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Wang P, Yang G, Lu H, Huang B. Infection with a novel polymycovirus enhances growth, conidiation and sensitivity to UV-B irradiation of the entomopathogenic fungus Metarhizium anisopliae. Front Microbiol 2023; 14:1214133. [PMID: 37469432 PMCID: PMC10352681 DOI: 10.3389/fmicb.2023.1214133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/14/2023] [Indexed: 07/21/2023] Open
Abstract
Metarhizium anisopliae is a well-studied entomopathogenic fungus that is widely used in biological control programs. The presence of polymycoviruses in this fungus is common, but their effects on fungal development and stress tolerance are not well understood. In this study, we report the discovery of a novel double-stranded RNA virus, named Metarhizium anisopliae polymycovirus 1 (MaPmV1), which comprises four dsRNAs ranging from 2.4 to 1.4 kbp in length. Phylogenetic analysis revealed that MaPmV1 belongs to the Polymycoviridae family. Biological comparison between MaPmV1-infected (Vi) and -free (Vf) isogenic lines showed that MaPmV1 remarkably enhances the growth rate and conidiation of the host fungus. The upregulation of growth- and conidiation-related genes in Vi strains supports this finding. In addition, MaPmV1 increases the sensitivity of the host to UV-B irradiation, which is evidenced by the downregulation of DNA damage repair genes in Vi strains. However, MaPmV1 does not appear to have any significant impact on the virulence of M. anisopliae. Furthermore, overexpression of individual viral proteins in M. anisopliae did not result in any significant phenotypic alterations, indicating that MaPmV1-mediated changes are not related to a single viral protein. Overall, our findings suggest that mycoviruses can be exploited to enhance fungal development in entomopathogenic fungi, which may lead to improved conidium production on a large scale.
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Affiliation(s)
- Ping Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Guogen Yang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
- School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Hanwen Lu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
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Zheng Y, Chen M, Li X, Dai F, Gao Z, Deng Q, Fang S, Zhang S, Pan S. Four distinct isolates of a novel polymycovirus identified in Setosphaeria turcica. Arch Virol 2023; 168:189. [PMID: 37351692 DOI: 10.1007/s00705-023-05819-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/19/2023] [Indexed: 06/24/2023]
Abstract
Isolation and analysis of double-stranded RNA (dsRNA) from the phytopathogenic fungus Setosphaeria turcica f. sp. zeae revealed the presence of a new double-stranded RNA (dsRNA) virus, tentatively named "Setosphaeria turcica polymycovirus 2" (StPmV2). The genome of StPmV2 consists of five segments (dsRNA1-5), ranging in size from 965 bp to 2462 bp. Each dsRNA contains one open reading frame (ORF) flanked by 5' and 3' untranslated regions (UTRs) with conserved terminal sequences. The putative protein encoded by dsRNA1 shows 64.52% amino acid sequence identity to the RNA-dependent RNA polymerase (RdRp) of the most closely related virus, Cladosporium cladosporioides virus 1, which belongs to the family Polymycoviridae. dsRNAs 2-4 encode the putative coat protein, methyltransferase (MTR), and proline-alanine-serine-rich protein (PASrp), respectively, and dsRNA5 encodes a protein of unknown function. Phylogenetic analysis based on the RdRp protein indicated that StPmV2 clustered with members of the family Polymycoviridae and is therefore a new mycovirus belonging to the genus Polymycovirus in the family Polymycoviridae. In addition, three other distinct isolates of StPmV2 were identified: one isolated from S. turcica f. sp. zeae and two from S. turcica f. sp. sorghi. To our knowledge, this is the first report of a polymycovirus infecting both S. turcica f. sp. zeae and S. turcica f. sp. sorghi.
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Affiliation(s)
- Yun Zheng
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou, 434025, China
| | - Miaomiao Chen
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou, 434025, China
| | - Xiquan Li
- Anshun Branch of Guizhou Tobacco Company, Anshun, 561000, China
| | - Fei Dai
- Anshun Branch of Guizhou Tobacco Company, Anshun, 561000, China
| | - Zhongnan Gao
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou, 434025, China
| | - Qingchao Deng
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou, 434025, China
| | - Shouguo Fang
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou, 434025, China
| | - Songbai Zhang
- MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), Hubei Engineering Research Center for Pest Forewarning and Management, Yangtze University, Jingzhou, 434025, China.
| | - Shouhui Pan
- Anshun Branch of Guizhou Tobacco Company, Anshun, 561000, China.
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Liu C, Jiang X, Tan Z, Wang R, Shang Q, Li H, Xu S, Aranda MA, Wu B. An Outstandingly Rare Occurrence of Mycoviruses in Soil Strains of the Plant-Beneficial Fungi from the Genus Trichoderma and a Novel Polymycoviridae Isolate. Microbiol Spectr 2023; 11:e0522822. [PMID: 37022156 PMCID: PMC10269472 DOI: 10.1128/spectrum.05228-22] [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: 12/24/2022] [Accepted: 01/31/2023] [Indexed: 04/07/2023] Open
Abstract
In fungi, viral infections frequently remain cryptic causing little or no phenotypic changes. It can indicate either a long history of coevolution or a strong immune system of the host. Some fungi are outstandingly ubiquitous and can be recovered from a great diversity of habitats. However, the role of viral infection in the emergence of environmental opportunistic species is not known. The genus of filamentous and mycoparasitic fungi Trichoderma (Hypocreales, Ascomycota) consists of more than 400 species, which mainly occur on dead wood, other fungi, or as endo- and epiphytes. However, some species are environmental opportunists because they are cosmopolitan, can establish in a diversity of habitats, and can also become pests on mushroom farms and infect immunocompromised humans. In this study, we investigated the library of 163 Trichoderma strains isolated from grassland soils in Inner Mongolia, China, and found only four strains with signs of the mycoviral nucleic acids, including a strain of T. barbatum infected with a novel strain of the Polymycoviridae and named and characterized here as Trichoderma barbatum polymycovirus 1 (TbPMV1). Phylogenetic analysis suggested that TbPMV1 was evolutionarily distinct from the Polymycoviridae isolated either from Eurotialean fungi or from the order Magnaportales. Although the Polymycoviridae viruses were also known from Hypocrealean Beauveria bassiana, the phylogeny of TbPMV1 did not reflect the phylogeny of the host. Our analysis lays the groundwork for further in-depth characterization of TbPMV1 and the role of mycoviruses in the emergence of environmental opportunism in Trichoderma. IMPORTANCE Although viruses infect all organisms, our knowledge of some groups of eukaryotes remains limited. For instance, the diversity of viruses infecting fungi-mycoviruses-is largely unknown. However, the knowledge of viruses associated with industrially relevant and plant-beneficial fungi, such as Trichoderma spp. (Hypocreales, Ascomycota), may shed light on the stability of their phenotypes and the expression of beneficial traits. In this study, we screened the library of soilborne Trichoderma strains because these isolates may be developed into bioeffectors for plant protection and sustainable agriculture. Notably, the diversity of endophytic viruses in soil Trichoderma was outstandingly low. Only 2% of 163 strains contained traces of dsRNA viruses, including the new Trichoderma barbatum polymycovirus 1 (TbPMV1) characterized in this study. TbPMV1 is the first mycovirus found in Trichoderma. Our results indicate that the limited data prevent the in-depth study of the evolutionary relationship between soilborne fungi and is worth further investigation.
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Affiliation(s)
- Chenchen Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiliang Jiang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhaoyan Tan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Rongqun Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qiaoxia Shang
- Key Laboratory for Northern Urban Agriculture of Ministry of Agriculture and Rural Affairs, Beijing University of Agriculture, Beijing, China
| | - Hongrui Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Horticulture and Landscapes, Tianjin Agricultural University, Tianjin, China
| | - Shujin Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Horticulture and Landscapes, Tianjin Agricultural University, Tianjin, China
| | - Miguel A. Aranda
- Department of Stress Biology and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura (CEBAS)-CSIC, Murcia, Spain
| | - Beilei Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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Huang H, Hua X, Pang X, Zhang Z, Ren J, Cheng J, Fu Y, Xiao X, Lin Y, Chen T, Li B, Liu H, Jiang D, Xie J. Discovery and Characterization of Putative Glycoprotein-Encoding Mycoviruses in the Bunyavirales. J Virol 2023; 97:e0138122. [PMID: 36625579 PMCID: PMC9888262 DOI: 10.1128/jvi.01381-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/16/2022] [Indexed: 01/11/2023] Open
Abstract
Although segmented negative-sense RNA viruses (SNSRVs) have been frequently discovered in various fungi, most SNSRVs reported only the large segments. In this study, we investigated the diversity of the mycoviruses in the phytopathogenic fungus Fusarium asiaticum using the metatranscriptomic technique. We identified 17 fungal single-stranded RNA (ssRNA) viruses including nine viruses within Mitoviridae, one each in Narnaviridae, Botourmiaviridae, Hypoviridae, Fusariviridae, and Narliviridae, two in Mymonaviridae, and one trisegmented virus temporarily named Fusarium asiaticum mycobunyavirus 1 (FaMBV1). The FaMBV1 genome comprises three RNA segments, large (L), medium (M), and small (S) with 6,468, 2,639, and 1,420 nucleotides, respectively. These L, M, and S segments putatively encode the L protein, glycoprotein, and nucleocapsid, respectively. Phylogenetic analysis based on the L protein showed that FaMBV1 is phylogenetically clustered with Alternaria tenuissima negative-stranded RNA virus 2 (AtNSRV2) and Sclerotinia sclerotiorum negative-stranded RNA virus 5 (SsNSRV5) but distantly related to the members of the family Phenuiviridae. FaMBV1 could be vertically transmitted by asexual spores with lower efficiency (16.7%, 2/42). Comparison between FaMBV1-free and -infected fungal strains revealed that FaMBV1 has little effect on hyphal growth, pathogenicity, and conidium production, and its M segment is dispensable for viral replication and lost during subculture and asexual conidiation. The M and S segments of AtNSRV2 and SsNSRV5 were found using bioinformatics methods, indicating that the two fungal NSRVs harbor trisegmented genomes. Our results provide a new example of the existence and evolution of the segmented negative-sense RNA viruses in fungi. IMPORTANCE Fungal segmented negative-sense RNA viruses (SNSRVs) have been frequently found. Only the large segment encoding RNA-dependent RNA polymerase (RdRp) has been reported in most fungal SNSRVs, except for a few fungal SNSRVs reported to encode nucleocapsids, nonstructural proteins, or movement proteins. Virome analysis of the Fusarium spp. that cause Fusarium head blight discovered a novel virus, Fusarium asiaticum mycobunyavirus 1 (FaMBV1), representing a novel lineage of the family Phenuiviridae. FaMBV1 harbors a trisegmented genome that putatively encodes RdRp, glycoproteins, and nucleocapsids. The putative glycoprotein was first described in fungal SNSRVs and shared homology with glycoprotein of animal phenuivirus but was dispensable for its replication in F. asiaticum. Two other trisegmented fungal SNSRVs that also encode glycoproteins were discovered, implying that three-segment bunyavirus infections may be common in fungi. These findings provide new insights into the ecology and evolution of SNSRVs, particularly those infecting fungi.
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Affiliation(s)
- Huang Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Xiangmin Hua
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Xidan Pang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Zhongmei Zhang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Jingyi Ren
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Xianyang, Shaanxi, China
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yanping Fu
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Xueqiong Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yang Lin
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Tao Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Bo Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Huiquan Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Xianyang, Shaanxi, China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
- Hubei Hongshan Laboratory, Wuhan, Hubei, China
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Zhang X, Wu C, Hua H, Cai Q, Wu X. Characterization of the First Alternavirus Identified in Fusarium avenaceum, the Causal Agent of Potato Dry Rot. Viruses 2023; 15:145. [PMID: 36680185 PMCID: PMC9864086 DOI: 10.3390/v15010145] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/03/2023] Open
Abstract
A novel virus with a double-stranded RNA (dsRNA) genome was isolated from Fusarium avenaceum strain GS-WW-224, the causal agent of potato dry rot. The virus has been designated as Fusarium avenaceum alternavirus 1 (FaAV1). Its genome consists of two dsRNA segments, 3538 bp (dsRNA1) and 2477 bp (dsRNA2) in length, encoding RNA-dependent RNA polymerase (RdRp) and a hypothetical protein (HP), respectively. The virions of FaAV1 are isometric spherical and approximately 30 nm in diameter. Multiple sequence alignments and phylogenetic analyses based on the amino acid sequences of RdRp and HP indicated that FaAV1 appears to be a new member of the proposed family Alternaviridae. No significant differences in colony morphology and spore production were observed between strains GS-WW-224 and GS-WW-224-VF, the latter strain being one in which FaAV1 was eliminated from strain GS-WW-224. Notably, however, the dry weight of mycelial biomass of GS-WW-224 was higher than that of mycelial biomass of GS-WW-224-VF. The depth and the width of lesions on potato tubers caused by GS-WW-224 were significantly greater, relative to GS-WW-224-VF, suggesting that FaAV1 confers hypervirulence to its host, F. avenaceum. Moreover, FaAV1 was successfully transmitted horizontally from GS-WW-224 to ten other species of Fusarium, and purified virions of FaAV1 were capable of transfecting wounded hyphae of the ten species of Fusarium. This is the first report of an alternavirus infecting F. avenaceum and conferring hypervirulence.
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Affiliation(s)
| | | | | | | | - Xuehong Wu
- College of Plant Protection, China Agricultural University, Haidian District, Beijing 100193, China
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Molecular characterization of a novel polymycovirus identified in the phytopathogenic fungus Colletotrichum gloeosporioides. Arch Virol 2022; 167:2805-2810. [PMID: 36308546 DOI: 10.1007/s00705-022-05591-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 07/27/2022] [Indexed: 12/14/2022]
Abstract
A novel polymycovirus isolated from the plant-pathogenic fungus Colletotrichum gloeosporioides was identified. The viral genome is composed of nine double-stranded RNA segments, ranging in size from 699 bp to 2,444 bp. With the exception of dsRNA5, which contains two open reading frames (ORF5-1 and ORF5-2), the other dsRNA segments each contain one ORF. The proteins encoded by ORFs 1-8 are homologous to the proteins encoded by ORFs 1-8 of Colletotrichum camelliae filamentous virus 1 (CcFV-1). The amino acid sequences of the RNA-dependent RNA polymerase (RdRp) encoded by ORF1 and the viral methyltransferase encoded by ORF3 share 87.6% and 83.3% identity with CcFV-1. The proline-alanine-serine-rich protein (PASrp) encoded by ORF4 shares 86.6% sequence identity with that of CcFV-1. The proteins encoded by ORFs 2, 5 - 1, 6, 7, and 8 share 86.6%, 82.5%, 89.0%, 45.7%, and 95.5% sequence identity, respectively, with the corresponding proteins of CcFV-1. dsRNA9 is a defective copy of dsRNA2 that lacks a stretch of 1556 bp (nt 519 to nt 2074). Phylogenetic analysis based on the RdRp protein indicated that the novel virus clustered with members of the family Polymycoviridae, and based on the above results, we have tentatively named it "Colletotrichum gloeosporioides polymycovirus virus 1" (CgPmV1). To our knowledge, this is the first report of a polymycovirus with a defective dsRNA genome in C. gloeosporioides.
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Teng L, Chen S, Hu Z, Chen J, Liu H, Zhang T. Molecular characterization and transcriptomic analysis of a novel polymycovirus in the fungus Talaromyces amestolkiae. Front Microbiol 2022; 13:1008409. [PMID: 36386701 PMCID: PMC9645161 DOI: 10.3389/fmicb.2022.1008409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 10/07/2022] [Indexed: 11/25/2022] Open
Abstract
Talaromyces amestolkiae is an important fungal species owing to its ubiquity in soils, plants, air, and food. In this study, we identified a novel six-segmented polymycovirus, Talaromyces amestolkiae polymycovirus 1 (TaPmV-1). Each of the double-stranded (ds) RNA segments of TaPmV-1 contained a single open reading frame, and the proteins encoded by dsRNA1, dsRNA2, dsRNA3, and dsRNA 5 shared significant amino acid identities of 56, 40, 47, and 43%, respectively, with the corresponding proteins of Aspergillus fumigatus polymycovirus-1(AfuPmV-1). DsRNA1, dsRNA3, and dsRNA5 of TaPmV-1 encoded an RNA-dependent RNA polymerase (RdRp), a viral methyltransferase, and a PAS-rich protein, respectively. The functions of the proteins encoded by dsRNA2, dsRNA4, and dsRNA6 have not been elucidated. Comparison of the virus-infected strain LSH3 with virus-cured strain LSHVF revealed that infection with TaPmV-l may reduce the production of red pigments and induce the clustering of fungal sclerotia. Furthermore, transcriptomic analyses demonstrated that infection with TaPmV-l downregulated the expression of transcripts related to metabolism, and may correlate with the reduced production of red pigments and clustering of sclerotia in T. amestolkiae. These results of this study provide novel insights into the mechanism of fungal gene regulation by polymycovirus infections at the transcriptome level, and this study is the first to report a novel polymycovirus of T. amestolkiae.
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Affiliation(s)
- Li Teng
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Engineering Research Center of Cellular Immunotherapy of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Immune Cells and Antibody Engineering Research Center of Guizhou Province, Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, China
| | - Sen Chen
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Engineering Research Center of Cellular Immunotherapy of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Immune Cells and Antibody Engineering Research Center of Guizhou Province, Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, China
| | - Zuquan Hu
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Engineering Research Center of Cellular Immunotherapy of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Immune Cells and Antibody Engineering Research Center of Guizhou Province, Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, China
| | - Jili Chen
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Engineering Research Center of Cellular Immunotherapy of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Immune Cells and Antibody Engineering Research Center of Guizhou Province, Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, China
| | - Hongmei Liu
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Engineering Research Center of Cellular Immunotherapy of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Immune Cells and Antibody Engineering Research Center of Guizhou Province, Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, China
- *Correspondence: Hongmei Liu, ; Tingting Zhang,
| | - Tingting Zhang
- Key Laboratory of Infectious Immune and Antibody Engineering of Guizhou Province, Engineering Research Center of Cellular Immunotherapy of Guizhou Province, School of Biology and Engineering/School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Immune Cells and Antibody Engineering Research Center of Guizhou Province, Key Laboratory of Biology and Medical Engineering, Guizhou Medical University, Guiyang, China
- Key Laboratory of Microbiology and Parasitology of Education Department of Guizhou, School of Basic Medical Science, Guizhou Medical University, Guiyang, China
- *Correspondence: Hongmei Liu, ; Tingting Zhang,
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Khan HA, Telengech P, Kondo H, Bhatti MF, Suzuki N. Mycovirus Hunting Revealed the Presence of Diverse Viruses in a Single Isolate of the Phytopathogenic Fungus Diplodia seriata From Pakistan. Front Cell Infect Microbiol 2022; 12:913619. [PMID: 35846770 PMCID: PMC9277117 DOI: 10.3389/fcimb.2022.913619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/06/2022] [Indexed: 12/23/2022] Open
Abstract
Diplodia seriata in the family Botryosphaeriaceae is a cosmopolitan phytopathogenic fungus and is responsible for causing cankers, fruit rot and leaf spots on economically important plants. In this study, we characterized the virome of a single Pakistani strain (L3) of D. seriata. Several viral-like contig sequences were obtained via a previously conducted next-generation sequencing analysis. Multiple infection of the L3 strain by eight RNA mycoviruses was confirmed through RT-PCR using total RNA samples extracted from this strain; the entire genomes were determined via Sanger sequencing of RT-PCR and RACE clones. A BLAST search and phylogenetic analyses indicated that these eight mycoviruses belong to seven different viral families. Four identified mycoviruses belong to double-stranded RNA viral families, including Polymycoviridae, Chrysoviridae, Totiviridae and Partitiviridae, and the remaining four identified mycoviruses belong to single-stranded RNA viral families, i.e., Botourmiaviridae, and two previously proposed families "Ambiguiviridae" and "Splipalmiviridae". Of the eight, five mycoviruses appear to represent new virus species. A morphological comparison of L3 and partially cured strain L3ht1 suggested that one or more of the three viruses belonging to Polymycoviridae, "Splipalmiviridae" and "Ambiguiviridae" are involved in the irregular colony phenotype of L3. To our knowledge, this is the first report of diverse virome characterization from D. seriata.
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Affiliation(s)
- Haris Ahmed Khan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Paul Telengech
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
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A Novel Heptasegmented Positive-Sense Single-Stranded RNA Virus from the Phytopathogenic Fungus Colletotrichum fructicola. J Virol 2022; 96:e0031822. [PMID: 35435725 DOI: 10.1128/jvi.00318-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, a novel positive-sense single-stranded RNA (+ssRNA) mycovirus, tentatively named Colletotrichum fructicola RNA virus 1 (CfRV1), was identified in the phytopathogenic fungus Colletotrichum fructicola. CfRV1 has seven genomic components, encoding seven proteins from open reading frames (ORFs) flanked by highly conserved untranslated regions (UTRs). Proteins encoded by ORFs 1, 2, 3, 5, and 6 are more similar to the putative RNA-dependent RNA polymerase (RdRp), hypothetical protein (P2), methyltransferase, and two hypothetical proteins of Hadaka virus 1 (HadV1), a capsidless 10- or 11-segmented +ssRNA virus, while proteins encoded by ORFs 4 and 7 showed no detectable similarity to any known proteins. Notably, proteins encoded by ORFs 1 to 3 also share considerably high similarity with the corresponding proteins of polymycoviruses. Phylogenetic analysis conducted based on the amino acid sequence of CfRV1 RdRp and related viruses placed CfRV1 and HadV1 together in the same clade, close to polymycoviruses and astroviruses. CfRV1-infected C. fructicola strains demonstrate a moderately attenuated growth rate and virulence compared to uninfected isolates. CfRV1 is capsidless and potentially encapsulated in vesicles inside fungal cells, as revealed by transmission electron microscopy. CfRV1 and HadV1 are +ssRNA mycoviruses closely related to polymycoviruses and astroviruses, represent a new linkage between +ssRNA viruses and the intermediate double-stranded RNA (dsRNA) polymycoviruses, and expand our understanding of virus diversity, taxonomy, evolution, and biological traits. IMPORTANCE A scenario proposing that dsRNA viruses evolved from +ssRNA viruses is still considered controversial due to intergroup knowledge gaps in virus diversity. Recently, polymycoviruses and hadakaviruses were found as intermediate dsRNA and +ssRNA stages, respectively, between +ssRNA and dsRNA viruses. Here, we identified a novel +ssRNA mycovirus, Colletotrichum fructicola RNA virus 1 (CfRV1), isolated from Colletotrichum fructicola in China. CfRV1 is phylogenetically related to the 10- or 11-segmented Hadaka virus 1 (HadV1) but consists of only seven genomic segments encoding two novel proteins. CfRV1 is naked and may be encapsulated in vesicles inside fungal cells, representing a potential novel lifestyle for multisegmented RNA viruses. CfRV1 and HadV1 are intermediate +ssRNA mycoviruses in the linkage between +ssRNA viruses and the intermediate dsRNA polymycoviruses and expand our understanding of virus diversity, taxonomy, and evolution.
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10
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Ma G, Wu C, Li Y, Mi Y, Zhou T, Zhao C, Wu X. Identification and genomic characterization of a novel polymycovirus from Alternaria alternata causing watermelon leaf blight. Arch Virol 2021; 167:223-227. [PMID: 34636952 DOI: 10.1007/s00705-021-05272-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/29/2021] [Indexed: 11/25/2022]
Abstract
A double-stranded RNA (dsRNA) mycovirus from the phytopathogenic fungus Alternaria alternata, which causes watermelon leaf blight, was characterized. The genome of this virus has eight dsRNA segments, ranging from 1039 bp to 2398 bp. DsRNAs 1-6 each contain a single large open reading frame (ORF), while dsRNAs 7 and 8 each dsRNA contain two ORFs. The RNA-dependent RNA polymerase (RdRp) encoded by dsRNA1 and the viral methyltransferase encoded by dsRNA3 share 97.6% and 98.9% amino acid sequence identity, respectively, with the corresponding proteins of Plasmopara viticola lesion associated polymycovirus 1. The dsRNA5-encoded proline-alanine-serine-rich protein shows 48.1% sequence identity to that of Beauveria bassiana polymycovirus 3. The proteins encoded on dsRNAs 2, 4, and 8 have 99.7%, 98.2%, and 65.1% sequence identity, respectively, to the corresponding proteins of a mycovirus identified in Alternaria sp. FA0703 (AltR1). The proteins encoded by dsRNAs 6 and 7 do not match any known proteins of mycoviruses. Phylogenetic analysis of the RdRp domain showed that the virus clustered with members of the family Polymycoviridae. Based on these characteristics, the mycovirus was identified as a polymycovirus and designated as "Alternaria alternata polymycovirus 1" (AaPmV1). This is the first report of a polymycovirus associated with A. alternata.
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Affiliation(s)
- Guoping Ma
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China.,Institute of Plant Protection, Shandong Academy of Agricultural Sciences/Shandong Key Laboratory of Plant Virology, Jinan, 250100, People's Republic of China
| | - Chunyan Wu
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Yuting Li
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Yiran Mi
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Tao Zhou
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China
| | - Can Zhao
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China. .,College of Horticulture, China Agricultural University, Haidian District, Beijing, 100193, People's Republic of China.
| | - Xuehong Wu
- College of Plant Protection, China Agricultural University, No. 2 Yuanmingyuan West Road, Haidian District, Beijing, 100193, People's Republic of China.
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11
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Complete genome sequence of the first chrysovirus from the phytopathogenic fungus Alternaria solani on potato in China. Arch Virol 2021; 166:3493-3497. [PMID: 34622361 DOI: 10.1007/s00705-021-05263-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
The complete genome sequence of a double-stranded RNA (dsRNA) mycovirus that was isolated from Alternaria solani strain DT-10 causing potato foliar disease was determined. The virus, designated as "Alternaria solani chrysovirus 1" (AsCV1), has four dsRNA segments (dsRNA 1-4) with a length of 3600 bp, 3128 bp, 2996 bp, and 2714 bp, respectively. The RNA-dependent RNA polymerase (RdRp, 1084 amino acids [aa]), putative capsid protein (905 aa), alphachryso-P3 (835 aa), and alphachryso-P4 (729 aa) were encoded by dsRNA1, dsRNA2, dsRNA3, and dsRNA4, respectively, which had the highest sequence identity of 41.77%-72.38% to their counterparts in Helminthosporium victoriae virus 145S (HvV145S) of the genus Alphachrysovirus, family Chrysoviridae. Moreover, the 5'-untranslated regions (UTRs) of AsCV1 dsRNA 1-4, which contained several unique inserts (3-37 bp) and deletions (5-64 bp), shared 51.65%-68.01% identity with those of HvV145S. Phylogenetic analysis based on RdRp sequences showed that AsCV1 clustered the most closely with HvV145S. Considering its distinct host specificity, the low sequence similarity of its encoded proteins to those of other viruses, the unusual features of the 5'-UTRs of its dsRNA 1-4, and the phylogenetic position of its RdRp gene, AsCV1 should be considered a member of a new species in the genus Alphachrysovirus. To the best of our knowledge, this is the first alphachrysovirus identified from phytopathogenic A. solani.
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12
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Mahillon M, Decroës A, Caulier S, Tiendrebeogo A, Legrève A, Bragard C. Genomic and biological characterization of a novel partitivirus infecting Fusarium equiseti. Virus Res 2021; 297:198386. [PMID: 33716183 DOI: 10.1016/j.virusres.2021.198386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/03/2021] [Accepted: 03/08/2021] [Indexed: 12/18/2022]
Abstract
This study describes a new mycovirus infecting a strain from the Fusarium incarnatum-equiseti species complex. Based on phylogenetic and genomic analyses, this virus belongs to the recently proposed genus "Zetapartitivirus" in the family Partitiviridae. The name "Fusarium equiseti partitivirus 1″ (FePV1) is therefore suggested for this novel viral species. Similar to other partitiviruses, FePV1 genome is composed by two dsRNA segments that exhibit each one large ORF encoding for an RdRp and a CP, respectively. A smaller dsRNA was also detected in infected mycelium and could be a satellite RNA of FePV1. In addition to characterized zetapartitiviruses, other FePV1-related sequences were retrieved from online databases and their significance is discussed. Following conidial isolation, an FePV1-free isogenic line of the fungal host was obtained. In comparison with the original infected strain, this line showed higher growth, biomass production and pathogenicity on tomato, advocating that FePV1 induces hypovirulence on its host.
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Affiliation(s)
- Mathieu Mahillon
- Earth and Life Institute, Applied Microbiology-Phytopathology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Alain Decroës
- Earth and Life Institute, Applied Microbiology-Phytopathology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Simon Caulier
- Earth and Life Institute, Applied Microbiology-Phytopathology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Assiata Tiendrebeogo
- Earth and Life Institute, Applied Microbiology-Phytopathology, UCLouvain, Louvain-la-Neuve, Belgium; Natural System, Agrosystem and Environmental Engineering, Phytopathology, Nazi Boni University, Bobo-Dioulasso, Burkina-Faso
| | - Anne Legrève
- Earth and Life Institute, Applied Microbiology-Phytopathology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Claude Bragard
- Earth and Life Institute, Applied Microbiology-Phytopathology, UCLouvain, Louvain-la-Neuve, Belgium.
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13
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Filippou C, Diss RM, Daudu JO, Coutts RHA, Kotta-Loizou I. The Polymycovirus-Mediated Growth Enhancement of the Entomopathogenic Fungus Beauveria bassiana Is Dependent on Carbon and Nitrogen Metabolism. Front Microbiol 2021; 12:606366. [PMID: 33603722 PMCID: PMC7884332 DOI: 10.3389/fmicb.2021.606366] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 01/04/2021] [Indexed: 11/13/2022] Open
Abstract
Polymycoviridae is a growing family of mycoviruses whose members typically have non-conventional capsids and multi-segmented, double-stranded (ds) RNA genomes. Beauveria bassiana polymycovirus (BbPmV) 1 is known to enhance the growth and virulence of its fungal host, the entomopathogenic ascomycete and popular biological control agent B. bassiana. Here we report the complete sequence of BbPmV-3, which has six genomic dsRNA segments. Phylogenetic analysis of RNA-dependent RNA polymerase (RdRp) protein sequences revealed that BbPmV-3 is closely related to the partially sequenced BbPmV-2 but not BbPmV-1. Nevertheless, both BbPmV-3 and BbPmV-1 have similar effects on their respective host isolates ATHUM 4946 and EABb 92/11-Dm, affecting pigmentation, sporulation, and radial growth. Production of conidia and radial growth are significantly enhanced in virus-infected isolates as compared to virus-free isogenic lines on Czapek-Dox complete and minimal media that contain sucrose and sodium nitrate. However, this polymycovirus-mediated effect on growth is dependent on the carbon and nitrogen sources available to the host fungus. Both BbPmV-3 and BbPmV-1 increase growth of ATHUM 4946 and EABb 92/11-Dm when sucrose is replaced by lactose, trehalose, glucose, or glycerol, while the effect is reversed on maltose and fructose. Similarly, both BbPmV-3 and BbPmV-1 decrease growth of ATHUM 4946 and EABb 92/11-Dm when sodium nitrate is replaced by sodium nitrite, potassium nitrate, or ammonium nitrate. In conclusion, the effects of polymycoviruses on B. bassiana are at least partially mediated via its metabolic pathways.
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Affiliation(s)
- Charalampos Filippou
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Department of Clinical, Pharmaceutical and Biological Science, University of Hertfordshire, Hatfield, United Kingdom
| | - Rebecca M Diss
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - John O Daudu
- Department of Clinical, Pharmaceutical and Biological Science, University of Hertfordshire, Hatfield, United Kingdom
| | - Robert H A Coutts
- Department of Clinical, Pharmaceutical and Biological Science, University of Hertfordshire, Hatfield, United Kingdom
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Imperial College London, London, United Kingdom
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14
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Takahashi-Nakaguchi A, Shishido E, Yahara M, Urayama SI, Ninomiya A, Chiba Y, Sakai K, Hagiwara D, Chibana H, Moriyama H, Gonoi T. Phenotypic and Molecular Biological Analysis of Polymycovirus AfuPmV-1M From Aspergillus fumigatus: Reduced Fungal Virulence in a Mouse Infection Model. Front Microbiol 2020; 11:607795. [PMID: 33424809 PMCID: PMC7794001 DOI: 10.3389/fmicb.2020.607795] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 11/24/2020] [Indexed: 11/30/2022] Open
Abstract
The filamentous fungal pathogen Aspergillus fumigatus is one of the most common causal agents of invasive fungal infection in humans; the infection is associated with an alarmingly high mortality rate. In this study, we investigated whether a mycovirus, named AfuPmV-1M, can reduce the virulence of A. fumigatus in a mouse infection model. AfuPmV-1M has high sequence similarity to AfuPmV-1, one of the polymycovirus that is a capsidless four-segment double-stranded RNA (dsRNA) virus, previously isolated from the genome reference strain of A. fumigatus, Af293. However, we found the isolate had an additional fifth dsRNA segment, referred to as open reading frame 5 (ORF5), which has not been reported in AfuPmV-1. We then established isogenic lines of virus-infected and virus-free A. fumigatus strains. Mycovirus infection had apparent influences on fungal phenotypes, with the virus-infected strain producing a reduced mycelial mass and reduced conidial number in comparison with these features of the virus-free strain. Also, resting conidia of the infected strain showed reduced adherence to pulmonary epithelial cells and reduced tolerance to macrophage phagocytosis. In an immunosuppressed mouse infection model, the virus-infected strain showed reduced mortality in comparison with mortality due to the virus-free strain. RNA sequencing and high-performance liquid chromatography (HPLC) analysis showed that the virus suppressed the expression of genes for gliotoxin synthesis and its production at the mycelial stage. Conversely, the virus enhanced gene expression and biosynthesis of fumagillin. Viral RNA expression was enhanced during conidial maturation, conidial germination, and the mycelial stage. We presume that the RNA or translation products of the virus affected fungal phenotypes, including spore formation and toxin synthesis. To identify the mycovirus genes responsible for attenuation of fungal virulence, each viral ORF was ectopically expressed in the virus-free KU strain. We found that the expression of ORF2 and ORF5 reduced fungal virulence in the mouse model. In addition, ORF3 affected the stress tolerance of host A. fumigatus in culture. We hypothesize that the respective viral genes work cooperatively to suppress the pathogenicity of the fungal host.
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Affiliation(s)
| | - Erika Shishido
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Misa Yahara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Syun-Ichi Urayama
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.,Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan
| | - Akihiro Ninomiya
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yuto Chiba
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kanae Sakai
- Medical Mycology Research Center, Chiba University, Chiba, Japan.,Graduate School of Science, Technology and Innovation, Kobe University, Kobe, Japan
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan.,Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.,Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan
| | - Hiroji Chibana
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Hiromitsu Moriyama
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tohru Gonoi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
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15
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Sato Y, Jamal A, Kondo H, Suzuki N. Molecular Characterization of a Novel Polymycovirus From Penicillium janthinellum With a Focus on Its Genome-Associated PASrp. Front Microbiol 2020; 11:592789. [PMID: 33193262 PMCID: PMC7606342 DOI: 10.3389/fmicb.2020.592789] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 09/18/2020] [Indexed: 12/24/2022] Open
Abstract
The genus Polymycovirus of the family Polymycoviridae accommodates fungal RNA viruses with different genomic segment numbers (four, five, or eight). It is suggested that four members form no true capsids and one forms filamentous virus particles enclosing double-stranded RNA (dsRNA). In both cases, viral dsRNA is associated with a viral protein termed “proline-alanine-serine-rich protein” (PASrp). These forms are assumed to be the infectious entity. However, the detailed molecular characteristics of PASrps remain unclear. Here, we identified a novel five-segmented polymycovirus, Penicillium janthinellum polymycovirus 1 (PjPmV1), and characterized its purified fraction form in detail. The PjPmV1 had five dsRNA segments associated with PASrp. Density gradient ultracentrifugation of the PASrp-associated PjPmV1 dsRNA revealed its uneven structure and a broad fractionation profile distinct from that of typical encapsidated viruses. Moreover, PjPmV1-PASrp interacted in vitro with various nucleic acids in a sequence-non-specific manner. These PjPmV1 features are discussed in view of the diversification of genomic segment numbers of the genus Polymycovirus.
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Affiliation(s)
- Yukiyo Sato
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Atif Jamal
- Crop Diseases Research Institute, National Agricultural Research Centre, Islamabad, Pakistan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
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16
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Sato Y, Shamsi W, Jamal A, Bhatti MF, Kondo H, Suzuki N. Hadaka Virus 1: a Capsidless Eleven-Segmented Positive-Sense Single-Stranded RNA Virus from a Phytopathogenic Fungus, Fusarium oxysporum. mBio 2020; 11:e00450-20. [PMID: 32457242 PMCID: PMC7251205 DOI: 10.1128/mbio.00450-20] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/28/2020] [Indexed: 12/16/2022] Open
Abstract
The search for viruses infecting fungi, or mycoviruses, has extended our knowledge about the diversity of RNA viruses, as exemplified by the discovery of polymycoviruses, a phylogenetic group of multisegmented RNA viruses with unusual forms. The genomic RNAs of known polymycoviruses, which show a phylogenetic affinity for animal positive-sense single-stranded RNA [(+)RNA] viruses such as caliciviruses, are comprised of four conserved segments with an additional zero to four segments. The double-stranded form of polymycovirus genomic RNA is assumed to be associated with a virally encoded protein (proline-alanine-serine-rich protein [PASrp]) in either of two manners: a capsidless colloidal form or a filamentous encapsidated form. Detailed molecular characterizations of polymycoviruses, however, have been conducted for only a few strains. Here, a novel polymyco-related virus named Hadaka virus 1 (HadV1), from the phytopathogenic fungus Fusarium oxysporum, was characterized. The genomic RNA of HadV1 consisted of an 11-segmented positive-sense RNA with highly conserved terminal nucleotide sequences. HadV1 shared the three conserved segments with known polymycoviruses but lacked the PASrp-encoding segment. Unlike the known polymycoviruses and encapsidated viruses, HadV1 was not pelleted by conventional ultracentrifugation, possibly due to the lack of PASrp. This result implied that HadV1 exists only as a soluble form with naked RNA. Nevertheless, the 11 genomic segments of HadV1 have been stably maintained through host subculturing and conidiation. Taken together, the results of this study revealed a virus with a potential novel virus lifestyle, carrying many genomic segments without typical capsids or PASrp-associated forms.IMPORTANCE Fungi collectively host various RNA viruses. Examples include encapsidated double-stranded RNA (dsRNA) viruses with diverse numbers of genomic segments (from 1 to 12) and capsidless viruses with nonsegmented (+)RNA genomes. Recently, viruses with unusual intermediate features of an infectious entity between encapsidated dsRNA viruses and capsidless (+)RNA viruses were found. They are called polymycoviruses, which typically have four to eight dsRNA genomic segments associated with one of the virus-encoded proteins and are phylogenetically distantly related to animal (+)RNA caliciviruses. Here, we identified a novel virus phylogenetically related to polymycoviruses, from the phytopathogenic fungus Fusarium oxysporum The virus, termed Hadaka virus 1 (HadV1), has 11 (+)RNA genomic segments, the largest number in known (+)RNA viruses. Nevertheless, HadV1 lacked a typical structural protein of polymycoviruses and was not pelleted by standard ultracentrifugation, implying an unusual capsidless nature of HadV1. This study reveals a potential novel lifestyle of multisegmented RNA viruses.
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Affiliation(s)
- Yukiyo Sato
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Wajeeha Shamsi
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Sector H-12, Islamabad, Pakistan
| | - Atif Jamal
- Crop Diseases Research Institute, National Agricultural Research Centre, Islamabad, Pakistan
| | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Sector H-12, Islamabad, Pakistan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
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17
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Description of a Novel Mycovirus in the Phytopathogen Fusarium culmorum and a Related EVE in the Yeast Lipomyces starkeyi. Viruses 2020; 12:v12050523. [PMID: 32397544 PMCID: PMC7290986 DOI: 10.3390/v12050523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/06/2020] [Accepted: 05/08/2020] [Indexed: 11/20/2022] Open
Abstract
A new mycovirus was found in the Fusarium culmorum strain A104-1 originally sampled on wheat in Belgium. This novel virus, for which the name Fusarium culmorum virus 1 (FcV1) is suggested, is phylogenetically related to members of the previously proposed family ‘’Unirnaviridae’’. FcV1 has a monopartite dsRNA genome of 2898 bp that harbors two large non-overlapping ORFs. A typical -1 slippery motif is found at the end of ORF1, advocating that ORF2 is translated by programmed ribosomal frameshifting. While ORF2 exhibits a conserved replicase domain, ORF1 encodes for an undetermined protein. Interestingly, a hypothetically transcribed gene similar to unirnaviruses ORF1 was found in the genome of Lipomyces starkeyi, presumably resulting from a viral endogenization in this yeast. Conidial isolation and chemical treatment were unsuccessful to obtain a virus-free isogenic line of the fungal host, highlighting a high retention rate for FcV1 but hindering its biological characterization. In parallel, attempt to horizontally transfer FcV1 to another strain of F. culmorum by dual culture failed. Eventually, a screening of other strains of the same fungal species suggests the presence of FcV1 in two other strains from Europe.
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