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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: 12] [Impact Index Per Article: 3.0] [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.
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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.
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Ejmal MA, Holland DJ, MacDiarmid RM, Pearson MN. A novel chrysovirus from a clinical isolate of Aspergillus thermomutatus affects sporulation. PLoS One 2018; 13:e0209443. [PMID: 30571748 PMCID: PMC6301774 DOI: 10.1371/journal.pone.0209443] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/05/2018] [Indexed: 12/15/2022] Open
Abstract
A clinical isolate of Aspergillus thermomutatus (Teleomorph: Neosartorya pseudofischeri) was found to contain ~35 nm isometric virus-like particles associated with four double-stranded (ds) RNA segments, each of which coded for a single open reading frame. The longest dsRNA element (3589 nt) encodes a putative RNA-dependent RNA polymerase (1114 aa), the second longest dsRNA element (2772 nt) encodes a coat protein (825 aa), and the other two dsRNAs (2676 nt, 2514 nt) encode hypothetical proteins of 768 aa and 711 aa, respectively. Phylogenetic analysis of the amino acid sequences showed 41-60% similarity to the proteins coded by the dsRNAs of the most closely related virus, Penicillium janczewskii chrysovirus 2, indicating that it is a new species based on the International Committee on Taxonomy of Viruses criteria for the genus Chrysovirus. This is the first virus reported from A. thermomutatus and was tentatively named Aspergillus thermomutatus chrysovirus 1. A virus free line of the fungal isolate, cured by cycloheximide treatment, produced large numbers of conidia but no ascospores at both 20°C and 37°C, whereas the virus infected line produced ten-fold fewer conidia at 20°C and a large number of ascospores at both temperatures. The effects of the virus on fungal sporulation have interesting implications for the spread of the fungus and possible use of the virus as a biological control agent.
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Affiliation(s)
- Mahjoub A. Ejmal
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
| | - David J. Holland
- Infectious Diseases Unit, Division of Medicine, Staff Centre, Middlemore Hospital, Auckland, New Zealand
| | - Robin M. MacDiarmid
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Michael N. Pearson
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
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Yun SH, Lee SH, So KK, Kim JM, Kim DH. Incidence of diverse dsRNA mycoviruses in Trichoderma spp. causing green mold disease of shiitake Lentinula edodes. FEMS Microbiol Lett 2016; 363:fnw220. [PMID: 27664058 DOI: 10.1093/femsle/fnw220] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/28/2016] [Accepted: 09/22/2016] [Indexed: 11/14/2022] Open
Abstract
A total of 315 fungal isolates causing green mold disease were collected from contaminated artificial logs and sawdust bags used for cultivating shiitake Lentinula edodes in Korea and were analyzed for the presence of double-stranded RNA (dsRNA). dsRNA, which was purified using dsRNA-specific chromatography and verified by dsRNA-specific RNaseIII digestion, was detected in 32 isolates. The molecular taxonomy of dsRNA-infected isolates indicated that all isolates belonged to the Trichoderma spp.. The number and size of dsRNAs varied among isolates and the band patterns could be categorized into 15 groups. Although there were seven dsRNA groups observed in multiple isolates, eight groups were found to occur in single isolates. The most common dsRNA group, group VI, which contained a band of 10 kb, occurred in 10 isolates encompassing three species of Trichoderma. Partial sequence analysis of two selected dsRNA groups revealed a high degree of similarity to sequences of a RNA-dependent RNA polymerase, hypothetical protein and polyprotein genes of other hypoviruses such as Macrophomina phaseolina hypovirus 1, Trichoderma hypovirus, and Fusarium graminearum hypovirus 2, respectively, indicating the occurrence of mycoviruses in Trichoderma spp.. Northern blot analysis suggested that many different mycoviruses, which have not been identified yet, exist in Trichoderma.
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Affiliation(s)
- Suk-Hyun Yun
- Department of Molecular Biology, Department of Bioactive Material Sciences, Institute for Molecular Biology and Genetics, Chonbuk National University, Jeonju, Chonbuk 561-756, Korea
| | - Song Hee Lee
- Department of Molecular Biology, Department of Bioactive Material Sciences, Institute for Molecular Biology and Genetics, Chonbuk National University, Jeonju, Chonbuk 561-756, Korea
| | - Kum-Kang So
- Department of Molecular Biology, Department of Bioactive Material Sciences, Institute for Molecular Biology and Genetics, Chonbuk National University, Jeonju, Chonbuk 561-756, Korea
| | - Jung-Mi Kim
- Department of Bio-Environmental Chemistry, Wonkwang University, Iksan, Chonbuk 570-749, Korea
| | - Dae-Hyuk Kim
- Department of Molecular Biology, Department of Bioactive Material Sciences, Institute for Molecular Biology and Genetics, Chonbuk National University, Jeonju, Chonbuk 561-756, Korea
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Magae Y. Molecular characterization of a novel mycovirus in the cultivated mushroom, Lentinula edodes. Virol J 2012; 9:60. [PMID: 22390839 PMCID: PMC3365873 DOI: 10.1186/1743-422x-9-60] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 03/06/2012] [Indexed: 11/13/2022] Open
Abstract
Background In the 1970s, mycoviruses were identified that infected the edible mushroom Lentinula edodes (shiitake), but they were not regarded as causal agents for mushroom diseases. None of their genes has been sequenced. In this study, the dsRNA genome of a mycovirus recently found in a shiitake commercial strain was sequenced and its molecular structure was characterized. Methods A cDNA library was constructed from a dsRNA purified from the fruiting body of L. edodes. The virus was tentatively named L. edodes mycovirus HKB (LeV). Based on the deduced RNA-dependent RNA polymerase (RdRp) sequence, phylogenetic analysis of LeV was conducted. Because no virion particles associated with the dsRNA were observed by electron microscopic observation, atomic force microscopy (AFM) observation was chosen for achieving molecular imaging of the virus. Results The 11,282-bp genome of LeV was obtained. The genome encoded two open reading frames (ORFs). ORF1 coded for a hypothetical protein and ORF2 for a putative RdRp, respectively. In addition, a region coding for a NUDIX domain was present in ORF1. There was a 62-bp intergenic region between ORF1 and RdRp. Similarity with coat protein of mycoviruses was not found within the whole sequence. Based on phylogenetic analysis of the putative RdRp sequence, LeV grouped into a clade with dsRNA found in the basidiomycetes Phlebiopsis gigantea and Helicobasidium mompa. The clade was placed apart from the Totiviridae and Chrysoviridae families. As suggested from the genome sequence, AFM revealed that the structure of LeV was linear unencapsidated dsRNA. Conclusions The results suggest that LeV represents a novel family of mycoviruses, found thus far only among the basidiomycetes.
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Affiliation(s)
- Yumi Magae
- Department of Applied Microbiology, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan.
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Cao YF, Zhu XW, Xiang Y, Li DQ, Yang JR, Mao QZ, Chen JS. Genomic characterization of a novel dsRNA virus detected in the phytopathogenic fungus Verticillium dahliae Kleb. Virus Res 2011; 159:73-8. [DOI: 10.1016/j.virusres.2011.04.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 04/27/2011] [Accepted: 04/28/2011] [Indexed: 12/20/2022]
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Jamal A, Bignell EM, Coutts RHA. Complete nucleotide sequences of four dsRNAs associated with a new chrysovirus infecting Aspergillus fumigatus. Virus Res 2010; 153:64-70. [PMID: 20621139 DOI: 10.1016/j.virusres.2010.07.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 07/01/2010] [Accepted: 07/05/2010] [Indexed: 12/26/2022]
Abstract
A new double-stranded RNA (dsRNA) virus designated A. fumigatus chrysovirus (AfuCV), belonging to the family Chrysoviridae, has been identified in the filamentous fungus Aspergillus fumigatus. The virus was detected in five of 390 A. fumigatus isolates screened. Analysis of purified dsRNA revealed four distinct species 3560, 3159, 3006 and 2863 base pairs in length (dsRNAs 1-4) which were cloned and sequenced. Each dsRNA contains a single open reading frame (ORF) with short 5' and 3' untranslated regions containing strictly conserved termini. The deduced 1114 amino acid (aa) protein (molecular mass=128 kDa) encoded by the dsRNA1 ORF showed homology to the RNA-dependent RNA polymerase (RdRP) of viruses belonging to the Chrysoviridae. Eight motifs characteristic of RdRPs were identified. The dsRNA2 ORF encodes the putative coat protein subunit (953aa; molecular mass=107 kDa). The dsRNA3 and dsRNA4 ORFs respectively encode putative proteins (891aa, molecular mass=99 kDa) and (847aa, molecular mass=95 kDa), both of which have significant similarity to proteins encoded by comparable chrysovirus dsRNAs. The dsRNA profile, amino acid sequence alignments, and phylogenetic analyses all indicate that AfuCV is a new species within the family Chrysoviridae.
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Affiliation(s)
- Atif Jamal
- Division of Biology, Faculty of Natural Sciences Imperial College London, Sir Alexander Fleming Building, Imperial College Road, London SW7 2AZ, United Kingdom
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Kim JM, Park JA, Park SM, Cha BJ, Yang MS, Kim DH. Nucleotide sequences of four segments of chrysovirus in Korean Cryphonectria nitschkei BS122 strain. Virus Genes 2010; 41:292-4. [PMID: 20549324 DOI: 10.1007/s11262-010-0495-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 05/22/2010] [Indexed: 10/19/2022]
Abstract
The near full-length genome consisting of four segments of dsRNA from a chrysovirus infecting Korean Cryphonectria nitschkei BS122 strain (CnV1-BS122) was sequenced. The open reading frames of segments 1, 2, 3, and 4 were 2,889, 2,721, 2,475, and 2,232 nucleotides (nt) in length, respectively. Sequence analysis and homology searches of the amino acid sequences deduced from the ORFs of each segment revealed that segments 1, 2, 3, and 4 encoded RNA-dependent RNA polymerase, capsid protein, a putative cysteine protease, and replication-associated protein, respectively. The entire 5' ends of segments 1, 2, and 4 were 82, 242, and 698 nt in length, respectively; the sequence of the 5' end of segment 3 was not determined because of difficulty in amplification. The entire 3' end of segment 3 was 77 nt in length. Partial amplification of the 3' ends of segments 1, 2, and 4 yielded amplimers of 7, 17, and 30 nt, respectively.
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Affiliation(s)
- Jung-Mi Kim
- Division of Biological Sciences, Institute of Molecular Biology and Genetics, Center for Fungal Pathogenesis, Chonbuk National University, Chonbuk, Korea
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