored by the soilborne fungus Olpidium brassicae. Recently, the role of LBVV in the etiology of big-vein disease has been questioned because a second soilborne virus, Mirafiori lettuce virus (MiLV), genus Ophiovirus, has been found frequently in big-vein-affected lettuce. LBVV and MiLV, detectable and distinguishable by enzyme-linked immunosorbent assay using specific antisera, were tested for their ability to be transmitted from lettuce to lettuce by mechanical inoculation of sap extracts, or by zoospores of O. brassicae, and to cause big-vein disease. Both viruses were mechanically transmissible from lettuce to herbaceous hosts and to lettuce, but very erratically. LBVV was transmitted by O. brassicae but lettuce infected with only this virus never showed symptoms. MiLV was transmitted in the same manner, and lettuce infected with this virus alone consistently developed big-vein symptoms regardless of the presence or absence of LBVV. With repeated mechanical transmission, isolates of both viruses appeared to lose the ability to be vectored, and MiLV appeared to lose the ability to cause big-vein symptoms. The recovery of MiLV (Mendocino isolate, from California) from stored O. brassicae resting spores puts the earliest directly demonstrable existence of MiLV at 1990.
Hervé Lot - One of the best experts on this subject based on the ideXlab platform.
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Transmission by Olpidium brassicae of Mirafiori lettuce virus and Lettuce big-vein virus, and Their Roles in Lettuce Big-Vein Etiology
Phytopathology®, 2002Co-Authors: Hervé Lot, Robert N. Campbell, Sylvie Souche, Robert G. Milne, Piero RoggeroAbstract:Lot, H., Campbell, R. N., Souche, S., Milne, R. G., and Roggero, P. 2002. Transmission by Olpidium brassicae of Mirafiori lettuce virus and Lettuce big-vein virus, and their roles in lettuce big-vein etiology. Phytopathology 92:288-293. Big-vein disease occurs on lettuce worldwide in temperate conditions; the causal agent has been presumed to be Lettuce big-vein virus (LBVV), genus Varicosavirus, vectored by the soilborne fungus Olpidium brassicae. Recently, the role of LBVV in the etiology of big-vein disease has been questioned because a second soilborne virus, Mirafiori lettuce virus (MiLV), genus Ophiovirus, has been found frequently in big-veinaffected lettuce. LBVV and MiLV, detectable and distinguishable by enzyme-linked immunosorbent assay using specific antisera, were tested for their ability to be transmitted from lettuce to lettuce by mechanical inoculation of sap extracts, or by zoospores of O. brassicae, and to cause big-vein disease. Both viruses were mechanically transmissible from lettuce to herbaceous hosts and to lettuce, but very erratically. LBVV was transmitted by O. brassicae but lettuce infected with only this virus never showed symptoms. MiLV was transmitted in the same manner, and lettuce infected with this virus alone consistently developed big-vein symptoms regardless of the presence or absence of LBVV. With repeated mechanical transmission, isolates of both viruses appeared to lose the ability to be vectored, and MiLV appeared to lose the ability to cause bigvein symptoms. The recovery of MiLV (Mendocino isolate, from California) from stored O. brassicae resting spores puts the earliest directly demonstrable existence of MiLV at 1990.
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Transmission by Olpidium brassicae of mirafiori lettuce virus and lettuce big-vein virus, and their roles in lettuce big-vein etiology
Phytopathology, 2002Co-Authors: Hervé Lot, Robert N. Campbell, Sylvie Souche, Robert G. Milne, Piero RoggeroAbstract:Big-vein disease occurs on lettuce worldwide in temperate conditions; the causal agent has been presumed to be Lettuce big-vein virus (LBVV), genus Varicosavirus, vectored by the soilborne fungus Olpidium brassicae. Recently, the role of LBVV in the etiology of big-vein disease has been questioned because a second soilborne virus, Mirafiori lettuce virus (MiLV), genus Ophiovirus, has been found frequently in big-vein-affected lettuce. LBVV and MiLV, detectable and distinguishable by enzyme-linked immunosorbent assay using specific antisera, were tested for their ability to be transmitted from lettuce to lettuce by mechanical inoculation of sap extracts, or by zoospores of O. brassicae, and to cause big-vein disease. Both viruses were mechanically transmissible from lettuce to herbaceous hosts and to lettuce, but very erratically. LBVV was transmitted by O. brassicae but lettuce infected with only this virus never showed symptoms. MiLV was transmitted in the same manner, and lettuce infected with this virus alone consistently developed big-vein symptoms regardless of the presence or absence of LBVV. With repeated mechanical transmission, isolates of both viruses appeared to lose the ability to be vectored, and MiLV appeared to lose the ability to cause big-vein symptoms. The recovery of MiLV (Mendocino isolate, from California) from stored O. brassicae resting spores puts the earliest directly demonstrable existence of MiLV at 1990.
Hiroki Koganezawa - One of the best experts on this subject based on the ideXlab platform.
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Molecular analysis of coat protein coding region of tobacco stunt virus shows that it is a strain of Lettuce big-vein virus in the genus Varicosavirus
Archives of Virology, 2005Co-Authors: Takahide Sasaya, K. Ishikawa, S. Kuwata, Hiroki KoganezawaAbstract:To evaluate the relationship between tobacco stunt virus (TStV) and Lettuce big-vein virus (LBVV), we determined nucleotide sequences of the coat protein (CP) coding region of five TStV and three LBVV isolates and compared them with those of one Japanese and four Spanish isolates of LBVV. CP coding regions were identical in size and the nucleotide and amino acid sequence identities between TStV and LBVV were 95.6–96.5% and 97.2–98.7%, respectively. Phylogenetic analysis of nucleotide sequences indicated that TStV was very closely related to LBVV and a strain of LBVV rather than a distinct species.
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Nucleotide sequence of RNA2 of Lettuce big-vein virus and evidence for a possible transcription termination/initiation strategy similar to that of rhabdoviruses.
The Journal of general virology, 2004Co-Authors: Takahide Sasaya, Koichi Ishikawa, Shinnosuke Kusaba, Hiroki KoganezawaAbstract:Lettuce big-vein virus (LBVV) is the type species of the genus Varicosavirus and is a two-segmented negative-sense single-stranded RNA virus. The larger LBVV genome segment (RNA1) consists of 6797 nt and encodes an L polymerase that resembles that of rhabdoviruses. Here, the nucleotide sequence of the second LBVV genome segment (RNA2) is reported. LBVV RNA2 consisted of 6081 nt and contained antisense information for five major ORFs: ORF1 (nt 210-1403 on the viral RNA), ORF2 (nt 1493-2494), ORF3 (nt 2617-3489), ORF4 (nt 3843-4337) and ORF5 (nt 4530-5636), which had coding capacities of 44, 36, 32, 19 and 41 kDa, respectively. The gene at the 3' end of the viral RNA encoded a coat protein, while the other four genes encoded proteins of unknown functions. The 3'-terminal 11 nt of LBVV RNA2 were identical to those of LBVV RNA1, and the 5'-terminal regions of LBVV RNA1 and RNA2 contained a long common nucleotide stretch of about 100 nt. Northern blot analysis using probes specific to the individual ORFs revealed that LBVV transcribes monocistronic RNAs. Analysis of the terminal sequences, and primer extension and RNase H digestion analysis of LBVV mRNAs, suggested that LBVV utilizes a transcription termination/initiation strategy comparable with that of rhabdoviruses.
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The Nucleotide Sequence of RNA1 of Lettuce big-vein virus, Genus Varicosavirus, Reveals Its Relation to Nonsegmented Negative-Strand RNA Viruses
Virology, 2002Co-Authors: Takahide Sasaya, Koichi Ishikawa, Hiroki KoganezawaAbstract:Abstract The complete nucleotide sequence of RNA1 from Lettuce big-vein virus (LBVV), the type member of the genus Varicosavirus , was determined. LBVV RNA1 consists of 6797 nucleotides and contains one large ORF that encodes a large (L) protein of 2040 amino acids with a predicted M r of 232,092. Northern blot hybridization analysis indicated that the LBVV RNA1 is a negative-sense RNA. Database searches showed that the amino acid sequence of L protein is homologous to those of L polymerases of nonsegmented negative-strand RNA viruses. A cluster dendrogram derived from alignments of the LBVV L protein and the L polymerases indicated that the L protein is most closely related to the L polymerases of plant rhabdoviruses. Transcription termination/polyadenylation signal-like poly(U) tracts that resemble those in rhabdovirus and paramyxovirus RNAs were present upstream and downstream of the coding region. Although LBVV is related to rhabdoviruses, a key distinguishing feature is that the genome of LBVV is segmented. The results reemphasize the need to reconsider the taxonomic position of Varicosaviruses.
Takahide Sasaya - One of the best experts on this subject based on the ideXlab platform.
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Negative-strand RNA viruses: the plant-infecting counterparts.
Virus Research, 2011Co-Authors: Richard Kormelink, Takahide Sasaya, Maria Laura Garcia, Michael Goodin, Anne-lise HaenniAbstract:While a large number of negative-strand (-)RNA viruses infect animals and humans, a relative small number have plants as their primary host. Some of these have been classified within families together with animal/human infecting viruses due to similarities in particle morphology and genome organization, while others have just recently been/or are still classified in floating genera. In most cases, at least two striking differences can still be discerned between the animal/human-infecting viruses and their plant-infecting counterparts which for the latter relate to their adaptation to plants as hosts. The first one is the capacity to modify plasmodesmata to facilitate systemic spread of infectious viral entities throughout the plant host. The second one is the capacity to counteract RNA interference (RNAi, also referred to as RNA silencing), the innate antiviral defence system of plants and insects. In this review an overview will be presented on the negative-strand RNA plant viruses classified within the families Bunyaviridae, Rhabdoviridae, Ophioviridae and floating genera Tenuivirus and Varicosavirus. Genetic differences with the animal-infecting counterparts and their evolutionary descendants will be described in light of the above processes.
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Molecular analysis of coat protein coding region of tobacco stunt virus shows that it is a strain of Lettuce big-vein virus in the genus Varicosavirus
Archives of Virology, 2005Co-Authors: Takahide Sasaya, K. Ishikawa, S. Kuwata, Hiroki KoganezawaAbstract:To evaluate the relationship between tobacco stunt virus (TStV) and Lettuce big-vein virus (LBVV), we determined nucleotide sequences of the coat protein (CP) coding region of five TStV and three LBVV isolates and compared them with those of one Japanese and four Spanish isolates of LBVV. CP coding regions were identical in size and the nucleotide and amino acid sequence identities between TStV and LBVV were 95.6–96.5% and 97.2–98.7%, respectively. Phylogenetic analysis of nucleotide sequences indicated that TStV was very closely related to LBVV and a strain of LBVV rather than a distinct species.
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Nucleotide sequence of RNA2 of Lettuce big-vein virus and evidence for a possible transcription termination/initiation strategy similar to that of rhabdoviruses.
The Journal of general virology, 2004Co-Authors: Takahide Sasaya, Koichi Ishikawa, Shinnosuke Kusaba, Hiroki KoganezawaAbstract:Lettuce big-vein virus (LBVV) is the type species of the genus Varicosavirus and is a two-segmented negative-sense single-stranded RNA virus. The larger LBVV genome segment (RNA1) consists of 6797 nt and encodes an L polymerase that resembles that of rhabdoviruses. Here, the nucleotide sequence of the second LBVV genome segment (RNA2) is reported. LBVV RNA2 consisted of 6081 nt and contained antisense information for five major ORFs: ORF1 (nt 210-1403 on the viral RNA), ORF2 (nt 1493-2494), ORF3 (nt 2617-3489), ORF4 (nt 3843-4337) and ORF5 (nt 4530-5636), which had coding capacities of 44, 36, 32, 19 and 41 kDa, respectively. The gene at the 3' end of the viral RNA encoded a coat protein, while the other four genes encoded proteins of unknown functions. The 3'-terminal 11 nt of LBVV RNA2 were identical to those of LBVV RNA1, and the 5'-terminal regions of LBVV RNA1 and RNA2 contained a long common nucleotide stretch of about 100 nt. Northern blot analysis using probes specific to the individual ORFs revealed that LBVV transcribes monocistronic RNAs. Analysis of the terminal sequences, and primer extension and RNase H digestion analysis of LBVV mRNAs, suggested that LBVV utilizes a transcription termination/initiation strategy comparable with that of rhabdoviruses.
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The Nucleotide Sequence of RNA1 of Lettuce big-vein virus, Genus Varicosavirus, Reveals Its Relation to Nonsegmented Negative-Strand RNA Viruses
Virology, 2002Co-Authors: Takahide Sasaya, Koichi Ishikawa, Hiroki KoganezawaAbstract:Abstract The complete nucleotide sequence of RNA1 from Lettuce big-vein virus (LBVV), the type member of the genus Varicosavirus , was determined. LBVV RNA1 consists of 6797 nucleotides and contains one large ORF that encodes a large (L) protein of 2040 amino acids with a predicted M r of 232,092. Northern blot hybridization analysis indicated that the LBVV RNA1 is a negative-sense RNA. Database searches showed that the amino acid sequence of L protein is homologous to those of L polymerases of nonsegmented negative-strand RNA viruses. A cluster dendrogram derived from alignments of the LBVV L protein and the L polymerases indicated that the L protein is most closely related to the L polymerases of plant rhabdoviruses. Transcription termination/polyadenylation signal-like poly(U) tracts that resemble those in rhabdovirus and paramyxovirus RNAs were present upstream and downstream of the coding region. Although LBVV is related to rhabdoviruses, a key distinguishing feature is that the genome of LBVV is segmented. The results reemphasize the need to reconsider the taxonomic position of Varicosaviruses.
Robert N. Campbell - One of the best experts on this subject based on the ideXlab platform.
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Transmission by Olpidium brassicae of Mirafiori lettuce virus and Lettuce big-vein virus, and Their Roles in Lettuce Big-Vein Etiology
Phytopathology®, 2002Co-Authors: Hervé Lot, Robert N. Campbell, Sylvie Souche, Robert G. Milne, Piero RoggeroAbstract:Lot, H., Campbell, R. N., Souche, S., Milne, R. G., and Roggero, P. 2002. Transmission by Olpidium brassicae of Mirafiori lettuce virus and Lettuce big-vein virus, and their roles in lettuce big-vein etiology. Phytopathology 92:288-293. Big-vein disease occurs on lettuce worldwide in temperate conditions; the causal agent has been presumed to be Lettuce big-vein virus (LBVV), genus Varicosavirus, vectored by the soilborne fungus Olpidium brassicae. Recently, the role of LBVV in the etiology of big-vein disease has been questioned because a second soilborne virus, Mirafiori lettuce virus (MiLV), genus Ophiovirus, has been found frequently in big-veinaffected lettuce. LBVV and MiLV, detectable and distinguishable by enzyme-linked immunosorbent assay using specific antisera, were tested for their ability to be transmitted from lettuce to lettuce by mechanical inoculation of sap extracts, or by zoospores of O. brassicae, and to cause big-vein disease. Both viruses were mechanically transmissible from lettuce to herbaceous hosts and to lettuce, but very erratically. LBVV was transmitted by O. brassicae but lettuce infected with only this virus never showed symptoms. MiLV was transmitted in the same manner, and lettuce infected with this virus alone consistently developed big-vein symptoms regardless of the presence or absence of LBVV. With repeated mechanical transmission, isolates of both viruses appeared to lose the ability to be vectored, and MiLV appeared to lose the ability to cause bigvein symptoms. The recovery of MiLV (Mendocino isolate, from California) from stored O. brassicae resting spores puts the earliest directly demonstrable existence of MiLV at 1990.
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Transmission by Olpidium brassicae of mirafiori lettuce virus and lettuce big-vein virus, and their roles in lettuce big-vein etiology
Phytopathology, 2002Co-Authors: Hervé Lot, Robert N. Campbell, Sylvie Souche, Robert G. Milne, Piero RoggeroAbstract:Big-vein disease occurs on lettuce worldwide in temperate conditions; the causal agent has been presumed to be Lettuce big-vein virus (LBVV), genus Varicosavirus, vectored by the soilborne fungus Olpidium brassicae. Recently, the role of LBVV in the etiology of big-vein disease has been questioned because a second soilborne virus, Mirafiori lettuce virus (MiLV), genus Ophiovirus, has been found frequently in big-vein-affected lettuce. LBVV and MiLV, detectable and distinguishable by enzyme-linked immunosorbent assay using specific antisera, were tested for their ability to be transmitted from lettuce to lettuce by mechanical inoculation of sap extracts, or by zoospores of O. brassicae, and to cause big-vein disease. Both viruses were mechanically transmissible from lettuce to herbaceous hosts and to lettuce, but very erratically. LBVV was transmitted by O. brassicae but lettuce infected with only this virus never showed symptoms. MiLV was transmitted in the same manner, and lettuce infected with this virus alone consistently developed big-vein symptoms regardless of the presence or absence of LBVV. With repeated mechanical transmission, isolates of both viruses appeared to lose the ability to be vectored, and MiLV appeared to lose the ability to cause big-vein symptoms. The recovery of MiLV (Mendocino isolate, from California) from stored O. brassicae resting spores puts the earliest directly demonstrable existence of MiLV at 1990.
