The Experts below are selected from a list of 618 Experts worldwide ranked by ideXlab platform

Pierre-yves Teycheney - One of the best experts on this subject based on the ideXlab platform.

  • Viruses for breakfast, lunch and dinner
    2020
    Co-Authors: Andrew D Geering, Nathalie Choisne, Simone Scalabrin, Hadi Quesneville, Silvia Vezzulli, R. Velasco, Pierre-yves Teycheney
    Abstract:

    Endogenous sequences from members of the Caulimoviridae and Geminiviridae have been identified in the genome of several plant species. These sequences are thought to result from illegitimate recombination events and are generally replication-defective. However, some endogenous caulimovirid sequences in tobacco, petunia and banana are capable of causing infection. We have performed in silico analyses on nucleotide sequences from plant genome databases and reconstituted twelve full length and potentially replication-competent viral genomes from endogenous viral sequences embedded in the genomes of monocotyledonous and dicotyledonous plant species of the Brassicaceae, Euphorbiaceae, Fabaceae, Myrtaceae, Poaceae, Rutaceae, Salicaceae and Vitaceae. Sequence analyses show that the corresponding viruses belong to a new genus in the family Caulimoviridae, tentatively named Dionyvirus. Maps showing the distribution of the endogenous dionyviral sequences in the genomes of Vitis vinifera, Prunus persica and Oryza sativa have been produced and copy numbers determined. Dionyvirus-specific primers were designed and used for a PCR-based large scale screening of plant germplasm, which demonstrated that that the endogenous dionyviral sequences are widespread among plants of temperate, tropical and subarctic origins. The potential contributions of endogenous viral sequences to normal plant functions and to plant and virus evolution will be discussed. (Resume d'auteur)

  • Endogenous caulimovirid sequences are widespread in plant genomes
    2020
    Co-Authors: Andrew D Geering, Nathalie Choisne, Hadi Quesneville, Silvia Vezzulli, R. Velasco, Tanya Sharahskin, Pierre-yves Teycheney
    Abstract:

    Endogenous sequences from members of the Caulimoviridae and Geminiviridae families have been identified in the genome of several plant species. They are thought to result from illegitimate recombination events and are generally replication-defective. However, some caulimovirid sequences of tobacco, petunia and banana are capable of causing infection. We performed in silico analyses on nucleotide sequences from plant genome databases and reconstituted 11 full length and potentially infectious viral genomes from endogenous viral sequences embedded in the genomes of monocotyledonous and dicotyledonous Brassicaceae, Euphorbiacae, Fabacae, Myrtaceae, Poaceae, Rutaceae, Saliaceae and Vitaceae plant species. Sequence comparisons show that the corresponding viruses belong to a new genus in the family Caulimoviridae, tentatively named Dionyvirus. Mapping of endogenous Dionyvirus sequences was achieved in two fully sequenced grape genomes, allowing for the first time the study of the distribution pattern of endogenous viral sequences at the host plant genome scale. Dionyvirus-specific primers were designed and used for a PCR-based large scale screening of plant germplasm. It showed that endogenous Dionyvirus sequences are widespread among plants of temperate, tropical and arctic origins, and belong to distinct viral species. Endogenous Dionyvirus sequences belonging to distinct viral species were also identified in single host plants, showing that endogenization of viral sequences is a common phenomenon in plants. Our work shed new lights on plant/virus molecular interactions. The potential contributions of endogenous viral sequences to normal plant functions and to plant and virus evolution will be discussed. (Texte integral)

  • Endogenous florendoviral elements are major components of plant genomes and molecular fossils of reverse-transcribing viruses with unique : O23.015
    2020
    Co-Authors: Andrew D Geering, Florian Maumus, Nathalie Choisne, Matthias Zytnicki, Alistair Mc R Taggart, Simone Scalabrin, Hadi Quesneville, Pierre-yves Teycheney
    Abstract:

    We have discovered a new genus of endogenous Caulimoviridae, for which we propose the name Florendovirus, and found that endogenous florendoviral elements (EFEs) are common in most flowering plants including members of the Monocotyledoneae, the Eudicotyledonae and the so-called ANITA grade angiosperms. The identification of EFEs in Amborella trichopoda, an ancient endemic species of New Caledonia, suggests a minimum age of 85 million years for the florendoviruses based on the timing of separation of this Pacific island from the Australian landmass. In Ricinus communis, Jatropha curcas, Vitis vinifera and Citrus clementina, EFEs constitute more than 0.5% of the total nuclear genome content, which is a level of abundance that is comparable to that of high copy number transposable elements. In V. vinifera, c. 9% of the EFEs are located within host gene introns and when combined with the detection of EFE-derived small RNAs, suggests a role in plant metabolism by modifying gene expression. Molecular evidence suggests that some EFEs could be replication competent and potentially infectious. By analyzing reconstructed florendovirus genomes, we demonstrate that the florendoviruses are most closely related to but distinct from Petunia vein clearing virus based on the presence of a second open reading frame. Some of the ancestral viruses appeared to have had a bipartite genome organization, a feature that has never been observed before for any viral retroelement and that provides insights into the evolution of the Caulimoviridae. (Resume d'auteur)

  • Endogenous Dionyvirus sequences are widespread in plant genomes
    2020
    Co-Authors: Andrew D Geering, Nathalie Choisne, Matthias Zytnicki, Simone Scalabrin, Hadi Quesneville, Silvia Vezzulli, R. Velasco, Pierre-yves Teycheney
    Abstract:

    Endogenous sequences from members of the Caulimoviridae and Geminiviridae families have been identified in the genome of several plant species [1, 2]. They are thought to result from illegitimate recombination events and are generally replication-defective. However, some caulimovirid sequences of tobacco, petunia and banana are capable of causing infection. We performed in silico analyses on nucleotide sequences from plant genome databases and reconstituted 11 full length and potentially infectious viral genomes from endogenous viral sequences embedded in the genomes of monocotyledonous and dicotyledonous plant species. Sequence comparisons show that the corresponding viruses belong to a new genus in the family Caulimoviridae, tentatively named Dionyvirus. Mapping of endogenous Dionyvirus sequences was achieved in the fully sequenced genomes of grape, poplar, peach and rice, allowing for the first time the study of the distribution pattern of endogenous viral sequences at the host plant genome scale. Using the TEannot pipeline from the REPET package [3], we sensitively detected virus fragments and were able to join them to recover fragmented virus sequences. Full length and partial virus sequences were found in all four genomes, evenly distributed along chromosomes; they appear to be repeated throughout the whole genome. Allelic variations of endogenous Dionyvirus sequences were also characterized in grape, using the complete sequences of a near-homozygous line and a highly heterozygous genotype, PN40024 and Pinot Noir clone ENTAV115 respectively. Dionyvirus-specific primers were designed and used for a PCR-based large scale screening of plant germplasm. It showed that endogenous Dionyvirus sequences belonging to distinct viral species are widespread among plants of temperate, tropical and arctic origins, and that endogenization of viral sequences is therefore a common phenomenon in plants. siRNAs homologous to endogenous Dionyvirus species were identified in grape, peach, soybean and orange, providing evidence that the expression of such endogenous sequences is tightly regulated and/or might trigger RNAi-based antiviral defence. (Texte integral)

  • Endogenous viral sequences in plant genomes
    2020
    Co-Authors: Pierre-yves Teycheney, Andrew D W Geering
    Abstract:

    Endogenous viral sequences from members of two virus families, the Caulimoviridae and Geminiviridae, have been discovered in several monocotyledonous and dicotyledonous plant species. For the most part, these sequences are replication-defective but those capable of causing infection have been discovered in tobacco (Nicotiana edwardsonii), petunia (Petunia hybrida) and banana and plantain (Musa spp.). Activation of endogenous caulimovirid sequences is one of the major impediments to international banana and plantain breeding efforts. Research on endogenous viral sequences in plants is still in its infancy, with little known about the contributions of these sequences to host and virus evolution, nor even a classification system adopted. On a practical note, problems still exist with differentially detecting viral genomic DNA in a host genetic background containing endogenous viral sequences, and a solution to the problem of activation of endogenous viral sequences in banana is still far away. In this review, answers to some of these questions are sought by drawing on research from the related fields of endogenous retroviruses in animals and LTR-retrotransposons in eukaryotes in general.

Thomas Hohn - One of the best experts on this subject based on the ideXlab platform.

  • Badnaviruses: The Current Global Scenario
    Viruses, 2016
    Co-Authors: Alangar Ishwara Bhat, Thomas Hohn, R. Selvarajan
    Abstract:

    Badnaviruses (Family: Caulimoviridae; Genus: Badnavirus) are non-enveloped bacilliform DNA viruses with a monopartite genome containing about 7.2 to 9.2 kb of dsDNA with three to seven open reading frames. They are transmitted by mealybugs and a few species by aphids in a semi-persistent manner. They are one of the most important plant virus groups and have emerged as serious pathogens affecting the cultivation of several horticultural crops in the tropics, especially banana, black pepper, cocoa, citrus, sugarcane, taro, and yam. Some badnaviruses are also known as endogenous viruses integrated into their host genomes and a few such endogenous viruses can be awakened, e.g., through abiotic stress, giving rise to infective episomal forms. The presence of endogenous badnaviruses poses a new challenge for the fool-proof diagnosis, taxonomy, and management of the diseases. The present review aims to highlight emerging disease problems, virus characteristics, transmission, and diagnosis of badnaviruses.

  • Plant pararetroviruses : replication and expression
    Current Opinion in Virology, 2013
    Co-Authors: Thomas Hohn, Helen M. Rothnie
    Abstract:

    True retroviruses are not known in plants; however, plant pararetroviruses (Caulimoviridae) share many retroviral properties, replicating by transcription in the nucleus followed by reverse transcription in the cytoplasm. Pararetroviruses have circular DNA genomes that do not integrate into the host genome, and display several unique expression strategies. Typical of plant pararetroviral pregenomic RNA is a highly structured leader of about 600nt long that is bypassed by scanning ribosomes. Caulimoviruses and Soymoviruses have a further interesting translation mechanism: at least six of the seven open reading frames are translated via polycistronic translation mediated by a specific transactivator (TAV), which modifies the translation complex. TAV also forms large intracellular inclusion bodies, which are the site of translation and virus assembly.

  • characterization of cestrum yellow leaf curling virus a new member of the family Caulimoviridae
    Journal of General Virology, 2003
    Co-Authors: Livia Stavolone, A Ragozzino, Thomas Hohn
    Abstract:

    Cestrum yellow leaf curling virus (CmYLCV) has been characterized as the aetiological agent of the Cestrum parqui mosaic disease. The virus genome was cloned and the clone was proven to be infectious to C. parqui. The presence of typical viroplasms in virus-infected plant tissue and the information obtained from the complete genomic sequence confirmed CmYLCV as a member of the Caulimoviridae family. All characteristic domains conserved in plant pararetroviruses were found in CmYLCV. Its genome is 8253 bp long and contains seven open reading frames (ORFs). Phylogenetic analysis of the relationships with other members of the Caulimoviridae revealed that CmYLCV is closely related to the Soybean chlorotic mottle virus (SbCMV)-like genus and particularly to SbCMV. However, in contrast to the other members of this genus, the primer-binding site is located in the intercistronic region following ORF Ib rather than within this ORF, and an ORF corresponding to ORF VII is missing.

  • Cestrum yellow leaf curling virus (CmYLCV) promoter: a new strong constitutive promoter for heterologous gene expression in a wide variety of crops
    Plant Molecular Biology, 2003
    Co-Authors: Livia Stavolone, Maria Kononova, Sandra Pauli, Antonio Ragozzino, Peter De Haan, Steve Milligan, Kay Lawton, Thomas Hohn
    Abstract:

    Appropriately regulated gene expression requires a suitable promoter. A number of promoters have been isolated and shown to be functional in plants, but only a few of them activate transcription of transgenes at high levels constitutively. We report here the cloning and characterization of a novel, constitutively expressed promoter isolated from Cestrum yellow leaf curling virus (CmYLCV), a double-stranded DNA plant pararetrovirus belonging to the Caulimoviridae family. The CmYLCV promoter is highly active in callus, meristems and vegetative and reproductive tissues in Arabidopsis thaliana, Nicotiana tabacum, Lycopersicon esculentum,Zea mays and Oryza sativa. Furthermore, the level of expression is comparable to, or higher than, that from the CaMV 35S, the `super-promoter' or the maize ubiquitin 1 promoters, three frequently used promoters in agricultural biotechnology. The heritable, strong and constitutive activity in both monocotyledonous and dicotyledonous plants, combined with the extremely narrow CmYLCV host range, makes the CmYLCV promoter an attractive tool for regulating transgene expression in a wide variety of plant species.

  • short communication characterization of cestrum yellow leaf curling virus a new member of the family Caulimoviridae
    2003
    Co-Authors: Livia Stavolone, A Ragozzino, Thomas Hohn
    Abstract:

    Cestrum yellow leaf curling virus (CmYLCV) has been characterized as the aetiological agent of the Cestrum parqui mosaic disease. The virus genome was cloned and the clone was proven to be infectious to C. parqui. The presence of typical viroplasms in virus-infected plant tissue and the information obtained from the complete genomic sequence confirmed CmYLCV as a member oftheCaulimoviridaefamily.All characteristic domains conserved inplantpararetroviruses were found in CmYLCV. Its genome is 8253 bp long and contains seven open reading frames (ORFs). Phylogenetic analysis of the relationships with other members of the Caulimoviridae revealed that CmYLCV is closely related to the Soybean chlorotic mottle virus (SbCMV)-like genus and particularly to SbCMV. However, in contrast to the other members of this genus, the primer-binding site is located in the intercistronic region following ORF Ib rather than within this ORF, and an ORF corresponding to ORF VII is missing.

Andrew D W Geering - One of the best experts on this subject based on the ideXlab platform.

  • Endogenous viral sequences in plant genomes
    2020
    Co-Authors: Pierre-yves Teycheney, Andrew D W Geering
    Abstract:

    Endogenous viral sequences from members of two virus families, the Caulimoviridae and Geminiviridae, have been discovered in several monocotyledonous and dicotyledonous plant species. For the most part, these sequences are replication-defective but those capable of causing infection have been discovered in tobacco (Nicotiana edwardsonii), petunia (Petunia hybrida) and banana and plantain (Musa spp.). Activation of endogenous caulimovirid sequences is one of the major impediments to international banana and plantain breeding efforts. Research on endogenous viral sequences in plants is still in its infancy, with little known about the contributions of these sequences to host and virus evolution, nor even a classification system adopted. On a practical note, problems still exist with differentially detecting viral genomic DNA in a host genetic background containing endogenous viral sequences, and a solution to the problem of activation of endogenous viral sequences in banana is still far away. In this review, answers to some of these questions are sought by drawing on research from the related fields of endogenous retroviruses in animals and LTR-retrotransposons in eukaryotes in general.

  • Exploring the role of Florendovirus in plant biology
    2019
    Co-Authors: Saad Serfraz, Andrew D W Geering, Florian Maumus, V. Sharma, Pierre-yves Teycheney
    Abstract:

    Endogenous viral elements (EVEs) are viral sequences that were captured in the genomes of their hosts through active or passive horizontal gene transfer (HGT). In plants, most characterized EVEs originate from viruses in the family Caulimoviridae. EVEs from a yet unknown genus in the family Caulimoviridae were discovered recently and found to be distributed widely in almost all tracheophytes spanning ferns, gymnosperms and angiosperms. This new genus was named Florendovirus and there is so far no evidence that any of its member still exists under an infectious form. The potential role of florendovirus EVEs in plant biology was investigated using a transcriptomic-based approach. A systematic search for transcripts containing florendovirus coat protein, movement protein, reverse transcriptase or RNAse H domain and host plant domains was performed on a total of 973 assembled transcriptomes originating from algae, ferns, club mosses, gymnosperms, monocots and dicots, using an annotation pipeline based on tblastx. Fused transcripts containing viral and host plant domains were found in 390 plant species, providing evidence that florendovirus genes are co-transcribed with host genes, including several genes involved in plant defense mechanisms. The results of these analyses will be presented and their implication on our understanding of the roles of florendovirus in plant.

  • Caulimoviridae plant pararetroviruses
    eLS, 2019
    Co-Authors: Andrew D W Geering
    Abstract:

    Family Caulimoviridae comprises seven genera of plant viruses whose members replicate by reverse transcription and whose virions contain double-stranded deoxyribonucleic acid. In a recent survey of the international scientific community, Cauliflower mosaic virus (CaMV), the type species of the family, was ranked sixth in the world in a list of the most scientifically or economically important plant viruses. This notoriety is due purely to the major conceptual advances that have been made in plant virology using CaMV as a model pathogen. However, several relatively lesser known viruses in the family, such as Rice tungro bacilliform virus and Cacao swollen shoot virus, are very serious constraints to crop production in tropical regions of the world. In this article, information on the taxonomy, replication cycle, vector transmission, epidemiology and disease management of this important group of plant viruses is summarised. Key Concepts: The Caulimoviridae is the only family of plant viruses with a double-stranded deoxyribonucleic acid (dsDNA) genome, and in common with all viral retroelements, incorporates a reverse transcription step in the replication cycle. Cauliflower mosaic virus is the type species of the family, and has been a very important model plant virus for elucidating fundamental aspects of virus replication, cell-to-cell movement and aphid transmission. Members of the Caulimoviridae are most prominent in tropical regions, where they cause serious diseases such as rice tungro, cacao swollen shoot and banana streak disease. The most important component of a control programme for these viruses is to reduced inoculum levels by using clean planting material, avoiding overlapping crops, and removing diseased plants and alternative hosts of the virus. In some host species, infection can arise as a consequence of activation of viral DNA that is integrated in the nuclear genome of the plant. Keywords: plant viruses; retroelement; pararetrovirus; reverse transcription; cauliflower mosaic virus; rice tungro; cacao swollen shoot; tropical crop

  • tracheophyte genomes keep track of the deep evolution of the Caulimoviridae
    Scientific Reports, 2018
    Co-Authors: Seydina Issa Diop, Andrew D W Geering, Pierre-yves Teycheney, Francoise Alfamadepauw, Mikael Loaec, Florian Maumus
    Abstract:

    Endogenous viral elements (EVEs) are viral sequences that are integrated in the nuclear genomes of their hosts and are signatures of viral infections that may have occurred millions of years ago. The study of EVEs, coined paleovirology, provides important insights into virus evolution. The Caulimoviridae is the most common group of EVEs in plants, although their presence has often been overlooked in plant genome studies. We have refined methods for the identification of caulimovirid EVEs and interrogated the genomes of a broad diversity of plant taxa, from algae to advanced flowering plants. Evidence is provided that almost every vascular plant (tracheophyte), including the most primitive taxa (clubmosses, ferns and gymnosperms) contains caulimovirid EVEs, many of which represent previously unrecognized evolutionary branches. In angiosperms, EVEs from at least one and as many as five different caulimovirid genera were frequently detected, and florendoviruses were the most widely distributed, followed by petuviruses. From the analysis of the distribution of different caulimovirid genera within different plant species, we propose a working evolutionary scenario in which this family of viruses emerged at latest during Devonian era (approx. 320 million years ago) followed by vertical transmission and by several cross-division host swaps.

  • tracheophyte genomes keep track of the deep evolution of the Caulimoviridae
    bioRxiv, 2017
    Co-Authors: Seydina Issa Diop, Andrew D W Geering, Pierre-yves Teycheney, Francoise Alfamadepauw, Mikael Loaec, Florian Maumus
    Abstract:

    Endogenous viral elements (EVEs) are viral sequences that are integrated in the nuclear genomes of their hosts and are signatures of viral infections that may have occurred millions of years ago. The study of EVEs, coined paleovirology, provides important insights into virus evolution. The Caulimoviridae is the most common group of EVEs in plants, although their presence has often been overlooked in plant genome studies due to misidentification by automatic annotation programs. We have refined methods for the identification of caulimovirid EVEs and interrogated the genomes of a broad diversity of plant taxa, from algae to advanced flowering plants. Evidence is provided that almost every vascular plant (tracheophyte), including the most primitive taxa (clubmosses, ferns and gymnosperms) contains caulimovirid EVEs, many of which represent previously unrecognized evolutionary branches. In angiosperms, EVEs from at least two and as many as five different caulimovirid genera were frequently detected and florendoviruses were the most widely distributed, followed by petuviruses. For reasons that are unknown, citrus and castor bean contained particularly high densities of caulimovirid EVEs, about 10 times higher than the average across all seed plants. From the analysis of the distribution of different caulimovirid genera within different plant species, we propose a working evolutionary scenario in which this family of viruses has emerged during the Silurian era (approx. 420 million years ago) when land plants first emerged.

Livia Stavolone - One of the best experts on this subject based on the ideXlab platform.

  • Caulimoviridae tubule guided transport is dictated by movement protein properties
    Journal of Virology, 2010
    Co-Authors: J A Sancheznavarro, T V M Fajardo, Stefania Zicca, Vicente Pallas, Livia Stavolone
    Abstract:

    Plant viruses move through plasmodesmata (PD) either as nucleoprotein complexes (NPCs) or as tubule-guided encapsidated particles with the help of movement proteins (MPs). To explore how and why MPs specialize in one mechanism or the other, we tested the exchangeability of MPs encoded by DNA and RNA virus genomes by means of an engineered alfalfa mosaic virus (AMV) system. We show that Caulimoviridae (DNA genome virus) MPs are competent for RNA virus particle transport but are unable to mediate NPC movement, and we discuss this restriction in terms of the evolution of DNA virus MPs as a means of mediating DNA viral genome entry into the RNA-trafficking PD pathway.

  • characterization of cestrum yellow leaf curling virus a new member of the family Caulimoviridae
    Journal of General Virology, 2003
    Co-Authors: Livia Stavolone, A Ragozzino, Thomas Hohn
    Abstract:

    Cestrum yellow leaf curling virus (CmYLCV) has been characterized as the aetiological agent of the Cestrum parqui mosaic disease. The virus genome was cloned and the clone was proven to be infectious to C. parqui. The presence of typical viroplasms in virus-infected plant tissue and the information obtained from the complete genomic sequence confirmed CmYLCV as a member of the Caulimoviridae family. All characteristic domains conserved in plant pararetroviruses were found in CmYLCV. Its genome is 8253 bp long and contains seven open reading frames (ORFs). Phylogenetic analysis of the relationships with other members of the Caulimoviridae revealed that CmYLCV is closely related to the Soybean chlorotic mottle virus (SbCMV)-like genus and particularly to SbCMV. However, in contrast to the other members of this genus, the primer-binding site is located in the intercistronic region following ORF Ib rather than within this ORF, and an ORF corresponding to ORF VII is missing.

  • Cestrum yellow leaf curling virus (CmYLCV) promoter: a new strong constitutive promoter for heterologous gene expression in a wide variety of crops
    Plant Molecular Biology, 2003
    Co-Authors: Livia Stavolone, Maria Kononova, Sandra Pauli, Antonio Ragozzino, Peter De Haan, Steve Milligan, Kay Lawton, Thomas Hohn
    Abstract:

    Appropriately regulated gene expression requires a suitable promoter. A number of promoters have been isolated and shown to be functional in plants, but only a few of them activate transcription of transgenes at high levels constitutively. We report here the cloning and characterization of a novel, constitutively expressed promoter isolated from Cestrum yellow leaf curling virus (CmYLCV), a double-stranded DNA plant pararetrovirus belonging to the Caulimoviridae family. The CmYLCV promoter is highly active in callus, meristems and vegetative and reproductive tissues in Arabidopsis thaliana, Nicotiana tabacum, Lycopersicon esculentum,Zea mays and Oryza sativa. Furthermore, the level of expression is comparable to, or higher than, that from the CaMV 35S, the `super-promoter' or the maize ubiquitin 1 promoters, three frequently used promoters in agricultural biotechnology. The heritable, strong and constitutive activity in both monocotyledonous and dicotyledonous plants, combined with the extremely narrow CmYLCV host range, makes the CmYLCV promoter an attractive tool for regulating transgene expression in a wide variety of plant species.

  • short communication characterization of cestrum yellow leaf curling virus a new member of the family Caulimoviridae
    2003
    Co-Authors: Livia Stavolone, A Ragozzino, Thomas Hohn
    Abstract:

    Cestrum yellow leaf curling virus (CmYLCV) has been characterized as the aetiological agent of the Cestrum parqui mosaic disease. The virus genome was cloned and the clone was proven to be infectious to C. parqui. The presence of typical viroplasms in virus-infected plant tissue and the information obtained from the complete genomic sequence confirmed CmYLCV as a member oftheCaulimoviridaefamily.All characteristic domains conserved inplantpararetroviruses were found in CmYLCV. Its genome is 8253 bp long and contains seven open reading frames (ORFs). Phylogenetic analysis of the relationships with other members of the Caulimoviridae revealed that CmYLCV is closely related to the Soybean chlorotic mottle virus (SbCMV)-like genus and particularly to SbCMV. However, in contrast to the other members of this genus, the primer-binding site is located in the intercistronic region following ORF Ib rather than within this ORF, and an ORF corresponding to ORF VII is missing.

  • Tetramerization is a conserved feature of the virion-associated protein in plant pararetroviruses.
    Journal of Virology, 2001
    Co-Authors: Livia Stavolone, Etienne Herzog, Denis Leclerc, Thomas Hohn
    Abstract:

    All plant pararetroviruses belong to the Caulimoviridae family. This family contains six genera of viruses with different biological, serological, and molecular characteristics. Although some important mechanisms of viral replication and host infection are understood, much remains to be discovered about the many functions of the viral proteins. The focus of this study, the virion-associated protein (VAP), is conserved among all members of the group and contains a coiled-coil structure that has been shown to assemble as a tetramer in the case of cauliflower mosaic virus. We have used the yeast two-hybrid system to characterize self-association of the VAPs of four distinct plant pararetroviruses, each belonging to a different genus of Caulimoviridae. Chemical cross-linking confirmed that VAPs assemble into tetramers. Tetramerization is thus a common property of these proteins in plant pararetroviruses. The possible implications of this conserved feature for VAP function are discussed.

Indranil Dasgupta - One of the best experts on this subject based on the ideXlab platform.

  • Characteristics of Tungrovirus Occurring in India
    A Century of Plant Virology in India, 2017
    Co-Authors: Shweta Sharma, Gaurav Kumar, Satyendra Mangrauthia, C. N. Neeraja, D. Krishnaveni, Indranil Dasgupta
    Abstract:

    The research on rice tungro bacilliform virus, the only species in the genus Tungrovirus (family Caulimoviridae), has a long history in India because of the association of the virus with rice tungro disease, an important rice disease prevalent in the eastern coastal rice growing regions. This research encompasses the transmission characteristics of the vector, characterization of strains, resistance sources, molecular properties of the virus, transgenic resistance and the use of virus-derived gene vector for plant biotechnology. This chapter gives a glimpse of the above research conducted to characterise the RTBV isolates occurring in India.

  • Bacilliform DNA‐containing plant viruses in the tropics: commonalities within a genetically diverse group
    Molecular Plant Pathology, 2013
    Co-Authors: Basanta K. Borah, Shweta Sharma, Ravi Kant, A. M. Anthony Johnson, Divi Venkata Ramana Saigopal, Indranil Dasgupta
    Abstract:

    Summary Plant viruses, possessing a bacilliform shape and containing double-stranded DNA, are emerging as important pathogens in a number of agricultural and horticultural crops in the tropics. They have been reported from a large number of countries in African and Asian continents, as well as from islands from the Pacific region. The viruses, belonging to two genera, Badnavirus and Tungrovirus, within the family Caulimoviridae, have genomes displaying a common plan, yet are highly variable, sometimes even between isolates of the same virus. In this article, we summarize the current knowledge with a view to revealing the common features embedded within the genetic diversity of this group of viruses. Taxonomy Virus; order Unassigned; family Caulimoviridae; genera Badnavirus and Tungrovirus; species Banana streak viruses, Bougainvillea spectabilis chlorotic vein banding virus, Cacao swollen shoot virus, Citrus yellow mosaic badnavirus, Dioscorea bacilliform viruses, Rice tungro bacilliform virus, Sugarcane bacilliform viruses and Taro bacilliform virus. Microbiological properties Bacilliform in shape; length, 60–900 nm; width, 35–50 nm; circular double-stranded DNA of approximately 7.5 kbp with one or more single-stranded discontinuities. Host range Each virus generally limited to its own host, including banana, bougainvillea, black pepper, cacao, citrus species, Dioscorea alata, rice, sugarcane and taro. Disease symptoms Foliar streaking in banana and sugarcane, swelling of shoots in cacao, yellow mosaic in leaves and stems in citrus, brown spot in the tubers in yam and yellow–orange discoloration and stunting in rice. Useful websites http://www.dpvweb.net.

  • Analysis of full-length sequences of two Citrus yellow mosaic badnavirus isolates infecting Citrus jambhiri (Rough Lemon) and Citrus sinensis L. Osbeck (Sweet Orange) from a nursery in India.
    Virus Genes, 2012
    Co-Authors: A. M. Anthony Johnson, Basanta K. Borah, D. V. R. Sai Gopal, Indranil Dasgupta
    Abstract:

    Citrus yellow mosaic badna virus (CMBV), a member of the Family Caulimoviridae, Genus Badnavirus is the causative agent of mosaic disease among Citrus species in southern India. Despite its reported prevalence in several citrus species, complete information on clear functional genomics or functional information of full-length genomes from all the CMBV isolates infecting citrus species are not available in publicly accessible databases. CMBV isolates from Rough Lemon and Sweet Orange collected from a nursery were cloned and sequenced. The analysis revealed high sequence homology of the two CMBV isolates with previously reported CMBV sequences implying that they represent new variants. Based on computational analysis of the predicted secondary structures, the possible functions of some CMBV proteins have been analyzed.

  • Sequencing and computational analysis of complete genome sequences of Citrus yellow mosaic badna virus from acid lime and pummelo
    Virus Genes, 2009
    Co-Authors: Basanta K. Borah, A. M. Anthony Johnson, D. V. R. Sai Gopal, Indranil Dasgupta
    Abstract:

    Citrus yellow mosaic badna virus (CMBV), a member of the Family Caulimoviridae, Genus Badnavirus , is the causative agent of Citrus mosaic disease in India. Although the virus has been detected in several citrus species, only two full-length genomes, one each from Sweet orange and Rangpur lime, are available in publicly accessible databases. In order to obtain a better understanding of the genetic variability of the virus in other citrus mosaic-affected citrus species, we performed the cloning and sequence analysis of complete genomes of CMBV from two additional citrus species, Acid lime and Pummelo. We show that CMBV genomes from the two hosts share high homology with previously reported CMBV sequences and hence conclude that the new isolates represent variants of the virus present in these species. Based on in silico sequence analysis, we predict the possible function of the protein encoded by one of the five ORFs.