1
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van der Loos LM, De Coninck L, Zell R, Lequime S, Willems A, De Clerck O, Matthijnssens J. Highly divergent CRESS DNA and picorna-like viruses associated with bleached thalli of the green seaweed Ulva. Microbiol Spectr 2023; 11:e0025523. [PMID: 37724866 PMCID: PMC10581178 DOI: 10.1128/spectrum.00255-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 07/19/2023] [Indexed: 09/21/2023] Open
Abstract
Marine macroalgae (seaweeds) are important primary producers and foundation species in coastal ecosystems around the world. Seaweeds currently contribute to an estimated 51% of the global mariculture production, with a long-term growth rate of 6% per year, and an estimated market value of more than US$11.3 billion. Viral infections could have a substantial impact on the ecology and aquaculture of seaweeds, but surprisingly little is known about virus diversity in macroalgal hosts. Using metagenomic sequencing, we characterized viral communities associated with healthy and bleached specimens of the commercially important green seaweed Ulva. We identified 20 putative new and divergent viruses, of which the majority belonged to the Circular Rep-Encoding Single-Stranded (CRESS) DNA viruses [single-stranded (ss)DNA genomes], Durnavirales [double-stranded (ds)RNA], and Picornavirales (ssRNA). Other newly identified RNA viruses were related to the Ghabrivirales, the Mitoviridae, and the Tombusviridae. Bleached Ulva samples contained particularly high viral read numbers. While reads matching assembled CRESS DNA viruses and picorna-like viruses were nearly absent from the healthy Ulva samples (confirmed by qPCR), they were very abundant in the bleached specimens. Therefore, bleaching in Ulva could be caused by one or a combination of the identified viruses but may also be the result of another causative agent or abiotic stress, with the viruses simply proliferating in already unhealthy seaweed tissue. This study highlights how little we know about the diversity and ecology of seaweed viruses, especially in relation to the health and diseases of the algal host, and emphasizes the need to better characterize the algal virosphere. IMPORTANCE Green seaweeds of the genus Ulva are considered a model system to study microbial interactions with the algal host. Remarkably little is known, however, about viral communities associated with green seaweeds, especially in relation to the health of the host. In this study, we characterized the viral communities associated with healthy and bleached Ulva. Our findings revealed the presence of 20 putative novel viruses associated with Ulva, encompassing both DNA and RNA viruses. The majority of these viruses were found to be especially abundant in bleached Ulva specimens. This is the first step toward understanding the role of viruses in the ecology and aquaculture of this green seaweed.
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Affiliation(s)
- Luna M. van der Loos
- Phycology Research Group, Department of Biology, Ghent University, Ghent, Belgium
- Laboratory of Microbiology, Department Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Lander De Coninck
- Laboratory of Clinical and Epidemiological Virology, Laboratory of Viral Metagenomics, Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Leuven, Belgium
| | - Roland Zell
- Section of Experimental Virology, Institute for Medical Microbiology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Sebastian Lequime
- Cluster of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Anne Willems
- Laboratory of Microbiology, Department Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Olivier De Clerck
- Phycology Research Group, Department of Biology, Ghent University, Ghent, Belgium
| | - Jelle Matthijnssens
- Laboratory of Clinical and Epidemiological Virology, Laboratory of Viral Metagenomics, Department of Microbiology, Immunology and Transplantation, Rega Institute, KU Leuven, Leuven, Belgium
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2
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Chiba Y, Tomaru Y, Shimabukuro H, Kimura K, Hirai M, Takaki Y, Hagiwara D, Nunoura T, Urayama SI. Viral RNA Genomes Identified from Marine Macroalgae and a Diatom. Microbes Environ 2021; 35. [PMID: 32554943 PMCID: PMC7511793 DOI: 10.1264/jsme2.me20016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Protists provide insights into the diversity and function of RNA viruses in marine systems. Among them, marine macroalgae are good targets for RNA virome analyses because they have a sufficient biomass in nature. However, RNA viruses in macroalgae have not yet been examined in detail, and only partial genome sequences have been reported for the majority of RNA viruses. Therefore, to obtain further insights into the distribution and diversity of RNA viruses associated with marine protists, we herein examined RNA viruses in macroalgae and a diatom. We report the putative complete genome sequences of six novel RNA viruses from two marine macroalgae and one diatom holobiont. Four viruses were not classified into established viral genera or families. Furthermore, a virus classified into Totiviridae showed a genome structure that has not yet been reported in this family. These results suggest that a number of distinct RNA viruses are widespread in a broad range of protists.
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Affiliation(s)
- Yuto Chiba
- Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), Department of Life and Environmental Sciences, University of Tsukuba.,Faculty of Science, International College of Arts and Science, Yokohama City University
| | - Yuji Tomaru
- Japan Fisheries Research and Education Agency, National Research Institute of Fisheries and Environment of the Inland Sea
| | - Hiromori Shimabukuro
- Japan Fisheries Research and Education Agency, National Research Institute of Fisheries and Environment of the Inland Sea
| | | | - Miho Hirai
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, JAMSTEC
| | - Yoshihiro Takaki
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, JAMSTEC
| | - Daisuke Hagiwara
- Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), Department of Life and Environmental Sciences, University of Tsukuba.,Microbiology Research Center for Sustainability (MiCS), University of Tsukuba
| | - Takuro Nunoura
- Research Center for Bioscience and Nanoscience (CeBN), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
| | - Syun-Ichi Urayama
- Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), Department of Life and Environmental Sciences, University of Tsukuba.,Microbiology Research Center for Sustainability (MiCS), University of Tsukuba.,Research Center for Bioscience and Nanoscience (CeBN), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
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3
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Charon J, Marcelino VR, Wetherbee R, Verbruggen H, Holmes EC. Metatranscriptomic Identification of Diverse and Divergent RNA Viruses in Green and Chlorarachniophyte Algae Cultures. Viruses 2020; 12:v12101180. [PMID: 33086653 PMCID: PMC7594059 DOI: 10.3390/v12101180] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/14/2022] Open
Abstract
Our knowledge of the diversity and evolution of the virosphere will likely increase dramatically with the study of microbial eukaryotes, including the microalgae within which few RNA viruses have been documented. By combining total RNA sequencing with sequence and structural-based homology detection, we identified 18 novel RNA viruses in cultured samples from two major groups of microbial algae: the chlorophytes and the chlorarachniophytes. Most of the RNA viruses identified in the green algae class Ulvophyceae were related to the Tombusviridae and Amalgaviridae viral families commonly associated with land plants. This suggests that the evolutionary history of these viruses extends to divergence events between algae and land plants. Seven Ostreobium sp-associated viruses exhibited sequence similarity to the mitoviruses most commonly found in fungi, compatible with horizontal virus transfer between algae and fungi. We also document, for the first time, RNA viruses associated with chlorarachniophytes, including the first negative-sense (bunya-like) RNA virus in microalgae, as well as a distant homolog of the plant virus Virgaviridae, potentially signifying viral inheritance from the secondary chloroplast endosymbiosis that marked the origin of the chlorarachniophytes. More broadly, these data suggest that the scarcity of RNA viruses in algae results from limited investigation rather than their absence.
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Affiliation(s)
- Justine Charon
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia; (J.C.); (V.R.M.)
| | - Vanessa Rossetto Marcelino
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia; (J.C.); (V.R.M.)
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW 2145, Australia
| | - Richard Wetherbee
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia; (R.W.); (H.V.)
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia; (R.W.); (H.V.)
| | - Edward C. Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia; (J.C.); (V.R.M.)
- Correspondence: ; Tel.: +61-2-9351-5591
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4
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Charon J, Marcelino VR, Wetherbee R, Verbruggen H, Holmes EC. Metatranscriptomic Identification of Diverse and Divergent RNA Viruses in Green and Chlorarachniophyte Algae Cultures. Viruses 2020; 12:v12101180. [PMID: 33086653 DOI: 10.1101/2020.06.08.141184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 05/26/2023] Open
Abstract
Our knowledge of the diversity and evolution of the virosphere will likely increase dramatically with the study of microbial eukaryotes, including the microalgae within which few RNA viruses have been documented. By combining total RNA sequencing with sequence and structural-based homology detection, we identified 18 novel RNA viruses in cultured samples from two major groups of microbial algae: the chlorophytes and the chlorarachniophytes. Most of the RNA viruses identified in the green algae class Ulvophyceae were related to the Tombusviridae and Amalgaviridae viral families commonly associated with land plants. This suggests that the evolutionary history of these viruses extends to divergence events between algae and land plants. Seven Ostreobium sp-associated viruses exhibited sequence similarity to the mitoviruses most commonly found in fungi, compatible with horizontal virus transfer between algae and fungi. We also document, for the first time, RNA viruses associated with chlorarachniophytes, including the first negative-sense (bunya-like) RNA virus in microalgae, as well as a distant homolog of the plant virus Virgaviridae, potentially signifying viral inheritance from the secondary chloroplast endosymbiosis that marked the origin of the chlorarachniophytes. More broadly, these data suggest that the scarcity of RNA viruses in algae results from limited investigation rather than their absence.
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Affiliation(s)
- Justine Charon
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Vanessa Rossetto Marcelino
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
- Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW 2145, Australia
| | - Richard Wetherbee
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Parkville, VIC 3010, Australia
| | - Edward C Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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5
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Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini FM, Kuhn JH. Global Organization and Proposed Megataxonomy of the Virus World. Microbiol Mol Biol Rev 2020; 84:e00061-19. [PMID: 32132243 PMCID: PMC7062200 DOI: 10.1128/mmbr.00061-19] [Citation(s) in RCA: 295] [Impact Index Per Article: 73.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Viruses and mobile genetic elements are molecular parasites or symbionts that coevolve with nearly all forms of cellular life. The route of virus replication and protein expression is determined by the viral genome type. Comparison of these routes led to the classification of viruses into seven "Baltimore classes" (BCs) that define the major features of virus reproduction. However, recent phylogenomic studies identified multiple evolutionary connections among viruses within each of the BCs as well as between different classes. Due to the modular organization of virus genomes, these relationships defy simple representation as lines of descent but rather form complex networks. Phylogenetic analyses of virus hallmark genes combined with analyses of gene-sharing networks show that replication modules of five BCs (three classes of RNA viruses and two classes of reverse-transcribing viruses) evolved from a common ancestor that encoded an RNA-directed RNA polymerase or a reverse transcriptase. Bona fide viruses evolved from this ancestor on multiple, independent occasions via the recruitment of distinct cellular proteins as capsid subunits and other structural components of virions. The single-stranded DNA (ssDNA) viruses are a polyphyletic class, with different groups evolving by recombination between rolling-circle-replicating plasmids, which contributed the replication protein, and positive-sense RNA viruses, which contributed the capsid protein. The double-stranded DNA (dsDNA) viruses are distributed among several large monophyletic groups and arose via the combination of distinct structural modules with equally diverse replication modules. Phylogenomic analyses reveal the finer structure of evolutionary connections among RNA viruses and reverse-transcribing viruses, ssDNA viruses, and large subsets of dsDNA viruses. Taken together, these analyses allow us to outline the global organization of the virus world. Here, we describe the key aspects of this organization and propose a comprehensive hierarchical taxonomy of viruses.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Valerian V Dolja
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Mart Krupovic
- Institut Pasteur, Archaeal Virology Unit, Department of Microbiology, Paris, France
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, Arizona, USA
- Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Observatory, Cape Town, South Africa
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - F Murilo Zerbini
- Departamento de Fitopatologia/Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, USA
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6
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Nerva L, Vigani G, Di Silvestre D, Ciuffo M, Forgia M, Chitarra W, Turina M. Biological and Molecular Characterization of Chenopodium quinoa Mitovirus 1 Reveals a Distinct Small RNA Response Compared to Those of Cytoplasmic RNA Viruses. J Virol 2019; 93:e01998-18. [PMID: 30651361 PMCID: PMC6430534 DOI: 10.1128/jvi.01998-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/08/2019] [Indexed: 02/07/2023] Open
Abstract
Indirect evidence of mitochondrial viruses in plants comes from discovery of genomic fragments integrated into the nuclear and mitochondrial DNA of a number of plant species. Here, we report the existence of replicating mitochondrial virus in plants: from transcriptome sequencing (RNA-seq) data of infected Chenopodium quinoa, a plant species commonly used as a test plant in virus host range experiments, among other virus contigs, we could assemble a 2.7-kb contig that had highest similarity to mitoviruses found in plant genomes. Northern blot analyses confirmed the existence of plus- and minus-strand RNA corresponding to the mitovirus genome. No DNA corresponding to the genomic RNA was detected, excluding the endogenization of such virus. We have tested a number of C. quinoa accessions, and the virus was present in a number of commercial varieties but absent from a large collection of Bolivian and Peruvian accessions. The virus could not be transmitted mechanically or by grafting, but it is transmitted vertically through seeds at a 100% rate. Small RNA analysis of a C. quinoa line carrying the mitovirus and infected by alfalfa mosaic virus showed that the typical antiviral silencing response active against cytoplasmic viruses (21- to 22-nucleotide [nt] vsRNA peaks) is not active against CqMV1, since in this specific case the longest accumulating vsRNA length is 16 nt, which is the same as that corresponding to RNA from mitochondrial genes. This is evidence of a distinct viral RNA degradation mechanism active inside mitochondria that also may have an antiviral effect.IMPORTANCE This paper reports the first biological characterization of a bona fide plant mitovirus in an important crop, Chenopodium quinoa, providing data supporting that mitoviruses have the typical features of cryptic (persistent) plant viruses. We, for the first time, demonstrate that plant mitoviruses are associated with mitochondria in plants. In contrast to fungal mitoviruses, plant mitoviruses are not substantially affected by the antiviral silencing pathway, and the most abundant mitovirus small RNA length is 16 nt.
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Affiliation(s)
- L Nerva
- Institute for Sustainable Plant Protection, CNR, Turin, Italy
- Council for Agricultural Research and Economics-Research Centre for Viticulture and Enology CREA-VE, Conegliano, Italy
| | - G Vigani
- Plant Physiology Unit, Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - D Di Silvestre
- Institute for Biomedical Technology, CNR, Segrate, Milan, Italy
| | - M Ciuffo
- Institute for Sustainable Plant Protection, CNR, Turin, Italy
| | - M Forgia
- Institute for Sustainable Plant Protection, CNR, Turin, Italy
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - W Chitarra
- Institute for Sustainable Plant Protection, CNR, Turin, Italy
- Council for Agricultural Research and Economics-Research Centre for Viticulture and Enology CREA-VE, Conegliano, Italy
| | - M Turina
- Institute for Sustainable Plant Protection, CNR, Turin, Italy
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7
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Abstract
The majority of the diverse viruses infecting eukaryotes have RNA genomes, including numerous human, animal, and plant pathogens. Recent advances of metagenomics have led to the discovery of many new groups of RNA viruses in a wide range of hosts. These findings enable a far more complete reconstruction of the evolution of RNA viruses than was attainable previously. This reconstruction reveals the relationships between different Baltimore classes of viruses and indicates extensive transfer of viruses between distantly related hosts, such as plants and animals. These results call for a major revision of the existing taxonomy of RNA viruses. Viruses with RNA genomes dominate the eukaryotic virome, reaching enormous diversity in animals and plants. The recent advances of metaviromics prompted us to perform a detailed phylogenomic reconstruction of the evolution of the dramatically expanded global RNA virome. The only universal gene among RNA viruses is the gene encoding the RNA-dependent RNA polymerase (RdRp). We developed an iterative computational procedure that alternates the RdRp phylogenetic tree construction with refinement of the underlying multiple-sequence alignments. The resulting tree encompasses 4,617 RNA virus RdRps and consists of 5 major branches; 2 of the branches include positive-sense RNA viruses, 1 is a mix of positive-sense (+) RNA and double-stranded RNA (dsRNA) viruses, and 2 consist of dsRNA and negative-sense (−) RNA viruses, respectively. This tree topology implies that dsRNA viruses evolved from +RNA viruses on at least two independent occasions, whereas −RNA viruses evolved from dsRNA viruses. Reconstruction of RNA virus evolution using the RdRp tree as the scaffold suggests that the last common ancestors of the major branches of +RNA viruses encoded only the RdRp and a single jelly-roll capsid protein. Subsequent evolution involved independent capture of additional genes, in particular, those encoding distinct RNA helicases, enabling replication of larger RNA genomes and facilitating virus genome expression and virus-host interactions. Phylogenomic analysis reveals extensive gene module exchange among diverse viruses and horizontal virus transfer between distantly related hosts. Although the network of evolutionary relationships within the RNA virome is bound to further expand, the present results call for a thorough reevaluation of the RNA virus taxonomy.
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8
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A novel monopartite dsRNA virus isolated from the phytopathogenic fungus Ustilaginoidea virens strain GZ-2. Arch Virol 2018; 163:3427-3431. [DOI: 10.1007/s00705-018-3976-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022]
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9
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Metagenomics reshapes the concepts of RNA virus evolution by revealing extensive horizontal virus transfer. Virus Res 2017; 244:36-52. [PMID: 29103997 PMCID: PMC5801114 DOI: 10.1016/j.virusres.2017.10.020] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/30/2017] [Accepted: 10/31/2017] [Indexed: 12/22/2022]
Abstract
Virus metagenomics is a young research filed but it has already transformed our understanding of virus diversity and evolution, and illuminated at a new level the connections between virus evolution and the evolution and ecology of the hosts. In this review article, we examine the new picture of the evolution of RNA viruses, the dominant component of the eukaryotic virome, that is emerging from metagenomic data analysis. The major expansion of many groups of RNA viruses through metagenomics allowed the construction of substantially improved phylogenetic trees for the conserved virus genes, primarily, the RNA-dependent RNA polymerases (RdRp). In particular, a new superfamily of widespread, small positive-strand RNA viruses was delineated that unites tombus-like and noda-like viruses. Comparison of the genome architectures of RNA viruses discovered by metagenomics and by traditional methods reveals an extent of gene module shuffling among diverse virus genomes that far exceeds the previous appreciation of this evolutionary phenomenon. Most dramatically, inclusion of the metagenomic data in phylogenetic analyses of the RdRp resulted in the identification of numerous, strongly supported groups that encompass RNA viruses from diverse hosts including different groups of protists, animals and plants. Notwithstanding potential caveats, in particular, incomplete and uneven sampling of eukaryotic taxa, these highly unexpected findings reveal horizontal virus transfer (HVT) between diverse hosts as the central aspect of RNA virus evolution. The vast and diverse virome of invertebrates, particularly nematodes and arthropods, appears to be the reservoir, from which the viromes of plants and vertebrates evolved via multiple HVT events.
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10
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A novel monopartite dsRNA virus isolated from the entomopathogenic and nematophagous fungus Purpureocillium lilacinum. Arch Virol 2016; 161:3375-3384. [DOI: 10.1007/s00705-016-3045-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 08/31/2016] [Indexed: 12/01/2022]
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11
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Rousvoal S, Bouyer B, López-Cristoffanini C, Boyen C, Collén J. Mutant swarms of a totivirus-like entities are present in the red macroalga Chondrus crispus and have been partially transferred to the nuclear genome. JOURNAL OF PHYCOLOGY 2016; 52:493-504. [PMID: 27151076 DOI: 10.1111/jpy.12427] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/15/2016] [Indexed: 06/05/2023]
Abstract
Chondrus crispus Stackhouse (Gigartinales) is a red seaweed found on North Atlantic rocky shores. Electrophoresis of RNA extracts showed a prominent band with a size of around 6,000 bp. Sequencing of the band revealed several sequences with similarity to totiviruses, double-stranded RNA viruses that normally infect fungi. This virus-like entity was named C. crispus virus (CcV). It should probably be regarded as an extreme viral quasispecies or a mutant swarm since low identity (<65%) was found between sequences. Totiviruses typically code for two genes: one capsid gene (gag) and one RNA-dependent RNA polymerase gene (pol) with a pseudoknot structure between the genes. Both the genes and the intergenic structures were found in the CcV sequences. A nonidentical gag gene was also found in the nuclear genome of C. crispus, with associated expressed sequence tags (EST) and upstream regulatory features. The gene was presumably horizontally transferred from the virus to the alga. Similar dsRNA bands were seen in extracts from different life cycle stages of C. crispus and from all geographic locations tested. In addition, similar bands were also observed in RNA extractions from other red algae; however, the significance of this apparently widespread phenomenon is unknown. Neither phenotype caused by the infection nor any virus particles or capsid proteins were identified; thus, the presence of viral particles has not been validated. These findings increase the known host range of totiviruses to include marine red algae.
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Affiliation(s)
- Sylvie Rousvoal
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688, Roscoff Cedex, France
- UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06, CS 90074, 29688, Roscoff Cedex, France
| | - Betty Bouyer
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688, Roscoff Cedex, France
- UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06, CS 90074, 29688, Roscoff Cedex, France
| | - Camilo López-Cristoffanini
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688, Roscoff Cedex, France
- UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06, CS 90074, 29688, Roscoff Cedex, France
| | - Catherine Boyen
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688, Roscoff Cedex, France
- UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06, CS 90074, 29688, Roscoff Cedex, France
| | - Jonas Collén
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688, Roscoff Cedex, France
- UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, Sorbonne Universités, UPMC Univ Paris 06, CS 90074, 29688, Roscoff Cedex, France
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12
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Atkins JF, Loughran G, Bhatt PR, Firth AE, Baranov PV. Ribosomal frameshifting and transcriptional slippage: From genetic steganography and cryptography to adventitious use. Nucleic Acids Res 2016; 44:7007-78. [PMID: 27436286 PMCID: PMC5009743 DOI: 10.1093/nar/gkw530] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022] Open
Abstract
Genetic decoding is not ‘frozen’ as was earlier thought, but dynamic. One facet of this is frameshifting that often results in synthesis of a C-terminal region encoded by a new frame. Ribosomal frameshifting is utilized for the synthesis of additional products, for regulatory purposes and for translational ‘correction’ of problem or ‘savior’ indels. Utilization for synthesis of additional products occurs prominently in the decoding of mobile chromosomal element and viral genomes. One class of regulatory frameshifting of stable chromosomal genes governs cellular polyamine levels from yeasts to humans. In many cases of productively utilized frameshifting, the proportion of ribosomes that frameshift at a shift-prone site is enhanced by specific nascent peptide or mRNA context features. Such mRNA signals, which can be 5′ or 3′ of the shift site or both, can act by pairing with ribosomal RNA or as stem loops or pseudoknots even with one component being 4 kb 3′ from the shift site. Transcriptional realignment at slippage-prone sequences also generates productively utilized products encoded trans-frame with respect to the genomic sequence. This too can be enhanced by nucleic acid structure. Together with dynamic codon redefinition, frameshifting is one of the forms of recoding that enriches gene expression.
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Affiliation(s)
- John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland School of Microbiology, University College Cork, Cork, Ireland Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Pramod R Bhatt
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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Zhou Q, Zhong J, Hu Y, Da Gao B. A novel nonsegmented double-stranded RNA mycovirus identified in the phytopathogenic fungus Nigrospora oryzae shows similarity to partitivirus-like viruses. Arch Virol 2015; 161:229-32. [DOI: 10.1007/s00705-015-2644-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 10/09/2015] [Indexed: 12/31/2022]
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14
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Virus world as an evolutionary network of viruses and capsidless selfish elements. Microbiol Mol Biol Rev 2015; 78:278-303. [PMID: 24847023 DOI: 10.1128/mmbr.00049-13] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Viruses were defined as one of the two principal types of organisms in the biosphere, namely, as capsid-encoding organisms in contrast to ribosome-encoding organisms, i.e., all cellular life forms. Structurally similar, apparently homologous capsids are present in a huge variety of icosahedral viruses that infect bacteria, archaea, and eukaryotes. These findings prompted the concept of the capsid as the virus "self" that defines the identity of deep, ancient viral lineages. However, several other widespread viral "hallmark genes" encode key components of the viral replication apparatus (such as polymerases and helicases) and combine with different capsid proteins, given the inherently modular character of viral evolution. Furthermore, diverse, widespread, capsidless selfish genetic elements, such as plasmids and various types of transposons, share hallmark genes with viruses. Viruses appear to have evolved from capsidless selfish elements, and vice versa, on multiple occasions during evolution. At the earliest, precellular stage of life's evolution, capsidless genetic parasites most likely emerged first and subsequently gave rise to different classes of viruses. In this review, we develop the concept of a greater virus world which forms an evolutionary network that is held together by shared conserved genes and includes both bona fide capsid-encoding viruses and different classes of capsidless replicons. Theoretical studies indicate that selfish replicons (genetic parasites) inevitably emerge in any sufficiently complex evolving ensemble of replicators. Therefore, the key signature of the greater virus world is not the presence of a capsid but rather genetic, informational parasitism itself, i.e., various degrees of reliance on the information processing systems of the host.
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15
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Zhang T, Jiang Y, Dong W. A novel monopartite dsRNA virus isolated from the phytopathogenic fungus Ustilaginoidea virens and ancestrally related to a mitochondria-associated dsRNA in the green alga Bryopsis. Virology 2014; 462-463:227-35. [DOI: 10.1016/j.virol.2014.06.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/20/2014] [Accepted: 06/04/2014] [Indexed: 01/19/2023]
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16
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17
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Lavrov DV, Brown WM, Boore JL. A novel type of RNA editing occurs in the mitochondrial tRNAs of the centipede Lithobius forficatus. Proc Natl Acad Sci U S A 2000; 97:13738-42. [PMID: 11095730 PMCID: PMC17645 DOI: 10.1073/pnas.250402997] [Citation(s) in RCA: 246] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We determined the complete mtDNA sequence of the centipede Lithobius forficatus and found that only one of the 22 inferred tRNA genes encodes a fully paired aminoacyl acceptor stem. The other 21 genes encode tRNAs with up to five mismatches in these stems, and some of these overlap extensively with the downstream genes. Because a well-paired acceptor stem is required for proper tRNA functioning, RNA editing in the products of these genes was suspected. We investigated this hypothesis by studying cDNA sequences from eight tRNAs and found the editing of up to 5 nt at their 3' ends. This editing appears to occur by a novel mechanism with the 5' end of the acceptor stem being used as a template for the de novo synthesis of the 3' end, presumably by an RNA-dependent RNA polymerase. In addition, unusual secondary structures for several tRNAs were found, including those lacking a TPsiC (T) or a dihydrouridine (D) arm, and having an unusual number of base pairs in the acceptor or anticodon stems.
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Affiliation(s)
- D V Lavrov
- Department of Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI 48109-1048, USA.
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