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Poimala A, Vainio E. Discovery and Identification of Viruses Infecting Oomycetes. Methods Mol Biol 2024; 2732:45-65. [PMID: 38060117 DOI: 10.1007/978-1-0716-3515-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
This chapter describes protocols suitable for the detection and identification of RNA viruses infecting oomycetes (so-called water molds of Kingdom Heterokonta, Stramenopila), focusing on species of Phytophthora and exemplified by P. fragariae. The protocol includes laboratory procedures for oomycete cultivation and total RNA extraction from harvested mycelia, followed by instructions on suitable parameters given for sequencing companies on ribosomal RNA depletion, cDNA library preparation, and total RNA-sequencing (RNA-Seq). We also describe the bioinformatics steps needed for de novo assembly of raw reads into contigs, removal of host-associated contigs, and virus identification by database searches, as well as host validation by RT-PCR. All steps are described using an exemplar RNA-Seq library containing a yet undescribed fusagravirus hosted by a P. fragariae isolate.
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Affiliation(s)
- Anna Poimala
- Natural Resources Institute Finland (Luke), Helsinki, Finland.
| | - Eeva Vainio
- Natural Resources Institute Finland (Luke), Helsinki, Finland
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2
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Chiba Y, Yabuki A, Takaki Y, Nunoura T, Urayama SI, Hagiwara D. The First Identification of a Narnavirus in Bigyra, a Marine Protist. Microbes Environ 2023; 38:ME22077. [PMID: 36858534 PMCID: PMC10037099 DOI: 10.1264/jsme2.me22077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/18/2022] [Indexed: 03/03/2023] Open
Abstract
Current information on the diversity and evolution of eukaryotic RNA viruses is biased towards host lineages, such as animals, plants, and fungi. Although protists represent the majority of eukaryotic diversity, our understanding of the protist RNA virosphere is still limited. To reveal untapped RNA viral diversity, we screened RNA viruses from 30 marine protist isolates and identified a novel RNA virus named Haloplacidia narnavirus 1 (HpNV1). A phylogenetic ana-lysis revealed that HpNV1 is a new member of the family Narnaviridae. The present study filled a gap in the distribution of narnaviruses and implies their wide distribution in Stramenopiles.
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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, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
| | - Akinori Yabuki
- Research Institute for Global Change (RIGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2–15 Natsushima-cho, Yokosuka 237–0061, Japan
| | - Yoshihiro Takaki
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, JAMSTEC, 2–15 Natsushima-cho, Yokosuka, Kanagawa 237–0061, Japan
| | - Takuro Nunoura
- Research Center for Bioscience and Nanoscience (CeBN), JAMSTEC, 2–15 Natsushima-cho, Yokosuka, Kanagawa 237–0061, Japan
| | - Syun-ichi Urayama
- Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), Department of Life and Environmental Sciences, University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
- Microbiology Research Center for Sustainability (MiCS), University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
| | - Daisuke Hagiwara
- Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), Department of Life and Environmental Sciences, University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
- Microbiology Research Center for Sustainability (MiCS), University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
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Ayllón MA, Vainio EJ. Mycoviruses as a part of the global virome: Diversity, evolutionary links and lifestyle. Adv Virus Res 2023; 115:1-86. [PMID: 37173063 DOI: 10.1016/bs.aivir.2023.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Knowledge of mycovirus diversity, evolution, horizontal gene transfer and shared ancestry with viruses infecting distantly related hosts, such as plants and arthropods, has increased vastly during the last few years due to advances in the high throughput sequencing methodologies. This also has enabled the discovery of novel mycoviruses with previously unknown genome types, mainly new positive and negative single-stranded RNA mycoviruses ((+) ssRNA and (-) ssRNA) and single-stranded DNA mycoviruses (ssDNA), and has increased our knowledge of double-stranded RNA mycoviruses (dsRNA), which in the past were thought to be the most common viruses infecting fungi. Fungi and oomycetes (Stramenopila) share similar lifestyles and also have similar viromes. Hypothesis about the origin and cross-kingdom transmission events of viruses have been raised and are supported by phylogenetic analysis and by the discovery of natural exchange of viruses between different hosts during virus-fungus coinfection in planta. In this review we make a compilation of the current information on the genome organization, diversity and taxonomy of mycoviruses, discussing their possible origins. Our focus is in recent findings suggesting the expansion of the host range of many viral taxa previously considered to be exclusively fungal, but we also address factors affecting virus transmissibility and coexistence in single fungal or oomycete isolates, as well as the development of synthetic mycoviruses and their use in investigating mycovirus replication cycles and pathogenicity.
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Affiliation(s)
- María A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación Agraria y Alimentaria (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain; Departamento Biotecnología-Biología Vegetal, E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain.
| | - Eeva J Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Helsinki, Finland
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Dominguez‐Huerta G, Wainaina JM, Zayed AA, Culley AI, Kuhn JH, Sullivan MB. The RNA virosphere: How big and diverse is it? Environ Microbiol 2023; 25:209-215. [PMID: 36511833 PMCID: PMC9852017 DOI: 10.1111/1462-2920.16312] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022]
Affiliation(s)
- Guillermo Dominguez‐Huerta
- Department of MicrobiologyOhio State UniversityColumbusOhioUSA
- Center of Microbiome ScienceOhio State UniversityColumbusOhioUSA
| | - James M. Wainaina
- Department of MicrobiologyOhio State UniversityColumbusOhioUSA
- Center of Microbiome ScienceOhio State UniversityColumbusOhioUSA
| | - Ahmed A. Zayed
- Department of MicrobiologyOhio State UniversityColumbusOhioUSA
- Center of Microbiome ScienceOhio State UniversityColumbusOhioUSA
| | - Alexander I. Culley
- Pacific Biosciences Research CenterUniversity of Hawai'i at MānoaHonoluluHawaiiUSA
| | - Jens H. Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious DiseasesNational Institutes of HealthFrederickMarylandUSA
| | - Matthew B. Sullivan
- Department of MicrobiologyOhio State UniversityColumbusOhioUSA
- Center of Microbiome ScienceOhio State UniversityColumbusOhioUSA
- Department of Civil, Environmental and Geodetic EngineeringOhio State UniversityColumbusOhioUSA
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5
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Poimala A, Raco M, Haikonen T, Černý M, Parikka P, Hantula J, Vainio EJ. Bunyaviruses Affect Growth, Sporulation, and Elicitin Production in Phytophthora cactorum. Viruses 2022; 14:v14122596. [PMID: 36560602 PMCID: PMC9788385 DOI: 10.3390/v14122596] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/02/2022] [Accepted: 11/20/2022] [Indexed: 11/24/2022] Open
Abstract
Phytophthora cactorum is an important oomycetous plant pathogen with numerous host plant species, including garden strawberry (Fragaria × ananassa) and silver birch (Betula pendula). P. cactorum also hosts mycoviruses, but their phenotypic effects on the host oomycete have not been studied earlier. In the present study, we tested polyethylene glycol (PEG)-induced water stress for virus curing and created an isogenic virus-free isolate for testing viral effects in pair with the original isolate. Phytophthora cactorum bunya-like viruses 1 and 2 (PcBV1 & 2) significantly reduced hyphal growth of the P. cactorum host isolate, as well as sporangia production and size. Transcriptomic and proteomic analyses revealed an increase in the production of elicitins due to bunyavirus infection. However, the presence of bunyaviruses did not seem to alter the pathogenicity of P. cactorum. Virus transmission through anastomosis was unsuccessful in vitro.
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Affiliation(s)
- Anna Poimala
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
- Correspondence: ; Tel.: +358-29-5322173
| | - Milica Raco
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic
| | - Tuuli Haikonen
- Natural Resources Institute Finland, Toivonlinnantie 518, FI-21500 Piikkiö, Finland
| | - Martin Černý
- Phytophthora Research Centre, Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic
| | - Päivi Parikka
- Natural Resources Institute Finland, Humppilantie 18, FI-31600 Jokioinen, Finland
| | - Jarkko Hantula
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
| | - Eeva J. Vainio
- Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland
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Raco M, Vainio EJ, Sutela S, Eichmeier A, Hakalová E, Jung T, Botella L. High Diversity of Novel Viruses in the Tree Pathogen Phytophthora castaneae Revealed by High-Throughput Sequencing of Total and Small RNA. Front Microbiol 2022; 13:911474. [PMID: 35783401 PMCID: PMC9244493 DOI: 10.3389/fmicb.2022.911474] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 04/21/2022] [Indexed: 12/11/2022] Open
Abstract
Phytophthora castaneae, an oomycete pathogen causing root and trunk rot of different tree species in Asia, was shown to harbor a rich diversity of novel viruses from different families. Four P. castaneae isolates collected from Chamaecyparis hodginsii in a semi-natural montane forest site in Vietnam were investigated for viral presence by traditional and next-generation sequencing (NGS) techniques, i.e., double-stranded RNA (dsRNA) extraction and high-throughput sequencing (HTS) of small RNAs (sRNAs) and total RNA. Genome organization, sequence similarity, and phylogenetic analyses indicated that the viruses were related to members of the order Bunyavirales and families Endornaviridae, Megabirnaviridae, Narnaviridae, Totiviridae, and the proposed family "Fusagraviridae." The study describes six novel viruses: Phytophthora castaneae RNA virus 1-5 (PcaRV1-5) and Phytophthora castaneae negative-stranded RNA virus 1 (PcaNSRV1). All six viruses were detected by sRNA sequencing, which demonstrates an active RNA interference (RNAi) system targeting viruses in P. castaneae. To our knowledge, this is the first report of viruses in P. castaneae and the whole Phytophthora major Clade 5, as well as of the activity of an RNAi mechanism targeting viral genomes among Clade 5 species. PcaRV1 is the first megabirnavirus described in oomycetes and the genus Phytophthora.
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Affiliation(s)
- Milica Raco
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Eeva J. Vainio
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Suvi Sutela
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Aleš Eichmeier
- Mendeleum-Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, Brno, Czechia
| | - Eliška Hakalová
- Mendeleum-Institute of Genetics, Faculty of Horticulture, Mendel University in Brno, Brno, Czechia
| | - Thomas Jung
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Leticia Botella
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
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Characterization of a Novel Double-Stranded RNA Virus from Phytophthora pluvialis in New Zealand. Viruses 2022; 14:v14020247. [PMID: 35215841 PMCID: PMC8878296 DOI: 10.3390/v14020247] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/06/2022] [Accepted: 01/12/2022] [Indexed: 02/05/2023] Open
Abstract
A new dsRNA virus from the oomycete Phytophthora pluvialis has been characterized and designated as Phytophthora pluvialis RNA virus 1 (PplRV1). The genome of the PplRV1 reference genome is 6742 bp that encodes two predicted open reading frames (ORFs). ORF1 and ORF2 overlap by a 47 nt “slippery” frameshift sequence. ORF1 encodes a putative protein of unknown function. ORF2 shows high similarity to the RNA-dependent RNA polymerase (RdRp) of other dsRNA viruses. Phylogenetic analysis of the putative PplRV1 RdRp and its most closely related viruses showed PplRV1 is distinct from other known viruses (below 33% amino acid similarity), which indicates this virus may belong to a new virus family. Analyses of the geographical distribution of PplRV1 in relation to two genetically distinct classes of its host revealed two corresponding genotypes of the PplRV1 (termed a and b), which share 92.3% nt identity. The reference genome for the second genotype is 6760 bp long and a prediction of its genetic organization shows three ORFs, with ORF2 being split into two ORFs, ORF2a and ORF2b, that is conserved in seven of eleven genotype b isolates. Additionally, a quick and simple diagnostic method using qPCR has been developed, which is suitable for large scale screens to identify PplRV1 in Phytophthora.
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Fukunishi M, Sasai S, Tojo M, Mochizuki T. Novel Fusari- and Toti-like Viruses, with Probable Different Origins, in the Plant Pathogenic Oomycete Globisporangiumultimum. Viruses 2021; 13:1931. [PMID: 34696361 PMCID: PMC8538416 DOI: 10.3390/v13101931] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/19/2021] [Accepted: 09/22/2021] [Indexed: 01/01/2023] Open
Abstract
To further classify the oomycete viruses that have been discovered in recent years, we investigated virus infection in the plant-parasitic oomycete Globisporangium ultimum in Japan. Double-stranded RNA detection, high-throughput sequencing, and RT-PCR revealed that the G. ultimum isolate UOP226 contained two viruses related to fusarivirus and totivirus, named Pythium ultimum RNA virus 1 (PuRV1) and Pythium ultimum RNA virus 2 (PuRV2), respectively. Phylogenetic analysis of the deduced amino acid sequence of the RNA-dependent RNA polymerase (RdRp) showed that fusari-like PuRV1 belonged to a different phylogenetic group than Plasmopara viticola lesion-associated fusari virus (PvlaFV) 1-3 from oomycete Plasmopara viticola. Codon usage bias of the PuRV1 RdRp gene was more similar to those of fungi than Globisporangium and Phytophthora, suggesting that the PuRV1 ancestor horizontally transmitted to G. ultimum ancestor from fungi. Phylogenetic analysis of the deduced amino acid sequence of the RdRp of toti-like PuRV2 showed a monophyletic group with the other toti-like oomycete viruses from Globisporangium, Phytophthora, and Pl. viticola. However, the nucleotide sequences of toti-like oomycete viruses were not so homologous, suggesting the possibility of convergent evolution of toti-like oomycete viruses.
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Affiliation(s)
- Miki Fukunishi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Japan
| | - Shinsaku Sasai
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Japan
| | - Motoaki Tojo
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Japan
| | - Tomofumi Mochizuki
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai 599-8531, Japan
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Characterization of the Mycovirome from the Plant-Pathogenic Fungus Cercospora beticola. Viruses 2021; 13:v13101915. [PMID: 34696345 PMCID: PMC8537984 DOI: 10.3390/v13101915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/16/2021] [Accepted: 09/19/2021] [Indexed: 12/25/2022] Open
Abstract
Cercospora leaf spot (CLS) caused by Cercospora beticola is a devastating foliar disease of sugar beet (Beta vulgaris), resulting in high yield losses worldwide. Mycoviruses are widespread fungi viruses and can be used as a potential biocontrol agent for fugal disease management. To determine the presence of mycoviruses in C. beticola, high-throughput sequencing analysis was used to determine the diversity of mycoviruses in 139 C. beticola isolates collected from major sugar beet production areas in China. The high-throughput sequencing reads were assembled and searched against the NCBI database using BLASTn and BLASTx. The results showed that the obtained 93 contigs were derived from eight novel mycoviruses, which were grouped into 3 distinct lineages, belonging to the families Hypoviridae, Narnaviridae and Botourmiaviridae, as well as some unclassified (−)ssRNA viruses in the order Bunyavirales and Mononegavirales. To the best of our knowledge, this is the first identification of highly diverse mycoviruses in C. beticola. The novel mycoviruses explored in this study will provide new viral materials to biocontrol Cercospora diseases. Future studies of these mycoviruses will aim to assess the roles of each mycovirus in biological function of C. beticola in the future.
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Charon J, Murray S, Holmes EC. Revealing RNA virus diversity and evolution in unicellular algae transcriptomes. Virus Evol 2021; 7:veab070. [PMID: 36819971 PMCID: PMC9927876 DOI: 10.1093/ve/veab070] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/04/2021] [Accepted: 08/07/2021] [Indexed: 12/15/2022] Open
Abstract
Remarkably little is known about the diversity and evolution of RNA viruses in unicellular eukaryotes. We screened a total of 570 transcriptomes from the Marine Microbial Eukaryote Transcriptome Sequencing Project that encompasses a wide diversity of microbial eukaryotes, including most major photosynthetic lineages (i.e. the microalgae). From this, we identified thirty new and divergent RNA virus species, occupying a range of phylogenetic positions within the overall diversity of RNA viruses. Approximately one-third of the newly described viruses comprised single-stranded positive-sense RNA viruses from the order Lenarviricota associated with fungi, plants, and protists, while another third were related to the order Ghabrivirales, including members of the protist and fungi-associated Totiviridae. Other viral species showed sequence similarity to positive-sense RNA viruses from the algae-associated Marnaviridae, the double-stranded RNA (ds-RNA) Partitiviridae, as well as tentative evidence for one negative-sense RNA virus related to the Qinviridae. Importantly, we were able to identify divergent RNA viruses from distant host taxa, revealing the ancestry of these viral families and greatly extending our knowledge of the RNA viromes of microalgal cultures. Both the limited number of viruses detected per sample and the low sequence identity to known RNA viruses imply that additional microalgal viruses exist that could not be detected at the current sequencing depth or were too divergent to be identified using sequence similarity. Together, these results highlight the need for further investigation of algal-associated RNA viruses as well as the development of new tools to identify RNA viruses that exhibit very high levels of sequence divergence.
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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
| | - Shauna Murray
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia
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Poimala A, Parikka P, Hantula J, Vainio EJ. Viral diversity in Phytophthora cactorum population infecting strawberry. Environ Microbiol 2021; 23:5200-5221. [PMID: 33848054 DOI: 10.1111/1462-2920.15519] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/18/2021] [Accepted: 04/08/2021] [Indexed: 01/31/2023]
Abstract
Eighty-eight Phytophthora cactorum strains isolated from crown or leather rot of strawberry in 1971-2019 were screened for viruses using RNA-seq and RT-PCR. Remarkably, all but one isolate were virus-infected, most of them harbouring more than one virus of different genera or species. The most common virus occurring in 94% of the isolates was the Phytophthora cactorum RNA virus 1 (PcRV1) resembling members of Totiviridae. Novel viruses related to members of Endornaviridae, named Phytophthora cactorum alphaendornaviruses 1-3 (PcAEV1-3), were found in 57% of the isolates. Four isolates hosted viruses with affinities to Bunyaviridae, named Phytophthora cactorum bunyaviruses 1-3 (PcBV1-3), and a virus resembling members of the proposed genus 'Ustivirus', named Phytophthora cactorum usti-like virus (PcUV1), was found in a single isolate. Most of the virus species were represented by several distinct strains sharing ≥81.4% aa sequence identity. We found no evidence of spatial differentiation but some temporal changes in the P. cactorum virus community were observed. Some isolates harboured two or more closely related strains of the same virus (PcAEV1 or PcRV1) sharing 86.6%-96.4% nt identity in their polymerase sequence. This was surprising as viruses with such a high similarity are typically mutually exclusive.
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Affiliation(s)
- Anna Poimala
- Natural Resources Institute Finland (Luke), Forest Health and Biodiversity, Latokartanonkaari 9, Helsinki, FI-00790, Finland
| | - Päivi Parikka
- Natural Resources Institute Finland (Luke), Plant Health, Humppilantie 18, Jokioinen, 31600, Finland
| | - Jarkko Hantula
- Natural Resources Institute Finland (Luke), Forest Health and Biodiversity, Latokartanonkaari 9, Helsinki, FI-00790, Finland
| | - Eeva J Vainio
- Natural Resources Institute Finland (Luke), Forest Health and Biodiversity, Latokartanonkaari 9, Helsinki, FI-00790, Finland
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12
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Botella L, Jung T. Multiple Viral Infections Detected in Phytophthora condilina by Total and Small RNA Sequencing. Viruses 2021; 13:v13040620. [PMID: 33916635 PMCID: PMC8067226 DOI: 10.3390/v13040620] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 12/13/2022] Open
Abstract
Marine oomycetes have recently been shown to be concurrently infected by (−)ssRNA viruses of the order Bunyavirales. In this work, even higher virus variability was found in a single isolate of Phytophthora condilina, a recently described member of Phytophthora phylogenetic Clade 6a, which was isolated from brackish estuarine waters in southern Portugal. Using total and small RNA-seq the full RdRp of 13 different potential novel bunya-like viruses and two complete toti-like viruses were detected. All these viruses were successfully confirmed by reverse transcription polymerase chain reaction (RT-PCR) using total RNA as template, but complementarily one of the toti-like and five of the bunya-like viruses were confirmed when dsRNA was purified for RT-PCR. In our study, total RNA-seq was by far more efficient for de novo assembling of the virus sequencing but small RNA-seq showed higher read numbers for most viruses. Two main populations of small RNAs (21 nts and 25 nts-long) were identified, which were in accordance with other Phytophthora species. To the best of our knowledge, this is the first study using small RNA sequencing to identify viruses in Phytophthora spp.
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Affiliation(s)
- Leticia Botella
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1, 61300 Brno, Czech Republic;
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, Na Sadkach 1780, 37005 Ceske Budejovice, Czech Republic
- Correspondence: ; Tel.: +420-389-032-942
| | - Thomas Jung
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1, 61300 Brno, Czech Republic;
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Uchida K, Sakuta K, Ito A, Takahashi Y, Katayama Y, Omatsu T, Mizutani T, Arie T, Komatsu K, Fukuhara T, Uematsu S, Okada R, Moriyama H. Two Novel Endornaviruses Co-infecting a Phytophthora Pathogen of Asparagus officinalis Modulate the Developmental Stages and Fungicide Sensitivities of the Host Oomycete. Front Microbiol 2021; 12:633502. [PMID: 33633714 PMCID: PMC7902037 DOI: 10.3389/fmicb.2021.633502] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/14/2021] [Indexed: 01/06/2023] Open
Abstract
Two novel endornaviruses, Phytophthora endornavirus 2 (PEV2) and Phytophthora endornavirus 3 (PEV3) were found in isolates of a Phytophthora pathogen of asparagus collected in Japan. A molecular phylogenetic analysis indicated that PEV2 and PEV3 belong to the genus Alphaendornavirus. The PEV2 and PEV3 genomes consist of 14,345 and 13,810 bp, and they contain single open reading frames of 4,640 and 4,603 codons, respectively. Their polyproteins contain the conserved domains of an RNA helicase, a UDP-glycosyltransferase, and an RNA-dependent RNA polymerase, which are conserved in other alphaendornaviruses. PEV2 is closely related to Brown algae endornavirus 2, whereas PEV3 is closely related to Phytophthora endornavirus 1 (PEV1), which infects a Phytophthora sp. specific to Douglas fir. PEV2 and PEV3 were detected at high titers in two original Phytophthora sp. isolates, and we found a sub-isolate with low titers of the viruses during subculture. We used the high- and low-titer isolates to evaluate the effects of the viruses on the growth, development, and fungicide sensitivities of the Phytophthora sp. host. The high-titer isolates produced smaller mycelial colonies and much higher numbers of zoosporangia than the low-titer isolate. These results suggest that PEV2 and PEV3 inhibited hyphal growth and stimulated zoosporangium formation. The high-titer isolates were more sensitive than the low-titer isolate to the fungicides benthiavalicarb-isopropyl, famoxadone, and chlorothalonil. In contrast, the high-titer isolates displayed lower sensitivity to the fungicide metalaxyl (an inhibitor of RNA polymerase I) when compared with the low-titer isolate. These results indicate that persistent infection with PEV2 and PEV3 may potentially affect the fungicide sensitivities of the host oomycete.
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Affiliation(s)
- Keiko Uchida
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Kohei Sakuta
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Aori Ito
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Yumi Takahashi
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Yukie Katayama
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tsutomu Omatsu
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tetsuya Mizutani
- Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tsutomu Arie
- Laboratory of Plant Pathology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Ken Komatsu
- Laboratory of Plant Pathology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Toshiyuki Fukuhara
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Seiji Uematsu
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Ryo Okada
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Hiromitsu Moriyama
- Laboratory of Molecular and Cellular Biology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
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14
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Zhao Y, Zhang Y, Wan X, She Y, Li M, Xi H, Xie J, Wen C. A Novel Ourmia-Like Mycovirus Confers Hypovirulence-Associated Traits on Fusarium oxysporum. Front Microbiol 2020; 11:569869. [PMID: 33362731 PMCID: PMC7756082 DOI: 10.3389/fmicb.2020.569869] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/12/2020] [Indexed: 12/20/2022] Open
Abstract
Fusarium wilt caused by Fusarium oxysporum f. sp. momordicae (FoM) is an important fungal disease that affects the production of bitter gourd. Hypovirulence-associated mycoviruses have great potential and application prospects for controlling the fungal disease. In this study, a novel ourmia-like virus, named Fusarium oxysporum ourmia-like virus 1 (FoOuLV1), was isolated from FoM strain HuN8. The viral genomic RNA is 2,712 nucleotides (nt) in length and contains an open reading frame (ORF) encoding a putative RNA-dependent RNA polymerase (RdRp) using either standard or mitochondrial codes. In strain HuN8, there was also a FoOuLV1-associated RNA segment with 1,173 nt in length with no sequence homology. Phylogenetic analysis showed that FoOuLV1 is a member of the genus Magoulivirus of the family Botourmiaviridae. FoOuLV1 was found to be associated with hypovirulence in FoM. Moreover, FoOuLV1 and its hypovirulence trait can be transmitted horizontally to other FoM strains and also to other formae speciale strains of F. oxysporum. In addition, FoOuLV1 showed significant biological control effect against the bitter gourd Fusarium wilt. To our knowledge, this study reveals the first description of a hypovirulence-associated ourmia-like mycovirus, which has the potential to the biological control of Fusarium wilt.
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Affiliation(s)
- Ying Zhao
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yuanyan Zhang
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xinru Wan
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Yuanyuan She
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Min Li
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Huijun Xi
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Caiyi Wen
- College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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15
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Chiapello M, Rodríguez-Romero J, Ayllón MA, Turina M. Analysis of the virome associated to grapevine downy mildew lesions reveals new mycovirus lineages. Virus Evol 2020; 6:veaa058. [PMID: 33324489 PMCID: PMC7724247 DOI: 10.1093/ve/veaa058] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The obligatory biotrophic oomycetes Plasmopara viticola is the causal agent of downy mildew, a destructive disease of grapevine worldwide. So far, chemical fungicides are widely employed to limit this pathogen, but their adverse effects are stimulating the quest for environmentally friendly alternative approaches. Here, we report on the search for mycoviruses that might be later developed as biocontrol agents for this pathogen. Symptomatic leaves were collected from various regions in Spain and Italy and mycelia associated to leaf lesions was harvested. Total RNA extractions were depleted of rRNA and metatranscriptomes were generated using a high-throughput sequencing approach. The virome associated to leaf lesions was then characterized through a bioinformatic pipeline relying on blast searches against current viral databases. Here, we present an inventory of 283 new RNA viruses: 222 positive strand RNA viruses, 29 negative strand RNA viruses, 27 double-stranded RNA viruses and 5 ORFan virus RdRP segments, which could not be reliably assigned to any existing group in the Riboviria. In addition to ORFan viruses, we found other surprising new evolutionary trajectories in this wide inventory of viruses. The most represented viruses in our collection are those in phylum Lenarviricota, and, among them, a group of mycovirus segments distantly related to narnaviruses, but characterized by a polymerase palm domain lacking subdomain C, with the putative GDD catalytic triad. We also provided evidence of a strict association between two RNA segments that form a new mycovirus clade of positive strand RNA in the phylum Kitrinoviricota, order Martellivirales. In the phylum Negarnaviricota, we report for the first time in the order Mononegavirales a clade of viruses that is ambisense, a feature that so far was present only in the order Bunyavirales. Furthermore, in the same phylum we detected the widespread occurrence and abundant accumulation in our libraries of a distinct mycovirus clade distantly related to the Muvirales and Goujanvirales orders, which so far include only viruses infecting invertebrates. Possible new oomycetes-specific virus clades are also described in the phylum Duplornaviricota. These data greatly expand the evolutionary history of mycoviruses adding new layers of diversity to the realm Riboviria.
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Affiliation(s)
- M Chiapello
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, Torino 10135, Italy
| | - J Rodríguez-Romero
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain.,Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid 28040, Spain
| | - M A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, Madrid 28223, Spain.,Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid 28040, Spain
| | - M Turina
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, Torino 10135, Italy
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16
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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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17
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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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18
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Botella L, Janoušek J, Maia C, Jung MH, Raco M, Jung T. Marine Oomycetes of the Genus Halophytophthora Harbor Viruses Related to Bunyaviruses. Front Microbiol 2020; 11:1467. [PMID: 32760358 PMCID: PMC7375090 DOI: 10.3389/fmicb.2020.01467] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 06/04/2020] [Indexed: 12/14/2022] Open
Abstract
We investigated the incidence of RNA viruses in a collection of Halophytophthora spp. from estuarine ecosystems in southern Portugal. The first approach to detect the presence of viruses was based on the occurrence of dsRNA, typically considered as a viral molecule in plants and fungi. Two dsRNA-banding patterns (∼7 and 9 kb) were observed in seven of 73 Halophytophthora isolates tested (9.6%). Consequently, two dsRNA-hosting isolates were chosen to perform stranded RNA sequencing for de novo virus sequence assembly. A total of eight putative novel virus species with genomic affinities to members of the order Bunyavirales were detected and their full-length RdRp gene characterized by RACE. Based on the direct partial amplification of their RdRp gene by RT-PCR multiple viral infections occur in both isolates selected. Likewise, the screening of those viruses in the whole collection of Halophytophthora isolates showed that their occurrence is limited to one single Halophytophthora species. To our knowledge, this is the first report demonstrating the presence of negative (−) ssRNA viruses in marine oomycetes.
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Affiliation(s)
- Leticia Botella
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia.,Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, Ceske Budejovice, Czechia
| | - Josef Janoušek
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Cristiana Maia
- Centre for Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - Marilia Horta Jung
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Milica Raco
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Thomas Jung
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
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19
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Espino-Vázquez AN, Bermúdez-Barrientos JR, Cabrera-Rangel JF, Córdova-López G, Cardoso-Martínez F, Martínez-Vázquez A, Camarena-Pozos DA, Mondo SJ, Pawlowska TE, Abreu-Goodger C, Partida-Martínez LP. Narnaviruses: novel players in fungal-bacterial symbioses. ISME JOURNAL 2020; 14:1743-1754. [PMID: 32269378 DOI: 10.1038/s41396-020-0638-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 03/11/2020] [Accepted: 03/17/2020] [Indexed: 12/31/2022]
Abstract
Rhizopus microsporus is an early-diverging fungal species with importance in ecology, agriculture, food production, and public health. Pathogenic strains of R. microsporus harbor an intracellular bacterial symbiont, Mycetohabitans (formerly named Burkholderia). This vertically transmitted bacterial symbiont is responsible for the production of toxins crucial to the pathogenicity of Rhizopus and remarkably also for fungal reproduction. Here we show that R. microsporus can live not only in symbiosis with bacteria but also with two viral members of the genus Narnavirus. Our experiments revealed that both viruses replicated similarly in the growth conditions we tested. Viral copies were affected by the developmental stage of the fungus, the substrate, and the presence or absence of Mycetohabitans. Absolute quantification of narnaviruses in isolated asexual sporangiospores and sexual zygospores indicates their vertical transmission. By curing R. microsporus of its viral and bacterial symbionts and reinfecting bacteria to reestablish symbiosis, we demonstrate that these viruses affect fungal biology. Narnaviruses decrease asexual reproduction, but together with Mycetohabitans, are required for sexual reproductive success. This fungal-bacterial-viral system represents an outstanding model to investigate three-way microbial symbioses and their evolution.
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Affiliation(s)
- Astrid N Espino-Vázquez
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - J Roberto Bermúdez-Barrientos
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico.,Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - J Francisco Cabrera-Rangel
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - Gonzalo Córdova-López
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico.,Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - Faviola Cardoso-Martínez
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - Azul Martínez-Vázquez
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - David A Camarena-Pozos
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - Stephen J Mondo
- US Department of Energy Joint Genome Institute, Walnut Creek, CA, 94598, USA.,Bioagricultural Science and Pest Management Department, Colorado State University, Fort Collins, CO, 80521, USA
| | - Teresa E Pawlowska
- School of Integrative Plant Science, Plant Pathology and Plant Microbe-Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Cei Abreu-Goodger
- Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico
| | - Laila P Partida-Martínez
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Irapuato, 36824, Mexico.
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20
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Dinan AM, Lukhovitskaya NI, Olendraite I, Firth AE. A case for a negative-strand coding sequence in a group of positive-sense RNA viruses. Virus Evol 2020; 6:veaa007. [PMID: 32064120 PMCID: PMC7010960 DOI: 10.1093/ve/veaa007] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Positive-sense single-stranded RNA viruses form the largest and most diverse group of eukaryote-infecting viruses. Their genomes comprise one or more segments of coding-sense RNA that function directly as messenger RNAs upon release into the cytoplasm of infected cells. Positive-sense RNA viruses are generally accepted to encode proteins solely on the positive strand. However, we previously identified a surprisingly long (∼1,000-codon) open reading frame (ORF) on the negative strand of some members of the family Narnaviridae which, together with RNA bacteriophages of the family Leviviridae, form a sister group to all other positive-sense RNA viruses. Here, we completed the genomes of three mosquito-associated narnaviruses, all of which have the long reverse-frame ORF. We systematically identified narnaviral sequences in public data sets from a wide range of sources, including arthropod, fungal, and plant transcriptomic data sets. Long reverse-frame ORFs are widespread in one clade of narnaviruses, where they frequently occupy >95 per cent of the genome. The reverse-frame ORFs correspond to a specific avoidance of CUA, UUA, and UCA codons (i.e. stop codon reverse complements) in the forward-frame RNA-dependent RNA polymerase ORF. However, absence of these codons cannot be explained by other factors such as inability to decode these codons or GC3 bias. Together with other analyses, we provide the strongest evidence yet of coding capacity on the negative strand of a positive-sense RNA virus. As these ORFs comprise some of the longest known overlapping genes, their study may be of broad relevance to understanding overlapping gene evolution and de novo origin of genes.
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Affiliation(s)
- Adam M Dinan
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Nina I Lukhovitskaya
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Ingrida Olendraite
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
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21
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Charon J, Grigg MJ, Eden JS, Piera KA, Rana H, William T, Rose K, Davenport MP, Anstey NM, Holmes EC. Novel RNA viruses associated with Plasmodium vivax in human malaria and Leucocytozoon parasites in avian disease. PLoS Pathog 2019; 15:e1008216. [PMID: 31887217 PMCID: PMC6953888 DOI: 10.1371/journal.ppat.1008216] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 01/10/2020] [Accepted: 11/13/2019] [Indexed: 12/15/2022] Open
Abstract
Eukaryotes of the genus Plasmodium cause malaria, a parasitic disease responsible for substantial morbidity and mortality in humans. Yet, the nature and abundance of any viruses carried by these divergent eukaryotic parasites is unknown. We investigated the Plasmodium virome by performing a meta-transcriptomic analysis of blood samples taken from patients suffering from malaria and infected with P. vivax, P. falciparum or P. knowlesi. This resulted in the identification of a narnavirus-like sequence, encoding an RNA polymerase and restricted to P. vivax samples, as well as an associated viral segment of unknown function. These data, confirmed by PCR, are indicative of a novel RNA virus that we term Matryoshka RNA virus 1 (MaRNAV-1) to reflect its analogy to a "Russian doll": a virus, infecting a parasite, infecting an animal. Additional screening revealed that MaRNAV-1 was abundant in geographically diverse P. vivax derived from humans and mosquitoes, strongly supporting its association with this parasite, and not in any of the other Plasmodium samples analyzed here nor Anopheles mosquitoes in the absence of Plasmodium. Notably, related bi-segmented narnavirus-like sequences (MaRNAV-2) were retrieved from Australian birds infected with a Leucocytozoon—a genus of eukaryotic parasites that group with Plasmodium in the Apicomplexa subclass hematozoa. Together, these data support the establishment of two new phylogenetically divergent and genomically distinct viral species associated with protists, including the first virus likely infecting Plasmodium parasites. As well as broadening our understanding of the diversity and evolutionary history of the eukaryotic virosphere, the restriction to P. vivax may be of importance in understanding P. vivax-specific biology in humans and mosquitoes, and how viral co-infection might alter host responses at each stage of the P. vivax life-cycle. While parasites are a major cause of human disease, they can themselves be infected by viruses. We asked whether three of the major malaria-causing parasites in humans—Plasmodium vivax, P. falciparum and P. knowlesi—were also infected by viruses. To this end we performed total RNA-Sequencing (“meta-transcriptomics”) on human blood samples infected with these Plasmodium species. This resulted in the discovery of an abundant bi-segmented virus—Matryoshka RNA virus 1 (MaRNAV-1)—in all P. vivax samples tested (but no other Plasmodium species) that contains a replicase segment related to those of narnaviruses, arguably the simplest type of RNA viruses discovered to date. By screening for MaRNAV-1 in a larger set of Plasmodium species we revealed a strong specificity between this virus and P. vivax, as well as the presence of a related virus—MaRNAV-2—in avian Leucocytozoon hematozoa parasites. This is the first discovery of a Plasmodium-associated virus and will assist in revealing the deep evolutionary history of RNA viruses and our understanding of Plasmodium biology and disease processes.
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Affiliation(s)
- Justine Charon
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Matthew J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Infectious Disease Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - John-Sebastian Eden
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
- Centre for Virus Research, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
| | - Kim A. Piera
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Hafsa Rana
- Centre for Virus Research, Westmead Institute for Medical Research, Westmead, New South Wales, Australia
| | - Timothy William
- Infectious Disease Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
- Clinical Research Centre – Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
- Gleneagles Hospital, Kota Kinabalu, Sabah, Malaysia
| | - Karrie Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, New South Wales, Australia
| | - Miles P. Davenport
- Kirby Institute for Infection and Immunity, University of New South Wales, Sydney, New South Wales, Australia
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Infectious Disease Society Kota Kinabalu Sabah – Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Edward C. Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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DeRisi JL, Huber G, Kistler A, Retallack H, Wilkinson M, Yllanes D. An exploration of ambigrammatic sequences in narnaviruses. Sci Rep 2019; 9:17982. [PMID: 31784609 PMCID: PMC6884476 DOI: 10.1038/s41598-019-54181-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/11/2019] [Indexed: 11/09/2022] Open
Abstract
Narnaviruses have been described as positive-sense RNA viruses with a remarkably simple genome of ~3 kb, encoding only a highly conserved RNA-dependent RNA polymerase (RdRp). Many narnaviruses, however, are 'ambigrammatic' and harbour an additional uninterrupted open reading frame (ORF) covering almost the entire length of the reverse complement strand. No function has been described for this ORF, yet the absence of stops is conserved across diverse narnaviruses, and in every case the codons in the reverse ORF and the RdRp are aligned. The >3 kb ORF overlap on opposite strands, unprecedented among RNA viruses, motivates an exploration of the constraints imposed or alleviated by the codon alignment. Here, we show that only when the codon frames are aligned can all stop codons be eliminated from the reverse strand by synonymous single-nucleotide substitutions in the RdRp gene, suggesting a mechanism for de novo gene creation within a strongly conserved amino-acid sequence. It will be fascinating to explore what implications this coding strategy has for other aspects of narnavirus biology. Beyond narnaviruses, our rapidly expanding catalogue of viral diversity may yet reveal additional examples of this broadly-extensible principle for ambigrammatic-sequence development.
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Affiliation(s)
- Joseph L DeRisi
- Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA, 94158, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Greg Huber
- Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA, 94158, USA
| | - Amy Kistler
- Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA, 94158, USA
| | - Hanna Retallack
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
| | - Michael Wilkinson
- Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA, 94158, USA
- School of Mathematics and Statistics, The Open University, Walton Hall, Milton Keynes, MK7 6AA, England
| | - David Yllanes
- Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA, 94158, USA.
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23
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Cai G, Fry WE, Hillman BI. PiRV-2 stimulates sporulation in Phytophthora infestans. Virus Res 2019; 271:197674. [DOI: 10.1016/j.virusres.2019.197674] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/21/2019] [Accepted: 07/22/2019] [Indexed: 02/05/2023]
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24
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Three ourmia-like viruses and their associated RNAs in Pyricularia oryzae. Virology 2019; 534:25-35. [DOI: 10.1016/j.virol.2019.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 05/20/2019] [Accepted: 05/24/2019] [Indexed: 11/18/2022]
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25
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Sutela S, Poimala A, Vainio EJ. Viruses of fungi and oomycetes in the soil environment. FEMS Microbiol Ecol 2019; 95:5542194. [DOI: 10.1093/femsec/fiz119] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/30/2019] [Indexed: 12/17/2022] Open
Abstract
ABSTRACTSoils support a myriad of organisms hosting highly diverse viromes. In this minireview, we focus on viruses hosted by true fungi and oomycetes (members of Stamenopila, Chromalveolata) inhabiting bulk soil, rhizosphere and litter layer, and representing different ecological guilds, including fungal saprotrophs, mycorrhizal fungi, mutualistic endophytes and pathogens. Viruses infecting fungi and oomycetes are characterized by persistent intracellular nonlytic lifestyles and transmission via spores and/or hyphal contacts. Almost all fungal and oomycete viruses have genomes composed of single-stranded or double-stranded RNA, and recent studies have revealed numerous novel viruses representing yet unclassified family-level groups. Depending on the virus–host combination, infections can be asymptomatic, beneficial or detrimental to the host. Thus, mycovirus infections may contribute to the multiplex interactions of hosts, therefore likely affecting the dynamics of fungal communities required for the functioning of soil ecosystems. However, the effects of fungal and oomycete viruses on soil ecological processes are still mostly unknown. Interestingly, new metagenomics data suggest an extensive level of horizontal virus transfer between plants, fungi and insects.
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Affiliation(s)
- Suvi Sutela
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Anna Poimala
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Eeva J Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
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26
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Li CX, Zhu JZ, Gao BD, Zhu HJ, Zhou Q, Zhong J. Characterization of a Novel Ourmia-Like Mycovirus Infecting Magnaporthe oryzae and Implications for Viral Diversity and Evolution. Viruses 2019; 11:v11030223. [PMID: 30841545 PMCID: PMC6465991 DOI: 10.3390/v11030223] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 01/06/2023] Open
Abstract
Here, the molecular characterization of a novel mycovirus that was isolated from a phytopathogenic fungus Magnaporthe oryzae and designed as Magnaporthe oryzae ourmia-like virus 4 (MOLV4) is reported. MOLV4 has a genome that is 2497 bp long and possesses a single open reading frame (ORF), which encodes the product RNA-dependent RNA polymerase (RdRp). Sequence similarities were found between the MOLV4 encoded RdRp and the counterparts of a few previously reported ourmia-like mycoviruses. Virus-curing and biological comparison indicate that the virus has no or mild effects on the morphology and mycelium growth rate of the host fungus. Phylogenetic analysis using the RdRp aa sequences was performed. The results show that MOLV4 is clustered with the ourmia-like mycoviruses, forming a clade closely related to ourmiaviruses but distinct from narnaviruses. In addition, database searches revealed that several MOLV4-related sequences are present in the transcriptome shotgun assembly (TSA) library, expressed sequence tag database (ESTdb), whole-genome shotgun (WGS) library, and genomic survey sequences (GSS) libraries of a few other species of eukaryote organisms. Our results show that MOLV4, together with other similar ourmia-like mycoviruses, might represent a virus clade that links the plant ourmiaviruses and fungal narnaviruses and has a wide range of hosts.
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Affiliation(s)
- Chang Xin Li
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Jun Zi Zhu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Bi Da Gao
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Hong Jian Zhu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Qian Zhou
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Jie Zhong
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
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27
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Cai G, Myers K, Fry WE, Hillman BI. Phytophthora infestans RNA virus 2, a novel RNA virus from Phytophthora infestans, does not belong to any known virus group. Arch Virol 2018; 164:567-572. [DOI: 10.1007/s00705-018-4050-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 09/23/2018] [Indexed: 12/12/2022]
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28
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Grybchuk D, Kostygov AY, Macedo DH, Votýpka J, Lukeš J, Yurchenko V. RNA Viruses in Blechomonas (Trypanosomatidae) and Evolution of Leishmaniavirus. mBio 2018; 9:e01932-18. [PMID: 30327446 PMCID: PMC6191543 DOI: 10.1128/mbio.01932-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 09/11/2018] [Indexed: 01/25/2023] Open
Abstract
In this work, we analyzed viral prevalence in trypanosomatid parasites (Blechomonas spp.) infecting Siphonaptera and discovered nine species of viruses from three different groups (leishbunyaviruses, narnaviruses, and leishmaniaviruses). Most of the flagellate isolates bore two or three viral types (mixed infections). Although no new viral groups were documented in Blechomonas spp., our findings are important for the comprehension of viral evolution. The discovery of bunyaviruses in blechomonads was anticipated, since these viruses have envelopes facilitating their interspecific transmission and have already been found in various trypanosomatids and metatranscriptomes with trypanosomatid signatures. In this work, we also provided evidence that even representatives of the family Narnaviridae are capable of host switching and evidently have accomplished switches multiple times in the course of their evolution. The most unexpected finding was the presence of leishmaniaviruses, a group previously solely confined to the human pathogens Leishmania spp. From phylogenetic inferences and analyses of the life cycles of Leishmania and Blechomonas, we concluded that a common ancestor of leishmaniaviruses most likely infected Leishmania first and was acquired by Blechomonas by horizontal transfer. Our findings demonstrate that evolution of leishmaniaviruses is more complex than previously thought and includes occasional host switching.IMPORTANCE Flagellates belonging to the genus Leishmania are important human parasites. Some strains of different Leishmania species harbor viruses (leishmaniaviruses), which facilitate metastatic spread of the parasites, thus aggravating the disease. Up until now, these viruses were known to be hosted only by Leishmania Here, we analyzed viral distribution in Blechomonas, a related group of flagellates parasitizing fleas, and revealed that they also bear leishmaniaviruses. Our findings shed light on the entangled evolution of these viruses. In addition, we documented that Blechomonas can be also infected by leishbunyaviruses and narnaviruses, viral groups known from other insects' flagellates.
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Affiliation(s)
- Danyil Grybchuk
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Alexei Y Kostygov
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Diego H Macedo
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Jan Votýpka
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice (Budweis), Czech Republic
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice (Budweis), Czech Republic
- Faculty of Sciences, University of South Bohemia, České Budejovice (Budweis), Czech Republic
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budejovice (Budweis), Czech Republic
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, Moscow, Russia
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29
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Sasai S, Tamura K, Tojo M, Herrero ML, Hoshino T, Ohki ST, Mochizuki T. A novel non-segmented double-stranded RNA virus from an Arctic isolate of Pythium polare. Virology 2018; 522:234-243. [DOI: 10.1016/j.virol.2018.07.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/09/2018] [Accepted: 07/09/2018] [Indexed: 10/28/2022]
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30
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Shiba K, Hatta C, Sasai S, Tojo M, T. Ohki S, Mochizuki T. Genome sequence of a novel partitivirus identified from the oomycete Pythium nunn. Arch Virol 2018; 163:2561-2563. [DOI: 10.1007/s00705-018-3880-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/08/2018] [Indexed: 11/30/2022]
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31
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Velasco L, Arjona-Girona I, Ariza-Fernández MT, Cretazzo E, López-Herrera C. A Novel Hypovirus Species From Xylariaceae Fungi Infecting Avocado. Front Microbiol 2018; 9:778. [PMID: 29867781 PMCID: PMC5952064 DOI: 10.3389/fmicb.2018.00778] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/05/2018] [Indexed: 12/22/2022] Open
Abstract
The white rot root disease caused by Rosellinia necatrix is a major concern for avocado cultivation in Spain. Healthy escapes of avocado trees surrounded by diseased trees prompted us to hypothesize the presence of hypovirulent R. necatrix due to mycovirus infections. Recently, we reported the presence of another fungal species, Entoleuca sp., belonging to the Xylariaceae, that was also found in healthy avocado trees and frequently co-infecting the same roots than R. necatrix. We investigated the presence of mycoviruses that might explain the hypovirulence. For that, we performed deep sequencing of dsRNAs from two isolates of Entoleuca sp. that revealed the simultaneous infection of several mycoviruses, not described previously. In this work, we report a new member of the Hypoviridae, tentatively named Entoleuca hypovirus 1 (EnHV1). The complete genome sequence was obtained for two EnHV1 strains, which lengths resulted to be 14,958 and 14,984 nt, respectively, excluding the poly(A) tails. The genome shows two ORFs separated by a 32-nt inter-ORF, and both 5′- and 3′-UTRs longer than any other hypovirus reported to date. The analysis of virus-derived siRNA populations obtained from Entoleuca sp. demonstrated antiviral silencing activity in this fungus. We screened a collection of Entoleuca sp. and R. necatrix isolates and found that EnHV1 was present in both fungal species. A genetic population analysis of EnHV1 strains revealed the presence of two main clades, each of them including members from both Entoleuca sp. and R. necatrix, which suggests intra- and interspecific virus transmission in the field. Several attempts failed to cure Entoleuca sp. from EnHV1. However, all Entoleuca sp. isolates collected from avocado, whether harboring the virus or not, showed hypovirulence. Conversely, all R. necatrix isolates were pathogenic to that crop, regardless of being infected by EnHV1.
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Affiliation(s)
- Leonardo Velasco
- Instituto Andaluz de Investigación y Formación Agraria, Málaga, Spain
| | - Isabel Arjona-Girona
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
| | | | - Enrico Cretazzo
- Instituto Andaluz de Investigación y Formación Agraria, Málaga, Spain
| | - Carlos López-Herrera
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
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32
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Viral discovery and diversity in trypanosomatid protozoa with a focus on relatives of the human parasite Leishmania. Proc Natl Acad Sci U S A 2017; 115:E506-E515. [PMID: 29284754 DOI: 10.1073/pnas.1717806115] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Knowledge of viral diversity is expanding greatly, but many lineages remain underexplored. We surveyed RNA viruses in 52 cultured monoxenous relatives of the human parasite Leishmania (Crithidia and Leptomonas), as well as plant-infecting PhytomonasLeptomonas pyrrhocoris was a hotbed for viral discovery, carrying a virus (Leptomonas pyrrhocoris ostravirus 1) with a highly divergent RNA-dependent RNA polymerase missed by conventional BLAST searches, an emergent clade of tombus-like viruses, and an example of viral endogenization. A deep-branching clade of trypanosomatid narnaviruses was found, notable as Leptomonas seymouri bearing Narna-like virus 1 (LepseyNLV1) have been reported in cultures recovered from patients with visceral leishmaniasis. A deep-branching trypanosomatid viral lineage showing strong affinities to bunyaviruses was termed "Leishbunyavirus" (LBV) and judged sufficiently distinct to warrant assignment within a proposed family termed "Leishbunyaviridae" Numerous relatives of trypanosomatid viruses were found in insect metatranscriptomic surveys, which likely arise from trypanosomatid microbiota. Despite extensive sampling we found no relatives of the totivirus Leishmaniavirus (LRV1/2), implying that it was acquired at about the same time the Leishmania became able to parasitize vertebrates. As viruses were found in over a quarter of isolates tested, many more are likely to be found in the >600 unsurveyed trypanosomatid species. Viral loss was occasionally observed in culture, providing potentially isogenic virus-free lines enabling studies probing the biological role of trypanosomatid viruses. These data shed important insights on the emergence of viruses within an important trypanosomatid clade relevant to human disease.
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33
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Phomopsis longicolla RNA virus 1 - Novel virus at the edge of myco- and plant viruses. Virology 2017; 506:14-18. [PMID: 28288321 DOI: 10.1016/j.virol.2017.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/03/2017] [Accepted: 03/08/2017] [Indexed: 11/23/2022]
Abstract
The complete nucleotide sequence of a new RNA mycovirus in the KY isolate of Phomopsis longicolla Hobbs 1985 and its protoplasts subcultures p5, p9, and ME711 was discovered. The virus, provisionally named Phomopsis longicolla RNA virus 1 (PlRV1), was localized in mitochondria and was determined to have a genome 2822 nucleotides long. A single open reading frame could be translated in silico by both standard and mitochondrial genetic codes into a product featuring conservative domains for an RNA-dependent RNA polymerase (RdRp). The RdRp of PlRV1 has no counterpart among mycoviruses, but it is about 30% identical with the RdRp of plant ourmiaviruses. Recently, new mycoviruses related to plant ourmiaviruses and forming one clade with PlRV1 have been discovered. This separate clade could represent the crucial link between plant and fungal viruses.
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34
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ssRNA viruses from biotrophic Oomycetes form a new phylogenetic group between Nodaviridae and Tombusviridae. Arch Virol 2017; 162:1319-1324. [DOI: 10.1007/s00705-017-3243-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
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35
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Kotta-Loizou I, Coutts RHA. Studies on the Virome of the Entomopathogenic Fungus Beauveria bassiana Reveal Novel dsRNA Elements and Mild Hypervirulence. PLoS Pathog 2017; 13:e1006183. [PMID: 28114361 PMCID: PMC5293280 DOI: 10.1371/journal.ppat.1006183] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 02/06/2017] [Accepted: 01/12/2017] [Indexed: 12/20/2022] Open
Abstract
The entomopathogenic fungus Beauveria bassiana has a wide host range and is used as a biocontrol agent against arthropod pests. Mycoviruses have been described in phytopathogenic fungi while in entomopathogenic fungi their presence has been reported only rarely. Here we show that 21.3% of a collection of B. bassiana isolates sourced from worldwide locations, harbor dsRNA elements. Molecular characterization of these elements revealed the prevalence of mycoviruses belonging to the Partitiviridae and Totiviridae families, the smallest reported virus to date, belonging to the family Narnaviridae, and viruses unassigned to a family or genus. Of particular importance is the discovery of members of a newly proposed family Polymycoviridae in B. bassiana. Polymycoviruses, previously designated as tetramycoviruses, consist of four non-conventionally encapsidated capped dsRNAs. The presence of additional non-homologous genomic segments in B. bassiana polymycoviruses and other fungi illustrates the unprecedented dynamic nature of the viral genome. Finally, a comparison of virus-free and virus-infected isogenic lines derived from an exemplar B. bassiana isolate revealed a mild hypervirulent effect of mycoviruses on the growth of their host isolate and on its pathogenicity against the greater wax moth Galleria mellonella, highlighting for the first time the potential of mycoviruses as enhancers of biocontrol agents.
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Affiliation(s)
- Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
- * E-mail:
| | - Robert H. A. Coutts
- Geography, Environment and Agriculture Division, Department of Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
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36
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Osaki H, Sasaki A, Nomiyama K, Tomioka K. Multiple virus infection in a single strain of Fusarium poae shown by deep sequencing. Virus Genes 2016; 52:835-847. [DOI: 10.1007/s11262-016-1379-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/08/2016] [Indexed: 01/22/2023]
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37
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Akopyants NS, Lye LF, Dobson DE, Lukeš J, Beverley SM. A Narnavirus in the Trypanosomatid Protist Plant Pathogen Phytomonas serpens. GENOME ANNOUNCEMENTS 2016; 4:e00711-16. [PMID: 27469953 PMCID: PMC4966457 DOI: 10.1128/genomea.00711-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 06/10/2016] [Indexed: 12/29/2022]
Abstract
We describe here a new RNA virus (PserNV1) from the plant protist parasite Phytomonas serpens (family Trypanosomatidae, Kinetoplastida, supergroup Excavata). The properties of PserNV1 permit assignment to the genus Narnavirus (Narnaviridae), the first reported from a host other than fungi or oomycetes.
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Affiliation(s)
- Natalia S Akopyants
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lon-Fye Lye
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Deborah E Dobson
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Julius Lukeš
- Biology Centre and Faculty of Sciences, Institute of Parasitology, University of South Bohemia, České Budějovice, Czech Republic Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Stephen M Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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38
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Donaire L, Rozas J, Ayllón MA. Molecular characterization of Botrytis ourmia-like virus, a mycovirus close to the plant pathogenic genus Ourmiavirus. Virology 2016; 489:158-64. [PMID: 26765967 DOI: 10.1016/j.virol.2015.11.027] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 11/20/2015] [Accepted: 11/25/2015] [Indexed: 11/24/2022]
Abstract
The molecular characterization of a novel single-stranded RNA virus, obtained by next generation sequencing using Illumina platform, in a field grapevine isolate of the plant pathogenic fungus Botrytis, is reported in this work. The sequence comparison of this virus against the NCBI database showed a strong identity with RNA dependent RNA polymerases (RdRps) of plant pathogenic viruses belonging to the genus Ourmiavirus, therefore, this novel virus was named Botrytis ourmia-like virus (BOLV). BOLV has one open reading frame of 2169 nucleotides, which encodes a protein of 722 amino acids showing conserved domains of plant RNA viruses RdRps such as the most conserved GDD active domain. Our analyses showed that BOLV is phylogenetically closer to the fungal Narnavirus and the plant Ourmiavirus than to Mitovirus of the family Narnaviridae. Hence, we proposed that BOLV might represent the link between fungal viruses of the family Narnaviridae and the plant ourmiaviruses.
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Affiliation(s)
- Livia Donaire
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Julio Rozas
- Departament de Genètica and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - María A Ayllón
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Campus de Montegancedo, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain.
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Bruenn JA, Warner BE, Yerramsetty P. Widespread mitovirus sequences in plant genomes. PeerJ 2015; 3:e876. [PMID: 25870770 PMCID: PMC4393810 DOI: 10.7717/peerj.876] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/13/2015] [Indexed: 11/25/2022] Open
Abstract
The exploration of the evolution of RNA viruses has been aided recently by the discovery of copies of fragments or complete genomes of non-retroviral RNA viruses (Non-retroviral Endogenous RNA Viral Elements, or NERVEs) in many eukaryotic nuclear genomes. Among the most prominent NERVEs are partial copies of the RNA dependent RNA polymerase (RdRP) of the mitoviruses in plant mitochondrial genomes. Mitoviruses are in the family Narnaviridae, which are the simplest viruses, encoding only a single protein (the RdRP) in their unencapsidated viral plus strand. Narnaviruses are known only in fungi, and the origin of plant mitochondrial mitovirus NERVEs appears to be horizontal transfer from plant pathogenic fungi. At least one mitochondrial mitovirus NERVE, but not its nuclear copy, is expressed.
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Affiliation(s)
- Jeremy A Bruenn
- Department of Biological Sciences, State University of New York at Buffalo , Buffalo, NY , USA
| | - Benjamin E Warner
- Department of Biological Sciences, State University of New York at Buffalo , Buffalo, NY , USA
| | - Pradeep Yerramsetty
- Department of Biological Sciences, State University of New York at Buffalo , Buffalo, NY , USA
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40
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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: 160] [Impact Index Per Article: 17.8] [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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Occurrence and genetic diversity of the Plasmopara halstedii virus in sunflower downy mildew populations of the world. Fungal Biol 2014; 119:170-8. [PMID: 25749368 DOI: 10.1016/j.funbio.2014.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/28/2014] [Accepted: 12/08/2014] [Indexed: 11/22/2022]
Abstract
Plasmopara halstedii virus (PhV) is a ss(+)RNA virus that exclusively occurs in the sunflower downy mildew pathogen Plasmopara halstedii, a biotrophic oomycete of severe economic impact. The virus origin and its genomic variability are unknown. A PCR-based screening of 128 samples of P. halstedii from five continents and up to 40 y old was conducted. PhV RNA was found in over 90 % of the isolates with no correlation to geographic origin or pathotype of its host. Sequence analyses of the two open reading frames (ORFs) revealed only 18 single nucleotide polymorphisms (SNPs) in 3873 nucleotides. The SNPs had no recognizable effect on the two encoded virus proteins. In 398 nucleotides of the untranslated regions (UTRs) of the RNA 2 strand eight additional SNPs and one short deletion was found. Modelling experiments revealed no effects of these variations on the secondary structure of the RNA. The results showed the presence of PhV in P. halstedii isolates of global origin and the existence of the virus since more than 40 y. The virus genome revealed a surprisingly low variation in both coding and noncoding parts. No sequence differences were correlated with host pathotype or geographic populations of the oomycete.
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Detection and genetic characterisation of a novel mycovirus in Hymenoscyphus fraxineus, the causal agent of ash dieback. INFECTION GENETICS AND EVOLUTION 2014; 28:78-86. [DOI: 10.1016/j.meegid.2014.09.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/29/2014] [Accepted: 09/01/2014] [Indexed: 12/11/2022]
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Cook S, Chung BYW, Bass D, Moureau G, Tang S, McAlister E, Culverwell CL, Glücksman E, Wang H, Brown TDK, Gould EA, Harbach RE, de Lamballerie X, Firth AE. Novel virus discovery and genome reconstruction from field RNA samples reveals highly divergent viruses in dipteran hosts. PLoS One 2013; 8:e80720. [PMID: 24260463 PMCID: PMC3832450 DOI: 10.1371/journal.pone.0080720] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 10/07/2013] [Indexed: 12/17/2022] Open
Abstract
We investigated whether small RNA (sRNA) sequenced from field-collected mosquitoes and chironomids (Diptera) can be used as a proxy signature of viral prevalence within a range of species and viral groups, using sRNAs sequenced from wild-caught specimens, to inform total RNA deep sequencing of samples of particular interest. Using this strategy, we sequenced from adult Anopheles maculipennis s.l. mosquitoes the apparently nearly complete genome of one previously undescribed virus related to chronic bee paralysis virus, and, from a pool of Ochlerotatus caspius and Oc. detritus mosquitoes, a nearly complete entomobirnavirus genome. We also reconstructed long sequences (1503-6557 nt) related to at least nine other viruses. Crucially, several of the sequences detected were reconstructed from host organisms highly divergent from those in which related viruses have been previously isolated or discovered. It is clear that viral transmission and maintenance cycles in nature are likely to be significantly more complex and taxonomically diverse than previously expected.
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Affiliation(s)
- Shelley Cook
- Department of Life Sciences, Natural History Museum, London, United Kingdom
- * E-mail: (SC); (AEF)
| | - Betty Y.-W. Chung
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - David Bass
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Gregory Moureau
- UMR_D 190 "Emergence des Pathologies Virales" (Aix-Marseille Univ. IRD French Institute of Research for Development EHESP French School of Public Health), Marseille, France
| | - Shuoya Tang
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Erica McAlister
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | | | - Edvard Glücksman
- Department of General Botany, University Duisburg-Essen, Essen, Germany
| | - Hui Wang
- Centre for Ecology & Hydrology, Wallingford, Oxfordshire, United Kingdom
| | - T. David K. Brown
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Ernest A. Gould
- UMR_D 190 "Emergence des Pathologies Virales" (Aix-Marseille Univ. IRD French Institute of Research for Development EHESP French School of Public Health), Marseille, France
- Centre for Ecology & Hydrology, Wallingford, Oxfordshire, United Kingdom
| | - Ralph E. Harbach
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Xavier de Lamballerie
- UMR_D 190 "Emergence des Pathologies Virales" (Aix-Marseille Univ. IRD French Institute of Research for Development EHESP French School of Public Health), Marseille, France
| | - Andrew E. Firth
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (SC); (AEF)
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Abstract
Phytophthora sp. is a genus in the oomycetes, which are similar to filamentous fungi in morphology and habitat, but phylogenetically more closely related to brown algae and diatoms and fall in the kingdom Stramenopila. In the past few years, several viruses have been characterized in Phytophthora species, including four viruses from Phytophthora infestans, the late blight pathogen, and an endornavirus from an unnamed Phytophthora species from Douglas fir. Studies on Phytophthora viruses have revealed several interesting systems. Phytophthora infestans RNA virus 1 (PiRV-1) and PiRV-2 are likely the first members of two new virus families; studies on PiRV-3 support the establishment of a new virus genus that is not affiliated with established virus families; PiRV-4 is a member of Narnaviridae, most likely in the genus Narnavirus; and Phytophthora endornavirus 1 (PEV1) was the first nonplant endornavirus at the time of reporting. Viral capsids have not been found in any of the above-mentioned viruses. PiRV-1 demonstrated a unique genome organization that requires further examination, and PiRV-2 may have played a role in late blight resurgence in 1980s-1990s.
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Affiliation(s)
- Guohong Cai
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ, USA.
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Grasse W, Zipper R, Totska M, Spring O. Plasmopara halstedii virus causes hypovirulence in Plasmopara halstedii, the downy mildew pathogen of the sunflower. Fungal Genet Biol 2013; 57:42-7. [DOI: 10.1016/j.fgb.2013.05.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/29/2013] [Accepted: 05/30/2013] [Indexed: 01/31/2023]
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46
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Cai G, Krychiw JF, Myers K, Fry WE, Hillman BI. A new virus from the plant pathogenic oomycete Phytophthora infestans with an 8 kb dsRNA genome: The sixth member of a proposed new virus genus. Virology 2013; 435:341-9. [DOI: 10.1016/j.virol.2012.10.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 07/25/2012] [Accepted: 10/06/2012] [Indexed: 12/18/2022]
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47
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Abstract
Members of the virus family Narnaviridae contain the simplest genomes of any RNA virus, ranging from 2.3 to 3.6 kb and encoding only a single polypeptide that has an RNA-dependent RNA polymerase domain. The family is subdivided into two genera based on subcellular location: members of the genus Narnavirus have been found in the yeast Saccharomyces cerevisiae and in the oomycete Phytophthora infestans and are confined to the cytosol, while members of the genus Mitovirus have been found only in filamentous fungi and are found in mitochondria. None identified thus far encodes a capsid protein; like several other RNA viruses of lower eukaryotes, their genomes are confined within lipid vesicles. As more family members are discovered, their importance as genetic elements is becoming evident. The unique association of the genus Mitovirus with mitochondria renders them potentially valuable tools to study biology of lower eukaryotes.
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