1
|
Dálya LB, Černý M, de la Peña M, Poimala A, Vainio EJ, Hantula J, Botella L. Diversity and impact of single-stranded RNA viruses in Czech Heterobasidion populations. mSystems 2024:e0050624. [PMID: 39287383 DOI: 10.1128/msystems.00506-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 08/04/2024] [Indexed: 09/19/2024] Open
Abstract
Heterobasidion annosum sensu lato comprises some of the most devastating pathogens of conifers. Exploring virocontrol as a potential strategy to mitigate economic losses caused by these fungi holds promise for the future. In this study, we conducted a comprehensive screening for viruses in 98 H. annosum s.l. specimens from different regions of Czechia aiming to identify viruses inducing hypovirulence. Initial examination for dsRNA presence was followed by RNA-seq analyses using pooled RNA libraries constructed from H. annosum and Heterobasidion parviporum, with diverse bioinformatic pipelines employed for virus discovery. Our study uncovered 25 distinct ssRNA viruses, including two ourmia-like viruses, one mitovirus, one fusarivirus, one tobamo-like virus, one cogu-like virus, one bisegmented narna-like virus and one segment of another narna-like virus, and 17 ambi-like viruses, for which hairpin and hammerhead ribozymes were detected. Coinfections of up to 10 viruses were observed in six Heterobasidion isolates, whereas another six harbored a single virus. Seventy-three percent of the isolates analyzed by RNA-seq were virus-free. These findings show that the virome of Heterobasidion populations in Czechia is highly diverse and differs from that in the boreal region. We further investigated the host effects of certain identified viruses through comparisons of the mycelial growth rate and proteomic analyses and found that certain tested viruses caused growth reductions of up to 22% and significant alterations in the host proteome profile. Their intraspecific transmission rates ranged from 0% to 33%. Further studies are needed to fully understand the biocontrol potential of these viruses in planta.IMPORTANCEHeterobasidion annosum sensu lato is a major pathogen causing significant damage to conifer forests, resulting in substantial economic losses. This study is significant as it explores the potential of using viruses (virocontrol) to combat these fungal pathogens. By identifying and characterizing a diverse array of viruses in H. annosum populations from Czechia, the research opens new avenues for biocontrol strategies. The discovery of 25 distinct ssRNA viruses, some of which reduce fungal growth and alter proteome profiles, suggests that these viruses could be harnessed to mitigate the impact of Heterobasidion. Understanding the interactions between these viruses and their fungal hosts is crucial for developing effective, environmentally friendly methods to protect conifer forests and maintain ecosystem health. This study lays the groundwork for future research on the application of mycoviruses in forest disease management.
Collapse
Affiliation(s)
- László Benedek Dálya
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| | - Martin Černý
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Marcos de la Peña
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, Valencia, Spain
| | - Anna Poimala
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Eeva J Vainio
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Jarkko Hantula
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Leticia Botella
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Brno, Czechia
| |
Collapse
|
2
|
Walterová L, Botella L, Hejna O, de la Peña M, Tonka T, Čurn V. Characterization of Mycoviruses in Armillaria ostoyae and A. cepistipes in the Czech Republic. Viruses 2024; 16:610. [PMID: 38675951 PMCID: PMC11053624 DOI: 10.3390/v16040610] [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: 03/18/2024] [Revised: 04/08/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
Members of the genus Armillaria are widespread forest pathogens against which effective protection has not yet been developed. Due to their longevity and the creation of large-scale cloning of Armillaria individuals, the use of mycoviruses as biocontrol agents (BCAs) against these pathogens could be an effective alternative. This work describes the detection and characterization of viruses in Armillaria spp. collected in the Czech Republic through the application of stranded total RNA sequencing. A total of five single-stranded RNA viruses were detected in Armillaria ostoyae and A. cepistipes, including viruses of the family Tymoviridae and four viruses belonging to the recently described "ambivirus" group with a circular ambisense genome arrangement. Both hammerhead (HHRz) and hairpin (HpRz) ribozymes were detected in all the ambiviricot sequences. Armillaria viruses were compared through phylogenetic analysis and confirmed their specific host by direct RT-PCR. One virus appears to infect both Armillaria species, suggesting the occurrence of interspecies transmission in nature.
Collapse
Affiliation(s)
- Lucie Walterová
- Department of Genetics and Agricultural Biotechnology, Faculty of Agriculture and Technology, University of South Bohemia in České Budějovice, Na Sádkách 1780, 370 05 České Budějovice, Czech Republic; (O.H.); (T.T.); (V.Č.)
| | - Leticia Botella
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic;
| | - Ondřej Hejna
- Department of Genetics and Agricultural Biotechnology, Faculty of Agriculture and Technology, University of South Bohemia in České Budějovice, Na Sádkách 1780, 370 05 České Budějovice, Czech Republic; (O.H.); (T.T.); (V.Č.)
| | - Marcos de la Peña
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, 46022 Valencia, Spain;
| | - Tomáš Tonka
- Department of Genetics and Agricultural Biotechnology, Faculty of Agriculture and Technology, University of South Bohemia in České Budějovice, Na Sádkách 1780, 370 05 České Budějovice, Czech Republic; (O.H.); (T.T.); (V.Č.)
| | - Vladislav Čurn
- Department of Genetics and Agricultural Biotechnology, Faculty of Agriculture and Technology, University of South Bohemia in České Budějovice, Na Sádkách 1780, 370 05 České Budějovice, Czech Republic; (O.H.); (T.T.); (V.Č.)
| |
Collapse
|
3
|
Villan Larios DC, Diaz Reyes BM, Pirovani CP, Loguercio LL, Santos VC, Góes-Neto A, Fonseca PLC, Aguiar ERGR. Exploring the Mycovirus Universe: Identification, Diversity, and Biotechnological Applications. J Fungi (Basel) 2023; 9:jof9030361. [PMID: 36983529 PMCID: PMC10052124 DOI: 10.3390/jof9030361] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/18/2023] Open
Abstract
Viruses that infect fungi are known as mycoviruses and are characterized by the lack of an extracellular phase. In recent years, the advances on nucleic acids sequencing technologies have led to a considerable increase in the number of fungi-infecting viral species described in the literature, with a special interest in assessing potential applications as fungal biocontrol agents. In the present study, we performed a comprehensive review using Scopus, Web of Science, and PubMed databases to mine mycoviruses data to explore their molecular features and their use in biotechnology. Our results showed the existence of 267 mycovirus species, of which 189 are recognized by the International Committee on Taxonomy of Viruses (ICTV). The majority of the mycoviruses identified have a dsRNA genome (38.6%), whereas the Botourmiaviridae (ssRNA+) alone represents 14% of all mycoviruses diversity. Regarding fungal hosts, members from the Sclerotinicaeae appeared as the most common species described to be infected by mycoviruses, with 16 different viral families identified so far. It is noteworthy that such results are directly associated with the high number of studies and strategies used to investigate the presence of viruses in members of the Sclerotinicaeae family. The knowledge about replication strategy and possible impact on fungi biology is available for only a small fraction of the mycoviruses studied, which is the main limitation for considering these elements potential targets for biotechnological applications. Altogether, our investigation allowed us to summarize the general characteristics of mycoviruses and their hosts, the consequences, and the implications of this knowledge on mycovirus–fungi interactions, providing an important source of information for future studies.
Collapse
Affiliation(s)
- Diana Carolina Villan Larios
- Department of Biological Sciences, Center for Biotechnology and Genetics, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil; (D.C.V.L.); (B.M.D.R.); (C.P.P.); (L.L.L.)
| | - Brayan Maudiel Diaz Reyes
- Department of Biological Sciences, Center for Biotechnology and Genetics, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil; (D.C.V.L.); (B.M.D.R.); (C.P.P.); (L.L.L.)
| | - Carlos Priminho Pirovani
- Department of Biological Sciences, Center for Biotechnology and Genetics, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil; (D.C.V.L.); (B.M.D.R.); (C.P.P.); (L.L.L.)
| | - Leandro Lopes Loguercio
- Department of Biological Sciences, Center for Biotechnology and Genetics, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil; (D.C.V.L.); (B.M.D.R.); (C.P.P.); (L.L.L.)
| | - Vinícius Castro Santos
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil;
| | - Aristóteles Góes-Neto
- Department of Microbiology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil;
| | - Paula Luize Camargos Fonseca
- Department of Biological Sciences, Center for Biotechnology and Genetics, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil; (D.C.V.L.); (B.M.D.R.); (C.P.P.); (L.L.L.)
- Department of Genetics, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil
- Correspondence: (P.L.C.F.); (E.R.G.R.A.)
| | - Eric Roberto Guimarães Rocha Aguiar
- Department of Biological Sciences, Center for Biotechnology and Genetics, Universidade Estadual de Santa Cruz, Ilhéus 45662-900, Bahia, Brazil; (D.C.V.L.); (B.M.D.R.); (C.P.P.); (L.L.L.)
- Correspondence: (P.L.C.F.); (E.R.G.R.A.)
| |
Collapse
|
4
|
Akata I, Edis G, Keskin E, Sahin E. Diverse partitiviruses hosted by the ectomycorrhizal agaric Hebeloma mesophaeum and the natural transmission of a partitivirus between phylogenetically distant, sympatric fungi. Virology 2023; 581:63-70. [PMID: 36913914 DOI: 10.1016/j.virol.2023.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/11/2023]
Abstract
Mycorrhizal fungi host diverse mycoviruses that contribute to our understanding of their diversity and evolution. Here we report on the identification and complete genome characterization of three novel partitiviruses naturally infecting the ectomycorrhizal fungus Hebeloma mesophaeum. During NGS derived viral sequence analyses, we identified a partitivirus that is conspecific with the previously reported partitivirus (LcPV1) described from a saprotrophic fungus Leucocybe candicans. The two distinct fungal specimens inhabited the same vicinity of a campus garden. RdRp sequences encoded by the LcPV1 isolates from both host fungi was found to be identical. Bio-tracking studies revealed that viral loads of LcPV1 drop significantly in L. candicans but not in H. mesophaeum within four years period. The physical proximity of the mycelial networks of both fungal specimens implied the occurrence of a virus transmission event with unknown mechanism. Nature of this virus transmission was discussed in relation to transient interspecific mycelial contact hypothesis.
Collapse
Affiliation(s)
- Ilgaz Akata
- Ankara University Faculty of Science Department of Biology, 06100, Tandogan, Ankara, Turkey
| | - Gulce Edis
- Ankara University Science Institute, 06110, Dışkapı, Ankara, Turkey
| | - Emre Keskin
- Evolutionary Genetics Laboratory (eGL), Faculty of Agriculture Department of Fisheries and Aquaculture, Ankara University, 06110, Dışkapı, Ankara, Turkey
| | - Ergin Sahin
- Dokuz Eylül University Faculty of Science Department of Biology, 35390, Buca, İzmir, Turkey; Dokuz Eylül University Fauna and Flora Research and Application Center, 35390, Buca, İzmir, Turkey.
| |
Collapse
|
5
|
Wang H, Salaipeth L, Miyazaki N, Suzuki N, Okamoto K. Capsid structure of a fungal dsRNA megabirnavirus reveals its previously unidentified surface architecture. PLoS Pathog 2023; 19:e1011162. [PMID: 36848381 PMCID: PMC9997902 DOI: 10.1371/journal.ppat.1011162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 03/09/2023] [Accepted: 01/25/2023] [Indexed: 03/01/2023] Open
Abstract
Rosellinia necatrix megabirnavirus 1-W779 (RnMBV1) is a non-enveloped icosahedral double-stranded (ds)RNA virus that infects the ascomycete fungus Rosellinia necatrix, a causative agent that induces a lethal plant disease white root rot. Herein, we have first resolved the atomic structure of the RnMBV1 capsid at 3.2 Å resolution using cryo-electron microscopy (cryo-EM) single-particle analysis. Compared with other non-enveloped icosahedral dsRNA viruses, the RnMBV1 capsid protein structure exhibits an extra-long C-terminal arm and a surface protrusion domain. In addition, the previously unrecognized crown proteins are identified in a symmetry-expanded cryo-EM model and are present over the 3-fold axes. These exclusive structural features of the RnMBV1 capsid could have been acquired for playing essential roles in transmission and/or particle assembly of the megabirnaviruses. Our findings, therefore, will reinforce the understanding of how the structural and molecular machineries of the megabirnaviruses influence the virulence of the disease-related ascomycete fungus.
Collapse
Affiliation(s)
- Han Wang
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Lakha Salaipeth
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, Japan
| | - Naoyuki Miyazaki
- Life Science Center of Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki, Japan
- * E-mail: (NM); (NS); (KO)
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, Japan
- * E-mail: (NM); (NS); (KO)
| | - Kenta Okamoto
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- * E-mail: (NM); (NS); (KO)
| |
Collapse
|
6
|
Interspecific spread of dsRNA mycoviruses in entomogenous fungi Beauveria spp. Virus Res 2022; 322:198933. [PMID: 36165923 DOI: 10.1016/j.virusres.2022.198933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/15/2022] [Accepted: 09/18/2022] [Indexed: 12/24/2022]
Abstract
Mycoviruses can spread interspecifically and intraspecifically in plant pathogenic fungi, as well as spreading intraspecifically in entomogenous fungi, especially Beauveria bassiana. However, whether mycoviruses are common in Beauveria spp. and can spread interspecifically between Beauveria species are unclear. Herein, four Beauveria species, but not B. bassiana, were randomly selected for double stranded RNA (dsRNA) detection. Furthermore, two previously reported dsRNA mycoviruses from B. bassiana, BbCV-2 and BbPmV-4, were used to study the interspecific transmission among B. bassiana, B. amorpha, and B. aranearum, using hyphal anastomosis and a novel insect coinfection transmission method. The results showed that dsRNA mycoviruses exist universally in Beauveria spp. and could spread interspecifically between different Beauveria species. The transmission efficiency from B. bassiana to the other two Beauveria species was significantly higher than that of the reverse transmission. Both viruses could stably and vertically spread in B. amorpha and B. aranearum, which affected their growth rate and colony morphology.
Collapse
|
7
|
Wagemans J, Holtappels D, Vainio E, Rabiey M, Marzachì C, Herrero S, Ravanbakhsh M, Tebbe CC, Ogliastro M, Ayllón MA, Turina M. Going Viral: Virus-Based Biological Control Agents for Plant Protection. ANNUAL REVIEW OF PHYTOPATHOLOGY 2022; 60:21-42. [PMID: 35300520 DOI: 10.1146/annurev-phyto-021621-114208] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The most economically important biotic stresses in crop production are caused by fungi, oomycetes, insects, viruses, and bacteria. Often chemical control is still the most commonly used method to manage them. However, the development of resistance in the different pathogens/pests, the putative damage on the natural ecosystem, the toxic residues in the field, and, thus, the contamination of the environment have stimulated the search for saferalternatives such as the use of biological control agents (BCAs). Among BCAs, viruses, a major driver for controlling host populations and evolution, are somewhat underused, mostly because of regulatory hurdles that make the cost of registration of such host-specific BCAs not affordable in comparison with the limited potential market. Here, we provide a comprehensive overview of the state of the art of virus-based BCAs against fungi, bacteria, viruses, and insects, with a specific focus on new approaches that rely on not only the direct biocidal virus component but also the complex ecological interactions between viruses and their hosts that do not necessarily result in direct damage to the host.
Collapse
Affiliation(s)
| | | | - Eeva Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Mojgan Rabiey
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Cristina Marzachì
- Istituto per la Protezione Sostenibile delle Piante, CNR, Torino, Italy;
| | - Salvador Herrero
- Department of Genetics and University Institute of Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Burjassot, Spain
| | | | - Christoph C Tebbe
- Thünen Institute of Biodiversity, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany
| | | | - María A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación Agraria y Alimentaria, 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, Madrid, Spain
| | - Massimo Turina
- Istituto per la Protezione Sostenibile delle Piante, CNR, Torino, Italy;
| |
Collapse
|
8
|
Kashif M, Jurvansuu J, Hyder R, Vainio EJ, Hantula J. Phenotypic Recovery of a Heterobasidion Isolate Infected by a Debilitation-Associated Virus Is Related to Altered Host Gene Expression and Reduced Virus Titer. Front Microbiol 2022; 12:661554. [PMID: 35310390 PMCID: PMC8930199 DOI: 10.3389/fmicb.2021.661554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
The fungal genus Heterobasidion includes forest pathogenic species hosting a diverse group of partitiviruses. They include the host debilitating Heterobasidion partitivirus 13 strain an1 (HetPV13-an1), which was originally observed in a slowly growing H. annosum strain 94233. In this study, a relatively fast-growing sector strain 94233-RC3 was isolated from a highly debilitated mycelial culture of 94233, and its gene expression and virus transcript quantities as well as the genomic sequence of HetPV13-an1 were examined. The sequence of HetPV13-an1 genome in 94233-RC3 was identical to that in the original 94233, and thus not the reason for the partial phenotypic recovery. According to RNA-seq analysis, the HetPV13-an1 infected 94233-RC3 transcribed eight genes differently from the partitivirus-free 94233-32D. Three of these genes were downregulated and five upregulated. The number of differentially expressed genes was considerably lower and the changes in their expression were small compared to those of the highly debilitated original strain 94233 with the exception of the most highly upregulated ones, and therefore viral effects on the host transcriptome correlated with the degree of the virus-caused debilitation. The amounts of RdRp and CP transcripts of HetPV13-an1 were considerably lower in 94233-RC3 and also in 94233 strain infected by a closely related mildly debilitating virus HetPV13-an2, suggesting that the virus titer would have a role in determining the effect of HetPV13 viruses on their hosts.
Collapse
Affiliation(s)
| | | | - Rafiqul Hyder
- Natural Resources Institute Finland, Helsinki, Finland
| | - Eeva J Vainio
- Natural Resources Institute Finland, Helsinki, Finland
| | | |
Collapse
|
9
|
Urayama SI, Takaki Y, Chiba Y, Zhao Y, Kuroki M, Hagiwara D, Nunoura T. Eukaryotic Microbial RNA Viruses-Acute or Persistent? Insights into Their Function in the Aquatic Ecosystem. Microbes Environ 2022; 37:ME22034. [PMID: 35922920 PMCID: PMC9763035 DOI: 10.1264/jsme2.me22034] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Isolated RNA viruses mainly parasitize eukaryotes. RNA viruses either expand horizontally by infecting hosts (acute type) or coexist with the host and are vertically inherited (persistent type). The significance of persistent-type RNA viruses in environmental viromes (the main hosts are expected to be microbes) was only recently reported because they had previously been overlooked in virology. In this review, we summarize the host-virus relationships of eukaryotic microbial RNA viruses. Picornavirales and Reoviridae are recognized as representative acute-type virus families, and most of the microbial viruses in Narnaviridae, Totiviridae, and Partitiviridae are categorized as representative persistent-type viruses. Acute-type viruses have only been found in aquatic environments, while persistent-type viruses are present in various environments, including aquatic environments. Moreover, persistent-type viruses are potentially widely spread in the RNA viral sequence space. This emerging evidence provides novel insights into RNA viral diversity, host-virus relationships, and their history of co-evolution.
Collapse
Affiliation(s)
- Syun-ichi Urayama
- Department of Life and Environmental Sciences, Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), 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, Corresponding author. E-mail: ; Tel: +81–29–853–6636; Fax: +81–29–853–4605
| | - Yoshihiro Takaki
- Super-cutting-edge Grand and Advanced Research (SUGAR) Program, Japan Agency for Marine Science and Technology (JAMSTEC), 2–15 Natsushima-cho, Yokosuka, Kanagawa 237–0061, Japan
| | - Yuto Chiba
- Department of Life and Environmental Sciences, Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
| | - Yanjie Zhao
- Department of Life and Environmental Sciences, Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
| | - Misa Kuroki
- Department of Life and Environmental Sciences, Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), University of Tsukuba, 1–1–1 Tennodai, Tsukuba, Ibaraki 305–8577, Japan
| | - Daisuke Hagiwara
- Department of Life and Environmental Sciences, Laboratory of Fungal Interaction and Molecular Biology (donated by IFO), 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
| | - Takuro Nunoura
- Research Center for Bioscience and Nanoscience (CeBN), JAMSTEC, 2–15 Natsushima-cho, Yokosuka, Kanagawa 237–0061, Japan
| |
Collapse
|
10
|
Sutela S, Piri T, Vainio EJ. Discovery and Community Dynamics of Novel ssRNA Mycoviruses in the Conifer Pathogen Heterobasidion parviporum. Front Microbiol 2021; 12:770787. [PMID: 34899655 PMCID: PMC8652122 DOI: 10.3389/fmicb.2021.770787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Accepted: 10/11/2021] [Indexed: 11/24/2022] Open
Abstract
Heterobasidion species are highly destructive basidiomycetous conifer pathogens of the Boreal forest region. Earlier studies have revealed dsRNA virus infections of families Curvulaviridae and Partitiviridae in Heterobasidion strains, and small RNA deep sequencing has also identified infections of Mitoviridae members in these fungi. In this study, the virome of Heterobasidion parviporum was examined for the first time by RNA-Seq using total RNA depleted of rRNA. This method successfully revealed new viruses representing two established (+)ssRNA virus families not found earlier in Heterobasidion: Narnaviridae and Botourmiaviridae. In addition, we identified the presence of a recently described virus group tentatively named “ambiviruses” in H. parviporum. The H. parviporum isolates included in the study originated from experimental forest sites located within 0.7 km range from each other, and a population analysis including 43 isolates was conducted at one of the experimental plots to establish the prevalence of the newly identified viruses in clonally spreading H. parviporum individuals. Our results indicate that viral infections are considerably more diverse and common among Heterobasidion isolates than known earlier and include ssRNA viruses with high prevalence and interspecies variation.
Collapse
Affiliation(s)
- Suvi Sutela
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Tuula Piri
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Eeva J Vainio
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| |
Collapse
|
11
|
Omnipresence of Partitiviruses in Rice Aggregate Sheath Spot Symptom-Associated Fungal Isolates from Paddies in Thailand. Viruses 2021; 13:v13112269. [PMID: 34835075 PMCID: PMC8625198 DOI: 10.3390/v13112269] [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: 10/17/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 01/09/2023] Open
Abstract
Partitiviruses are one of the most prevalent double-stranded RNA viruses that have been identified mostly in filamentous fungi and plants. Partitiviruses generally infect host fungi asymptomatically but infrequently exert significant effect(s) on morphology and virulence, thus being considered a potential source of biological control agents against pathogenic fungi. In this study, we performed a screening for mycoviruses of a collection of Thai isolates of rice fungal pathogen Rhizoctonia oryzae-sativae, a causal agent of rice aggregated sheath spot disease. As a result, 36% of tested isolates carried potentially viral double-stranded RNAs with sizes ranging from 2 to 3 kbp. By conventional cDNA library construction and RNA-seq, we determined six new alphapartitiviruses that infected three isolates: tentatively named Rhizoctonia oryzae-sativae partitivirus 1 to 6 (RosPV1-6). Furthermore, RT-PCR detection of each virus revealed their omnipresent nature in different R. oryzae-sativae isolates. Although virus-curing of basidiomycetous fungi is generally difficult, our repeated attempts successfully obtained virus-free (for RosPV1, RosPV2, and uncharacterized partitiviruses), isogenic strain of R. oryzae-sativae TSS190442. The virus-cured strain showed slightly faster colony growth on the synthetic media and severe symptom development on the rice sheath compared to its virus-infected counterpart. Overall, this study shed light on the distribution of partitiviruses in R. oryzae-sativae in a paddy environment and exemplified a virus-curing protocol that may be applicable for other basidiomycetous fungi.
Collapse
|
12
|
Abstract
This study provides new information on the infection biology and pathogenicity of an important root-rot fungus, Heterobasidion annosum sensu stricto (Fr.) Bref., through a detailed examination of the vegetative spread of clonal individuals and their capacity to produce fruiting bodies on young pine seedlings. The seedlings were planted in a clear-cutting area (c. 1.2 ha in size) after a pine generation that showed slight external symptoms of Heterobasidion root rot. The first dead seedlings were found five years after planting and during a nine-year monitoring period; nearly 600 seedlings were killed by H. annosum s.s. in 48 individual disease centers. Based on pairing tests of 482 isolates, 117 different H. annosum s.s. genotypes were identified. On average, 2.9 genotypes occurred in a single disease center. The extensive secondary spread of genotypes within root systems (up to 48 pine seedlings infected by the same genotype) resulted in annually expanding disease centers. In addition, more than half of the seedlings killed by H. annosum s.s. produced perennial fruiting bodies thus providing air-borne inoculum. The risk of spore infection should be taken into account in any type of cutting operation in young pine stands. Moreover, new control measures directed towards the secondary spread of H. annosum s.s. in pine regeneration are urgently needed in order to maintain the productivity of the pine forest on infested sites.
Collapse
|
13
|
Levanova AA, Vainio EJ, Hantula J, Poranen MM. RNA-Dependent RNA Polymerase from Heterobasidion RNA Virus 6 Is an Active Replicase In Vitro. Viruses 2021; 13:v13091738. [PMID: 34578320 PMCID: PMC8473416 DOI: 10.3390/v13091738] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 11/16/2022] Open
Abstract
Heterobasidion RNA virus 6 (HetRV6) is a double-stranded (ds)RNA mycovirus and a member of the recently established genus Orthocurvulavirus within the family Orthocurvulaviridae. The purpose of the study was to determine the biochemical requirements for RNA synthesis catalyzed by HetRV6 RNA-dependent RNA polymerase (RdRp). HetRV6 RdRp was expressed in Escherichia coli and isolated to near homogeneity using liquid chromatography. The enzyme activities were studied in vitro using radiolabeled UTP. The HetRV6 RdRp was able to initiate RNA synthesis in a primer-independent manner using both virus-related and heterologous single-stranded (ss)RNA templates, with a polymerization rate of about 46 nt/min under optimal NTP concentration and temperature. NTPs with 2'-fluoro modifications were also accepted as substrates in the HetRV6 RdRp-catalyzed RNA polymerization reaction. HetRV6 RdRp transcribed viral RNA genome via semi-conservative mechanism. Furthermore, the enzyme demonstrated terminal nucleotidyl transferase (TNTase) activity. Presence of Mn2+ was required for the HetRV6 RdRp catalyzed enzymatic activities. In summary, our study shows that HetRV6 RdRp is an active replicase in vitro that can be potentially used in biotechnological applications, molecular biology, and biomedicine.
Collapse
Affiliation(s)
- Alesia A. Levanova
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
- Correspondence: (A.A.L.); (M.M.P.)
| | - Eeva J. Vainio
- Natural Resources Institute Finland, 00790 Helsinki, Finland; (E.J.V.); (J.H.)
| | - Jarkko Hantula
- Natural Resources Institute Finland, 00790 Helsinki, Finland; (E.J.V.); (J.H.)
| | - Minna M. Poranen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00790 Helsinki, Finland
- Correspondence: (A.A.L.); (M.M.P.)
| |
Collapse
|
14
|
Rumbou A, Vainio EJ, Büttner C. Towards the Forest Virome: High-Throughput Sequencing Drastically Expands Our Understanding on Virosphere in Temperate Forest Ecosystems. Microorganisms 2021; 9:microorganisms9081730. [PMID: 34442809 PMCID: PMC8399312 DOI: 10.3390/microorganisms9081730] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 12/22/2022] Open
Abstract
Thanks to the development of HTS technologies, a vast amount of genetic information on the virosphere of temperate forests has been gained in the last seven years. To estimate the qualitative/quantitative impact of HTS on forest virology, we have summarized viruses affecting major tree/shrub species and their fungal associates, including fungal plant pathogens, mutualists and saprotrophs. The contribution of HTS methods is extremely significant for forest virology. Reviewed data on viral presence in holobionts allowed us a first attempt to address the role of virome in holobionts. Forest health is dependent on the variability of microorganisms interacting with the host tree/holobiont; symbiotic microbiota and pathogens engage in a permanent interplay, which influences the host. Through virus–virus interplays synergistic or antagonistic relations may evolve, which may drastically affect the health of the holobiont. Novel insights of these interplays may allow practical applications for forest plant protection based on endophytes and mycovirus biocontrol agents. The current analysis is conceived in light of the prospect that novel viruses may initiate an emergent infectious disease and that measures for the avoidance of future outbreaks in forests should be considered.
Collapse
Affiliation(s)
- Artemis Rumbou
- Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universität zu Berlin, 14195 Berlin, Germany;
- Correspondence:
| | - Eeva J. Vainio
- Natural Resources Institute Finland, Forest Health and Biodiversity, Latokartanonkaari 9, 00790 Helsinki, Finland;
| | - Carmen Büttner
- Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universität zu Berlin, 14195 Berlin, Germany;
| |
Collapse
|
15
|
Abstract
Species of Armillaria are distributed globally and include some of the most important pathogens of forest and ornamental trees. Some of them form large long-living clones that are considered as one of the largest organisms on earth and are capable of long-range spore-mediated transfer as well as vegetative spread by drought-resistant hyphal cords called rhizomorphs. However, the virus community infecting these species has remained unknown. In this study we used dsRNA screening and high-throughput sequencing to search for possible virus infections in a collection of Armillaria isolates representing three different species: Armillaria mellea from South Africa, A. borealis from Finland and Russia (Siberia) and A. cepistipes from Finland. Our analysis revealed the presence of both negative-sense RNA viruses and positive-sense RNA viruses, while no dsRNA viruses were detected. The viruses included putative new members of virus families Mymonaviridae, Botourmiaviridae and Virgaviridae and members of a recently discovered virus group tentatively named "ambiviruses" with ambisense bicistronic genomic organization. We demonstrated that Armillaria isolates can be cured of viruses by thermal treatment, which enables the examination of virus effects on host growth and phenotype using isogenic virus-infected and virus-free strains.
Collapse
|
16
|
Shahi S, Chiba S, Kondo H, Suzuki N. Cryphonectria nitschkei chrysovirus 1 with unique molecular features and a very narrow host range. Virology 2020; 554:55-65. [PMID: 33383414 DOI: 10.1016/j.virol.2020.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/21/2020] [Accepted: 11/23/2020] [Indexed: 12/20/2022]
Abstract
Cryphonectria nitschkei chrysovirus 1 (CnCV1), was described earlier from an ascomycetous fungus, Cryphonectria nitschkei strain OB5/11, collected in Japan; its partial sequence was reported a decade ago. Complete sequencing of the four genomic dsRNA segments revealed molecular features similar to but distinct from previously reported members of the family Chrysoviridae. Unique features include the presence of a mini-cistron preceding the major large open reading frame in each genomic segment. Common features include the presence of CAA repeats in the 5'-untranslated regions and conserved terminal sequences. CnCV1-OB5/11 could be laterally transferred to C. nitschkei and its relatives C. radicalis and C. naterciae via coculturing, virion transfection and protoplast fusion, but not to fungal species other than the three species mentioned above, even within the genus Cryphonectria, suggesting a very narrow host range. Phenotypic comparison of a few sets of CnCV1-infected and -free isogenic strains showed symptomless infection in new hosts.
Collapse
Affiliation(s)
- Sabitree Shahi
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Sotaro Chiba
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan.
| |
Collapse
|
17
|
Jacquat AG, Theumer MG, Cañizares MC, Debat HJ, Iglesias J, García Pedrajas MD, Dambolena JS. A Survey of Mycoviral Infection in Fusarium spp. Isolated from Maize and Sorghum in Argentina Identifies the First Mycovirus from Fusarium verticillioides. Viruses 2020; 12:v12101161. [PMID: 33066620 PMCID: PMC7602464 DOI: 10.3390/v12101161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/28/2020] [Accepted: 10/09/2020] [Indexed: 12/30/2022] Open
Abstract
Mycoviruses appear to be widespread in Fusarium species worldwide. The aim of this work was to identify mycoviral infections in Fusarium spp., isolated from maize and sorghum grown in Argentina, and to estimate their potential effects on the pathogenicity and toxigenesis of the host fungus towards maize. Mycoviruses were identified in 2 out of 105 isolates analyzed; Fusarium verticillioides strain Sec505 and Fusarium andiyazi strain 162. They were characterized as members of the genus Mitovirus by high-throughput sequencing and sequence analysis. The F. verticillioides mitovirus was a novel mycovirus whereas the F. andiyazi mitovirus was found to be a new strain of a previously identified mitovirus. We have named these mitoviruses, Fusarium verticillioides mitovirus 1 (FvMV1) and Fusarium andiyazi mitovirus 1 strain 162 (FaMV1-162). To our knowledge, FvMV1 is the first mycovirus reported as naturally infecting F. verticillioides, the major causal agent of ear rot and fumonisin producer in corn. Both mitoviruses exhibited 100% vertical transmission rate to microconidia. The Fa162 strain infected with FaMV1-162 did not show phenotypic alterations. In contract, F. verticillioides Sec505 infected with FvMV1 showed increased virulence as well as microconidia and fumonisin-B1 production, compared with two uninfected strains. These results suggest that FvMV1 could have a role in modulating F. verticillioides pathogenicity and toxin production worth further exploring.
Collapse
Affiliation(s)
- Andrés Gustavo Jacquat
- Facultad de Ciencias Exactas Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Córdoba 5000, Argentina;
- Instituto Multidisciplinario de Biología Vegetal (IMBIV), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Vélez Sarsfield 1611, Córdoba X5016GCA, Argentina
| | - Martín Gustavo Theumer
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas (FCQ), Universidad Nacional de Córdoba (UNC), Córdoba 5000, Argentina;
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Haya de la Torre y Medina Allende—Ciudad Universitaria, Córdoba X5000HUA, Argentina
| | - María Carmen Cañizares
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM—UMA—CSIC), Estación Experimental “La Mayora”, Avenida Dr. Wienberg s/n, 29750 Algarrobo-Costa, Málaga, Spain;
| | - Humberto Julio Debat
- Instituto de Patología Vegetal, Centro de Investigaciones Agropecuarias, Instituto Nacional de Tecnología Agropecuaria (IPAVE—CIAP—INTA), Camino 60 Cuadras Km 5.5, Córdoba X5020ICA, Argentina;
| | - Juliana Iglesias
- Estación Experimental Pergamino, (EEA) INTA Pergamino, Universidad Nacional Noroeste (UNNOBA), Pergamino (Buenos Aires) B2700, Argentina;
| | - María Dolores García Pedrajas
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas (IHSM—UMA—CSIC), Estación Experimental “La Mayora”, Avenida Dr. Wienberg s/n, 29750 Algarrobo-Costa, Málaga, Spain;
- Correspondence: (M.D.G.P.); (J.S.D.)
| | - José Sebastián Dambolena
- Facultad de Ciencias Exactas Físicas y Naturales (FCEFyN), Universidad Nacional de Córdoba (UNC), Córdoba 5000, Argentina;
- Instituto Multidisciplinario de Biología Vegetal (IMBIV), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Vélez Sarsfield 1611, Córdoba X5016GCA, Argentina
- Correspondence: (M.D.G.P.); (J.S.D.)
| |
Collapse
|
18
|
Cross ST, Maertens BL, Dunham TJ, Rodgers CP, Brehm AL, Miller MR, Williams AM, Foy BD, Stenglein MD. Partitiviruses Infecting Drosophila melanogaster and Aedes aegypti Exhibit Efficient Biparental Vertical Transmission. J Virol 2020; 94:e01070-20. [PMID: 32759315 PMCID: PMC7527066 DOI: 10.1128/jvi.01070-20] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/22/2020] [Indexed: 12/26/2022] Open
Abstract
Partitiviruses are segmented, multipartite double-stranded RNA (dsRNA) viruses that until recently were only known to infect fungi, plants, and protozoans. Metagenomic surveys have revealed that partitivirus-like sequences are also commonly associated with arthropods. One arthropod-associated partitivirus, galbut virus, is common in wild populations of Drosophila melanogaster To begin to understand the processes that underlie this virus's high global prevalence, we established colonies of wild-caught infected flies. Infection remained at stably high levels over 3 years, with between 63 and 100% of individual flies infected. Galbut virus infects fly cells and replicates in tissues throughout infected adults, including reproductive tissues and the gut epithelium. We detected no evidence of horizontal transmission via ingestion, but vertical transmission from either infected females or infected males was ∼100% efficient. Vertical transmission of a related partitivirus, verdadero virus, that we discovered in a laboratory colony of Aedes aegypti mosquitoes was similarly efficient. This suggests that efficient biparental vertical transmission may be a feature of at least a subset of insect-infecting partitiviruses. To study the impact of galbut virus infection free from the confounding effect of other viruses, we generated an inbred line of flies with galbut virus as the only detectable virus infection. We were able to transmit infection experimentally via microinjection of homogenate from these galbut-only flies. This sets the stage for experiments to understand the biological impact and possible utility of partitiviruses infecting model organisms and disease vectors.IMPORTANCE Galbut virus is a recently discovered partitivirus that is extraordinarily common in wild populations of the model organism Drosophila melanogaster Like for most viruses discovered through metagenomics, most of the basic biological questions about this virus remain unanswered. We found that galbut virus, along with a closely related partitivirus found in Aedes aegypti mosquitoes, is transmitted from infected females or males to offspring with ∼100% efficiency and can be maintained in laboratory colonies over years. This efficient transmission mechanism likely underlies the successful spread of these viruses through insect populations. We created Drosophila lines that contained galbut virus as the only virus infection and showed that these flies can be used as a source for experimental infections. This provides insight into how arthropod-infecting partitiviruses may be maintained in nature and sets the stage for exploration of their biology and potential utility.
Collapse
Affiliation(s)
- Shaun T Cross
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Bernadette L Maertens
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Tillie J Dunham
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Case P Rodgers
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Ali L Brehm
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Megan R Miller
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Alissa M Williams
- Department of Biology, College of Natural Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Brian D Foy
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Mark D Stenglein
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Vainio EJ, Sutela S. Mixed infection by a partitivirus and a negative-sense RNA virus related to mymonaviruses in the polypore fungus Bondarzewia berkeleyi. Virus Res 2020; 286:198079. [PMID: 32599089 DOI: 10.1016/j.virusres.2020.198079] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 11/30/2022]
Abstract
Virus communities of forest fungi remain poorly characterized. In this study, we detected two new viruses co-infecting an isolate of the polypore fungus Bondarzewia berkeleyi using high-throughput sequencing. One of them was a putative new partitivirus designated as Bondarzewia berkeleyi partitivirus 1 (BbPV1), with two linear dsRNA genome segments of 1928 and 1863 bp encoding a putative RNA-dependent RNA polymerase (RdRP) of 591 aa and a putative capsid protein of 538 aa. The other virus, designated as Bondarzewia berkeleyi negative-strand RNA virus 1 (BbNSRV1), had a non-segmented negative-sense RNA genome of 10,983 nt and was related to members of family Mymonaviridae. The BbNSRV1 genome includes six predicted open reading frames (ORFs) of 279, 425, 230, 174, 200 and 1970 aa. The longest ORF contained conserved regions corresponding to Mononegavirales RdRP and mRNA-capping enzyme region V constituting the mononegavirus Large protein. In addition, a low level of sequence identity was detected between the putative nucleocapsid protein-coding ORF2 of Lentinula edodes negative-strand RNA virus 1 and BbNSRV1. The viruses characterized in this study are the first ones described in Bondarzewia spp., and BbNSRV1 is the second mymona-like virus described in a basidiomycete host.
Collapse
Affiliation(s)
- Eeva J Vainio
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland.
| | - Suvi Sutela
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| |
Collapse
|
21
|
Velasco L, López-Herrera C, Cretazzo E. Two novel partitiviruses that accumulate differentially in Rosellinia necatrix and Entoleuca sp. infecting avocado. Virus Res 2020; 285:198020. [PMID: 32416260 DOI: 10.1016/j.virusres.2020.198020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/09/2020] [Accepted: 05/09/2020] [Indexed: 01/26/2023]
Abstract
Rosellinia necatrix is responsible for the white rot root disease of avocado in Southern Spain. Entoleuca sp. is a fungus isolated from roots of these same trees, but it is not pathogenic in avocado. Here, we describe two new species of partitiviruses detected in isolates of the avocado sympatric fungi Entoleuca sp. and R. necatrix, termed Entoleuca partitivirus 1 (EnPV1), genus Alphapartitivirus, and Entoleuca partitivirus 2 (EnPV2), genus Betapartitivirus. For both R. necatrix and Entoleuca sp., the dsRNA of the RdRp genomic segment of EnPV1 accumulates at a higher rate than the CP dsRNA, except for a set of Entoleuca sp. isolates where titers of the CP dsRNA are 35-50 times higher than those of the RdRp dsRNA and between 250-380 times higher than the CP dsRNA titers found in the rest of Entoleuca sp. and R. necatrix isolates. For EnPV2, the accumulation rates of the RdRp dsRNA in Entoleuca sp., is in most of the cases, higher than the CP dsRNA. In contrast, in R. necatrix isolates, EnPV2 dsRNA2 generally accumulates at a higher rate. Genetic analysis of the partitiviruses revealed that there is no apparent variation in the nucleotide sequences among the strains. RNA silencing of the partitiviruses appears to be limited in Entoleuca sp., as shown by small RNA sequencing. Finally, the investigation of the presence of these partitiviruses in a fungal collection revealed that they have no role in the pathogenicity of R. necatrix in avocado or in the avirulence of Entoleuca sp. in this host.
Collapse
Affiliation(s)
- Leonardo Velasco
- Instituto Andaluz De Investigación y Formación Agraria (IFAPA), 29130, Málaga, Spain.
| | | | - Enrico Cretazzo
- Instituto Andaluz De Investigación y Formación Agraria (IFAPA), 29130, Málaga, Spain
| |
Collapse
|
22
|
Sutela S, Vainio EJ. Virus population structure in the ectomycorrhizal fungi Lactarius rufus and L. tabidus at two forest sites in Southern Finland. Virus Res 2020; 285:197993. [PMID: 32360299 DOI: 10.1016/j.virusres.2020.197993] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/25/2020] [Accepted: 04/25/2020] [Indexed: 01/27/2023]
Abstract
Lactarius fungi belong to the Russulaceae family and have an important ecological role as ectomycorrhizal symbionts of coniferous and deciduous trees. Two Lactarius species, L. tabidus and L. rufus have been shown to harbor bisegmented dsRNA viruses belonging to an unclassified virus group including the mutualistic Curvularia thermal tolerance virus (CThTV). In this study, we characterized the first complete genome sequences of these viruses designated as Lactarius tabidus RNA virus 1 (LtRV1) and Lactarius rufus RNA virus 1 (LrRV1), both of which included two genome segments of 2241 and 2049 bp. We also analyzed spatial distribution and sequence diversity of the viruses in sixty host strains at two forest sites, and showed that the viruses are species-specific at sites where both host species co-occur. We also found that single virus isolates inhabited several different conspecific host strains, and were involved in persistent infections during up to eight years.
Collapse
Affiliation(s)
- Suvi Sutela
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790 Helsinki, Finland.
| | - Eeva J Vainio
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790 Helsinki, Finland
| |
Collapse
|
23
|
Hantula J, Mäkelä S, Xu P, Brusila V, Nuorteva H, Kashif M, Hyder R, Vainio EJ. Multiple virus infections on Heterobasidion sp. Fungal Biol 2020; 124:102-109. [DOI: 10.1016/j.funbio.2019.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/26/2019] [Accepted: 12/05/2019] [Indexed: 11/27/2022]
|
24
|
He MQ, Zhao RL, Hyde KD, Begerow D, Kemler M, Yurkov A, McKenzie EHC, Raspé O, Kakishima M, Sánchez-Ramírez S, Vellinga EC, Halling R, Papp V, Zmitrovich IV, Buyck B, Ertz D, Wijayawardene NN, Cui BK, Schoutteten N, Liu XZ, Li TH, Yao YJ, Zhu XY, Liu AQ, Li GJ, Zhang MZ, Ling ZL, Cao B, Antonín V, Boekhout T, da Silva BDB, De Crop E, Decock C, Dima B, Dutta AK, Fell JW, Geml J, Ghobad-Nejhad M, Giachini AJ, Gibertoni TB, Gorjón SP, Haelewaters D, He SH, Hodkinson BP, Horak E, Hoshino T, Justo A, Lim YW, Menolli N, Mešić A, Moncalvo JM, Mueller GM, Nagy LG, Nilsson RH, Noordeloos M, Nuytinck J, Orihara T, Ratchadawan C, Rajchenberg M, Silva-Filho AGS, Sulzbacher MA, Tkalčec Z, Valenzuela R, Verbeken A, Vizzini A, Wartchow F, Wei TZ, Weiß M, Zhao CL, Kirk PM. Notes, outline and divergence times of Basidiomycota. FUNGAL DIVERS 2019. [DOI: 10.1007/s13225-019-00435-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AbstractThe Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota. The present work provides an overview of all validly published, currently used basidiomycete genera to date in a single document. An outline of all genera of Basidiomycota is provided, which includes 1928 currently used genera names, with 1263 synonyms, which are distributed in 241 families, 68 orders, 18 classes and four subphyla. We provide brief notes for each accepted genus including information on classification, number of accepted species, type species, life mode, habitat, distribution, and sequence information. Furthermore, three phylogenetic analyses with combined LSU, SSU, 5.8s, rpb1, rpb2, and ef1 datasets for the subphyla Agaricomycotina, Pucciniomycotina and Ustilaginomycotina are conducted, respectively. Divergence time estimates are provided to the family level with 632 species from 62 orders, 168 families and 605 genera. Our study indicates that the divergence times of the subphyla in Basidiomycota are 406–430 Mya, classes are 211–383 Mya, and orders are 99–323 Mya, which are largely consistent with previous studies. In this study, all phylogenetically supported families were dated, with the families of Agaricomycotina diverging from 27–178 Mya, Pucciniomycotina from 85–222 Mya, and Ustilaginomycotina from 79–177 Mya. Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system, and also provide a better understanding of their phylogeny and evolution.
Collapse
|
25
|
Vainio EJ. Mitoviruses in the conifer root rot pathogens Heterobasidion annosum and H. parviporum. Virus Res 2019; 271:197681. [PMID: 31394105 DOI: 10.1016/j.virusres.2019.197681] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 10/26/2022]
Abstract
Mitoviral infections are highly common among fungi, but so far only one mitovirus has been described in Heterobasidion spp. conifer pathogens. Here, the occurrence of further mitoviruses was investigated using a previously published RNA-Seq dataset for de novo contig assembly. This allowed the identification of two additional mitovirus strains designated as Heterobasidion mitovirus 2 (HetMV2) and HetMV3 with genome lengths of ca. 2.9 and 5.0 kb. Furthermore, the occurrence of similar viruses was screened among a collection of Heterobasidion isolates using RT-PCR. Mitoviruses were detected in six more fungal isolates and two different host species, H. annosum and H. parviporum.
Collapse
Affiliation(s)
- Eeva J Vainio
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790 Helsinki, Finland.
| |
Collapse
|
26
|
Velasco L, Arjona-Girona I, Cretazzo E, López-Herrera C. Viromes in Xylariaceae fungi infecting avocado in Spain. Virology 2019; 532:11-21. [PMID: 30986551 DOI: 10.1016/j.virol.2019.03.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 12/25/2022]
Abstract
Four isolates of Entoleuca sp., family Xylariaceae, Ascomycota, recovered from avocado rhizosphere in Spain were analyzed for mycoviruses presence. For that, the dsRNAs from the mycelia were extracted and subjected to metagenomics analysis that revealed the presence of eleven viruses putatively belonging to families Partitiviridae, Hypoviridae, Megabirnaviridae, and orders Tymovirales and Bunyavirales, in addition to one ourmia-like virus plus other two unclassified virus species. Moreover, a sequence with 98% nucleotide identity to plant endornavirus Phaseolus vulgaris alphaendornavirus 1 has been identified in the Entoleuca sp. isolates. Concerning the virome composition, the four isolates only differed in the presence of the bunyavirus and the ourmia-like virus, while all other viruses showed common patterns. Specific primers allowed the detection by RT-PCR of these viruses in a collection of Entoleuca sp. and Rosellinia necatrix isolates obtained from roots of avocado trees. Results indicate that intra- and interspecies horizontal virus transmission occur frequently in this pathosystem.
Collapse
Affiliation(s)
- Leonardo Velasco
- Instituto Andaluz de Investigación y Formación Agraria (IFAPA), 29140, Churriana, Málaga, Spain.
| | - Isabel Arjona-Girona
- Departamento de Protección de Cultivos, Instituto de Agricultura Sostenible, C.S.I.C, Córdoba, Spain
| | - Enrico Cretazzo
- Instituto Andaluz de Investigación y Formación Agraria (IFAPA), 29140, Churriana, Málaga, Spain
| | - Carlos López-Herrera
- Departamento de Protección de Cultivos, Instituto de Agricultura Sostenible, C.S.I.C, Córdoba, Spain
| |
Collapse
|
27
|
Kashif M, Jurvansuu J, Vainio EJ, Hantula J. Alphapartitiviruses of Heterobasidion Wood Decay Fungi Affect Each Other's Transmission and Host Growth. Front Cell Infect Microbiol 2019; 9:64. [PMID: 30972301 PMCID: PMC6443826 DOI: 10.3389/fcimb.2019.00064] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/01/2019] [Indexed: 11/13/2022] Open
Abstract
Heterobasidion spp. root rot fungi are highly destructive forest pathogens of the northern boreal forests, and are known to host a diverse community of partitiviruses. The transmission of these mycoviruses occurs horizontally among host strains via mycelial anastomoses. We revealed using dual cultures that virus transmission rates are affected by pre-existing virus infections among two strains of H. annosum. The transmission efficacy of mycovirus HetPV15-pa1 to a pre-infected host was elevated from zero to 50% by the presence of HetPV13-an1, and a double infection of these viruses in the donor resulted in an overall transmission rate of 90% to a partitivirus-free recipient. On contrary, pre-existing virus infections of two closely related strains of HetPV11 hindered each other's transmission, but had unexpectedly dissimilar effects on the transmission of more distantly related viruses. The co-infection of HetPV13-an1 and HetPV15-pa1 significantly reduced host growth, whereas double infections including HetPV11 strains had variable effects. Moreover, the results showed that RdRp transcripts are generally more abundant than capsid protein (CP) transcripts and the four different virus strains express unique transcripts ratios of RdRp and CP. Taken together, the results show that the interplay between co-infecting viruses and their host is extremely complex and highly unpredictable.
Collapse
Affiliation(s)
- Muhammad Kashif
- Forest Health and Biodiversity, Natural Resources Institute Finland, Helsinki, Finland
| | | | - Eeva J Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland, Helsinki, Finland
| | - Jarkko Hantula
- Forest Health and Biodiversity, Natural Resources Institute Finland, Helsinki, Finland
| |
Collapse
|
28
|
Characterization of a Botybirnavirus Conferring Hypovirulence in the Phytopathogenic Fungus Botryosphaeria dothidea. Viruses 2019; 11:v11030266. [PMID: 30884907 PMCID: PMC6466033 DOI: 10.3390/v11030266] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 01/12/2023] Open
Abstract
A double-stranded RNA (dsRNA) virus was isolated and characterized from strain EW220 of the phytopathogenic fungus Botryosphaeria dothidea. The full-length cDNAs of the dsRNAs were 6434 bp and 5986 bp in size, respectively. The largest dsRNA encodes a cap-pol fusion protein that contains a coat protein gene and an RNA-dependent RNA polymerase (RdRp) domain, and the second dsRNA encodes a hypothetical protein. Genome sequence analysis revealed that the sequences of the dsRNA virus shared 99% identity with Bipolaris maydis botybirnavirus 1(BmBRV1) isolated from the causal agent of corn southern leaf blight, Bipolaris maydis. Hence, the dsRNA virus constitutes a new strain of BmBRV1 and was named Bipolaris maydis botybirnavirus 1 strain BdEW220 (BmBRV1-BdEW220). BmBRV1-BdEW220 contains spherical virions that are 37 nm in diameter and consist of two dsRNA segments. The structural proteins of the BmBRV1-BdEW220 virus particles were 110 kDa, 90 kDa, and 80 kDa and were encoded by dsRNA1 and 2-ORFs. Phylogenetic reconstruction indicated that BmBRV1 and BmBRV1-BdEW220 are phylogenetically related to the genus Botybirnavirus. Importantly, BmBRV1-BdEW220 influences the growth of B. dothidea and confers hypovirulence to the fungal host. To our knowledge, this is the first report of a botybirnavirus in B. dothidea.
Collapse
|
29
|
Botella L, Hantula J. Description, Distribution, and Relevance of Viruses of the Forest Pathogen Gremmeniella abietina. Viruses 2018; 10:v10110654. [PMID: 30463286 PMCID: PMC6267220 DOI: 10.3390/v10110654] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 01/29/2023] Open
Abstract
The European race of the ascomycetous species Gremmeniella abietina (Lagerberg) Morelet includes causal agents of shoot blight and stem canker of several conifers in Europe and North America, which are known to host a diverse virome. GaRV6 is the latest and sixth mycovirus species reported within G. abietina. Before its description, one victorivirus and one gammapartitivirus species were described in biotype A, two mitoviruses in both biotypes A and B and a betaendornavirus in biotype B. Possible phenotypic changes produced by mycoviruses on G. abietina mycelial growth have been reported in Spanish mitovirus-free and GaRV6-hosting G. abietina isolates, which had higher growth rates at the optimal temperature of 15 °C, but no other major differences have been observed between partitivirus-like dsRNA and dsRNA-free isolates. In this review, we reappraise the diversity of viruses found in G. abietina so far, and their relevance in clarifying the taxonomy of G. abietina. We also provide evidence for the presence of two new viruses belonging to the families Fusariviridae and Endornaviridae in Spanish isolates.
Collapse
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, 613 00 Brno, Czech Republic.
| | - Jarkko Hantula
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland.
| |
Collapse
|
30
|
Detection of a Conspecific Mycovirus in Two Closely Related Native and Introduced Fungal Hosts and Evidence for Interspecific Virus Transmission. Viruses 2018; 10:v10110628. [PMID: 30428556 PMCID: PMC6266060 DOI: 10.3390/v10110628] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/09/2018] [Accepted: 11/10/2018] [Indexed: 11/17/2022] Open
Abstract
Hymenoscyphus albidus is a native fungus in Europe where it behaves as a harmless decomposer of leaves of common ash. Its close relative Hymenoscyphus fraxineus was introduced into Europe from Asia and currently threatens ash (Fraxinus sp.) stands all across the continent causing ash dieback. H. fraxineus isolates from Europe were previously shown to harbor a mycovirus named Hymenoscyphus fraxineus Mitovirus 1 (HfMV1). In the present study, we describe a conspecific mycovirus that we detected in H. albidus. HfMV1 was consistently identified in H. albidus isolates (mean prevalence: 49.3%) which were collected in the sampling areas before the arrival of ash dieback. HfMV1 strains in both fungal hosts contain a single ORF of identical length (717 AA) for which a mean pairwise identity of 94.5% was revealed. The occurrence of a conspecific mitovirus in H. albidus and H. fraxineus is most likely the result of parallel virus evolution in the two fungal hosts. HfMV1 sequences from H. albidus showed a higher nucleotide diversity and a higher number of mutations compared to those from H. fraxineus, probably due to a bottleneck caused by the introduction of H. fraxineus in Europe. Our data also points to multiple interspecific virus transfers from H. albidus to H. fraxineus, which could have contributed to the intraspecific virus diversity found in H. fraxineus.
Collapse
|
31
|
Wang J, Guo M, Sun Y, Bian Y, Zhou Y, Xu Z. Genetic variation and phylogenetic analyses reveal transmission clues of Lentinula edodes partitivirus 1 (LePV1) from the Chinese L. edodes core collection. Virus Res 2018; 255:127-132. [DOI: 10.1016/j.virusres.2018.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/14/2018] [Accepted: 07/19/2018] [Indexed: 11/28/2022]
|
32
|
Novel Partitivirus Enhances Virulence of and Causes Aberrant Gene Expression in Talaromyces marneffei. mBio 2018; 9:mBio.00947-18. [PMID: 29895639 PMCID: PMC6016240 DOI: 10.1128/mbio.00947-18] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Talaromyces marneffei is the most important thermal dimorphic fungus causing systemic mycosis in Southeast Asia. We report the discovery of a novel partitivirus, Talaromyces marneffeipartitivirus-1 (TmPV1). TmPV1 was detected in 7 (12.7%) of 55 clinical T. marneffei isolates. Complete genome sequencing of the seven TmPV1 isolates revealed two double-stranded RNA (dsRNA) segments encoding RNA-dependent RNA polymerase (RdRp) and capsid protein, respectively. Phylogenetic analysis showed that TmPV1 occupied a distinct clade among the members of the genus Gammapartitivirus Transmission electron microscopy confirmed the presence of isometric, nonenveloped viral particles of 30 to 45 nm in diameter, compatible with partitiviruses, in TmPV1-infected T. marneffei Quantitative reverse transcription-PCR (qRT-PCR) demonstrated higher viral load of TmPV1 in the yeast phase than in the mycelial phase of T. marneffei Two virus-free isolates, PM1 and PM41, were successfully infected by purified TmPV1 using protoplast transfection. Mice challenged with TmPV1-infected T. marneffei isolates showed significantly shortened survival time (P < 0.0001) and higher fungal burden in organs than mice challenged with isogenic TmPV1-free isolates. Transcriptomic analysis showed that TmPV1 causes aberrant expression of various genes in T. marneffei, with upregulation of potential virulence factors and suppression of RNA interference (RNAi)-related genes. This is the first report of a mycovirus in a thermally dimorphic fungus. Further studies are required to ascertain the mechanism whereby TmPV1 enhances the virulence of T. marneffei in mice and the potential role of RNAi-related genes in antiviral defense in T. marneffeiIMPORTANCETalaromyces marneffei (formerly Penicillium marneffei) is the most important thermal dimorphic fungus in Southeast Asia, causing highly fatal systemic penicilliosis in HIV-infected and immunocompromised patients. We discovered a novel mycovirus, TmPV1, in seven clinical isolates of T. marneffei TmPV1 belongs to the genus Gammapartitivirus of the family Partitiviridae We showed that TmPV1 enhanced the virulence of T. marneffei in mice, with shortened survival time and higher fungal burden in the organs of mice challenged with TmPV1-infected T. marneffei isolates than in those of mice challenged with virus-free isogenic isolates. Transcriptomics analysis showed that TmPV1 altered the expression of genes involved in various cellular processes in T. marneffei, with upregulation of potential virulence factors and suppression of RNAi machinery which may be involved in antiviral defense. This is the first report of a mycovirus in a thermal dimorphic fungus. The present results offer insights into mycovirus-fungus interactions and pathogenesis of thermal dimorphic fungi.
Collapse
|
33
|
Arjona-Lopez JM, Telengech P, Jamal A, Hisano S, Kondo H, Yelin MD, Arjona-Girona I, Kanematsu S, Lopez-Herrera CJ, Suzuki N. Novel, diverse RNA viruses from Mediterranean isolates of the phytopathogenic fungus, Rosellinia necatrix: insights into evolutionary biology of fungal viruses. Environ Microbiol 2018; 20:1464-1483. [PMID: 29411500 DOI: 10.1111/1462-2920.14065] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/02/2018] [Indexed: 11/30/2022]
Abstract
To reveal mycovirus diversity, we conducted a search of as-yet-unexplored Mediterranean isolates of the phytopathogenic ascomycete Rosellinia necatrix for virus infections. Of seventy-nine, eleven fungal isolates tested RNA virus-positive, with many showing coinfections, indicating a virus incidence of 14%, which is slightly lower than that (approximately 20%) previously reported for extensive surveys of over 1000 Japanese R. necatrix isolates. All viral sequences were fully or partially characterized by Sanger and next-generation sequencing. These sequences appear to represent isolates of various new species spanning at least 6 established or previously proposed families such as Partiti-, Hypo-, Megabirna-, Yado-kari-, Fusagra- and Fusarividae, as well as a newly proposed family, Megatotiviridae. This observation greatly expands the diversity of R. necatrix viruses, because no hypo-, fusagra- or megatotiviruses were previously reported from R. necatrix. The sequence analyses showed a rare horizontal gene transfer event of the 2A-like protease domain between a dsRNA (phlegivirus) and a positive-sense, single-stranded RNA virus (hypovirus). Moreover, many of the newly detected viruses showed the closest relation to viruses reported from fungi other than R. necatrix, such as Fusarium spp., which are sympatric to R. necatrix. These combined results imply horizontal virus transfer between these soil-inhabitant fungi.
Collapse
Affiliation(s)
- Juan Manuel Arjona-Lopez
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan.,Instituto de Agricultura Sostenible C.S.I.C., Alameda del Obispo, s/n. CP: 14004, Cordoba, Spain
| | - Paul Telengech
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan
| | - Atif Jamal
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan.,Crop Diseases Research Institute, National Agricultural Research Centre, Islamabad 45500, Pakistan
| | - Sakae Hisano
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan
| | - Mery Dafny Yelin
- Northern Agriculture Research & Development, Migal Galilee Technology Center, P.O.B. 831, Kiryat Shemona 11016, Israel
| | - Isabel Arjona-Girona
- Instituto de Agricultura Sostenible C.S.I.C., Alameda del Obispo, s/n. CP: 14004, Cordoba, Spain
| | - Satoko Kanematsu
- NARO Headquarter, National Agriculture and Food Research Organization (NARO), 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8517, Japan.,Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), Morioka, Iwate 020-0123, Japan
| | | | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan
| |
Collapse
|
34
|
Hyder R, Piri T, Hantula J, Nuorteva H, Vainio EJ. Distribution of Viruses Inhabiting Heterobasidion annosum in a Pine-Dominated Forest Plot in Southern Finland. MICROBIAL ECOLOGY 2018; 75:622-630. [PMID: 28779297 DOI: 10.1007/s00248-017-1027-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
We investigated the diversity and spatial distribution of viruses infecting strains of the root rot fungus Heterobasidion annosum collected from pine stumps at a heavily infected forest site. Four different partitiviruses were detected in 14 H. annosum isolates at the study site, constituting approximately 29% of all Heterobasidion isolates investigated (N = 48). Two of the viruses detected were new partitiviruses designated here as Heterobasidion partitivirus 16 (HetPV16) and HetPV20, and two were previously known partitiviruses: HetPV7 and HetPV13. The two new partitiviruses found, HetPV16-an1 and HetPV20-an1, shared ~70% RdRp nucleotide sequence identity with the alphapartitivirus Rosellinia necatrix partitivirus 2, and less than 40% identity with known viruses of Heterobasidion spp. HetPV7-an1 was closely similar to HetPV7-pa1 isolated earlier from Heterobasidion parviporum, supporting the view of conspecific virus pools in different Heterobasidion species. Three fungal isolates were found to be co-infected with two different partitivirus strains (HetPV7-an1 and HetPV13-an2 or HetPV16-an1 and HetPV20-an1). Different isolates representing each host clone had variable virus compositions, and virus strains occurring in more than one host clone showed minor sequence variations between clones.
Collapse
Affiliation(s)
- Rafiqul Hyder
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland.
| | - Tuula Piri
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Jarkko Hantula
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Heikki Nuorteva
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Eeva J Vainio
- Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| |
Collapse
|
35
|
Heterobasidion Partitivirus 13 Mediates Severe Growth Debilitation and Major Alterations in the Gene Expression of a Fungal Forest Pathogen. J Virol 2018; 92:JVI.01744-17. [PMID: 29237832 DOI: 10.1128/jvi.01744-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 11/28/2017] [Indexed: 11/20/2022] Open
Abstract
The fungal genus Heterobasidion includes some of the most devastating conifer pathogens in the boreal forest region. In this study, we showed that the alphapartitivirus Heterobasidion partitivirus 13 from Heterobasidion annosum (HetPV13-an1) is the main causal agent of severe phenotypic debilitation in the host fungus. Based on RNA sequencing using isogenic virus-infected and cured fungal strains, HetPV13-an1 affected the transcription of 683 genes, of which 60% were downregulated and 40% upregulated. Alterations observed in carbohydrate and amino acid metabolism suggest that the virus causes a state of starvation, which is compensated for by alternative synthesis routes. We used dual cultures to transmit HetPV13-an1 into new strains of H. annosum and Heterobasidion parviporum The three strains of H. parviporum that acquired the virus showed noticeable growth reduction on rich culturing medium, while only two of six H. annosum isolates tested showed significant debilitation. Based on reverse transcription-quantitative PCR (RT-qPCR) analysis, the response toward HetPV13-an1 infection was somewhat different in H. annosum and H. parviporum We assessed the effects of HetPV13-an1 on the wood colonization efficacy of H. parviporum in a field experiment where 46 Norway spruce trees were inoculated with isogenic strains with or without the virus. The virus-infected H. parviporum strain showed considerably less growth within living trees than the isolate without HetPV13-an1, indicating that the virus also causes growth debilitation in natural substrates.IMPORTANCE A biocontrol method restricting the spread of Heterobasidion species would be highly beneficial to forestry, as these fungi are difficult to eradicate from diseased forest stands and cause approximate annual losses of €800 million in Europe. We used virus curing and reintroduction experiments and RNA sequencing to show that the alphapartitivirus HetPV13-an1 affects many basic cellular functions of the white rot wood decay fungus Heterobasidion annosum, which results in aberrant hyphal morphology and a low growth rate. Dual fungal cultures were used to introduce HetPV13-an1 into a new host species, Heterobasidion parviporum, and field experiments confirmed the capability of the virus to reduce the growth of H. parviporum in living spruce wood. Taken together, our results suggest that HetPV13-an1 shows potential for the development of a future biocontrol agent against Heterobasidion fungi.
Collapse
|
36
|
Sahin E, Akata I. Viruses infecting macrofungi. Virusdisease 2018; 29:1-18. [PMID: 29607353 DOI: 10.1007/s13337-018-0434-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/25/2018] [Indexed: 11/26/2022] Open
Abstract
Ever since their discovery just about 56 years ago in the cultivated mushroom Agaricus bisporus, many more viruses infecting fungi have been identified in a wide range of fungal taxa. With mostly being asymptomatic, especially the ones that are detrimental to their phytopathogenic hosts are intensively studied due to their considerable importance in developing novel plant protection measures. Contrary to the rapid accumulation of notable data on viruses of plant pathogenic microfungi, much less information have hitherto been obtained in regards to the viruses whose hosts are macrofungi. According to the current literature, only more than 80 distinct viruses bearing either linear dsRNA or linear positive sense ssRNA genome and infecting a total number of 34 macrofungal species represented with four Ascomycota and 30 Basidiomycota have been identified so far. Among these 34 macrofungal species, 14 are cultivated edible and wild edible mushroom species. According to the 10th ICTV (International Committee on Taxonomy of Viruses) Report, macrofungal viruses with linear dsRNA genome are classified into five families (Partitiviridae, Totiviridae, Chrysoviridae, Endornaviridae and Hypoviridae) and macrofungal viruses with linear positive sense ssRNA genome are classified into seven families (Betaflexiviridae, Gammaflexiviridae, Barnaviridae, Narnaviridae, Virgaviridae, Benyviridae and Tymoviridae). In this review, following a brief overview of some general characteristics of fungal viruses, an up to date knowledge on viruses infecting macrofungal hosts were presented by summarizing the previous, recent and prospective studies of the field.
Collapse
Affiliation(s)
- Ergin Sahin
- Faculty of Science, Department of Biology, Ankara University, Ankara, Turkey
| | - Ilgaz Akata
- Faculty of Science, Department of Biology, Ankara University, Ankara, Turkey
| |
Collapse
|
37
|
Mycoviruses in the Plant Pathogen Ustilaginoidea virens Are Not Correlated with the Genetic Backgrounds of Its Hosts. Int J Mol Sci 2017; 18:ijms18050963. [PMID: 28467379 PMCID: PMC5454876 DOI: 10.3390/ijms18050963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 04/21/2017] [Accepted: 04/26/2017] [Indexed: 11/27/2022] Open
Abstract
Ustilaginoidea virens, the causal agent of rice false smut, is one of the most devastating grain diseases that causes loss of yield in most rice-growing areas worldwide. In this study, we performed a dsRNA screen to isolate mycoviruses from 35 U. virens strains. The results revealed that 34 of the tested isolates were infected by various dsRNA elements, displaying highly viral diversity and mixed infections. We characterized a 5.3 kbp dsRNA from a typical isolate containing dsRNA segments with sizes ranging from 0.5 to 5.3 kbp. Sequence analysis of its genomic properties indicated that it is a novel victorivirus, named Ustilaginoidea virens RNA virus 5 (UvRV5), that belongs to the family Totiviridae. RT-PCR detection was performed and indicated that not all the dsRNA bands that were 5.3 kbp in size contained UvRV5. Moreover, the genetic relatedness of all the U. virens strains was estimated according to phylogenetic analysis of the partial intergenic spacer region (IGS) sequences. However, concordance was not found between the dsRNA profiles and the IGS-based genetic relatedness of their host fungi.
Collapse
|
38
|
Yaegashi H, Kanematsu S. Natural infection of the soil-borne fungus Rosellinia necatrix with novel mycoviruses under greenhouse conditions. Virus Res 2015; 219:83-91. [PMID: 26555164 DOI: 10.1016/j.virusres.2015.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 11/20/2022]
Abstract
Fungi are an important component of the soil ecosystem. Mycoviruses have numerous potential impacts on soil fungi, including phytopathogenic fungal species. However, the diversity and ecology of mycoviruses in soil fungi is largely unexplored. Our previous work has shown that the soil-borne phytopathogenic fungus Rosellinia necatrix was infected with several novel mycoviruses after growing for 2-3 years in an apple orchard. In this study, we investigated whether natural infection of R. necatrix with mycoviruses occurs under limited conditions. Virus-free R. necatrix isolates were grown in a small bucket containing soil samples for a short time (1.5-4.5 months) under greenhouse conditions. Screening of dsRNA mycoviruses among 365 retrieved isolates showed that four, including 6-31, 6-33, 6-35, and 7-11, harbored virus-like dsRNAs. Molecular characterization of the dsRNAs revealed that three retrieved isolates, 6-31, 6-33, and 6-35 were infected with a novel endornavirus and isolate 7-11 is infected with a novel partitivirus belonging to the genus Alphapartitivirus. These novel mycoviruses had no overt biological impact on R. necatrix. Overall, this study indicates that natural infections of R. necatrix with new mycoviruses can occur under experimental soil conditions.
Collapse
Affiliation(s)
- Hajime Yaegashi
- Apple Research Division, Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), Japan
| | - Satoko Kanematsu
- Apple Research Division, Institute of Fruit Tree Science, National Agriculture and Food Research Organization (NARO), Japan.
| |
Collapse
|
39
|
Vainio EJ, Hantula J. Taxonomy, biogeography and importance of Heterobasidion viruses. Virus Res 2015; 219:2-10. [PMID: 26477938 DOI: 10.1016/j.virusres.2015.10.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/08/2015] [Accepted: 10/10/2015] [Indexed: 11/17/2022]
Abstract
The genus Heterobasidion consists of several species of necrotrophic and saprotrophic fungi, and includes some of the most detrimental organisms in boreal conifer forests. These fungi host a widespread and diverse mycovirus community composed of more than 16 species of Partitiviridae, a species of Narnaviridae and one taxonomically unassigned virus related to the Curvularia thermal tolerance virus. These viruses are able to cross species borders, co-infect single host strains and cause phenotypic changes in their hosts. The abundance of viruses increases over time in Heterobasidion infection centers, and they are targeted by fungal RNA interference. Long-term field studies are essential for obtaining a comprehensive view of virus effects in the nature.
Collapse
Affiliation(s)
- Eeva J Vainio
- Natural Resources Institute Finland (Luke), Jokiniemenkuja 1, POB 18, 01301 Vantaa, Finland.
| | - Jarkko Hantula
- Natural Resources Institute Finland (Luke), Jokiniemenkuja 1, POB 18, 01301 Vantaa, Finland.
| |
Collapse
|
40
|
Roossinck MJ. Metagenomics of plant and fungal viruses reveals an abundance of persistent lifestyles. Front Microbiol 2015; 5:767. [PMID: 25628611 PMCID: PMC4290624 DOI: 10.3389/fmicb.2014.00767] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/16/2014] [Indexed: 02/01/2023] Open
Affiliation(s)
- Marilyn J Roossinck
- Department of Plant Pathology and Environmental Microbiology, Center for Infectious Disease Dynamics, Pennsylvania State University University Park, PA, USA
| |
Collapse
|
41
|
Kashif M, Hyder R, De Vega Perez D, Hantula J, Vainio E. Heterobasidion wood decay fungi host diverse and globally distributed viruses related to Helicobasidium mompa partitivirus V70. Virus Res 2015; 195:119-23. [DOI: 10.1016/j.virusres.2014.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/05/2014] [Accepted: 09/06/2014] [Indexed: 10/24/2022]
|
42
|
Prevalence and diversity of mycoviruses infecting the plant pathogen Ustilaginoidea virens. Virus Res 2015; 195:47-56. [DOI: 10.1016/j.virusres.2014.08.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/28/2014] [Accepted: 08/29/2014] [Indexed: 12/15/2022]
|
43
|
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.
Collapse
|
44
|
Botella L, Tuomivirta TT, Hantula J, Diez JJ, Jankovsky L. The European race of Gremmeniella abietina hosts a single species of Gammapartitivirus showing a global distribution and possible recombinant events in its history. Fungal Biol 2014; 119:125-35. [PMID: 25749364 PMCID: PMC7102696 DOI: 10.1016/j.funbio.2014.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 11/28/2022]
Abstract
The population genetics of the family Partitiviridae was studied within the European race of the conifer pathogen Gremmeniella abietina. One hundred sixty-two isolates were collected from different countries, including Canada, the Czech Republic, Finland, Italy, Montenegro, Serbia, Spain, Switzerland, Turkey and the United States. A unique species of G. abietina RNA virus-MS1 (GaRV-MS1) appears to occur indistinctly in G. abietina biotypes A and B, without a particular geographical distribution pattern. Forty-six isolates were shown to host GaRV-MS1 according to direct specific RT-PCR screening, and the virus was more common in biotype A than B. Phylogenetic analysis based on 46 partial coat protein (CP) cDNA sequences divided the GaRV-MS1 population into two closely related clades, while RNA-dependent RNA polymerase (RdRp) sequences revealed only one clade. The evolution of the virus appears to mainly occur through purifying selection but also through recombination. Recombination events were detected within alignments of the three complete CP and RdRp sequences of GaRV-MS1. This is the first time that recombination events have been directly identified in fungal partitiviruses and in G. abietina in particular. The results suggest that the population dynamics of GaRV-MS1 do not have a direct impact on the genetic structure of its host, G. abietina, though they might have had an innocuous ancestral relationship.
Collapse
Affiliation(s)
- Leticia Botella
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1, 61300 Brno, Czech Republic.
| | - Tero T Tuomivirta
- Finnish Forest Research Institute, Vantaa Research Unit, PO Box 18, 01301 Vantaa, Finland
| | - Jarkko Hantula
- Finnish Forest Research Institute, Vantaa Research Unit, PO Box 18, 01301 Vantaa, Finland
| | - Julio J Diez
- Sustainable Forest Management Research Institute, University of Valladolid - INIA, Avenida de Madrid 44, 34071 Palencia, Spain
| | - Libor Jankovsky
- Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1, 61300 Brno, Czech Republic
| |
Collapse
|
45
|
Vainio EJ, Jurvansuu J, Streng J, Rajamäki ML, Hantula J, Valkonen JPT. Diagnosis and discovery of fungal viruses using deep sequencing of small RNAs. J Gen Virol 2014; 96:714-725. [PMID: 25480928 DOI: 10.1099/jgv.0.000003] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Analysis of virus-derived small RNAs with high-throughput sequencing has been successful for detecting novel viruses in plants and invertebrates. However, the applicability of this method has not been demonstrated in fungi, although fungi were among the first organisms reported to utilize RNA silencing. Here, we used virus-infected isolates of the fungal species complex Heterobasidion annosum sensu lato as a model system to test whether mycovirus genome segments can be detected with small RNA deep sequencing. Species of the genus Heterobasidion are some of the most devastating forest pathogens in boreal forests. These fungi cause wood decay and are commonly infected with species of the family Partitiviridae and the unassigned virus species Heterobasidion RNA virus 6. Small RNA deep sequencing allowed the simultaneous detection of all eight double-stranded RNA virus strains known to be present in the tested samples and one putative mitovirus species (family Narnaviridae) with a single-stranded RNA genome, designated here as Heterobasidion mitovirus 1. Prior to this study, no members of the family Narnaviridae had been described as infecting species of Heterobasidion. Quantification of viral double- and single-stranded RNA with quantitative PCR indicated that co-infecting viral species and viruses with segmented genomes can be detected with small RNA deep sequencing despite vast differences in the amount of RNA. This is the first study demonstrating the usefulness of this method for detecting fungal viruses. Moreover, the results suggest that viral genomes are processed into small RNAs by different species of Heterobasidion.
Collapse
Affiliation(s)
- Eeva J Vainio
- Finnish Forest Research Institute, Vantaa Research Unit, Jokiniemenkuja 1, Vantaa, Finland
| | - Jaana Jurvansuu
- Finnish Forest Research Institute, Vantaa Research Unit, Jokiniemenkuja 1, Vantaa, Finland
| | - Janne Streng
- Department of Agricultural Sciences, P.O. Box 27, University of Helsinki, FI-00014 Helsinki, Finland
| | - Minna-Liisa Rajamäki
- Department of Agricultural Sciences, P.O. Box 27, University of Helsinki, FI-00014 Helsinki, Finland
| | - Jarkko Hantula
- Finnish Forest Research Institute, Vantaa Research Unit, Jokiniemenkuja 1, Vantaa, Finland
| | - Jari P T Valkonen
- Department of Agricultural Sciences, P.O. Box 27, University of Helsinki, FI-00014 Helsinki, Finland
| |
Collapse
|
46
|
Viruses accumulate in aging infection centers of a fungal forest pathogen. ISME JOURNAL 2014; 9:497-507. [PMID: 25126757 DOI: 10.1038/ismej.2014.145] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 05/06/2014] [Accepted: 07/07/2014] [Indexed: 11/09/2022]
Abstract
Fungal viruses (mycoviruses) with RNA genomes are believed to lack extracellular infective particles. These viruses are transmitted laterally among fungal strains through mycelial anastomoses or vertically via their infected spores, but little is known regarding their prevalence and patterns of dispersal under natural conditions. Here, we examined, in detail, the spatial and temporal changes in a mycovirus community and its host fungus Heterobasidion parviporum, the most devastating fungal pathogen of conifers in the Boreal forest region. During the 7-year sampling period, viruses accumulated in clonal host individuals as a result of indigenous viruses spreading within and between clones as well as novel strains arriving via airborne spores. Viral community changes produced pockets of heterogeneity within large H. parviporum clones. The appearance of novel viral infections in aging clones indicated that transient cell-to-cell contacts between Heterobasidion strains are likely to occur more frequently than what was inferred from genotypic analyses. Intraspecific variation was low among the three partitivirus species at the study site, whereas the unassigned viral species HetRV6 was highly polymorphic. The accumulation of point mutations during persistent infections resulted in viral diversification, that is, the presence of nearly identical viral sequence variants within single clones. Our results also suggest that co-infections by distantly related viral species are more stable than those between conspecific strains, and mutual exclusion may play a role in determining mycoviral communities.
Collapse
|
47
|
Jurvansuu J, Kashif M, Vaario L, Vainio E, Hantula J. Partitiviruses of a fungal forest pathogen have species-specific quantities of genome segments and transcripts. Virology 2014; 462-463:25-33. [DOI: 10.1016/j.virol.2014.05.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/12/2014] [Accepted: 05/20/2014] [Indexed: 11/16/2022]
|
48
|
Nibert ML, Ghabrial SA, Maiss E, Lesker T, Vainio EJ, Jiang D, Suzuki N. Taxonomic reorganization of family Partitiviridae and other recent progress in partitivirus research. Virus Res 2014; 188:128-41. [DOI: 10.1016/j.virusres.2014.04.007] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 10/25/2022]
|
49
|
Suzuki N. [Cryphonectria parasitica as a host of fungal viruses: a tool useful to unravel the mycovirus world]. Uirusu 2014; 64:11-24. [PMID: 25765976 DOI: 10.2222/jsv.64.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There appear to be over a million of fungal species including those that have been unidentified and unreported, where a variety of viruses make a world as well. Studies on a very small number of them conducted during the last two decades demonstrated the infectivity of fungal viruses that had previously been assumed to be inheritable, indigenus and non-infectious. Also, great technical advances were achieved. The chest blight fungus (Cryphonectria parasitica), a phytopathogenic ascomycetous fungus, has emerged as a model filamentous fungus for fungal virology. The genome sequence with annotations, albeit not thorough, many useful research tools, and gene manipulation technologies are available for this fungus. Importantly, C. parasitica can support replication of homologous viruses naturally infecting it, in addition to heterologous viruses infecting another plant pathogenic fungus, Rosellinia necatrix taxonomically belonging to a different order. In this article, I overview general properties of fungal viruses and advantages of the chestnut blight fungus as a mycovirus host. Furthermore, I introduce two recent studies carried out using this fungal host:''Defective interfering RNA and RNA silencing that regulate the replication of a partitivirus'' and'' RNA silencing and RNA recombination''.
Collapse
Affiliation(s)
- Nobuhiro Suzuki
- Agrivirology Laboratory, Group of Plant/Microbe Interactions, Institute of Plant Science and Resources, Okayama University
| |
Collapse
|
50
|
Hyder R, Pennanen T, Hamberg L, Vainio EJ, Piri T, Hantula J. Two viruses of Heterobasidion confer beneficial, cryptic or detrimental effects to their hosts in different situations. FUNGAL ECOL 2013. [DOI: 10.1016/j.funeco.2013.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|