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Arvind Varsani - One of the best experts on this subject based on the ideXlab platform.
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discovery of the first maize infecting mastrevirus in the americas using a vector enabled metagenomics approach
2018Co-Authors: D M T Alvesfreitas, Pedro Italo Tanno Silva, Josemar Foresti, Paulo R Silva, Marcio Tadeu Godinho, Rinaldo S. Fontenele, Arvind Varsani, S G RibeiroAbstract:The genus Mastrevirus (family Geminiviridae) is composed of single-stranded DNA viruses that infect mono- and dicotyledonous plants and are transmitted by leafhoppers. In South America, there have been only two previous reports of mastreviruses, both identified in sweet potatoes (from Peru and Uruguay). As part of a general viral surveillance program, we used a vector-enabled metagenomics (VEM) approach and sampled leafhoppers (Dalbulus maidis) in Itumbiara (State of Goias), Brazil. High-throughput sequencing of viral DNA purified from the leafhopper sample revealed mastrevirus-like contigs. Using a set of abutting primers, a 2746-nt circular genome was recovered. The circular genome has a typical mastrevirus genome organization and shares 99% pairwise identity with the one from the leafhopper. This is the first report of a maize-infecting mastrevirus in the Americas, the first identified in a non-vegetatively propagated mastrevirus host in South America, and the first mastrevirus to be identified in Brazil.
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ICTV Virus Taxonomy Profile: Geminiviridae
2017Co-Authors: F. Murilo Zerbini, Ali M. Idris, Darren P. Martin, Philippe Roumagnac, Rafael F. Rivera-bustamante, Enrique Moriones, Jesús Navas-castillo, Arvind VarsaniAbstract:The geminiviruses are a family of small, non-enveloped viruses with single-stranded, circular DNA genomes of 2500–5200 bases. Geminiviruses are transmitted by various types of insect (whiteflies, leafhoppers, treehoppers and aphids). Members of the genus Begomovirus are transmitted by whiteflies, those in the genera Becurtovirus, Curtovirus, Grablovirus, Mastrevirus and Turncurtovirus are transmitted by specific leafhoppers, the single member of the genus Topocuvirus is transmitted by a treehopper and one member of the genus Capulavirus is transmitted by an aphid. Geminiviruses are plant pathogens causing economically important diseases in most tropical and subtropical regions of the world. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Geminiviridae which is available at www.ictv.global/report/Geminiviridae.
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Capulavirus and Grablovirus: two new genera in the family Geminiviridae.
2017Co-Authors: Arvind Varsani, Philippe Roumagnac, Rafael F. Rivera-bustamante, Enrique Moriones, Jesús Navas-castillo, Marc Fuchs, Ali Idris, F Murilo Zerbini, Darren P. MartinAbstract:Geminiviruses are plant-infecting single-stranded DNA viruses that occur in most parts of the world. Currently, there are seven genera within the family Geminiviridae (Becurtovirus, Begomovirus, Curtovirus, Eragrovirus, Mastrevirus, Topocuvirus and Turncurtovirus). The rate of discovery of new geminiviruses has increased significantly over the last decade as a result of new molecular tools and approaches (rolling-circle amplification and deep sequencing) that allow for high-throughput workflows. Here, we report the establishment of two new genera: Capulavirus, with four new species (Alfalfa leaf curl virus, Euphorbia caput-medusae latent virus, French bean severe leaf curl virus and Plantago lanceolata latent virus), and Grablovirus, with one new species (Grapevine red blotch virus). The aphid species Aphis craccivora has been shown to be a vector for Alfalfa leaf curl virus, and the treehopper species Spissistilus festinus is the likely vector of Grapevine red blotch virus. In addition, two highly divergent groups of viruses found infecting citrus and mulberry plants have been assigned to the new species Citrus chlorotic dwarf associated virus and Mulberry mosaic dwarf associated virus, respectively. These species have been left unassigned to a genus by the ICTV because their particle morphology and insect vectors are unknown.
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okra enation leaf curl virus in papaya from iran displaying severe leaf curl symptoms
2016Co-Authors: K Bananej, Simona Kraberger, Arvind VarsaniAbstract:During a survey of the Bahoo-Kalat and Zar-Abad areas of Iran in February 2010, papaya plants were found with severe leaf curling and vein swelling. A begomovirus (family Geminiviridae) was suspected of being responsible for the disease, so begomovirus-specific degenerate primers and PCR on total DNA were used to obtain amplicons. Based on the sequence of these amplicons, abutting primers were designed to recover the complete begomovirus from seven PCR positive papaya plants. Seven distinct begomovirus molecules (2746 nt each) were recovered that share 85.5-91.6% genome-wide sequence identity with Okra enation leaf curl virus (OELCuV) isolates. Phylogenetic analyses with available OELCuV sequences support the identification of the papaya-infecting begomovirus from Iran as an isolate of OELCuV. To our knowledge this is the first report of a begomovirus infecting papaya in Iran and the first record of papaya as host of OELCuV.
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establishment of three new genera in the family Geminiviridae becurtovirus eragrovirus and turncurtovirus
2014Co-Authors: Jesus Navascastillo, Murilo F Zerbini, Judith K. Brown, Arvind Varsani, Enrique Moriones, Cecilia Hernandezzepeda, A M Idris, Darren P. MartinAbstract:The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.
Judith K. Brown - One of the best experts on this subject based on the ideXlab platform.
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first report of okra enation leaf curl virus and associated cotton leaf curl multan betasatellite and cotton leaf curl multan alphasatellite infecting cotton in pakistan a new member of the cotton leaf curl disease complex
2014Co-Authors: Usman Hameed, Muhammad Saleem Haider, Muhammad Ziaurrehman, Hans Werner Herrmann, Judith K. BrownAbstract:Cotton (Gossypium hirsutum L.) is an important and widely cultivated crop in Pakistan, upon which many rely for economic security. Cotton leaf curl disease (CLCuD) is caused by a complex comprising of more than eight species in the genus Begomovirus (family Geminiviridae) with associated betasatellite and alphasatellites. During 2011, characteristic symptoms of leaf curl disease were widespread (>40%), and the whitefly Bemisia tabaci (Genn.) vector of the leaf curl complex was abundant in commercial cotton fields in Burewala, Pakistan. Symptoms included vein thickening, upward or downward leaf curling, and foliar enations. To test for the presence of a begomovirus(es), total DNA was extracted from 100 mg of symptomatic leaf tissues from five different plants (isolates CLCuDBur1 to 5) using the CTAB method (1). Total DNA extracts were used for rolling circle amplification (RCA) using TempliPhi DNA Amplification Kit (GE Healthcare). Of the five field isolates, the RCA product for only one, CLCuDBur3, digest...
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establishment of three new genera in the family Geminiviridae becurtovirus eragrovirus and turncurtovirus
2014Co-Authors: Jesus Navascastillo, Murilo F Zerbini, Judith K. Brown, Arvind Varsani, Enrique Moriones, Cecilia Hernandezzepeda, A M Idris, Darren P. MartinAbstract:The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.
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A new, previously undescribed monopartite begomovirus infecting Premna serratifolia in Vietnam
2013Co-Authors: Xiaoman She, Judith K. BrownAbstract:The complete genome sequence of a monopartite begomovirus isolate infecting Creek Premna (Premna serratifolia L.) plants that exhibited leaf curl, vein swelling, and enation symptoms in Nha Trang, Vietnam, was cloned and sequenced. It comprises 2,753 nucleotides (JQ793786) and has a typical organization of begomoviruses DNA-A with AV1 and AV2 open reading frames (ORFs) in the viral-sense strand and AC1, AC2, AC3, AC4 and AC5 ORFs in the complementary-sense strand. The full-length genome sequence of the isolate (clone VN7) shared the highest level of nucleotide sequence identity (83 %) with the isolate IN:Pusa:Tb:10 of tobacco leaf curl Pusa virus (HQ180391). The phylogenetic relationship of VN7 to other begomoviruses was also investigated. VN7 grouped most closely with a clade containing begomoviruses from China, India and Japan. According to the current taxonomic criteria for the genus Begomovirus, family Geminiviridae, the isolate VN7 represents a new species, herein named “Premna leaf curl virus” (PrLCV).
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a genome wide pairwise identity based proposal for the classification of viruses in the genus mastrevirus family Geminiviridae
2013Co-Authors: Brejnev M Muhire, R F Riverabustamante, Jesus Navascastillo, Varagur Ganesan Malathi, Murilo F Zerbini, Judith K. Brown, Darren P. Martin, Enrique Moriones, Arvind VarsaniAbstract:Recent advances in the ease with which the genomes of small circular single-stranded DNA viruses can be amplified, cloned, and sequenced have greatly accelerated the rate at which full genome sequences of mastreviruses (family Geminiviridae, genus Mastrevirus) are being deposited in public sequence databases. Although guidelines currently exist for species-level classification of newly determined, complete mastrevirus genome sequences, these are difficult to apply to large sequence datasets and are permissive enough that, effectively, a high degree of leeway exists for the proposal of new species and strains. The lack of a standardised and rigorous method for testing whether a new genome sequence deserves such a classification is resulting in increasing numbers of questionable mastrevirus species proposals. Importantly, the recommended sequence alignment and pairwise identity calculation protocols of the current guidelines could easily be modified to make the classification of newly determined mastrevirus genome sequences significantly more objective. Here, we propose modified versions of these protocols that should substantially minimise the degree of classification inconsistency that is permissible under the current system. To facilitate the objective application of these guidelines for mastrevirus species demarcation, we additionally present a user-friendly computer program, SDT (species demarcation tool), for calculating and graphically displaying pairwise genome identity scores. We apply SDT to the 939 full genome sequences of mastreviruses that were publically available in May 2012, and based on the distribution of pairwise identity scores yielded by our protocol, we propose mastrevirus species and strain demarcation thresholds of >78 % and >94 % identity, respectively.
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introduction of the exotic monopartite tomato yellow leaf curl virus into west coast mexico
2006Co-Authors: Judith K. Brown, A M IdrisAbstract:Leaf curl symptoms that are reminiscent of begomovirus (genus Begomovirus, family Geminiviridae) infection were observed widespread in the tomato crop during the early fall 2005 through the spring 2006 growing seasons in Sinaloa State, Mexico. Symptoms were widespread in three major valleys (Culiacan, Guasave, and Los Mochis) that are largely dedicated to fresh-market tomato production for the U.S. market from October to June. Symptoms included stunting of leaves, shortened internodes, distortion of leaf margins, and green vein banding. Fruit set was reduced significantly (as much as 90%) on the portion of the plant that developed above the point of symptom expression. Tomato fields were heavily infested with the B biotype of the whitefly Bemisia tabaci (Genn.) vector and no other insect vectors were noted in the fields. Total DNA was extracted from six symptomatic tomato plants (two from each valley) and used as template to amplify, clone, and sequence the core region of the begomovirus CP. BLAST analysi...
Darren P. Martin - One of the best experts on this subject based on the ideXlab platform.
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maize streak virus Geminiviridae
2020Co-Authors: Darren P. Martin, Adérito L. MonjaneAbstract:Abstract Maize streak virus (MSV) is the type species of the genus Mastrevirus of the family Geminiviridae and the causal agent of maize streak disease (MSD), one of the most important viral diseases of maize in sub-Saharan Africa. The virus remains largely uncontrolled in most parts of the continent and in epidemic years it contributes to widespread yield losses and famine. Eleven major MSV strains have been identified so far, of which only the MSV-A strain is known to produce economically important infections in maize. Apart from maize, however, these various MSV strains infect over 80 other grass species including wheat, barley, and rye. The epidemiological complexity of MSD contrasts starkly with the genomic simplicity of MSV. The MSV genome contains two intergenic regions and only three genes. Whereas the intergenic regions are involved in replication and the regulation of gene expression, the genes encode four different proteins. Two of the proteins, Rep and RepA, are expressed from a single alternatively spliced gene and are involved in genome replication and the regulation of host and virus gene expression. The two other proteins, MP (movement protein) and CP (coat protein), are involved in systemic spread within plants and the encapsidation of viral DNA within characteristic geminate particles. Control of MSV is primarily via insecticide targeting its leafhopper vector and the use of resistant maize genotypes that have been derived through traditional breeding approaches.
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ICTV Virus Taxonomy Profile: Geminiviridae
2017Co-Authors: F. Murilo Zerbini, Ali M. Idris, Darren P. Martin, Philippe Roumagnac, Rafael F. Rivera-bustamante, Enrique Moriones, Jesús Navas-castillo, Arvind VarsaniAbstract:The geminiviruses are a family of small, non-enveloped viruses with single-stranded, circular DNA genomes of 2500–5200 bases. Geminiviruses are transmitted by various types of insect (whiteflies, leafhoppers, treehoppers and aphids). Members of the genus Begomovirus are transmitted by whiteflies, those in the genera Becurtovirus, Curtovirus, Grablovirus, Mastrevirus and Turncurtovirus are transmitted by specific leafhoppers, the single member of the genus Topocuvirus is transmitted by a treehopper and one member of the genus Capulavirus is transmitted by an aphid. Geminiviruses are plant pathogens causing economically important diseases in most tropical and subtropical regions of the world. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Geminiviridae which is available at www.ictv.global/report/Geminiviridae.
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Capulavirus and Grablovirus: two new genera in the family Geminiviridae.
2017Co-Authors: Arvind Varsani, Philippe Roumagnac, Rafael F. Rivera-bustamante, Enrique Moriones, Jesús Navas-castillo, Marc Fuchs, Ali Idris, F Murilo Zerbini, Darren P. MartinAbstract:Geminiviruses are plant-infecting single-stranded DNA viruses that occur in most parts of the world. Currently, there are seven genera within the family Geminiviridae (Becurtovirus, Begomovirus, Curtovirus, Eragrovirus, Mastrevirus, Topocuvirus and Turncurtovirus). The rate of discovery of new geminiviruses has increased significantly over the last decade as a result of new molecular tools and approaches (rolling-circle amplification and deep sequencing) that allow for high-throughput workflows. Here, we report the establishment of two new genera: Capulavirus, with four new species (Alfalfa leaf curl virus, Euphorbia caput-medusae latent virus, French bean severe leaf curl virus and Plantago lanceolata latent virus), and Grablovirus, with one new species (Grapevine red blotch virus). The aphid species Aphis craccivora has been shown to be a vector for Alfalfa leaf curl virus, and the treehopper species Spissistilus festinus is the likely vector of Grapevine red blotch virus. In addition, two highly divergent groups of viruses found infecting citrus and mulberry plants have been assigned to the new species Citrus chlorotic dwarf associated virus and Mulberry mosaic dwarf associated virus, respectively. These species have been left unassigned to a genus by the ICTV because their particle morphology and insect vectors are unknown.
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establishment of three new genera in the family Geminiviridae becurtovirus eragrovirus and turncurtovirus
2014Co-Authors: Jesus Navascastillo, Murilo F Zerbini, Judith K. Brown, Arvind Varsani, Enrique Moriones, Cecilia Hernandezzepeda, A M Idris, Darren P. MartinAbstract:The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.
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a genome wide pairwise identity based proposal for the classification of viruses in the genus mastrevirus family Geminiviridae
2013Co-Authors: Brejnev M Muhire, R F Riverabustamante, Jesus Navascastillo, Varagur Ganesan Malathi, Murilo F Zerbini, Judith K. Brown, Darren P. Martin, Enrique Moriones, Arvind VarsaniAbstract:Recent advances in the ease with which the genomes of small circular single-stranded DNA viruses can be amplified, cloned, and sequenced have greatly accelerated the rate at which full genome sequences of mastreviruses (family Geminiviridae, genus Mastrevirus) are being deposited in public sequence databases. Although guidelines currently exist for species-level classification of newly determined, complete mastrevirus genome sequences, these are difficult to apply to large sequence datasets and are permissive enough that, effectively, a high degree of leeway exists for the proposal of new species and strains. The lack of a standardised and rigorous method for testing whether a new genome sequence deserves such a classification is resulting in increasing numbers of questionable mastrevirus species proposals. Importantly, the recommended sequence alignment and pairwise identity calculation protocols of the current guidelines could easily be modified to make the classification of newly determined mastrevirus genome sequences significantly more objective. Here, we propose modified versions of these protocols that should substantially minimise the degree of classification inconsistency that is permissible under the current system. To facilitate the objective application of these guidelines for mastrevirus species demarcation, we additionally present a user-friendly computer program, SDT (species demarcation tool), for calculating and graphically displaying pairwise genome identity scores. We apply SDT to the 939 full genome sequences of mastreviruses that were publically available in May 2012, and based on the distribution of pairwise identity scores yielded by our protocol, we propose mastrevirus species and strain demarcation thresholds of >78 % and >94 % identity, respectively.
Enrique Moriones - One of the best experts on this subject based on the ideXlab platform.
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ICTV Virus Taxonomy Profile: Geminiviridae
2017Co-Authors: F. Murilo Zerbini, Ali M. Idris, Darren P. Martin, Philippe Roumagnac, Rafael F. Rivera-bustamante, Enrique Moriones, Jesús Navas-castillo, Arvind VarsaniAbstract:The geminiviruses are a family of small, non-enveloped viruses with single-stranded, circular DNA genomes of 2500–5200 bases. Geminiviruses are transmitted by various types of insect (whiteflies, leafhoppers, treehoppers and aphids). Members of the genus Begomovirus are transmitted by whiteflies, those in the genera Becurtovirus, Curtovirus, Grablovirus, Mastrevirus and Turncurtovirus are transmitted by specific leafhoppers, the single member of the genus Topocuvirus is transmitted by a treehopper and one member of the genus Capulavirus is transmitted by an aphid. Geminiviruses are plant pathogens causing economically important diseases in most tropical and subtropical regions of the world. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Geminiviridae which is available at www.ictv.global/report/Geminiviridae.
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Capulavirus and Grablovirus: two new genera in the family Geminiviridae.
2017Co-Authors: Arvind Varsani, Philippe Roumagnac, Rafael F. Rivera-bustamante, Enrique Moriones, Jesús Navas-castillo, Marc Fuchs, Ali Idris, F Murilo Zerbini, Darren P. MartinAbstract:Geminiviruses are plant-infecting single-stranded DNA viruses that occur in most parts of the world. Currently, there are seven genera within the family Geminiviridae (Becurtovirus, Begomovirus, Curtovirus, Eragrovirus, Mastrevirus, Topocuvirus and Turncurtovirus). The rate of discovery of new geminiviruses has increased significantly over the last decade as a result of new molecular tools and approaches (rolling-circle amplification and deep sequencing) that allow for high-throughput workflows. Here, we report the establishment of two new genera: Capulavirus, with four new species (Alfalfa leaf curl virus, Euphorbia caput-medusae latent virus, French bean severe leaf curl virus and Plantago lanceolata latent virus), and Grablovirus, with one new species (Grapevine red blotch virus). The aphid species Aphis craccivora has been shown to be a vector for Alfalfa leaf curl virus, and the treehopper species Spissistilus festinus is the likely vector of Grapevine red blotch virus. In addition, two highly divergent groups of viruses found infecting citrus and mulberry plants have been assigned to the new species Citrus chlorotic dwarf associated virus and Mulberry mosaic dwarf associated virus, respectively. These species have been left unassigned to a genus by the ICTV because their particle morphology and insect vectors are unknown.
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recombination as a motor of host switches and virus emergence geminiviruses as case studies
2015Co-Authors: Pierre Lefeuvre, Enrique MorionesAbstract:Genetic recombination facilitates the transfer of genetic information in a parasexual reproduction manner even between distantly related species. Within the Geminiviridae family, a group of plant-infecting viruses that severely constrain cropping systems worldwide, it is highly suspected that recombination was pivotal in the emergence as a devastating phytopathological problem. Whereas extensive evidence of recombination suggests that this mechanism might be adaptive in this family, direct demonstration remains scarce. Here we assemble lines of evidences indicating that recombination was crucial in driving host switches and further emergence of geminiviruses, making these viruses such successful plant pathogens.
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establishment of three new genera in the family Geminiviridae becurtovirus eragrovirus and turncurtovirus
2014Co-Authors: Jesus Navascastillo, Murilo F Zerbini, Judith K. Brown, Arvind Varsani, Enrique Moriones, Cecilia Hernandezzepeda, A M Idris, Darren P. MartinAbstract:The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.
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complete genome sequence of jacquemontia yellow mosaic virus a novel begomovirus from venezuela related to other new world bipartite begomoviruses infecting convolvulaceae
2014Co-Authors: Elvira Fialloolive, Enrique Moriones, Dorys T Chirinos, Francis Geraudpouey, Jesus NavascastilloAbstract:The complete genome of a bipartite begomovirus (genus Begomovirus, family Geminiviridae) infecting Jacquemontia sp. (Convolvulaceae) in Venezuela has been cloned and sequenced. Sequence comparison and phylogenetic analysis have shown that it represents an isolate of a novel species with closest relatives being two New World bipartite begomoviruses that infect Convolvulaceae, Jacquemontia mosaic Yucatan virus and Merremia mosaic virus. The DNA-As of these begomoviruses, however, share only 77.0-78.4 % nucleotide sequence identity with the DNA-A of the isolate described here, for which a recombinant origin is suggested. Based on the symptoms observed in the field, the name Jacquemontia yellow mosaic virus (JacYMV) is proposed for this novel bipartite begomovirus.
Jesus Navascastillo - One of the best experts on this subject based on the ideXlab platform.
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infectivity effects on helper viruses and whitefly transmission of the deltasatellites associated with sweepoviruses genus begomovirus family Geminiviridae
2016Co-Authors: Ishtiaq Hassan, Rob W. Briddon, Elvira Fialloolive, Anelise F Orilio, Jesus NavascastilloAbstract:Begomoviruses (family Geminiviridae) are whitefly-transmitted viruses with single-stranded DNA genomes that are frequently associated with DNA satellites. These satellites include non-coding satellites, for which the name deltasatellites has been proposed. Although the first deltasatellite was identified in the late 1990s, little is known about the effects they have on infections of their helper begomoviruses. Recently a group of deltasatellites were identified associated with sweepoviruses, a group of phylogenetically distinct begomoviruses that infect plants of the family Convolvulaceae including sweet potato. In this work, the deltasatellites associated with sweepoviruses are shown to be transreplicated and maintained in plants by the virus with which they were identified, sweet potato leaf curl virus (SPLCV). These deltasatellites were shown generally to reduce symptom severity of the virus infection by reducing virus DNA levels. Additionally they were shown to be maintained in plants, and reduce the symptoms induced by two Old World monopartite begomoviruses, tomato yellow leaf curl virus and tomato yellow leaf curl Sardinia virus. Finally one of the satellites was shown to be transmitted plant-to-plant in the presence of SPLCV by the whitefly vector of the virus, Bemisia tabaci, being the first time a deltasatellite has been shown to be insect transmitted.
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establishment of three new genera in the family Geminiviridae becurtovirus eragrovirus and turncurtovirus
2014Co-Authors: Jesus Navascastillo, Murilo F Zerbini, Judith K. Brown, Arvind Varsani, Enrique Moriones, Cecilia Hernandezzepeda, A M Idris, Darren P. MartinAbstract:The family Geminiviridae includes plant-infecting circular single-stranded DNA viruses that have geminate particle morphology. Members of this family infect both monocotyledonous and dicotyledonous plants and have a nearly global distribution. With the advent of new molecular tools and low-cost sequencing, there has been a significant increase in the discovery of new geminiviruses in various cultivated and non-cultivated plants. In this communication, we highlight the establishment of three new genera (Becurtovirus, Eragrovirus and Turncurtovirus) to accommodate various recently discovered geminiviruses that are highly divergent and, in some cases, have unique genome architectures. The genus Becurtovirus has two viral species, Beet curly top Iran virus (28 isolates; leafhopper vector Circulifer haematoceps) and Spinach curly top Arizona virus (1 isolate; unknown vector), whereas the genera Eragrovirus and Turncurtovirus each have a single assigned species: Eragrostis curvula streak virus (6 isolates; unknown vector) and Turnip curly top virus (20 isolates; leafhopper vector Circulifer haematoceps), respectively. Based on analysis of all of the genome sequences available in public databases for each of the three new genera, we provide guidelines and protocols for species and strain classification within these three new genera.
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complete genome sequence of jacquemontia yellow mosaic virus a novel begomovirus from venezuela related to other new world bipartite begomoviruses infecting convolvulaceae
2014Co-Authors: Elvira Fialloolive, Enrique Moriones, Dorys T Chirinos, Francis Geraudpouey, Jesus NavascastilloAbstract:The complete genome of a bipartite begomovirus (genus Begomovirus, family Geminiviridae) infecting Jacquemontia sp. (Convolvulaceae) in Venezuela has been cloned and sequenced. Sequence comparison and phylogenetic analysis have shown that it represents an isolate of a novel species with closest relatives being two New World bipartite begomoviruses that infect Convolvulaceae, Jacquemontia mosaic Yucatan virus and Merremia mosaic virus. The DNA-As of these begomoviruses, however, share only 77.0-78.4 % nucleotide sequence identity with the DNA-A of the isolate described here, for which a recombinant origin is suggested. Based on the symptoms observed in the field, the name Jacquemontia yellow mosaic virus (JacYMV) is proposed for this novel bipartite begomovirus.
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a genome wide pairwise identity based proposal for the classification of viruses in the genus mastrevirus family Geminiviridae
2013Co-Authors: Brejnev M Muhire, R F Riverabustamante, Jesus Navascastillo, Varagur Ganesan Malathi, Murilo F Zerbini, Judith K. Brown, Darren P. Martin, Enrique Moriones, Arvind VarsaniAbstract:Recent advances in the ease with which the genomes of small circular single-stranded DNA viruses can be amplified, cloned, and sequenced have greatly accelerated the rate at which full genome sequences of mastreviruses (family Geminiviridae, genus Mastrevirus) are being deposited in public sequence databases. Although guidelines currently exist for species-level classification of newly determined, complete mastrevirus genome sequences, these are difficult to apply to large sequence datasets and are permissive enough that, effectively, a high degree of leeway exists for the proposal of new species and strains. The lack of a standardised and rigorous method for testing whether a new genome sequence deserves such a classification is resulting in increasing numbers of questionable mastrevirus species proposals. Importantly, the recommended sequence alignment and pairwise identity calculation protocols of the current guidelines could easily be modified to make the classification of newly determined mastrevirus genome sequences significantly more objective. Here, we propose modified versions of these protocols that should substantially minimise the degree of classification inconsistency that is permissible under the current system. To facilitate the objective application of these guidelines for mastrevirus species demarcation, we additionally present a user-friendly computer program, SDT (species demarcation tool), for calculating and graphically displaying pairwise genome identity scores. We apply SDT to the 939 full genome sequences of mastreviruses that were publically available in May 2012, and based on the distribution of pairwise identity scores yielded by our protocol, we propose mastrevirus species and strain demarcation thresholds of >78 % and >94 % identity, respectively.
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novel begomovirus species of recombinant nature in sweet potato ipomoea batatas and ipomoea indica taxonomic and phylogenetic implications
2009Co-Authors: Gloria Lozano, Helena P Trenado, Rodrigo A Valverde, Jesus NavascastilloAbstract:Viral diseases occur wherever sweet potato (Ipomoea batatas) is cultivated and because this crop is vegetatively propagated, accumulation and perpetuation of viruses can become a major constraint for production. Up to 90 % reductions in yield have been reported in association with viral infections. About 20 officially accepted or tentative virus species have been found in sweet potato and other Ipomoea species. They include three species of begomoviruses (genus Begomovirus, family Geminiviridae) whose genomes have been fully sequenced. In this investigation, we conducted a search for begomoviruses infecting sweet potato and Ipomoea indica in Spain and characterized the complete genome of 15 isolates. In addition to sweet potato leaf curl virus (SPLCV) and Ipomoea yellowing vein virus, we identified three new begomovirus species and a novel strain of SPLCV. Our analysis also demonstrated that extensive recombination events have shaped the populations of Ipomoea-infecting begomoviruses in Spain. The increased complexity of the unique Ipomoea-infecting begomovirus group, highlighted by our results, open new horizons to understand the phylogeny and evolution of the family Geminiviridae.