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Jari P. T. Valkonen - One of the best experts on this subject based on the ideXlab platform.
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rna silencing mediated resistance to a crinivirus Closteroviridae in cultivated sweetpotato ipomoea batatas l and development of sweetpotato virus disease following co infection with a potyvirus
Molecular Plant Pathology, 2008Co-Authors: Jan Kreuze, Ilanit Samolski Klein, Milton Untiveros Lazaro, Wilmer Cuellar J Chuquiyuri, Gabriela Lajo Morgan, Patricia Cipriani G Mejia, Marc Ghislain, Jari P. T. ValkonenAbstract:SUMMARY Sweetpotato chlorotic stunt virus (SPCSV; genus Crinivirus, family Closteroviridae) is one of the most important pathogens of sweetpotato (Ipomoea batatas L.). It can reduce yields by 50% by itself and cause various synergistic disease complexes when co-infecting with other viruses, including sweetpotato feathery mottle virus (SPFMV; genus Potyvirus, family Potyviridae). Because no sources of true resistance to SPCSV are available in sweetpotato germplasm, a pathogen-derived transgenic resistance strategy was tested as an alternative solution in this study. A Peruvian sweetpotato landrace ‘Huachano’ was transformed with an intron-spliced hairpin construct targeting the replicase encoding sequences of SPCSV and SPFMV using an improved genetic transformation procedure with reproducible efficiency. Twenty-eight independent transgenic events were obtained in three transformation experiments using a highly virulent Agrobacterium tumefaciens strain and regeneration through embryogenesis. Molecular analysis indicated that all regenerants were transgenic, with 1–7 transgene loci. Accumulation of transgene-specific siRNA was detected in most of them. None of the transgenic events was immune to SPCSV, but ten of the 20 tested transgenic events exhibited mild or no symptoms following infection, and accumulation of SPCSV was significantly reduced. There are few previous reports of RNA silencing-mediated transgenic resistance to viruses of Closteroviridae in cultivated plants. However, the high levels of resistance to accumulation of SPCSV could not prevent development of synergistic sweet potato virus disease in those transgenic plants also infected with SPFMV.
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analysis of gene content in sweet potato chlorotic stunt virus rna1 reveals the presence of the p22 rna silencing suppressor in only a few isolates implications for viral evolution and synergism
Journal of General Virology, 2008Co-Authors: Wilmer J Cuellar, Jan Kreuze, Fred Tairo, Jari P. T. ValkonenAbstract:Sweet potato chlorotic stunt virus (genus Crinivirus) belongs to the family Closteroviridae, members of which have a conserved overall genomic organization but are variable in gene content. In the bipartite criniviruses, heterogeneity is pronounced in the 3'-proximal region of RNA1, which in sweet potato chlorotic stuat virus (SPCSV) encodes two novel proteins, RNase3 (RNase III endonuclease) and p22 (RNA silencing suppressor). This study showed that two Ugandan SPCSV isolates contained the p22 gene, in contrast to three isolates of the East African strain from Tanzania and Peru and an isolate of the West African strain from Israel, which were missing a 767 nt fragment of RNA1 that included the p22 gene. Regardless of the presence of p22, all tested SPCSV isolates acted synergistically with potyvirus sweet potato feathery mottle virus (SPFMV; genus Potyvirus, family Potyviridae) in co-infected sweetpotato plants (Ipomoea batatas), which greatly enhanced SPFMV titres and caused severe sweetpotato virus disease (SPVD). Therefore, the results indicate that any efforts to engineer pathogen-derived RNA silencing-based resistance to SPCSV and SPVD in sweetpotato should not rely on p22 as the transgene. The data from this study demonstrate that isolates of this virus species can vary in the genes encoding RNA silencing suppressor proteins. This study also provides the first example of intraspecific variability in gene content of the family Closteroviridae and may be a new example of the recombination-mediated gene gain that is characteristic of virus evolution in this virus family.
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comparative and functional genomics of closteroviruses
Virus Research, 2006Co-Authors: V.v. Dolja, Jan Kreuze, Jari P. T. ValkonenAbstract:The largest extant RNA genomes are found in two diverse families of positive-strand RNA viruses, the animal Coronaviridae and the plant Closteroviridae. Comparative analysis of the viruses from the latter family reveals three levels of gene conservation. The most conserved gene module defines RNA replication and is shared with plant and animal viruses in the alphavirus-like superfamily. A module of five genes that function in particle assembly and transport is a hallmark of the family Closteroviridae and was likely present in the ancestor of all three closterovirus genera. This module includes a homologue of Hsp70 molecular chaperones and three diverged copies of the capsid protein gene. The remaining genes show dramatic variation in their numbers, functions, and origins among closteroviruses within and between the genera. Proteins encoded by these genes include suppressors of RNA silencing, RNAse III, papain-like proteases, the AlkB domain implicated in RNA repair, Zn-ribbon-containing protein, and a variety of proteins with no detectable homologues in the current databases. The evolutionary processes that have shaped the complex and fluid genomes of the large RNA viruses might be similar to those that have been involved in evolution of genomic complexity in other divisions of life.
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Some molecular characteristics of three viruses from SPVD-affected sweet potato plants in Egypt.
Archives of virology, 2003Co-Authors: J.a. Ishak, Jan Kreuze, A. Johansson, Settumba B. Mukasa, Fred Tairo, F.m. Abo El-abbas, Jari P. T. ValkonenAbstract:Sweet potato feathery mottle virus (SPFMV, genus Potyvirus, family Potyviridae), Sweet potato chlorotic stunt virus (SPCSV, genus Crinivirus, family Closteroviridae) and sweet potato virus G (SPVG) were detected in naturally infected sweet potato plants grown in the Delta region in Egypt. Before this study, SPVG was reported only from China. Two isolates of SPFMV and one isolate of SPVG were characterized for the 3′-proximal genomic sequences. Phylogenetic analyses indicated that the SPFMV isolates belong to the ‘russet crack’ strain group (RC). Serological tests using monoclonal antibodies, and phylogenetic analysis of a partial sequence of the Hsp70 gene, indicated that the Egyptian SPCSV belongs to the so-called non-East African strain group of SPCSV.
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Complete Genome Sequence and Analyses of the Subgenomic RNAs of Sweet Potato Chlorotic Stunt Virus Reveal Several New Features for the Genus Crinivirus
Journal of virology, 2002Co-Authors: Jan Kreuze, Eugene I. Savenkov, Jari P. T. ValkonenAbstract:The complete nucleotide sequences of genomic RNA1 (9,407 nucleotides [nt]) and RNA2 (8,223 nt) of Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus, family Closteroviridae) were determined, revealing that SPCSV possesses the second largest identified positive-strand single-stranded RNA genome among plant viruses after Citrus tristeza virus. RNA1 contains two overlapping open reading frames (ORFs) that encode the replication module, consisting of the putative papain-like cysteine proteinase, methyltransferase, helicase, and polymerase domains. RNA2 contains the Closteroviridae hallmark gene array represented by a heat shock protein homologue (Hsp70h), a protein of 50 to 60 kDa depending on the virus, the major coat protein, and a divergent copy of the coat protein. This grouping resembles the genome organization of Lettuce infectious yellows virus (LIYV), the only other crinivirus for which the whole genomic sequence is available. However, in striking contrast to LIYV, the two genomic RNAs of SPCSV contained nearly identical 208-nt-long 3' terminal sequences, and the ORF for a putative small hydrophobic protein present in LIYV RNA2 was found at a novel position in SPCSV RNA1. Furthermore, unlike any other plant or animal virus, SPCSV carried an ORF for a putative RNase III-like protein (ORF2 on RNA1). Several subgenomic RNAs (sgRNAs) were detected in SPCSV-infected plants, indicating that the sgRNAs formed from RNA1 accumulated earlier in infection than those of RNA2. The 5' ends of seven sgRNAs were cloned and sequenced by an approach that provided compelling evidence that the sgRNAs are capped in infected plants, a novel finding for members of the Closteroviridae.
Jan Kreuze - One of the best experts on this subject based on the ideXlab platform.
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rna silencing mediated resistance to a crinivirus Closteroviridae in cultivated sweetpotato ipomoea batatas l and development of sweetpotato virus disease following co infection with a potyvirus
Molecular Plant Pathology, 2008Co-Authors: Jan Kreuze, Ilanit Samolski Klein, Milton Untiveros Lazaro, Wilmer Cuellar J Chuquiyuri, Gabriela Lajo Morgan, Patricia Cipriani G Mejia, Marc Ghislain, Jari P. T. ValkonenAbstract:SUMMARY Sweetpotato chlorotic stunt virus (SPCSV; genus Crinivirus, family Closteroviridae) is one of the most important pathogens of sweetpotato (Ipomoea batatas L.). It can reduce yields by 50% by itself and cause various synergistic disease complexes when co-infecting with other viruses, including sweetpotato feathery mottle virus (SPFMV; genus Potyvirus, family Potyviridae). Because no sources of true resistance to SPCSV are available in sweetpotato germplasm, a pathogen-derived transgenic resistance strategy was tested as an alternative solution in this study. A Peruvian sweetpotato landrace ‘Huachano’ was transformed with an intron-spliced hairpin construct targeting the replicase encoding sequences of SPCSV and SPFMV using an improved genetic transformation procedure with reproducible efficiency. Twenty-eight independent transgenic events were obtained in three transformation experiments using a highly virulent Agrobacterium tumefaciens strain and regeneration through embryogenesis. Molecular analysis indicated that all regenerants were transgenic, with 1–7 transgene loci. Accumulation of transgene-specific siRNA was detected in most of them. None of the transgenic events was immune to SPCSV, but ten of the 20 tested transgenic events exhibited mild or no symptoms following infection, and accumulation of SPCSV was significantly reduced. There are few previous reports of RNA silencing-mediated transgenic resistance to viruses of Closteroviridae in cultivated plants. However, the high levels of resistance to accumulation of SPCSV could not prevent development of synergistic sweet potato virus disease in those transgenic plants also infected with SPFMV.
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analysis of gene content in sweet potato chlorotic stunt virus rna1 reveals the presence of the p22 rna silencing suppressor in only a few isolates implications for viral evolution and synergism
Journal of General Virology, 2008Co-Authors: Wilmer J Cuellar, Jan Kreuze, Fred Tairo, Jari P. T. ValkonenAbstract:Sweet potato chlorotic stunt virus (genus Crinivirus) belongs to the family Closteroviridae, members of which have a conserved overall genomic organization but are variable in gene content. In the bipartite criniviruses, heterogeneity is pronounced in the 3'-proximal region of RNA1, which in sweet potato chlorotic stuat virus (SPCSV) encodes two novel proteins, RNase3 (RNase III endonuclease) and p22 (RNA silencing suppressor). This study showed that two Ugandan SPCSV isolates contained the p22 gene, in contrast to three isolates of the East African strain from Tanzania and Peru and an isolate of the West African strain from Israel, which were missing a 767 nt fragment of RNA1 that included the p22 gene. Regardless of the presence of p22, all tested SPCSV isolates acted synergistically with potyvirus sweet potato feathery mottle virus (SPFMV; genus Potyvirus, family Potyviridae) in co-infected sweetpotato plants (Ipomoea batatas), which greatly enhanced SPFMV titres and caused severe sweetpotato virus disease (SPVD). Therefore, the results indicate that any efforts to engineer pathogen-derived RNA silencing-based resistance to SPCSV and SPVD in sweetpotato should not rely on p22 as the transgene. The data from this study demonstrate that isolates of this virus species can vary in the genes encoding RNA silencing suppressor proteins. This study also provides the first example of intraspecific variability in gene content of the family Closteroviridae and may be a new example of the recombination-mediated gene gain that is characteristic of virus evolution in this virus family.
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comparative and functional genomics of closteroviruses
Virus Research, 2006Co-Authors: V.v. Dolja, Jan Kreuze, Jari P. T. ValkonenAbstract:The largest extant RNA genomes are found in two diverse families of positive-strand RNA viruses, the animal Coronaviridae and the plant Closteroviridae. Comparative analysis of the viruses from the latter family reveals three levels of gene conservation. The most conserved gene module defines RNA replication and is shared with plant and animal viruses in the alphavirus-like superfamily. A module of five genes that function in particle assembly and transport is a hallmark of the family Closteroviridae and was likely present in the ancestor of all three closterovirus genera. This module includes a homologue of Hsp70 molecular chaperones and three diverged copies of the capsid protein gene. The remaining genes show dramatic variation in their numbers, functions, and origins among closteroviruses within and between the genera. Proteins encoded by these genes include suppressors of RNA silencing, RNAse III, papain-like proteases, the AlkB domain implicated in RNA repair, Zn-ribbon-containing protein, and a variety of proteins with no detectable homologues in the current databases. The evolutionary processes that have shaped the complex and fluid genomes of the large RNA viruses might be similar to those that have been involved in evolution of genomic complexity in other divisions of life.
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Some molecular characteristics of three viruses from SPVD-affected sweet potato plants in Egypt.
Archives of virology, 2003Co-Authors: J.a. Ishak, Jan Kreuze, A. Johansson, Settumba B. Mukasa, Fred Tairo, F.m. Abo El-abbas, Jari P. T. ValkonenAbstract:Sweet potato feathery mottle virus (SPFMV, genus Potyvirus, family Potyviridae), Sweet potato chlorotic stunt virus (SPCSV, genus Crinivirus, family Closteroviridae) and sweet potato virus G (SPVG) were detected in naturally infected sweet potato plants grown in the Delta region in Egypt. Before this study, SPVG was reported only from China. Two isolates of SPFMV and one isolate of SPVG were characterized for the 3′-proximal genomic sequences. Phylogenetic analyses indicated that the SPFMV isolates belong to the ‘russet crack’ strain group (RC). Serological tests using monoclonal antibodies, and phylogenetic analysis of a partial sequence of the Hsp70 gene, indicated that the Egyptian SPCSV belongs to the so-called non-East African strain group of SPCSV.
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Complete Genome Sequence and Analyses of the Subgenomic RNAs of Sweet Potato Chlorotic Stunt Virus Reveal Several New Features for the Genus Crinivirus
Journal of virology, 2002Co-Authors: Jan Kreuze, Eugene I. Savenkov, Jari P. T. ValkonenAbstract:The complete nucleotide sequences of genomic RNA1 (9,407 nucleotides [nt]) and RNA2 (8,223 nt) of Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus, family Closteroviridae) were determined, revealing that SPCSV possesses the second largest identified positive-strand single-stranded RNA genome among plant viruses after Citrus tristeza virus. RNA1 contains two overlapping open reading frames (ORFs) that encode the replication module, consisting of the putative papain-like cysteine proteinase, methyltransferase, helicase, and polymerase domains. RNA2 contains the Closteroviridae hallmark gene array represented by a heat shock protein homologue (Hsp70h), a protein of 50 to 60 kDa depending on the virus, the major coat protein, and a divergent copy of the coat protein. This grouping resembles the genome organization of Lettuce infectious yellows virus (LIYV), the only other crinivirus for which the whole genomic sequence is available. However, in striking contrast to LIYV, the two genomic RNAs of SPCSV contained nearly identical 208-nt-long 3' terminal sequences, and the ORF for a putative small hydrophobic protein present in LIYV RNA2 was found at a novel position in SPCSV RNA1. Furthermore, unlike any other plant or animal virus, SPCSV carried an ORF for a putative RNase III-like protein (ORF2 on RNA1). Several subgenomic RNAs (sgRNAs) were detected in SPCSV-infected plants, indicating that the sgRNAs formed from RNA1 accumulated earlier in infection than those of RNA2. The 5' ends of seven sgRNAs were cloned and sequenced by an approach that provided compelling evidence that the sgRNAs are capped in infected plants, a novel finding for members of the Closteroviridae.
Jesús Navas-castillo - One of the best experts on this subject based on the ideXlab platform.
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The p22 RNA Silencing Suppressor of the Crinivirus Tomato chlorosis virus is Dispensable for Local Viral Replication but Important for Counteracting an Antiviral RDR6-Mediated Response during Systemic Infection.
Viruses, 2016Co-Authors: Yazmín M. Landeo-ríos, Enrique Moriones, Jesús Navas-castillo, M. Carmen CañizaresAbstract:Among the components of the RNA silencing pathway in plants, RNA-dependent RNA polymerases (RDRs) play fundamental roles in antiviral defence. Here, we demonstrate that the Nicotiana benthamiana RDR6 is involved in defence against the bipartite crinivirus (genus Crinivirus, family Closteroviridae) Tomato chlorosis virus (ToCV). Additionally, by producing a p22-deficient ToCV infectious mutant clone (ToCVΔp22), we studied the role of this viral suppressor of RNA silencing in viral infection in both wild-type and RDR6-silenced N. benthamiana (NbRDR6i) plants. We demonstrate that p22 is dispensable for the replication of ToCV, where RDR6 appears not to have any effect. Furthermore, the finding that ToCV∆p22 systemic accumulation was impaired in wild-type N. benthamiana but not in NbRDR6i plants suggests a role for p22 in counteracting an RDR6-mediated antiviral response of the plant during systemic infection.
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Genetic diversity and silencing suppression activity of the p22 protein of Tomato chlorosis virus isolates from tomato and sweet pepper
Virus Genes, 2015Co-Authors: Yazmín M. Landeo-ríos, Enrique Moriones, Jesús Navas-castillo, M. Carmen CañizaresAbstract:As for other bipartite criniviruses (genus Crinivirus , family Closteroviridae ), the genome of Tomato chlorosis virus encodes an RNA silencing suppressor, the protein p22, in the 3′-proximal region of RNA1. This protein has been reported as having one of the longest lasting local suppressor activities when transiently expressed in Nicotiana benthamiana . Here, we examined the genetic diversity of the p22 gene in ToCV isolates from tomato and sweet pepper. The p22 gene sequences clearly grouped into two separated clades. However, functional analysis of both types of p22 proteins indicated no evident differences in suppressor activity. Our findings provide experimental evidence that the presence of a “strong” silencing suppressor is a conserved feature of ToCV isolates.
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The complete nucleotide sequence of the RNA2 of the crinivirus tomato infectious chlorosis virus: isolates from North America and Europe are essentially identical.
Archives of virology, 2009Co-Authors: Anelise F. Orílio, Jesús Navas-castilloAbstract:The complete nucleotide sequences of the RNA2 of two isolates of Tomato infectious chlorosis virus (TICV, genus Crinivirus, family Closteroviridae) from the United States and Spain, respectively, were determined. The sequences of both isolates were found to be nearly identical. TICV RNA2 consisted of 7,914 nucleotides in both isolates and contains eight open reading frames that encompass the Closteroviridae hallmark gene array represented by a heat shock protein 70 family homologue, a protein of 59 kDa, the major coat protein, and a divergent copy of the coat protein. Phylogenetic analysis suggested that TICV is most similar to Lettuce infectious yellows virus (LIYV), the type species of the genus Crinivirus.
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Multiple suppressors of RNA silencing encoded by both genomic RNAs of the crinivirus, Tomato chlorosis virus.
Virology, 2008Co-Authors: M. Carmen Cañizares, Jesús Navas-castillo, Enrique MorionesAbstract:Viruses express proteins with silencing suppression activity to counteract the RNA silencing-mediated defense response of the host. In the family Closteroviridae, examples of multiple-component RNA silencing suppression systems have been reported. To ascertain if this is a general strategy in this group of viruses, we have explored the bipartite genome of Tomato chlorosis virus (ToCV, genus Crinivirus). We have identified the RNA1-encoded p22 protein as an effective silencing suppressor by using a Agrobacterium co-infiltration assay. p22 suppressed local RNA silencing induced either by sense RNA or dsRNA very efficiently, but did not interfere with short or long-distance systemic spread of silencing. We have also demonstrated by using the heterologous vector PVX the silencing suppression activity of the RNA-2 encoded coat protein (CP) and minor coat protein (CPm). In this study, we demonstrate an even greater complexity of silencing suppressor activity for a plant virus, and for the first time we show the presence of RNA silencing suppressor genes encoded by both genomic RNA molecules of a bipartite genome in the complex family Closteroviridae.
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Complete nucleotide sequence of the RNA2 of the crinivirus tomato chlorosis virus.
Archives of virology, 2005Co-Authors: Gloria Lozano, Enrique Moriones, Jesús Navas-castilloAbstract:The complete sequence of genomic RNA2 of Tomato chlorosis virus (ToCV; genus Crinivirus, family Closteroviridae), isolate AT80/99 from Spain, was determined and compared with those from the other members of the genus sequenced to date. RNA2 is 8244 nucleotides (nt) long and putatively encodes nine ORFs that encompass the hallmark gene array of the family Closteroviridae, which includes a heat shock protein 70 family homologue, a 59 kDa protein, the coat protein, and a diverged coat protein. Phylogenetic analysis confirmed assignment of ToCV in the genus Crinivirus, being most similar to sweet potato chlorotic stunt virus and cucurbit yellow stunting disorder virus.
Ioannis E. Tzanetakis - One of the best experts on this subject based on the ideXlab platform.
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Epidemiology of criniviruses: an emerging problem in world agriculture
Frontiers in microbiology, 2013Co-Authors: Ioannis E. Tzanetakis, Robert R. Martin, William M WintermantelAbstract:The genus Crinivirus includes the whitefly-transmitted members of the family Closteroviridae. Whitefly-transmitted viruses have emerged as a major problem for world agriculture and are responsible for diseases that lead to losses measured in the billions of dollars annually. Criniviruses emerged as a major agricultural threat at the end of the twentieth century with the establishment and naturalization of their whitefly vectors, members of the genera Trialeurodes and Bemisia, in temperate climates around the globe. Several criniviruses cause significant diseases in single infections whereas others remain asymptomatic and only cause disease when found in mixed infections with other viruses. Characterization of the majority of criniviruses has been done in the last twenty years and this article provides a detailed review on the epidemiology of this important group of viruses.
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Diodia vein chlorosis virus is a group-1 crinivirus
Archives of Virology, 2011Co-Authors: Ioannis E. Tzanetakis, William M Wintermantel, Bindu Poudel, Jing ZhouAbstract:Members of the family Closteroviridae have emerged as a major problem in agricultural crops in the past two decades. Diodia vein chlorosis virus (DVCV) is an understudied whitefly-transmitted closterovirus. Given the presence of the primary host for the virus in major agricultural production areas in the United States, we characterized the virus at the molecular level, demonstrating that it belongs in the genus Crinivirus , developed detection protocols, evaluated its host range among hosts known to harbor viruses closely related to DVCV, and confirmed transmission by a second whitefly species, Trialeurodes vaporariorum .
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Identification and characterization of Raspberry mottle virus, a novel member of the Closteroviridae
Virus Research, 2007Co-Authors: Ioannis E. Tzanetakis, Anne Halgren, Nola J. Mosier, Robert R. MartinAbstract:Raspberry mosaic is one of the most important viral diseases of raspberry. Four virus and virus-like agents, two of which are poorly characterized, have been implicated in the disease complex based on symptom development in Rubus indicators. Three novel viruses were identified in a red raspberry plant that caused typical raspberry mosaic symptoms when grafted onto indicators. This communication focuses on one of these viruses, Raspberry mottle virus (RMoV), a new member of the family Closteroviridae. The complete nucleotide sequence of RMoV has been determined and exceeds 17 kilobases encoding 10 genes. The genome organization of RMoV is similar to that of Beet yellows virus, the type member of the Closterovirus genus, and phylogenetic analysis using the polymerase conserved motifs and the heat shock protein 70 homolog revealed a close relationship of RMoV with Strawberry chlorotic fleck associated virus and Citrus tristeza virus, which suggests the possibility of an aphid vector. The virus was detected in symptomatic raspberry plants in production areas in mixed infections with several other viruses, indicating that RMoV may impact raspberry production.
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yellow vein affected blackberries and the presence of a novel crinivirus
Plant Pathology, 2006Co-Authors: James Susaimuthu, Ioannis E. Tzanetakis, Rose C Gergerich, Robert R. MartinAbstract:During the last 5 years, blackberry plants in Arkansas and North and South Carolina exhibited virus-like symptoms of vein yellowing and mosaic, followed in some cases by death. Diagnostic tests for known blackberry viruses failed to identify a causal agent. Double-stranded RNA was extracted from affected plants and cloned. A new member of the Closteroviridae was identified and designated Blackberry yellow vein associated virus (BYVaV). Molecular and immunological assays have been developed for BYVaV, and examination of plants with symptoms revealed a close association of disease symptoms with the presence of BYVaV, although the virus was also found in symptomless plants. Molecular characterization of isolates from plants exhibiting different degrees of disease severity indicated that sequence diversity is probably not the cause of the observed phenotypic differences.
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Yellow vein‐affected blackberries and the presence of a novel Crinivirus
Plant Pathology, 2006Co-Authors: James Susaimuthu, Ioannis E. Tzanetakis, Rose C Gergerich, Robert R. MartinAbstract:During the last 5 years, blackberry plants in Arkansas and North and South Carolina exhibited virus-like symptoms of vein yellowing and mosaic, followed in some cases by death. Diagnostic tests for known blackberry viruses failed to identify a causal agent. Double-stranded RNA was extracted from affected plants and cloned. A new member of the Closteroviridae was identified and designated Blackberry yellow vein associated virus (BYVaV). Molecular and immunological assays have been developed for BYVaV, and examination of plants with symptoms revealed a close association of disease symptoms with the presence of BYVaV, although the virus was also found in symptomless plants. Molecular characterization of isolates from plants exhibiting different degrees of disease severity indicated that sequence diversity is probably not the cause of the observed phenotypic differences.
Robert R. Martin - One of the best experts on this subject based on the ideXlab platform.
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Epidemiology of criniviruses: an emerging problem in world agriculture
Frontiers in microbiology, 2013Co-Authors: Ioannis E. Tzanetakis, Robert R. Martin, William M WintermantelAbstract:The genus Crinivirus includes the whitefly-transmitted members of the family Closteroviridae. Whitefly-transmitted viruses have emerged as a major problem for world agriculture and are responsible for diseases that lead to losses measured in the billions of dollars annually. Criniviruses emerged as a major agricultural threat at the end of the twentieth century with the establishment and naturalization of their whitefly vectors, members of the genera Trialeurodes and Bemisia, in temperate climates around the globe. Several criniviruses cause significant diseases in single infections whereas others remain asymptomatic and only cause disease when found in mixed infections with other viruses. Characterization of the majority of criniviruses has been done in the last twenty years and this article provides a detailed review on the epidemiology of this important group of viruses.
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Identification and characterization of Raspberry mottle virus, a novel member of the Closteroviridae
Virus Research, 2007Co-Authors: Ioannis E. Tzanetakis, Anne Halgren, Nola J. Mosier, Robert R. MartinAbstract:Raspberry mosaic is one of the most important viral diseases of raspberry. Four virus and virus-like agents, two of which are poorly characterized, have been implicated in the disease complex based on symptom development in Rubus indicators. Three novel viruses were identified in a red raspberry plant that caused typical raspberry mosaic symptoms when grafted onto indicators. This communication focuses on one of these viruses, Raspberry mottle virus (RMoV), a new member of the family Closteroviridae. The complete nucleotide sequence of RMoV has been determined and exceeds 17 kilobases encoding 10 genes. The genome organization of RMoV is similar to that of Beet yellows virus, the type member of the Closterovirus genus, and phylogenetic analysis using the polymerase conserved motifs and the heat shock protein 70 homolog revealed a close relationship of RMoV with Strawberry chlorotic fleck associated virus and Citrus tristeza virus, which suggests the possibility of an aphid vector. The virus was detected in symptomatic raspberry plants in production areas in mixed infections with several other viruses, indicating that RMoV may impact raspberry production.
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yellow vein affected blackberries and the presence of a novel crinivirus
Plant Pathology, 2006Co-Authors: James Susaimuthu, Ioannis E. Tzanetakis, Rose C Gergerich, Robert R. MartinAbstract:During the last 5 years, blackberry plants in Arkansas and North and South Carolina exhibited virus-like symptoms of vein yellowing and mosaic, followed in some cases by death. Diagnostic tests for known blackberry viruses failed to identify a causal agent. Double-stranded RNA was extracted from affected plants and cloned. A new member of the Closteroviridae was identified and designated Blackberry yellow vein associated virus (BYVaV). Molecular and immunological assays have been developed for BYVaV, and examination of plants with symptoms revealed a close association of disease symptoms with the presence of BYVaV, although the virus was also found in symptomless plants. Molecular characterization of isolates from plants exhibiting different degrees of disease severity indicated that sequence diversity is probably not the cause of the observed phenotypic differences.
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Yellow vein‐affected blackberries and the presence of a novel Crinivirus
Plant Pathology, 2006Co-Authors: James Susaimuthu, Ioannis E. Tzanetakis, Rose C Gergerich, Robert R. MartinAbstract:During the last 5 years, blackberry plants in Arkansas and North and South Carolina exhibited virus-like symptoms of vein yellowing and mosaic, followed in some cases by death. Diagnostic tests for known blackberry viruses failed to identify a causal agent. Double-stranded RNA was extracted from affected plants and cloned. A new member of the Closteroviridae was identified and designated Blackberry yellow vein associated virus (BYVaV). Molecular and immunological assays have been developed for BYVaV, and examination of plants with symptoms revealed a close association of disease symptoms with the presence of BYVaV, although the virus was also found in symptomless plants. Molecular characterization of isolates from plants exhibiting different degrees of disease severity indicated that sequence diversity is probably not the cause of the observed phenotypic differences.
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Nucleotide sequence of Blackberry yellow vein associated virus, a novel member of the Closteroviridae.
Virus research, 2005Co-Authors: Ioannis E. Tzanetakis, James Susaimuthu, Rose C Gergerich, Robert R. MartinAbstract:The complete nucleotide sequence of a novel member of the genus Crinivirus (family Closteroviridae), isolated from blackberry and tentatively named Blackberry yellow vein associated virus, was determined. The virus possesses a bipartite genome. RNA 1 is 7,801 nucleotides in length and papain-like protease, methyltransferase, RNA helicase and RNA-dependent RNA polymerase motifs have been identified in the proteins coded for by this molecule. The polymerase is probably expressed via a +1 ribosomal frameshift, a common feature among members of the Closteroviridae. RNA 2 is 7,917 nucleotides long and encodes nine open reading frames, similar in size and position to orthologous genes of other criniviruses with the exception of a second hydrophobic peptide found near the 5' terminus of the molecule. Phylogenetic analysis revealed a close relationship between Blackberry yellow vein associated virus and Beet pseudo yellows virus, another crinivirus that infects small fruit crops.