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Valerian V. Dolja - One of the best experts on this subject based on the ideXlab platform.
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Virion Tails of Beet Yellows Virus: Coordinated Assembly by Three Structural Proteins
Virology, 2006Co-Authors: Dina V. Alzhanova, Valera V. Peremyslov, Alexey I. Prokhnevsky, Valerian V. DoljaAbstract:Abstract Filamentous virions of Beet Yellows Virus contain a long body formed by a major capsid protein and a short tail that is assembled by a minor capsid protein (CPm), an Hsp70-homolog (Hsp70h), a 64-kDa protein (p64), and a 20-kDa protein (p20). Using mutation analysis and newly developed in planta assays, here we investigate the genetic requirements for the tail assembly. We show that the inactivation of CPm dramatically reduces incorporation of both Hsp70h and p64. Furthermore, inactivation of Hsp70h prevents incorporation of p64 into virions and vice versa. Hsp70h and p64 are each required for efficient incorporation of CPm. We also show that the tails possessing normal relative amounts of CPm, Hsp70h, and p64 can be formed in the absence of the major capsid protein and p20. Similar to the tails isolated from the wild-type virions, these mutant tails encapsidate the ∼ 700 nt-long, 5′-terminal segments of the viral RNA. Taken together, our results imply that CPm, Hsp70h and p64 act cooperatively to encapsidate a defined region of the closteroVirus genome.
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Complex molecular architecture of Beet Yellows Virus particles.
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Valera V. Peremyslov, Igor A. Andreev, Alexey I. Prokhnevsky, George H. Duncan, Michael Taliansky, Valerian V. DoljaAbstract:ClosteroViruses possess exceptionally long filamentous Virus particles that mediate protection and active transport of the genomic RNA within infected plants. These virions are composed of a long “body” and short “tail” whose principal components are the major and minor capsid proteins, respectively. Here we use biochemical, genetic, and ultrastructural analyses to dissect the molecular composition and architecture of particles of Beet Yellows Virus, a closteroVirus. We demonstrate that the virion tails encapsidate the 5′-terminal, ≈650-nt-long, part of the viral RNA. In addition to the minor capsid protein, the viral Hsp70-homolog, 64-kDa protein, and 20-kDa protein are also incorporated into the virion tail. Atomic force microscopy of virions revealed that the tail possesses a striking, segmented morphology with the tip segment probably being built of 20-kDa protein. The unexpectedly complex structure of closteroVirus virions has important mechanistic and functional implications that may also apply to other Virus families.
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Leader Proteinase of Beet Yellows Virus Functions in Long-Distance Transport
Journal of virology, 2003Co-Authors: Chih-wen Peng, Alberto J. Napuli, Valerian V. DoljaAbstract:The 66-kDa leader proteinase (L-Pro) of the Beet Yellows Virus (BYV) possesses a nonconserved N-terminal domain and a conserved, papain-like C-terminal domain. Previous work revealed that the N-terminal domain functions in RNA amplification, whereas the C-terminal domain is required for autoproteolysis. Alanine-scanning mutagenesis was applied to complete the functional analysis of L-Pro throughout the Virus life cycle. This analysis indicated that the C-terminal domain of L-Pro, in addition to being required for proteolysis, also functions in RNA amplification and that these two functions are genetically separable. Examination of the role of L-Pro in BYV cell-to-cell movement revealed that none of the 20 examined replication-competent mutants was movement defective. In contrast, six of the L-Pro mutations affected the long-distance transport of BYV to various degrees, whereas three mutations completely abolished the transport. Because these mutations were located throughout the protein molecule, both domains of L-Pro function in Virus transport. We conclude that in addition to previously identified functions of L-Pro, it also serves as the BYV long-distance transport factor.
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Beet Yellows Virus: the importance of being different.
Molecular plant pathology, 2003Co-Authors: Valerian V. DoljaAbstract:SUMMARY Taxonomic relationship: Type member of the genus ClosteroVirus, family Closteroviridae. A member of the alphaVirus-like supergroup of positive-strand RNA Viruses. Physical properties: Virions are flexuous filaments of approximately 1300 nm in length and approximately 12 nm in diameter that are made up of a approximately 15.5 kb RNA and five proteins. The major capsid protein forms virion body of helical symmetry that constitutes approximately 95% of the virion length. The short virion tail is assembled by the minor capsid protein, Hsp70-homologue, approximately 64-kDa protein, and approximately 20-kDa protein. Viral proteins: The 5'-most ORFs 1a and 1b encode leader proteinase and RNA replicase. The remaining ORFs 2-8 are expressed by subgenomic mRNAs that encode 6-kDa membrane protein, Hsp70 homologue, approximately 64-kDa protein, minor and major capsid proteins, approximately 20-kDa protein, and approximately 21-kDa protein, respectively. Hosts: The principal crop plants affected by Beet Yellows Virus (BYV) are sugar Beet (Beta vulgaris) and spinach (Spinacea oleracea). In addition, BYV was reported to infect approximately 120 species in 15 families. Most suitable propagation species are Nicotiana benthamiana, Tetragonia expansa, and Claytonia perfoliata.
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Suppressor of RNA silencing encoded by Beet Yellows Virus
Virology, 2003Co-Authors: Jonathan C. Reed, Alexey I. Prokhnevsky, Kristin D. Kasschau, K. Gopinath, Gregory P. Pogue, James C. Carrington, Valerian V. DoljaAbstract:Using an Agrobacterium-mediated transient assay, we screened the 15.5-kb genome of the Beet Yellows Virus for proteins with RNA silencing suppressor activity. Among eight proteins tested, only a 21-kDa protein (p21) was able to suppress double-stranded (ds) RNA-induced silencing of the green fluorescent protein (GFP) mRNA. Restoration of GFP expression by p21 under these conditions had no apparent effect on accumulation of the small interfering RNAs. In addition, p21 elevated the transient expression level of the GFP mRNA in the absence of dsRNA inducer. Similar activities were detected using homologs of p21 encoded by other members of the genus ClosteroVirus. Computer analysis indicated that p21-like proteins constitute a novel protein family that is unrelated to other recognized suppressors of RNA silencing. Examination of the subcellular distribution in BYV-infected plants revealed that p21 is partitioned between soluble cytoplasmic form and proteinaceous inclusion bodies at the cell periphery.
Alexey I. Prokhnevsky - One of the best experts on this subject based on the ideXlab platform.
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Rapid Communication Suppressor of RNA silencing encoded by Beet Yellows Virus
2014Co-Authors: Jonathan C. Reed, Alexey I. Prokhnevsky, Kristin D. Kasschau, Gregory P. Pogue, James C. Carrington, Kodetham A Gopinath, Valerian V. DoljaaAbstract:Using an Agrobacterium-mediated transient assay, we screened the 15.5-kb genome of the Beet Yellows Virus for proteins with RNA silencing suppressor activity. Among eight proteins tested, only a 21-kDa protein (p21) was able to suppress double-stranded (ds) RNA-induced silencing of the green fluorescent protein (GFP) mRNA. Restoration of GFP expression by p21 under these conditions had no apparent effect on accumulation of the small interfering RNAs. In addition, p21 elevated the transient expression level of the GFP mRNA in the absence of dsRNA inducer. Similar activities were detected using homologs of p21 encoded by other members of the genus ClosteroVirus. Computer analysis indicated that p21-like proteins constitute a novel protein family that is unrelated to other recognized suppressors of RNA silencing. Examination of the subcellular distribution in BYV-infected plants revealed that p21 is partitioned betwee
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Virion Tails of Beet Yellows Virus: Coordinated Assembly by Three Structural Proteins
Virology, 2006Co-Authors: Dina V. Alzhanova, Valera V. Peremyslov, Alexey I. Prokhnevsky, Valerian V. DoljaAbstract:Abstract Filamentous virions of Beet Yellows Virus contain a long body formed by a major capsid protein and a short tail that is assembled by a minor capsid protein (CPm), an Hsp70-homolog (Hsp70h), a 64-kDa protein (p64), and a 20-kDa protein (p20). Using mutation analysis and newly developed in planta assays, here we investigate the genetic requirements for the tail assembly. We show that the inactivation of CPm dramatically reduces incorporation of both Hsp70h and p64. Furthermore, inactivation of Hsp70h prevents incorporation of p64 into virions and vice versa. Hsp70h and p64 are each required for efficient incorporation of CPm. We also show that the tails possessing normal relative amounts of CPm, Hsp70h, and p64 can be formed in the absence of the major capsid protein and p20. Similar to the tails isolated from the wild-type virions, these mutant tails encapsidate the ∼ 700 nt-long, 5′-terminal segments of the viral RNA. Taken together, our results imply that CPm, Hsp70h and p64 act cooperatively to encapsidate a defined region of the closteroVirus genome.
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Complex molecular architecture of Beet Yellows Virus particles.
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Valera V. Peremyslov, Igor A. Andreev, Alexey I. Prokhnevsky, George H. Duncan, Michael Taliansky, Valerian V. DoljaAbstract:ClosteroViruses possess exceptionally long filamentous Virus particles that mediate protection and active transport of the genomic RNA within infected plants. These virions are composed of a long “body” and short “tail” whose principal components are the major and minor capsid proteins, respectively. Here we use biochemical, genetic, and ultrastructural analyses to dissect the molecular composition and architecture of particles of Beet Yellows Virus, a closteroVirus. We demonstrate that the virion tails encapsidate the 5′-terminal, ≈650-nt-long, part of the viral RNA. In addition to the minor capsid protein, the viral Hsp70-homolog, 64-kDa protein, and 20-kDa protein are also incorporated into the virion tail. Atomic force microscopy of virions revealed that the tail possesses a striking, segmented morphology with the tip segment probably being built of 20-kDa protein. The unexpectedly complex structure of closteroVirus virions has important mechanistic and functional implications that may also apply to other Virus families.
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Suppressor of RNA silencing encoded by Beet Yellows Virus
Virology, 2003Co-Authors: Jonathan C. Reed, Alexey I. Prokhnevsky, Kristin D. Kasschau, K. Gopinath, Gregory P. Pogue, James C. Carrington, Valerian V. DoljaAbstract:Using an Agrobacterium-mediated transient assay, we screened the 15.5-kb genome of the Beet Yellows Virus for proteins with RNA silencing suppressor activity. Among eight proteins tested, only a 21-kDa protein (p21) was able to suppress double-stranded (ds) RNA-induced silencing of the green fluorescent protein (GFP) mRNA. Restoration of GFP expression by p21 under these conditions had no apparent effect on accumulation of the small interfering RNAs. In addition, p21 elevated the transient expression level of the GFP mRNA in the absence of dsRNA inducer. Similar activities were detected using homologs of p21 encoded by other members of the genus ClosteroVirus. Computer analysis indicated that p21-like proteins constitute a novel protein family that is unrelated to other recognized suppressors of RNA silencing. Examination of the subcellular distribution in BYV-infected plants revealed that p21 is partitioned between soluble cytoplasmic form and proteinaceous inclusion bodies at the cell periphery.
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Interaction between Long-Distance Transport Factor and Hsp70-Related Movement Protein of Beet Yellows Virus
Journal of virology, 2002Co-Authors: Alexey I. Prokhnevsky, Valera V. Peremyslov, Alberto J. Napuli, Valerian V. DoljaAbstract:Systemic spread of Viruses in plants involves local movement from cell to cell and long-distance transport through the vascular system. The cell-to-cell movement of the Beet Yellows Virus (BYV) is mediated by a movement protein that is an Hsp70 homolog (Hsp70h). This protein is required for the assembly of movement-competent virions that incorporate Hsp70h. By using the yeast two-hybrid system, in vitro coimmunoprecipitation, and in planta coexpression approaches, we show here that the Hsp70h interacts with a 20-kDa BYV protein (p20). We further demonstrate that p20 is associated with the virions presumably via binding to Hsp70h. Genetic and immunochemical analyses indicate that p20 is dispensable for assembly and cell-to-cell movement of BYV but is required for the long-distance transport of Virus through the phloem. These results reveal a novel activity for the Hsp70h that provides a molecular link between the local and systemic spread of a plant Virus by docking a long-distance transport factor to virions.
W. Van Der Werf - One of the best experts on this subject based on the ideXlab platform.
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EFFECTS OF Beet Yellows Virus AND Beet MILD YELLOWING Virus ON LEAF AREA DYNAMICS OF SUGAR Beet (BETA VULGARIS L.)
Field Crops Research, 1999Co-Authors: K.j. De Koeijer, W. Van Der WerfAbstract:Abstract Field experiments were conducted over three years to investigate the effects of Beet Yellows Virus (BYV) and Beet mild yellowing Virus (BMYV) on leaf area dynamics in sugar Beet (Beta vulgaris L.). Plants infected with BMYV showed normal leaf area growth and the leaf area index (LAI) was not significantly affected by Virus infection. Up to 1.4 m2 (leaf) m−2 (soil) of leaf area was yellow, resulting in a maximum proportion of yellow leaf area of ca. 35%. Yellowing symptoms were only found on mature leaves. Plants infected with BYV showed a reduced formation of leaf area compared to healthy or BMYV-infected plants; leaves appearing after infection remained smaller than in healthy or BMYV-infected plots. As for BMYV, only mature leaves developed yellowing symptoms. The total amount of yellow leaf area on BYV-infected plants was similar to that induced by BMYV, but due to the smaller total leaf area index, the proportion of yellow leaf area was greater, up to ca. 50%. Infection with BYV substantially reduced the life span of infected leaves. Both Viruses caused a ±20% decrease of specific leaf area in mature yellow leaves, compared to healthy leaves. As a result of a lower LAI and a greater proportion of yellow leaf area, BYV causes a greater reduction of crop light interception on green leaves than BMYV. In BMYV-infected plots, proportion of soil cover by yellow leaves was generally similar to the proportion of yellow leaf area, but significant differences from this pattern were observed for BYV.
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Early-season predation impacts the establishment of aphids and spread of Beet Yellows Virus in sugar Beet
Entomophaga, 1997Co-Authors: D.a. Landis, W. Van Der WerfAbstract:The potential of predators to impact the establishment of aphid vectors and the spread of Beet Yellows Virus in sugar Beet was examined.
Valera V. Peremyslov - One of the best experts on this subject based on the ideXlab platform.
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Virion Tails of Beet Yellows Virus: Coordinated Assembly by Three Structural Proteins
Virology, 2006Co-Authors: Dina V. Alzhanova, Valera V. Peremyslov, Alexey I. Prokhnevsky, Valerian V. DoljaAbstract:Abstract Filamentous virions of Beet Yellows Virus contain a long body formed by a major capsid protein and a short tail that is assembled by a minor capsid protein (CPm), an Hsp70-homolog (Hsp70h), a 64-kDa protein (p64), and a 20-kDa protein (p20). Using mutation analysis and newly developed in planta assays, here we investigate the genetic requirements for the tail assembly. We show that the inactivation of CPm dramatically reduces incorporation of both Hsp70h and p64. Furthermore, inactivation of Hsp70h prevents incorporation of p64 into virions and vice versa. Hsp70h and p64 are each required for efficient incorporation of CPm. We also show that the tails possessing normal relative amounts of CPm, Hsp70h, and p64 can be formed in the absence of the major capsid protein and p20. Similar to the tails isolated from the wild-type virions, these mutant tails encapsidate the ∼ 700 nt-long, 5′-terminal segments of the viral RNA. Taken together, our results imply that CPm, Hsp70h and p64 act cooperatively to encapsidate a defined region of the closteroVirus genome.
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Complex molecular architecture of Beet Yellows Virus particles.
Proceedings of the National Academy of Sciences of the United States of America, 2004Co-Authors: Valera V. Peremyslov, Igor A. Andreev, Alexey I. Prokhnevsky, George H. Duncan, Michael Taliansky, Valerian V. DoljaAbstract:ClosteroViruses possess exceptionally long filamentous Virus particles that mediate protection and active transport of the genomic RNA within infected plants. These virions are composed of a long “body” and short “tail” whose principal components are the major and minor capsid proteins, respectively. Here we use biochemical, genetic, and ultrastructural analyses to dissect the molecular composition and architecture of particles of Beet Yellows Virus, a closteroVirus. We demonstrate that the virion tails encapsidate the 5′-terminal, ≈650-nt-long, part of the viral RNA. In addition to the minor capsid protein, the viral Hsp70-homolog, 64-kDa protein, and 20-kDa protein are also incorporated into the virion tail. Atomic force microscopy of virions revealed that the tail possesses a striking, segmented morphology with the tip segment probably being built of 20-kDa protein. The unexpectedly complex structure of closteroVirus virions has important mechanistic and functional implications that may also apply to other Virus families.
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Interaction between Long-Distance Transport Factor and Hsp70-Related Movement Protein of Beet Yellows Virus
Journal of virology, 2002Co-Authors: Alexey I. Prokhnevsky, Valera V. Peremyslov, Alberto J. Napuli, Valerian V. DoljaAbstract:Systemic spread of Viruses in plants involves local movement from cell to cell and long-distance transport through the vascular system. The cell-to-cell movement of the Beet Yellows Virus (BYV) is mediated by a movement protein that is an Hsp70 homolog (Hsp70h). This protein is required for the assembly of movement-competent virions that incorporate Hsp70h. By using the yeast two-hybrid system, in vitro coimmunoprecipitation, and in planta coexpression approaches, we show here that the Hsp70h interacts with a 20-kDa BYV protein (p20). We further demonstrate that p20 is associated with the virions presumably via binding to Hsp70h. Genetic and immunochemical analyses indicate that p20 is dispensable for assembly and cell-to-cell movement of BYV but is required for the long-distance transport of Virus through the phloem. These results reveal a novel activity for the Hsp70h that provides a molecular link between the local and systemic spread of a plant Virus by docking a long-distance transport factor to virions.
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Identification of the subgenomic mRNAs that encode 6-kDa movement protein and Hsp70 homolog of Beet Yellows Virus.
Virology, 2002Co-Authors: Valera V. Peremyslov, Valerian V. DoljaAbstract:Abstract A tandem arrangement of the genes encoding the ∼6-kDa hydrophobic protein (p6) and Hsp70 homolog (Hsp70h) is conserved among the members of the ClosteroVirus genus. It was not known, however, if these movement proteins are expressed from one or two subgenomic (sg) RNAs. Here we employ RNA ligase-mediated RACE to show that the Beet Yellows Virus (BYV), a prototype Closterovius, produces separate sgRNAs encoding p6 and Hsp70h. This result is further supported by generation of the recombinant BYV in which the truncated variants of these sgRNAs are resolved by Northern analysis. The 5′-termini of the p6 and Hsp70h sgRNAs are localized to BYV nucleotides G-9402 and A-9467, respectively. Each of the sgRNAs was generated in vitro and found to direct the expected product upon translation in wheat germ extract. Inactivation of the first start codons in these sgRNAs abolished translation of the each product. The polyclonal antibodies raised to synthetic C-terminal peptides of p6 and Hsp70h specifically recognized corresponding translation products, as well as p6 and Hsp70h produced in BYV-infected plants. Taken together with the previous work, our data demonstrate that expression of the BYV genome involves the formation of as many as seven sgRNAs.
Thierry Hance - One of the best experts on this subject based on the ideXlab platform.
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Bottom-up regulation of a tritrophic system by Beet Yellows Virus infection: consequences for aphid-parasitoid foraging behaviour and development
Oecologia, 2019Co-Authors: Loulou Albittar, Mohannad Ismail, Gertrud Lohaus, Arnaud Ameline, Bertanne Visser, Claude Bragard, Thierry HanceAbstract:Effects of plants on herbivores can cascade up the food web and modulate the abundance of higher trophic levels. In agro-ecosystems, plant Viruses can affect the interactions between crops, crop pests, and natural enemies. Little is known, however, about the effects of Viruses on higher trophic levels, including parasitoids and their ability for pest regulation. We tested the hypothesis that a plant Virus affects parasitoid foraging behaviour through cascading effects on higher trophic levels. We predicted that the semi-persistent Beet Yellows Virus (BYV) would influence plant ( Beta vulgaris ) quality, as well as aphid host ( Aphis fabae ) quality for a parasitoid Lysiphlebus fabarum . We determined amino acid and sugar content in healthy and infected plants (first trophic level), lipid content and body size of aphids (second trophic level) fed on both plants, as well as foraging behaviour and body size of parasitoids (third trophic level) that developed on aphids fed on both plants. Our results showed that Virus infection increased sugars and decreased total amino acid content in B. vulgaris . We further observed an increase in aphid size without modification in host aphid quality (i.e., lipid content), and a slight effect on parasitoid behaviour through an increased number of antennal contacts with host aphids. Although the BYV Virus clearly affected the first two trophic levels, it did not affect development or emergence of parasitoids. As the parasitoid L. fabarum does not seem to be affected by the Virus, we discuss the possibility of using it for the development of targeted biological control against aphids.
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Bottom-up regulation of a tritrophic system by Beet Yellows Virus infection: consequences for aphid-parasitoid foraging behaviour and development.
Oecologia, 2019Co-Authors: Loulou Albittar, Mohannad Ismail, Gertrud Lohaus, Arnaud Ameline, Bertanne Visser, Claude Bragard, Thierry HanceAbstract:Effects of plants on herbivores can cascade up the food web and modulate the abundance of higher trophic levels. In agro-ecosystems, plant Viruses can affect the interactions between crops, crop pests, and natural enemies. Little is known, however, about the effects of Viruses on higher trophic levels, including parasitoids and their ability for pest regulation. We tested the hypothesis that a plant Virus affects parasitoid foraging behaviour through cascading effects on higher trophic levels. We predicted that the semi-persistent Beet Yellows Virus (BYV) would influence plant (Beta vulgaris) quality, as well as aphid host (Aphis fabae) quality for a parasitoid Lysiphlebus fabarum. We determined amino acid and sugar content in healthy and infected plants (first trophic level), lipid content and body size of aphids (second trophic level) fed on both plants, as well as foraging behaviour and body size of parasitoids (third trophic level) that developed on aphids fed on both plants. Our results showed that Virus infection increased sugars and decreased total amino acid content in B. vulgaris. We further observed an increase in aphid size without modification in host aphid quality (i.e., lipid content), and a slight effect on parasitoid behaviour through an increased number of antennal contacts with host aphids. Although the BYV Virus clearly affected the first two trophic levels, it did not affect development or emergence of parasitoids. As the parasitoid L. fabarum does not seem to be affected by the Virus, we discuss the possibility of using it for the development of targeted biological control against aphids.