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Domènech-Eres R, Jaeckel M, Hadeler B, Lienemann T, Lutz T, Heinze C. A GFP-expressing minigenome of a chrysovirus replicating in fungi. Virology 2024; 591:109987. [PMID: 38219372 DOI: 10.1016/j.virol.2024.109987] [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: 10/30/2023] [Revised: 12/11/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
The Fusarium graminearum virus China 9 (FgV-ch9) is a member of the genus Betachrysovirus in the Chrysoviridae family and causes hypovirulence in its host, Fusarium graminearum, the causal agent of Fusarium head blight. Although insights into viral biology of FgV-ch9 have expanded in recent years, questions regarding the function of virus-encoded proteins, cis-acting elements, and virus transmission are yet to be answered. Therefore, we developed a tool for the establishment of an artificial 6th segment of FgV-ch9, which encodes a GFP gene flanked by the non-translated regions of FgV-ch9 segment 1. Subsequently, we have proved successful encapsidation of this artificial segment into virus particles as well as its horizontal transmission. Expression of GFP was further verified via immunoassay and life cell imaging. Thus far, we were able to establish for the first time a mini-replicon system for segmented dsRNA viruses replicating in fungi.
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Affiliation(s)
- Robert Domènech-Eres
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Mareike Jaeckel
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Birgit Hadeler
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Tim Lienemann
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Tobias Lutz
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Cornelia Heinze
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
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2
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Wang Y, Li Q, Wu Y, Han S, Xiao Y, Kong L. The Effects of Mycovirus BmPV36 on the Cell Structure and Transcription of Bipolaris maydis. J Fungi (Basel) 2024; 10:133. [PMID: 38392805 PMCID: PMC10890528 DOI: 10.3390/jof10020133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 02/24/2024] Open
Abstract
Bipolaris maydis partitivirus 36 (BmPV36) is a mycovirus that can significantly reduce the virulence of the host Bipolaris maydis, but its hypovirulence mechanism is not clear. To investigate the response of B. maydis to BmPV36, the effects of BmPV36 on host cell structure and gene expression were studied via transmission electron microscopy and transcriptome sequencing using BmPV36-carrying and virus-free mycelium on the second and fifth culture. The results of transmission electron microscopy showed that the cell wall microfibrils of B. maydis were shortened, the cell membrane was broken, and membrane-bound vesicles and vacuoles appeared in the cells after carrying BmPV36. Transcriptome sequencing results showed that after carrying BmPV36, B. maydis membrane-related genes were significantly up-regulated, but membrane transport-related genes were significantly down-regulated. Genes related to carbohydrate macromolecule polysaccharide metabolic and catabolic processes were significantly down-regulated, as were genes related to the synthesis of toxins and cell wall degrading enzymes. Therefore, we speculated that BmPV36 reduces the virulence of B. maydis by destroying the host's cell structure, inhibiting the synthesis of toxins and cell wall degrading enzymes, and reducing cell metabolism. Gaining insights into the hypovirulence mechanism of mycoviruses will provide environmentally friendly strategies for the control of fungal diseases.
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Affiliation(s)
- Yajiao Wang
- Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China
| | - Qiusheng Li
- Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China
| | - Yuxing Wu
- Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China
| | - Sen Han
- Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China
| | - Ying Xiao
- Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China
| | - Lingxiao Kong
- Institute of Plant Protection, Hebei Academy of Agricultural and Forestry Sciences, Baoding 071000, China
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Córdoba L, Ruiz-Padilla A, Pardo-Medina J, Rodríguez-Romero JL, Ayllón MA. Construction of a Mycoviral Infectious Clone for Reverse Genetics in Botrytis cinerea. Methods Mol Biol 2024; 2751:47-68. [PMID: 38265709 DOI: 10.1007/978-1-0716-3617-6_4] [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] [Indexed: 01/25/2024]
Abstract
The most important advances in our understanding of the viral life cycle, such as genome replication, packaging, transmission, and host interactions, have been made via the development of viral infectious full-length clones. Here, we describe the detailed protocols for the construction of an infectious clone derived from Botrytis virus F (BVF), a mycoflexivirus infecting the plant pathogenic fungus Botrytis cinerea, the determination of the complete sequence of the cloned mycovirus, the preparation of fungal protoplasts, and the transfection of protoplasts using transcripts derived from the BVF infectious clone.
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Affiliation(s)
- Laura Córdoba
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
| | - Ana Ruiz-Padilla
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
| | - Javier Pardo-Medina
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Julio L Rodríguez-Romero
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain
| | - María A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA/CSIC), Madrid, Spain.
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain.
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4
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Contreras-Soto MB, Tovar-Pedraza JM. Viruses of plant-pathogenic fungi: a promising biocontrol strategy for Sclerotinia sclerotiorum. Arch Microbiol 2023; 206:38. [PMID: 38142438 DOI: 10.1007/s00203-023-03774-8] [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: 10/20/2023] [Revised: 11/17/2023] [Accepted: 11/26/2023] [Indexed: 12/26/2023]
Abstract
Plant pathogenic fungi pose a significant and ongoing threat to agriculture and food security, causing economic losses and significantly reducing crop yields. Effectively managing these fungal diseases is crucial for sustaining agricultural productivity, and in this context, mycoviruses have emerged as a promising biocontrol option. These viruses alter the physiology of their fungal hosts and their interactions with the host plants. This review encompasses the extensive diversity of reported mycoviruses, including their taxonomic classification and range of fungal hosts. We highlight representative examples of mycoviruses that affect economically significant plant-pathogenic fungi and their distinctive characteristics, with a particular emphasis on mycoviruses impacting Sclerotinia sclerotiorum. These mycoviruses exhibit significant potential for biocontrol, supported by their specificity, efficacy, and environmental safety. This positions mycoviruses as valuable tools in crop protection against diseases caused by this pathogen, maintaining their study and application as promising research areas in agricultural biotechnology. The remarkable diversity of mycoviruses, coupled with their ability to infect a broad range of plant-pathogenic fungi, inspires optimism, and suggests that these viruses have the potential to serve as an effective management strategy against major fungi-causing plant diseases worldwide.
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Affiliation(s)
- María Belia Contreras-Soto
- Laboratorio de Fitopatología, Centro de Investigación en Alimentación y Desarrollo, Coordinación Regional Culiacán, 80110, Culiacán, Sinaloa, Mexico
| | - Juan Manuel Tovar-Pedraza
- Laboratorio de Fitopatología, Centro de Investigación en Alimentación y Desarrollo, Coordinación Regional Culiacán, 80110, Culiacán, Sinaloa, Mexico.
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5
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Khan HA, Mukhtar M, Bhatti MF. Mycovirus-induced hypovirulence in notorious fungi Sclerotinia: a comprehensive review. Braz J Microbiol 2023; 54:1459-1478. [PMID: 37523037 PMCID: PMC10485235 DOI: 10.1007/s42770-023-01073-4] [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: 04/21/2023] [Accepted: 07/18/2023] [Indexed: 08/01/2023] Open
Abstract
Members of the genus Sclerotinia are notorious plant pathogens with a diverse host range that includes many important crops. A huge number of mycoviruses have been identified in this genus; some of these viruses are reported to have a hypovirulent effect on the fitness of their fungal hosts. These mycoviruses are important to researchers from a biocontrol perspective which was first implemented against fungal diseases in 1990. In this review, we have presented the data of all hypovirulent mycoviruses infecting Sclerotinia sclerotiorum isolates. The data of hypovirulent mycoviruses ranges from 1992 to 2023. Currently, mycoviruses belonging to 17 different families, including (+) ssRNA, (-ssRNA), dsRNA, and ssDNA viruses, have been reported from this genus. Advances in studies had shown a changed expression of certain host genes (responsible for cell cycle regulation, DNA replication, repair pathways, ubiquitin proteolysis, gene silencing, methylation, pathogenesis-related, sclerotial development, carbohydrate metabolism, and oxalic acid biosynthesis) during the course of mycoviral infection, which were termed differentially expressed genes (DEGs). Together, research on fungal viruses and hypovirulence in Sclerotinia species can deepen our understanding of the cellular processes that affect how virulence manifests in these phytopathogenic fungi and increase the potential of mycoviruses as a distinct mode of biological control. Furthermore, the gathered data can also be used for in-silico analysis, which includes finding the signature sites [e.g., hypovirus papain-like protease (HPP) domain, "CCHH" motif, specific stem-loop structures, p29 motif as in CHV1, A-rich sequence, CA-rich sequences as in MoV1, GCU motif as in RnMBV1, Core motifs in hypovirus-associated RNA elements (HAREs) as in CHV1] that are possibly responsible for hypovirulence in mycoviruses.
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Affiliation(s)
- Haris Ahmed Khan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000, Pakistan.
- Department of Biotechnology, University of Mianwali, Mianwali, Punjab, 42200, Pakistan.
| | - Mamuna Mukhtar
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000, Pakistan
| | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000, Pakistan
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Han Z, Liu J, Kong L, He Y, Wu H, Xu W. A special satellite-like RNA of a novel hypovirus from Pestalotiopsis fici broadens the definition of fungal satellite. PLoS Pathog 2023; 19:e1010889. [PMID: 37285391 DOI: 10.1371/journal.ppat.1010889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 05/23/2023] [Indexed: 06/09/2023] Open
Abstract
Satellites associated with plant or animal viruses have been largely detected and characterized, while those from mycoviruses together with their roles remain far less determined. Three dsRNA segments (dsRNA 1 to 3 termed according to their decreasing sizes) were identified in a strain of phytopathogenic fungus Pestalotiopsis fici AH1-1 isolated from a tea leaf. The complete sequences of dsRNAs 1 to 3, with the sizes of 10316, 5511, and 631 bp, were determined by random cloning together with a RACE protocol. Sequence analyses support that dsRNA1 is a genome of a novel hypovirus belonging to genus Alphahypovirus of the family Hypoviridae, tentatively named Pestalotiopsis fici hypovirus 1 (PfHV1); dsRNA2 is a defective RNA (D-RNA) generating from dsRNA1 with septal deletions; and dsRNA3 is the satellite component of PfHV1 since it could be co-precipitated with other dsRNA components in the same sucrose fraction by ultra-centrifuge, suggesting that it is encapsulated together with PfHV1 genomic dsRNAs. Moreover, dsRNA3 shares an identical stretch (170 bp) with dsRNAs 1 and 2 at their 5' termini and the remaining are heterogenous, which is distinct from a typical satellite that generally has very little or no sequence similarity with helper viruses. More importantly, dsRNA3 lacks a substantial open reading frame (ORF) and a poly (A) tail, which is unlike the known satellite RNAs of hypoviruses, as well as unlike those in association with Totiviridae and Partitiviridae since the latters are encapsidated in coat proteins. As up-regulated expression of RNA3, dsRNA1 was significantly down-regulated, suggesting that dsRNA3 negatively regulates the expression of dsRNA1, whereas dsRNAs 1 to 3 have no obvious impact on the biological traits of the host fungus including morphologies and virulence. This study indicates that PfHV1 dsRNA3 is a special type of satellite-like nucleic acid that has substantial sequence homology with the host viral genome without encapsidation in a coat protein, which broadens the definition of fungal satellite.
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Affiliation(s)
- Zhenhao Han
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Lab of Plant Pathology of Hubei Province, Wuhan, China
| | - Jiwen Liu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Lab of Plant Pathology of Hubei Province, Wuhan, China
| | - Linghong Kong
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Lab of Plant Pathology of Hubei Province, Wuhan, China
| | - Yunqiang He
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Lab of Plant Pathology of Hubei Province, Wuhan, China
| | - Hongqu Wu
- Key Laboratory of Microbial Pesticides, Ministry of Agriculture and Rural Affairs; Hubei Biopesticide Engineering Research Centre, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Wenxing Xu
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Wuhan, China
- Hubei Hongshan Laboratory, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
- Key Lab of Plant Pathology of Hubei Province, Wuhan, China
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Hough B, Steenkamp E, Wingfield B, Read D. Fungal Viruses Unveiled: A Comprehensive Review of Mycoviruses. Viruses 2023; 15:1202. [PMID: 37243288 PMCID: PMC10224137 DOI: 10.3390/v15051202] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/07/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
Mycoviruses (viruses of fungi) are ubiquitous throughout the fungal kingdom and are currently classified into 23 viral families and the genus botybirnavirus by the International Committee on the Taxonomy of Viruses (ICTV). The primary focus of mycoviral research has been on mycoviruses that infect plant pathogenic fungi, due to the ability of some to reduce the virulence of their host and thus act as potential biocontrol against these fungi. However, mycoviruses lack extracellular transmission mechanisms and rely on intercellular transmission through the hyphal anastomosis, which impedes successful transmission between different fungal strains. This review provides a comprehensive overview of mycoviruses, including their origins, host range, taxonomic classification into families, effects on their fungal counterparts, and the techniques employed in their discovery. The application of mycoviruses as biocontrol agents of plant pathogenic fungi is also discussed.
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Affiliation(s)
| | | | - Brenda Wingfield
- Forestry & Agricultural Biotechnology Institute (FABI), Department of Biochemistry, Genetics & Microbiology, University of Pretoria, Pretoria 0002, South Africa; (B.H.); (E.S.); (D.R.)
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8
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Ayllón MA, Vainio EJ. Mycoviruses as a part of the global virome: Diversity, evolutionary links and lifestyle. Adv Virus Res 2023; 115:1-86. [PMID: 37173063 DOI: 10.1016/bs.aivir.2023.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Knowledge of mycovirus diversity, evolution, horizontal gene transfer and shared ancestry with viruses infecting distantly related hosts, such as plants and arthropods, has increased vastly during the last few years due to advances in the high throughput sequencing methodologies. This also has enabled the discovery of novel mycoviruses with previously unknown genome types, mainly new positive and negative single-stranded RNA mycoviruses ((+) ssRNA and (-) ssRNA) and single-stranded DNA mycoviruses (ssDNA), and has increased our knowledge of double-stranded RNA mycoviruses (dsRNA), which in the past were thought to be the most common viruses infecting fungi. Fungi and oomycetes (Stramenopila) share similar lifestyles and also have similar viromes. Hypothesis about the origin and cross-kingdom transmission events of viruses have been raised and are supported by phylogenetic analysis and by the discovery of natural exchange of viruses between different hosts during virus-fungus coinfection in planta. In this review we make a compilation of the current information on the genome organization, diversity and taxonomy of mycoviruses, discussing their possible origins. Our focus is in recent findings suggesting the expansion of the host range of many viral taxa previously considered to be exclusively fungal, but we also address factors affecting virus transmissibility and coexistence in single fungal or oomycete isolates, as well as the development of synthetic mycoviruses and their use in investigating mycovirus replication cycles and pathogenicity.
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Affiliation(s)
- María A Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación Agraria y Alimentaria (INIA/CSIC), Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain; Departamento Biotecnología-Biología Vegetal, E.T.S.I. Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), Madrid, Spain.
| | - Eeva J Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Helsinki, Finland
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Viral cross-class transmission results in disease of a phytopathogenic fungus. THE ISME JOURNAL 2022; 16:2763-2774. [PMID: 36045287 PMCID: PMC9428384 DOI: 10.1038/s41396-022-01310-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/10/2022] [Accepted: 08/15/2022] [Indexed: 12/15/2022]
Abstract
Interspecies transmission of viruses is a well-known phenomenon in animals and plants whether via contacts or vectors. In fungi, interspecies transmission between distantly related fungi is often suspected but rarely experimentally documented and may have practical implications. A newly described double-strand RNA (dsRNA) virus found asymptomatic in the phytopathogenic fungus Leptosphaeria biglobosa of cruciferous crops was successfully transmitted to an evolutionarily distant, broad-host range pathogen Botrytis cinerea. Leptosphaeria biglobosa botybirnavirus 1 (LbBV1) was characterized in L. biglobosa strain GZJS-19. Its infection in L. biglobosa was asymptomatic, as no significant differences in radial mycelial growth and pathogenicity were observed between LbBV1-infected and LbBV1-free strains. However, cross-species transmission of LbBV1 from L. biglobosa to infection in B. cinerea resulted in the hypovirulence of the recipient B. cinerea strain t-459-V. The cross-species transmission was succeeded only by inoculation of mixed spores of L. biglobosa and B. cinerea on PDA or on stems of oilseed rape with the efficiency of 4.6% and 18.8%, respectively. To investigate viral cross-species transmission between L. biglobosa and B. cinerea in nature, RNA sequencing was carried out on L. biglobosa and B. cinerea isolates obtained from Brassica samples co-infected by these two pathogens and showed that at least two mycoviruses were detected in both fungal groups. These results indicate that cross-species transmission of mycoviruses may occur frequently in nature and result in the phenotypical changes of newly invaded phytopathogenic fungi. This study also provides new insights for using asymptomatic mycoviruses as biocontrol agent.
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Pedersen CJ, Marzano SYL. Characterization of Transcriptional Responses to Genomovirus Infection of the White Mold Fungus, Sclerotinia sclerotiorum. Viruses 2022; 14:v14091892. [PMID: 36146699 PMCID: PMC9506476 DOI: 10.3390/v14091892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/18/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
Soybean leaf-associated gemygorvirus-1 (SlaGemV−1) is a CRESS-DNA virus classified in the family Genomoviridae, which causes hypovirulence and abolishes sclerotia formation in infected fungal pathogens under the family Sclerotiniaceae. To investigate the mechanisms involved in the induction of hypovirulence, RNA-Seq was compared between virus-free and SlaGemV−1-infected Sclerotinia sclerotiorum strain DK3. Overall, 4639 genes were differentially expressed, with 50.5% up regulated and 49.5% down regulated genes. GO enrichments suggest changes in integral membrane components and transmission electron microscopy images reveal virus-like particles localized near the inner cell membrane. Differential gene expression analysis focused on genes responsible for cell cycle and DNA replication and repair pathways, ubiquitin proteolysis, gene silencing, methylation, pathogenesis-related, sclerotial development, carbohydrate metabolism, and oxalic acid biosynthesis. Carbohydrate metabolism showed the most changes, with two glycoside hydrolase genes being the most down regulated by −2396.1- and −648.6-fold. Genes relating to pathogenesis showed consistent down regulation with the greatest being SsNep1, SsSSVP1, and Endo2 showing, −4555-, −14.7-, and −12.3-fold changes. The cell cycle and DNA replication/repair pathways were almost entirely up regulated including a putative cyclin and separase being up regulated 8.3- and 5.2-fold. The oxalate decarboxylase genes necessary for oxalic acid catabolism and oxalic acid precursor biosynthesis genes and its metabolism show down regulations of −17.2- and −12.1-fold changes. Sclerotial formation genes also appear differentially regulated including a melanin biosynthesis gene Pks1 and a sclerotia formation gene Sl2 with fold changes of 3.8 and −2.9.
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Affiliation(s)
- Connor J. Pedersen
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA
- United States Department of Agriculture/Agricultural Research Service, Toledo, OH 43606, USA
| | - Shin-Yi Lee Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA
- United States Department of Agriculture/Agricultural Research Service, Toledo, OH 43606, USA
- Department of Horticulture, and Plant Science, South Dakota State University, Brookings, SD 57007, USA
- Correspondence:
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De Miccolis Angelini RM, Raguseo C, Rotolo C, Gerin D, Faretra F, Pollastro S. The Mycovirome in a Worldwide Collection of the Brown Rot Fungus Monilinia fructicola. J Fungi (Basel) 2022; 8:jof8050481. [PMID: 35628739 PMCID: PMC9147972 DOI: 10.3390/jof8050481] [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: 03/20/2022] [Revised: 04/26/2022] [Accepted: 05/03/2022] [Indexed: 11/16/2022] Open
Abstract
The fungus Monilinia fructicola is responsible for brown rot on stone and pome fruit and causes heavy yield losses both pre- and post-harvest. Several mycoviruses are known to infect fungal plant pathogens. In this study, a metagenomic approach was applied to obtain a comprehensive characterization of the mycovirome in a worldwide collection of 58 M. fructicola strains. Deep sequencing of double-stranded (ds)RNA extracts revealed a great abundance and variety of mycoviruses. A total of 32 phylogenetically distinct positive-sense (+) single-stranded (ss)RNA viruses were identified. They included twelve mitoviruses, one in the proposed family Splipalmiviridae, and twelve botourmiaviruses (phylum Lenarviricota), eleven of which were novel viral species; two hypoviruses, three in the proposed family Fusariviridae, and one barnavirus (phylum Pisuviricota); as well as one novel beny-like virus (phylum Kitrinoviricota), the first one identified in Ascomycetes. A partial sequence of a new putative ssDNA mycovirus related to viruses within the Parvoviridae family was detected in a M. fructicola isolate from Serbia. The availability of genomic sequences of mycoviruses will serve as a solid basis for further research aimed at deepening the knowledge on virus–host and virus–virus interactions and to explore their potential as biocontrol agents against brown rot disease.
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12
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Córdoba L, Ruiz-Padilla A, Rodríguez-Romero J, Ayllón MA. Construction and Characterization of a Botrytis Virus F Infectious Clone. J Fungi (Basel) 2022; 8:jof8050459. [PMID: 35628716 PMCID: PMC9146958 DOI: 10.3390/jof8050459] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/15/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022] Open
Abstract
Botrytis virus F (BVF) is a positive-sense, single-stranded RNA (+ssRNA) virus within the Gammaflexiviridae family of the plant-pathogenic fungus Botrytis cinerea. In this study, the complete sequence of a BVF strain isolated from B. cinerea collected from grapevine fields in Spain was analyzed. This virus, in this work BVF-V448, has a genome of 6827 nt in length, excluding the poly(A) tail, with two open reading frames encoding an RNA dependent RNA polymerase (RdRP) and a coat protein (CP). The 5′- and 3′-terminal regions of the genome were determined by rapid amplification of cDNA ends (RACE). Furthermore, a yet undetected subgenomic RNA species in BVF-V448 was identified, indicating that the CP is expressed via 3′ coterminal subgenomic RNAs (sgRNAs). We also report the successful construction of the first BVF full-length cDNA clone and synthesized in vitro RNA transcripts using the T7 polymerase, which could efficiently transfect two different strains of B. cinerea, B05.10 and Pi258.9. The levels of growth in culture and virulence on plants of BVF-V448 transfected strains were comparable to BVF-free strains. The infectious clones generated in this work provide a useful tool for the future development of an efficient BVF foreign gene expression vector and a virus-induced gene silencing (VIGS) vector as a biological agent for the control of B. cinerea.
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Affiliation(s)
- Laura Córdoba
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
| | - Ana Ruiz-Padilla
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
| | - Julio Rodríguez-Romero
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - María A. Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
- Correspondence:
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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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14
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Wang Z, Neupane A, Feng J, Pedersen C, Lee Marzano SY. Direct Metatranscriptomic Survey of the Sunflower Microbiome and Virome. Viruses 2021; 13:v13091867. [PMID: 34578448 PMCID: PMC8473204 DOI: 10.3390/v13091867] [Citation(s) in RCA: 3] [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: 08/02/2021] [Revised: 08/30/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
Sunflowers (Helianthus annuus L.) are susceptible to multiple diseases in field production. In this study, we collected diseased sunflower leaves in fields located in South Dakota, USA, for virome investigation. The leaves showed visible symptoms on the foliage, indicating phomopsis and rust infections. To identify the viruses potentially associated with the disease diagnosed, symptomatic leaves were obtained from diseased plants. Total RNA was extracted corresponding to each disease diagnosed to generate libraries for paired-end high throughput sequencing. Short sequencing reads were assembled de novo and the contigs with similarities to viruses were identified by aligning against a custom protein database. We report the discovery of two novel mitoviruses, four novel partitiviruses, one novel victorivirus, and nine novel totiviruses based on similarities to RNA-dependent RNA polymerases and capsid proteins. Contigs similar to bean yellow mosaic virus and Sclerotinia sclerotiorum hypovirulence-associated DNA virus were also detected. To the best of our knowledge, this is the first report of direct metatranscriptomics discovery of viruses associated with fungal infections of sunflowers bypassing culturing. These newly discovered viruses represent a natural genetic resource from which we can further develop potential biopesticide to control sunflower diseases.
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Affiliation(s)
- Ziyi Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA; (Z.W.); (A.N.); (C.P.)
| | - Achal Neupane
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA; (Z.W.); (A.N.); (C.P.)
| | - Jiuhuan Feng
- Department of Agronomy, Horticulture and Plant Science, South Dakota State University, Brookings, SD 57007, USA;
| | - Connor Pedersen
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA; (Z.W.); (A.N.); (C.P.)
- United States Department of Agriculture-Agricultural Research Service, Toledo, OH 43606, USA
| | - Shin-Yi Lee Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA; (Z.W.); (A.N.); (C.P.)
- Department of Agronomy, Horticulture and Plant Science, South Dakota State University, Brookings, SD 57007, USA;
- United States Department of Agriculture-Agricultural Research Service, Toledo, OH 43606, USA
- Correspondence: ; Tel.: +1-419-530-5053
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Feng C, Feng J, Wang Z, Pedersen C, Wang X, Saleem H, Domier L, Marzano SYL. Identification of the Viral Determinant of Hypovirulence and Host Range in Sclerotiniaceae of a Genomovirus Reconstructed from the Plant Metagenome. J Virol 2021; 95:e0026421. [PMID: 34132570 PMCID: PMC8354332 DOI: 10.1128/jvi.00264-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/09/2021] [Indexed: 12/14/2022] Open
Abstract
Uncharacterized viral genomes that encode circular replication-associated proteins of single-stranded DNA viruses have been discovered by metagenomics/metatranscriptomics approaches. Some of these novel viruses are classified in the newly formed family Genomoviridae. Here, we determined the host range of a novel genomovirus, SlaGemV-1, through the transfection of Sclerotinia sclerotiorum with infectious clones. Inoculating with the rescued virions, we further transfected Botrytis cinerea and Monilinia fructicola, two economically important members of the family Sclerotiniaceae, and Fusarium oxysporum. SlaGemV-1 causes hypovirulence in S. sclerotiorum, B. cinerea, and M. fructicola. SlaGemV-1 also replicates in Spodoptera frugiperda insect cells but not in Caenorhabditis elegans or plants. By expressing viral genes separately through site-specific integration, the replication protein alone was sufficient to cause debilitation. Our study is the first to demonstrate the reconstruction of a metagenomically discovered genomovirus without known hosts with the potential of inducing hypovirulence, and the infectious clone allows for studying mechanisms of genomovirus-host interactions that are conserved across genera. IMPORTANCE Little is known about the exact host range of widespread genomoviruses. The genome of soybean leaf-associated gemygorvirus-1 (SlaGemV-1) was originally assembled from a metagenomic/metatranscriptomic study without known hosts. Here, we rescued SlaGemV-1 and found that it could infect three important plant-pathogenic fungi and fall armyworm (S. frugiperda Sf9) insect cells but not a model nematode, C. elegans, or model plant species. Most importantly, SlaGemV-1 shows promise for inducing hypovirulence of the tested fungal species in the family Sclerotiniaceae, including Sclerotinia sclerotiorum, Botrytis cinerea, and Monilinia fructicola. The viral determinant of hypovirulence was further identified as replication initiation protein. As a proof of concept, we demonstrate that viromes discovered in plant metagenomes can be a valuable genetic resource when novel viruses are rescued and characterized for their host range.
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Affiliation(s)
- Chenchen Feng
- Department of Horticulture, Agronomy, and Plant Sciences, South Dakota State University, Brookings, South Dakota, USA
| | - Jiuhuan Feng
- Department of Horticulture, Agronomy, and Plant Sciences, South Dakota State University, Brookings, South Dakota, USA
| | - Ziyi Wang
- Department of Horticulture, Agronomy, and Plant Sciences, South Dakota State University, Brookings, South Dakota, USA
| | - Connor Pedersen
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Xiuqing Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Huma Saleem
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Leslie Domier
- United States Department of Agriculture/Agricultural Research Service, Urbana, Illinois, USA
| | - Shin-Yi Lee Marzano
- Department of Horticulture, Agronomy, and Plant Sciences, South Dakota State University, Brookings, South Dakota, USA
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
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16
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Honda S, Eusebio-Cope A, Miyashita S, Yokoyama A, Aulia A, Shahi S, Kondo H, Suzuki N. Establishment of Neurospora crassa as a model organism for fungal virology. Nat Commun 2020; 11:5627. [PMID: 33159072 PMCID: PMC7648066 DOI: 10.1038/s41467-020-19355-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 10/08/2020] [Indexed: 01/07/2023] Open
Abstract
The filamentous fungus Neurospora crassa is used as a model organism for genetics, developmental biology and molecular biology. Remarkably, it is not known to host or to be susceptible to infection with any viruses. Here, we identify diverse RNA viruses in N. crassa and other Neurospora species, and show that N. crassa supports the replication of these viruses as well as some viruses from other fungi. Several encapsidated double-stranded RNA viruses and capsid-less positive-sense single-stranded RNA viruses can be experimentally introduced into N. crassa protoplasts or spheroplasts. This allowed us to examine viral replication and RNAi-mediated antiviral responses in this organism. We show that viral infection upregulates the transcription of RNAi components, and that Dicer proteins (DCL-1, DCL-2) and an Argonaute (QDE-2) participate in suppression of viral replication. Our study thus establishes N. crassa as a model system for the study of host-virus interactions. The fungus Neurospora crassa is a model organism for the study of various biological processes, but it is not known to be infected by any viruses. Here, Honda et al. identify RNA viruses that infect N. crassa and examine viral replication and RNAi-mediated antiviral responses, thus establishing this fungus as a model for the study of host-virus interactions.
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Affiliation(s)
- Shinji Honda
- Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
| | - Ana Eusebio-Cope
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Shuhei Miyashita
- Graduate School of Agricultural Science, Tohoku University, 468-1, Aramaki-Aza- Aoba, Sendai, 980-0845, Japan
| | - Ayumi Yokoyama
- Faculty of Medical Sciences, University of Fukui, Fukui, 910-1193, Japan
| | - Annisa Aulia
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, Japan
| | - Sabitree Shahi
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, 710-0046, 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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17
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A moderate level of hypovirulence conferred by a hypovirus in the avocado white root rot fungus, Rosellinia necatrix. Fungal Biol 2020; 125:69-76. [PMID: 33317778 DOI: 10.1016/j.funbio.2020.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 10/06/2020] [Accepted: 10/16/2020] [Indexed: 11/23/2022]
Abstract
Two isolates of Rosellinia necatrix (Rn118-8 and Rn480) have previously obtained from diseased avocado trees in commercial orchards of the coastal area in southern Spain. Rn118-8 and Rn480 have weak virulence on avocado plants, and are infected by R. necatrix hypovirus 2 (RnHV2). In this work, the possible biological effects of the hypovirus on R. necatrix were tested. First, RnHV2 was transmitted from each of Rn118-8 and Rn480 to a highly virulent, RnHV2-free isolate of R. necatrix (Rn400) through hyphal anastomosis, using zinc compounds which attenuate the mycelial incompatibility reactions and allow for horizontal virus transfer between vegetatively incompatible fungal strains. Next, we carried out an analysis of growth rate in vitro and a virulence test of these newly infected strains in avocado plants. We obtained five strains of Rn400 infected by RnHV2 after horizontal transmission, and showed some of them to have lower colony growth in vitro and lower virulence on avocado plants compared with virus-free Rn400. These results suggest that R. necatrix isolates infected by RnHV2 could be used as novel virocontrol agents to combat avocado white root rot.
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18
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Li P, Wang S, Zhang L, Qiu D, Zhou X, Guo L. A tripartite ssDNA mycovirus from a plant pathogenic fungus is infectious as cloned DNA and purified virions. SCIENCE ADVANCES 2020; 6:eaay9634. [PMID: 32284975 PMCID: PMC7138691 DOI: 10.1126/sciadv.aay9634] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 01/09/2020] [Indexed: 05/27/2023]
Abstract
Here, we describe a tripartite circular single-stranded (ss) DNA mycovirus, named Fusarium graminearum gemytripvirus 1 (FgGMTV1). The genome of FgGMTV1 comprises three circular ssDNA segments (DNA-A, DNA-B, and DNA-C). Sequence alignments and phylogenetic analyses showed that FgGMTV1 is nested within the family Genomoviridae. We also constructed the first infectious DNA clones of a DNA mycovirus. Our results show that DNA-A and DNA-B are mutually interdependent for their replication and are associated with severely reduced colony growth and hypovirulence. DNA-C relies on DNA-A and DNA-B for replication and is necessary for the recovery of abnormal fungal phenotypes. DNA-C also enhances the accumulation of viral DNA in infected fungi and permits stable colonization and easy transmission via conidia. This is the first multipartite DNA virus isolated from a fungus. Our phylogenetic analyses also suggest that the multipartite genome of FgGMTV1 may have evolved from a monopartite genome of an ancient genomovirus.
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19
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Wang Q, Mu F, Xie J, Cheng J, Fu Y, Jiang D. A Single ssRNA Segment Encoding RdRp Is Sufficient for Replication, Infection, and Transmission of Ourmia-Like Virus in Fungi. Front Microbiol 2020; 11:379. [PMID: 32256466 PMCID: PMC7093599 DOI: 10.3389/fmicb.2020.00379] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/20/2020] [Indexed: 01/07/2023] Open
Abstract
Recently, an increasing number of ourmia-like viruses have been found in fungi; however, the features of these viruses remain unknown. Here, we report a novel ourmia-like virus isolated from Sclerotinia sclerotiorum. This virus, named S. sclerotiorum ourmia-like virus 4 (SsOLV4), has a genome 2,982 nt in length with a G-pentamer (GGGGG) at the 5'-terminus and a C-pentamer (CCCCC) at the 3'-terminus. The SsOLV4 genome has only one large putative open reading frame (ORF) predicted with both standard codes and mitochondrial codes and encodes an RNA-dependent RNA polymerase (RdRp). SsOLV4 is closely phylogenetically related to Pyricularia oryzae ourmia-like virus 1, with 42% identity between the RdRp amino acid sequences. We constructed full-length cDNA of SsOLV4 and synthesized RNA in vitro using the T7 RNA polymerase. The synthesized RNA could transfect S. sclerotiorum protoplasts efficiently. We further found that viral RNA could infect mycelia when mixed with PEG buffer. Our study suggests that a novel genus in family Botourmiaviridae should be established for SsOLV4 and other related viruses and demonstrates that one single-stranded RNA segment encoding RdRp is sufficient for ourmia-like viruses in fungi.
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Affiliation(s)
- Qihua Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fan Mu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yanping Fu
- Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Plant Pathology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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20
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Torres-Trenas A, Cañizares MC, García-Pedrajas MD, Pérez-Artés E. Molecular and Biological Characterization of the First Hypovirus Identified in Fusarium oxysporum. Front Microbiol 2020; 10:3131. [PMID: 32038565 PMCID: PMC6992542 DOI: 10.3389/fmicb.2019.03131] [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: 07/22/2019] [Accepted: 12/24/2019] [Indexed: 12/12/2022] Open
Abstract
A novel mycovirus named Fusarium oxysporum f. sp. dianthi hypovirus 2 (FodHV2) has been identified infecting isolates Fod 408 and Fod 409 of Fusarium oxysporum f. sp. dianthi from Morocco. The genome of FodHV2 is 9,444 nucleotides long excluding the poly(A) tail, and has a single open reading frame encoding a polyprotein. The polyprotein contains three highly conserved domains of UDP glucose/sterol glucosyltransferase, RNA-dependent RNA polymerase, and viral RNA helicase. In addition, particular residues of Cys, Hys, and Gly detected in the N-terminal region suggest the presence of the catalytic site of a highly diverged papain-like protease. Genomic organization, presence of particular conserved motifs, and phylogenetic analyses based on multiple alignments clearly grouped FodHV2 with the members of the family Hypoviridae. FodHV2 was transferred by hyphal anastomosis to a recipient HygR-tagged virus-free strain. The comparison of the infected and non-infected isogenic strains showed that FodHV2 did not alter the vegetative growth, neither the conidiation nor the virulence of its fungal host. Efficiency of FodHV2 transmission through the conidia was 100% in both the original and the recipient infected-isolates. To the best of our knowledge, this is the first report of a hypovirus infecting the plant pathogen F. oxysporum, and also the first one of a hypovirus detected in a fungal strain from the African continent.
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Affiliation(s)
- Almudena Torres-Trenas
- Departamento de Protección de Cultivos, Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - M. Carmen Cañizares
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - M. Dolores García-Pedrajas
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”, Universidad de Málaga, Consejo Superior de Investigaciones Científicas, Málaga, Spain
| | - Encarnación Pérez-Artés
- Departamento de Protección de Cultivos, Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Córdoba, Spain
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21
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García-Pedrajas MD, Cañizares MC, Sarmiento-Villamil JL, Jacquat AG, Dambolena JS. Mycoviruses in Biological Control: From Basic Research to Field Implementation. PHYTOPATHOLOGY 2019; 109:1828-1839. [PMID: 31398087 DOI: 10.1094/phyto-05-19-0166-rvw] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mycoviruses from plant pathogens can induce hypovirulence (reduced virulence) in their host fungi and have gained considerable attention as potential biocontrol tools. An increasing number of mycoviruses that induce fungal hypovirulence, from a wide variety of taxonomic groups, are currently being reported. Successful application of these viruses in disease management is greatly dependent on their ability to spread in the natural populations of the pathogen. Mycoviruses generally lack extracellular routes of transmission. Hyphal anastomosis is the main route of horizontal mycovirus transmission to other isolates, and conidia of vertical transmission to the progeny. Transmission efficiencies are influenced by both the fungal host and the infecting virus. Interestingly, artificial transfection methods have shown that potential biocontrol mycoviruses often have the ability to infect a variety of fungi. This expands their possible use to the control of pathogens others than those where they were identified. Mycovirus research is also focused on gaining insights into their complex molecular biology and the molecular bases of fungus-virus interactions. This knowledge could be exploited to manipulate the mycovirus and/or the host and generate combinations with enhanced properties in biological control. Finally, when exploring the use of mycoviruses in field conditions, the pathogen life style and the characteristics of the disease and crops affected will deeply impact the specific challenges to overcome, and the development of biocontrol formulations and delivery methods.
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Affiliation(s)
- M D 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," 29750 Algarrobo-Costa, Málaga, Spain
| | - M C Cañizares
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"-Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental "La Mayora," 29750 Algarrobo-Costa, Málaga, Spain
| | - J L Sarmiento-Villamil
- Centre d'étude de la Forêt (CEF) and Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, QC G1V 0A6, Canada
| | - A G Jacquat
- Instituto Multidisciplinario de Biología Vegetal (IMBiV-CONICET), Universidad Nacional de Córdoba, Avenida Vélez Sarsfield 1611, Córdoba, X5016GCA, Argentina
| | - J S Dambolena
- Instituto Multidisciplinario de Biología Vegetal (IMBiV-CONICET), Universidad Nacional de Córdoba, Avenida Vélez Sarsfield 1611, Córdoba, X5016GCA, Argentina
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22
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Neupane A, Feng C, Mochama PK, Saleem H, Lee Marzano SY. Roles of Argonautes and Dicers on Sclerotinia sclerotiorum Antiviral RNA Silencing. FRONTIERS IN PLANT SCIENCE 2019; 10:976. [PMID: 31440265 PMCID: PMC6694225 DOI: 10.3389/fpls.2019.00976] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 07/11/2019] [Indexed: 05/30/2023]
Abstract
RNA silencing or RNA interference (RNAi) is an essential mechanism in animals, fungi, and plants that functions in gene regulation and defense against foreign nucleic acids. In fungi, RNA silencing has been shown to function primarily in defense against invasive nucleic acids. We previously determined that mycoviruses are triggers and targets of RNA silencing in Sclerotinia sclerotiorum. However, recent progresses in RNAi or dsRNA-based pest control requires more detailed characterization of the RNA silencing pathways in S. sclerotiorum to investigate the utility of dsRNA-based strategy for white mold control. This study elucidates the roles of argonaute enzymes, agl-2 and agl-4, in small RNA metabolism in S. sclerotiorum. Gene disruption mutants of agl-2 and agl-4 were compared for changes in phenotype, virulence, viral susceptibility, and small RNA profiles. The Δagl-2 mutant but not the Δagl-4 mutant had significantly slower growth and virulence prior to virus infection. Similarly, the Δagl-2 mutant but not the Δagl-4 mutant, showed greater debilitation under virus infection compared to uninfected strains. The responses were confirmed in complementation studies and revealed the antiviral role of agl-2. Gene disruption mutants of agl-2, agl-4, Dicer-like (dcl)-1, and dcl-2 did not change the stability of the most abundant endogenous small RNAs, which suggests the existence of alternative enzymes/pathways for small RNA biogenesis in S. sclerotiorum. Furthermore, in vitro synthesized dsRNA targeting agl-2 showed a significantly reduced average lesion diameter (P < 0.05) on canola leaves with agl-2 down-regulated compared to controls. This is the first report describing the effectiveness of RNA pesticides targeting S. sclerotiorum RNA silencing pathway for the control of the economically important pathogen.
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Affiliation(s)
- Achal Neupane
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Chenchen Feng
- Department of Agronomy, Horticulture and Plant Science, South Dakota State University, Brookings, SD, United States
| | - Pauline K. Mochama
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Huma Saleem
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
| | - Shin-Yi Lee Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, United States
- Department of Agronomy, Horticulture and Plant Science, South Dakota State University, Brookings, SD, United States
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Li P, Bhattacharjee P, Wang S, Zhang L, Ahmed I, Guo L. Mycoviruses in Fusarium Species: An Update. Front Cell Infect Microbiol 2019; 9:257. [PMID: 31380300 PMCID: PMC6657619 DOI: 10.3389/fcimb.2019.00257] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/03/2019] [Indexed: 12/12/2022] Open
Abstract
Fusarium is an important genus of plant pathogenic fungi, and is widely distributed in soil and associated with plants worldwide. The diversity of mycoviruses in Fusarium is increasing continuously due to the development and extensive use of state-of-the-art RNA deep sequencing techniques. To date, fully-sequenced mycoviruses have been reported in 13 Fusarium species: Fusarium asiaticum, F. boothii, F. circinatum, F. coeruleum, F. globosum, F. graminearum, F. incarnatum, F. langsethiae, F. oxysporum, F. poae, F. pseudograminearum, F. solani, and F. virguliforme. Most Fusarium mycoviruses establish latent infections, but some mycoviruses such as Fusarium graminearum virus 1 (FgV1), Fusarium graminearum virus-ch9 (FgV-ch9), Fusarium graminearum hypovirus 2 (FgHV2), and Fusarium oxysporum f. sp. dianthi mycovirus 1 (FodV1) cause hypovirulence. Rapid advances in various omics technologies used to elucidate genes or biological processes can facilitate an improved understanding of mycovirus-host interactions. The review aims to illuminate the recent advances in studies of mycoviruses in Fusarium, including those related to diversity, molecular mechanisms of virus-host interaction. We also discuss the induction and suppression of RNA silencing including the role of RNAi components as an antiviral defense response.
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Affiliation(s)
- Pengfei Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Pallab Bhattacharjee
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shuangchao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lihang Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Irfan Ahmed
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lihua Guo
- 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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Li H, Bian R, Liu Q, Yang L, Pang T, Salaipeth L, Andika IB, Kondo H, Sun L. Identification of a Novel Hypovirulence-Inducing Hypovirus From Alternaria alternata. Front Microbiol 2019; 10:1076. [PMID: 31156589 PMCID: PMC6530530 DOI: 10.3389/fmicb.2019.01076] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/29/2019] [Indexed: 11/13/2022] Open
Abstract
Mycoviruses are wide spread throughout almost all groups of fungi but only a small number of mycoviruses can attenuate the growth and virulence of their fungal hosts. Alternaria alternata is an ascomycete fungus that causes leaf spot diseases on various crop plants. In this study, we identified a novel ssRNA mycovirus infecting an A. alternata f. sp. mali strain isolated from an apple orchard in China. Sequence analyses revealed that this virus is related to hypoviruses, in particular to Wuhan insect virus 14, an unclassified hypovirus identified from insect meta-transcriptomics, as well as other hypoviruses belonging to the genus Hypovirus, and therefore this virus is designed as Alternaria alternata hypovirus 1 (AaHV1). The genome of AaHV1 contains a single large open-reading frame encoding a putative polyprotein (∼479 kDa) with a cysteine proteinase-like and replication-associated domains. Curing AaHV1 from the fungal host strain indicated that the virus is responsible for the slow growth and reduced virulence of the host. AaHV1 defective RNA (D-RNA) with internal deletions emerging during fungal subcultures but the presence of D-RNA does not affect AaHV1 accumulation and pathogenicities. Moreover, AaHV1 could replicate and confer hypovirulence in Botryosphaeria dothidea, a fungal pathogen of apple white rot disease. This finding could facilitate better understanding of A. alternata pathogenicity and is relevant for development of biocontrol methods of fungal diseases.
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Affiliation(s)
- Huan Li
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Ruiling Bian
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Qian Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Liu Yang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Tianxing Pang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Lakha Salaipeth
- School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
| | - Ida Bagus Andika
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - Liying Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
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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.
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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
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Investigation of Host Range of and Host Defense against a Mitochondrially Replicating Mitovirus. J Virol 2019; 93:JVI.01503-18. [PMID: 30626664 DOI: 10.1128/jvi.01503-18] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/18/2018] [Indexed: 01/19/2023] Open
Abstract
Mitoviruses (genus Mitovirus, family Narnaviridae) are mitochondrially replicating viruses that have the simplest positive-sense RNA genomes of 2.2 to 4.4 kb with a single open reading frame (ORF) encoding an RNA-dependent RNA polymerase. Cryphonectria parasitica mitovirus 1 (CpMV1) from U.S. strain NB631 of the chestnut blight fungus, Cryphonectria parasitica, was the first virus identified as a mitochondrially replicating virus. Despite subsequent discovery of many other mitoviruses from diverse fungi, no great advances in understanding mitovirus biology have emerged, partly because of the lack of inoculation methods. Here we developed a protoplast fusion-based protocol for horizontal transmission of CpMV1 that entailed fusion of recipient and donor protoplasts, hyphal anastomosis, and single-conidium isolation. This method allowed expansion of the host range to many other C. parasitica strains. Species within and outside the family Cryphonectriaceae, Cryphonectria radicalis and Valsa ceratosperma, also supported the replication of CpMV1 at a level comparable to that in the natural host. No stable maintenance of CpMV1 was observed in Helminthosporium victoriae PCR-based haplotyping of virus-infected fungal strains confirmed the recipient mitochondrial genetic background. Phenotypic comparison between CpMV1-free and -infected isogenic strains revealed no overt effects of the virus. Taking advantage of the infectivity to the standard strain C. parasitica EP155, accumulation levels were compared among antiviral RNA silencing-proficient and -deficient strains in the EP155 background. Comparable accumulation levels were observed among these strains, suggesting the avoidance of antiviral RNA silencing by CpMV1, which is consistent with its mitochondrial replication. Collectively, the results of study provide a foundation to further explore the biology of mitoviruses.IMPORTANCE Capsidless mitoviruses, which are ubiquitously detected in filamentous fungi, have the simplest RNA genomes of 2.2 to 4.4 kb, encoding only RNA-dependent RNA polymerase. Despite their simple genomes, detailed biological characterization of mitoviruses has been hampered by their mitochondrial location within the cell, posing challenges to their experimental introduction and study. Here we developed a protoplast fusion-based protocol for horizontal transfer of the prototype mitovirus, Cryphonectria parasitica mitovirus 1 (CpMV1), which was isolated from strain NB631 of the chestnut blight fungus (Cryphonectria parasitica), a model filamentous fungus for studying virus-host interactions. The host range of CpMV1 has been expanded to many different strains of C. parasitica and different fungal species within and outside the Cryphonectriaceae. Comparison of CpMV1 accumulation among various RNA silencing-deficient and -competent strains showed clearly that the virus was unaffected by RNA silencing. This study provides a solid foundation for further exploration of mitovirus-host interactions.
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Co-Infection with Three Mycoviruses Stimulates Growth of a Monilinia fructicola Isolate on Nutrient Medium, but Does Not Induce Hypervirulence in a Natural Host. Viruses 2019; 11:v11010089. [PMID: 30669656 PMCID: PMC6356717 DOI: 10.3390/v11010089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 12/02/2022] Open
Abstract
Monilinia fructicola and Monilinia laxa are the most destructive fungal species infecting stone fruit (Prunus species). High-throughput cDNA sequencing of M. laxa and M. fructicola isolates collected from stone fruit orchards revealed that 14% of isolates were infected with one or more of three mycoviruses: Sclerotinia sclerotiorum hypovirus 2 (SsHV2, genus Hypovirus), Fusarium poae virus 1 (FPV1, genus Betapartitivirus), and Botrytis virus F (BVF, genus Mycoflexivirus). Isolate M196 of M. fructicola was co-infected with all three viruses, and this isolate was studied further. Several methods were applied to cure M196 of one or more mycoviruses. Of these treatments, hyphal tip culture either alone or in combination with antibiotic treatment generated isogenic lines free of one or more mycoviruses. When isogenic fungal lines were cultured on nutrient agar medium in vitro, the triple mycovirus-infected parent isolate M196 grew 10% faster than any of the virus-cured isogenic lines. BVF had a slight inhibitory effect on growth, and FPV1 did not influence growth. Surprisingly, after inoculation to fruits of sweet cherry, there were no significance differences in disease progression between isogenic lines, suggesting that these mycoviruses did not influence the virulence of M. fructicola on a natural host.
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28
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Lee Marzano SY, Neupane A, Domier L. Transcriptional and Small RNA Responses of the White Mold Fungus Sclerotinia sclerotiorum to Infection by a Virulence-Attenuating Hypovirus. Viruses 2018; 10:E713. [PMID: 30558121 PMCID: PMC6315951 DOI: 10.3390/v10120713] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 12/19/2022] Open
Abstract
Mycoviruses belonging to the family Hypoviridae cause persistent infection of many different host fungi. We previously determined that the white mold fungus, Sclerotiniasclerotiorum, infected with Sclerotinia sclerotiorum hypovirus 2-L (SsHV2-L) exhibits reduced virulence, delayed/reduced sclerotial formation, and enhanced production of aerial mycelia. To gain better insight into the cellular basis for these changes, we characterized changes in mRNA and small RNA (sRNA) accumulation in S.sclerotiorum to infection by SsHV2-L. A total of 958 mRNAs and 835 sRNA-producing loci were altered after infection by SsHV2-L, among which >100 mRNAs were predicted to encode proteins involved in the metabolism and trafficking of carbohydrates and lipids. Both S. sclerotiorum endogenous and virus-derived sRNAs were predominantly 22 nt in length suggesting one dicer-like enzyme cleaves both. Novel classes of endogenous small RNAs were predicted, including phasiRNAs and tRNA-derived small RNAs. Moreover, S. sclerotiorum phasiRNAs, which were derived from noncoding RNAs and have the potential to regulate mRNA abundance in trans, showed differential accumulation due to virus infection. tRNA fragments did not accumulate differentially after hypovirus infection. Hence, in-depth analysis showed that infection of S. sclerotiorum by a hypovirulence-inducing hypovirus produced selective, large-scale reprogramming of mRNA and sRNA production.
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Affiliation(s)
- Shin-Yi Lee Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USA.
- Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD 57006, USA.
| | - Achal Neupane
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USA.
| | - Leslie Domier
- United States Department of Agriculture, Agricultural Research Service, Department of Crop Sciences, University of Illinois, Urbana, IL 61801, USA.
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Zhu JZ, Zhu HJ, Gao BD, Zhou Q, Zhong J. Diverse, Novel Mycoviruses From the Virome of a Hypovirulent Sclerotium rolfsii Strain. FRONTIERS IN PLANT SCIENCE 2018; 9:1738. [PMID: 30542362 PMCID: PMC6277794 DOI: 10.3389/fpls.2018.01738] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/08/2018] [Indexed: 05/10/2023]
Abstract
Sclerotium rolfsii, which causes southern blight in a wide variety of crops, is a devastating plant pathogen worldwide. Mycoviruses that induce hypovirulence in phytopathogenic fungi are potential biological control resources against fungal plant diseases. However, in S. rolfsii, mycoviruses are rarely reported. In a previous study, we found a hypovirulent strain carrying a diverse pattern of dsRNAs. Here, we utilized the RNA_Seq technique to detect viral sequences. Deep sequencing, RT-PCR and Sanger sequencing validation analyses revealed that this strain harbors various new viral species that show affinity to the distinctly established and proposed families Benyviridae, Endornaviridae, Fusariviridae, Hypoviridae, and Fusagraviridae. Moreover, some viral sequences that could not be assigned to any of the existing families or orders were also identified and showed similarities to the Alphavirus, Ourmiavirus, phlegivirus-like and Curvularia thermal tolerance virus-like groups. In addition, we also conducted deep sequencing analysis of small RNAs in the virus-infecting fugal strain. The results indicated that the Dicer-mediated gene silencing mechanism was present in S. rolfsii. This is the first report of viral diversity in a single S. rolfsii fungal strain, and the results presented herein might provide insight into the taxonomy and evolution of mycoviruses and be useful for the exploration of mycoviruses as biocontrol agents.
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Affiliation(s)
| | | | | | - Qian Zhou
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China
| | - Jie Zhong
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, China
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A Novel Deltaflexivirus that Infects the Plant Fungal Pathogen, Sclerotinia sclerotiorum, Can Be Transmitted Among Host Vegetative Incompatible Strains. Viruses 2018; 10:v10060295. [PMID: 29857477 PMCID: PMC6024712 DOI: 10.3390/v10060295] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 05/25/2018] [Accepted: 05/29/2018] [Indexed: 11/17/2022] Open
Abstract
Various mycoviruses have been isolated from Sclerotinia sclerotiorum. Here, we identified a viral RNA sequence contig, representing a novel virus, Sclerotinia sclerotiorum deltaflexivirus 2 (SsDFV2), from an RNA_Seq database. We found that SsDFV2 was harbored in the hypovirulent strain, 228, which grew slowly on potato dextrose agar, produced a few sclerotia, and could not induce typical lesions on detached rapeseed (Brassica napus) leaves. Strain 228 was also infected by Botrytis porri RNA Virus 1 (BpRV1), a virus originally isolated from Botrytis porri. The genome of SsDFV2 comprised 6711 nucleotides, excluding the poly (A) tail, and contained a single large predicted open reading frame encoding a putative viral RNA replicase. Phylogenetic analysis demonstrated that SsDFV2 is closely related to viruses in the family Deltaflexiviridae; however, it also differs significantly from members of this family, suggesting that it may represent a new species. Further we determined that SsDFV2 could be efficiently transmitted to host vegetative incompatible individuals by dual culture. To our best knowledge, this is the first report that a (+) ssRNA mycovirus can overcome the transmission limitations of the vegetative incompatibility system, a phenomenon that may facilitate the potential use of mycoviruses for the control of crop fungal diseases.
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Mochama P, Jadhav P, Neupane A, Lee Marzano SY. Mycoviruses as Triggers and Targets of RNA Silencing in White Mold Fungus Sclerotinia sclerotiorum. Viruses 2018; 10:v10040214. [PMID: 29690568 PMCID: PMC5923508 DOI: 10.3390/v10040214] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/18/2018] [Accepted: 04/20/2018] [Indexed: 02/05/2023] Open
Abstract
This study aimed to demonstrate the existence of antiviral RNA silencing mechanisms in Sclerotinia sclerotiorum by infecting wild-type and RNA-silencing-deficient strains of the fungus with an RNA virus and a DNA virus. Key silencing-related genes were disrupted to dissect the RNA silencing pathway. Specifically, dicer genes (dcl-1, dcl-2, and both dcl-1/dcl-2) were displaced by selective marker(s). Disruption mutants were then compared for changes in phenotype, virulence, and susceptibility to virus infections. Wild-type and mutant strains were transfected with a single-stranded RNA virus, SsHV2-L, and copies of a single-stranded DNA mycovirus, SsHADV-1, as a synthetic virus constructed in this study. Disruption of dcl-1 or dcl-2 resulted in no changes in phenotype compared to wild-type S. sclerotiorum; however, the double dicer mutant strain exhibited significantly slower growth. Furthermore, the Δdcl-1/dcl-2 double mutant, which was slow growing without virus infection, exhibited much more severe debilitation following virus infections including phenotypic changes such as slower growth, reduced pigmentation, and delayed sclerotial formation. These phenotypic changes were absent in the single mutants, Δdcl-1 and Δdcl-2. Complementation of a single dicer in the double disruption mutant reversed viral susceptibility to the wild-type state. Virus-derived small RNAs were accumulated from virus-infected wild-type strains with strand bias towards the negative sense. The findings of these studies indicate that S. sclerotiorum has robust RNA silencing mechanisms that process both DNA and RNA mycoviruses and that, when both dicers are silenced, invasive nucleic acids can greatly debilitate the virulence of this fungus.
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Affiliation(s)
- Pauline Mochama
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
| | - Prajakta Jadhav
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
| | - Achal Neupane
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
| | - Shin-Yi Lee Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
- Department of Horticulture, Agronomy, and Plant Sciences, South Dakota State University, Brookings, SD 57007, USA.
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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.
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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
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Suzuki N, Ghabrial SA, Kim KH, Pearson M, Marzano SYL, Yaegashi H, Xie J, Guo L, Kondo H, Koloniuk I, Hillman BI, Ictv Report Consortium. ICTV Virus Taxonomy Profile: Hypoviridae. J Gen Virol 2018; 99:615-616. [PMID: 29589826 DOI: 10.1099/jgv.0.001055] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Hypoviridae, comprising one genus, Hypovirus, is a family of capsidless viruses with positive-sense, ssRNA genomes of 9.1-12.7 kb that possess either a single large ORF or two ORFs. The ORFs appear to be translated from genomic RNA by non-canonical mechanisms, i.e. internal ribosome entry site-mediated and stop/restart translation. Hypoviruses have been detected in ascomycetous or basidiomycetous filamentous fungi, and are considered to be replicated in host Golgi-derived, lipid vesicles that contain their dsRNA as a replicative form. Some hypoviruses induce hypovirulence to host fungi, while others do not. This is a summary of the current ICTV report on the taxonomy of the Hypoviridae, which is available at www.ictv.global/report/hypoviridae.
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Affiliation(s)
- Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - Said A Ghabrial
- Plant Pathology Department, University of Kentucky, Lexington, KY 40504, USA
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology and College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Michael Pearson
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Shin-Yi L Marzano
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.,Department of Agronomy, Horticulture, and Plant Science, South Dakota State University, Brookings, SD 57007, USA
| | - Hajime Yaegashi
- Division of Apple Research, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Morioka, Japan
| | - Jiatao Xie
- Plant Pathology Department, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, PR China
| | - Lihua Guo
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Hideki Kondo
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - Igor Koloniuk
- Department of Plant Virology, Institute of Plant Molecular Biology, Biology Centre of the Czech Academy of Sciences, v.v.i., Branišovská 31, 370 05 České Budějovice, Czech Republic
| | - Bradley I Hillman
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ 08901, USA
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Abstract
In contrast to well-established internal ribosomal entry site (IRES)-mediated translational initiation in animals and plants, no IRESs were established in fungal viral or cellular RNAs. To identify IRES elements in mycoviruses, we developed a luciferase-based dual-reporter detection system in Cryphonectria parasitica, a model filamentous fungus for virus-host interactions. A bicistronic construct entails a codon-optimized Renilla and firefly luciferase (ORluc and OFluc, respectively) gene, between which potential IRES sequences can be inserted. In this system, ORluc serves as an internal control, while OFluc represents IRES activity. Virus sequences in the 5′ untranslated regions (UTRs) of the genomes of diverse positive-sense single-stranded RNA and double-stranded RNA (dsRNA) viruses were analyzed. The results show relatively high IRES activities for Cryphonectria hypovirus 1 (CHV1) and CHV2 and faint but measurable activity for CHV3. The weak IRES signal of CHV3 may be explained by its monocistronic nature, differing from the bicistronic nature of CHV1 and CHV2. This would allow these three hypoviruses to have similar rates of translation of replication-associated protein per viral mRNA molecule. The importance of 24 5′-proximal codons of CHV1 as well as the 5′ UTR for IRES function was confirmed. Furthermore, victoriviruses and chrysoviruses tested IRES positive, whereas mycoreoviruses, partitiviruses, and quadriviruses showed similar Fluc activities as the negative controls. Overall, this study represents the first development of an IRES identification system in filamentous fungi based on the codon-optimized dual-luciferase assay and provides evidence for IRESs in filamentous fungi. Cap-independent, internal ribosomal entry site (IRES)-mediated translational initiation is often used by virus mRNAs and infrequently by cellular mRNAs in animals and plants. However, no IRESs have been established in fungal virus RNAs or cellular RNAs in filamentous fungi. Here, we report the development of a dual-luciferase assay system and measurement of the IRES activities of fungal RNA viruses in a model filamentous fungal host, Cryphonectria parasitica. Viruses identified as IRES positive include hypoviruses (positive-sense RNA viruses, members of the expanded Picornavirus supergroup), totiviruses (nonsegmented dsRNA viruses), and chrysoviruses (tetrasegmented dsRNA viruses). No IRES activities were observed in the 5′ untranslated regions of mycoreoviruses (11-segmented dsRNA viruses), quadriviruses (tetrasegmented dsRNA viruses), or partitiviruses (bisegmented dsRNA viruses). This study provides the first evidence for IRES activities in diverse RNA viruses in filamentous fungi and is a first step toward identifying trans-acting host factors and cis-regulatory viral RNA elements.
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Picarelli MASC, Gobatto D, Patrício F, Rivas EB, Colariccio A. Vírus que infectam fungos fitopatogênicos. ARQUIVOS DO INSTITUTO BIOLÓGICO 2018. [DOI: 10.1590/1808-1657000162016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO: Micovírus são vírus que infectam todos os taxa de fungos. São geralmente crípticos (latentes), mas podem causar pequenas ou imperceptíveis alterações no hospedeiro. Nos fungos fitopatogênicos, os vírus podem interferir com os sintomas e, em alguns casos, reduzir a virulência de seu hospedeiro; por esta razão, são objeto de estudo, por serem um potencial agente de biocontrole e por serem ferramentas importantes para o conhecimento sobre os mecanismos de patogênese de fungos. A presente revisão teve o objetivo de reunir os dados de literatura relacionados aos aspectos gerais da biologia e do comportamento dos micovírus presentes em alguns fungos fitopatogênicos.
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Mu F, Xie J, Cheng S, You MP, Barbetti MJ, Jia J, Wang Q, Cheng J, Fu Y, Chen T, Jiang D. Virome Characterization of a Collection of S. sclerotiorum from Australia. Front Microbiol 2018; 8:2540. [PMID: 29375495 PMCID: PMC5768646 DOI: 10.3389/fmicb.2017.02540] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/06/2017] [Indexed: 11/13/2022] Open
Abstract
Sclerotinia sclerotiorum is a devastating plant pathogen that attacks numerous economically important broad acre and vegetable crops worldwide. Mycoviruses are widespread viruses that infect fungi, including S. sclerotiorum. As there were no previous reports of the presence of mycoviruses in this pathogen in Australia, studies were undertaken using RNA_Seq analysis to determine the diversity of mycoviruses in 84 Australian S. sclerotiorum isolates collected from various hosts. After RNA sequences were subjected to BLASTp analysis using NCBI database, 285 contigs representing partial or complete genomes of 57 mycoviruses were obtained, and 34 of these (59.6%) were novel viruses. These 57 viruses were grouped into 10 distinct lineages, namely Endornaviridae (four novel mycoviruses), Genomoviridae (isolate of SsHADV-1), Hypoviridae (two novel mycoviruses), Mononegavirales (four novel mycovirusess), Narnaviridae (10 novel mycoviruses), Partitiviridae (two novel mycoviruses), Ourmiavirus (two novel mycovirus), Tombusviridae (two novel mycoviruses), Totiviridae (one novel mycovirus), Tymovirales (five novel mycoviruses), and two non-classified mycoviruses lineages (one Botrytis porri RNA virus 1, one distantly related to Aspergillus fumigatus tetramycovirus-1). Twenty-five mitoviruses were determined and mitoviruses were dominant in the isolates tested. This is not only the first study to show existence of mycoviruses in S. sclerotiorum in Australia, but highlights how they are widespread and that many novel mycoviruses occur there. Further characterization of these mycoviruses is warranted, both in terms of exploring these novel mycoviruses for innovative biocontrol of Sclerotinia diseases and in enhancing our overall knowledge on viral diversity, taxonomy, ecology, and evolution.
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Affiliation(s)
- Fan Mu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Shufen Cheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Ming Pei You
- Faculty of Science, UWA School of Agriculture and Environment and The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - Martin J. Barbetti
- Faculty of Science, UWA School of Agriculture and Environment and The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - Jichun Jia
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Qianqian Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Yanping Fu
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Tao Chen
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- The Provincial Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
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A neo-virus lifestyle exhibited by a (+)ssRNA virus hosted in an unrelated dsRNA virus: Taxonomic and evolutionary considerations. Virus Res 2018; 244:75-83. [DOI: 10.1016/j.virusres.2017.11.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/04/2017] [Accepted: 11/05/2017] [Indexed: 12/21/2022]
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Abstract
Plant-associated fungi are infected by viruses at the incidence rates from a few % to over 90%. Multiple viruses often coinfect fungal hosts, and occasionally alter their phenotypes, but most of the infections are asymptomatic. Phenotypic alterations are grouped into two types: harmful or beneficial to the host fungi. Harmful interactions between viruses and hosts include hypovirulence and/or debilitation that are documented in a number of phytopathogenic fungi, exemplified by the chestnut blight, white root rot, and rapeseed rot fungi. Beneficial interactions are observed in a limited number of plant endophytic and pathogenic fungi where heat tolerance and virulence are enhanced, respectively. Coinfections of fungi provided a platform for discoveries of interesting virus/virus interactions that include synergistic, as in the case for those in plants, and unique antagonistic and mutualistic interactions between unrelated RNA viruses. Also discussed here are coinfection-induced genome rearrangements and frequently observed coinfections by the simplest positive-strand RNA virus, the mitoviruses.
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Affiliation(s)
- Bradley I Hillman
- Plant Biology and Pathology, Rutgers University, New Brunswick, NJ, United States.
| | - Aulia Annisa
- Institute of Plant Science and Resources (IPSR), Okayama University, Kurashiki, Japan
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources (IPSR), Okayama University, Kurashiki, Japan.
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Thekke-Veetil T, McCoppin NK, Domier LL. Strain-specific association of soybean dwarf virus small subgenomic RNA with virus particles. Virus Res 2017; 242:100-105. [PMID: 28893654 DOI: 10.1016/j.virusres.2017.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/05/2017] [Accepted: 09/07/2017] [Indexed: 10/18/2022]
Abstract
Soybean dwarf virus (SbDV) produces a large subgenomic RNA (LsgRNA) for expression of structural and movement proteins and a small subgenomic RNA (SsgRNA) that does not contain an open reading frame. Sucrose gradient-purified SbDV virions from soybean plants systemically infected with SbDV by aphids and Nicotiana benthamiana leaves agroinfiltrated with infectious clones of two red clover SbDV isolates encapsidated genomic RNA and were associated with SsgRNA in a strain-specific manner. The LsgRNA was protected from RNase degradation, but not packaged into virions as indicated by its presence primarily in ELISA-negative fractions near the tops of sucrose gradients even in mutants that did not express coat protein. Nucleotide differences in the SsgRNA region between isolates conferred differential association of SsgRNA with virions.
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Affiliation(s)
| | - Nancy K McCoppin
- United State Department of Agriculture, Agricultural Research Service, Urbana, IL, 61801, USA
| | - Leslie L Domier
- United State Department of Agriculture, Agricultural Research Service, Urbana, IL, 61801, USA.
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40
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Zhong J, Chen D, Zhu HJ, Gao BD, Zhou Q. Hypovirulence of Sclerotium rolfsii Caused by Associated RNA Mycovirus. Front Microbiol 2016; 7:1798. [PMID: 27891121 PMCID: PMC5103162 DOI: 10.3389/fmicb.2016.01798] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/26/2016] [Indexed: 11/21/2022] Open
Abstract
Mycoviruses associated with hypovirulence are potential biological control agents and could be useful to study the pathogenesis of fungal host pathogens. Sclerotium rolfsii, a pathogenic fungus, causes southern blight in a wide variety of crops. In this study, we isolated a series of dsRNAs from a debilitated S. rolfsii strain, BLH-1, which had pronounced phenotypic aberrations including reduced pathogenicity, mycelial growth and deficient sclerotia production. Virus-curing and horizontal transmission experiments that eliminated or transmitted, respectively, all dsRNA elements showed that the dsRNAs were involved in the hypovirulent traits of BLH-1. Ultrastructure examination also showed hyphae fracture and cytoplasm or organelle degeneration in BLH-1 hyphal cells compared to the virus-free strain. Three assembled cDNA contigs generated from the cDNA library cloned from the purified dsRNA indicated that strain BLH-1 was infected by at least three novel mycoviruses. One has similarity to the hypovirulence-associated Sclerotinia sclerotiorum hypovirus 2 (SsHV2) in the family Hypoviridae, and the other two are related to two different unclassified dsRNA mycovirus families. To our knowledge, this is the first report of S. rolfsii hypovirulence that was correlated with its associated dsRNA.
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Affiliation(s)
- Jie Zhong
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China
| | - Dan Chen
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China
| | - Hong J Zhu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China
| | - Bi D Gao
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China
| | - Qian Zhou
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China
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Identification of Diverse Mycoviruses through Metatranscriptomics Characterization of the Viromes of Five Major Fungal Plant Pathogens. J Virol 2016; 90:6846-6863. [PMID: 27194764 DOI: 10.1128/jvi.00357-16] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/11/2016] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Mycoviruses can have a marked effect on natural fungal communities and influence plant health and productivity. However, a comprehensive picture of mycoviral diversity is still lacking. To characterize the viromes of five widely dispersed plant-pathogenic fungi, Colletotrichum truncatum, Macrophomina phaseolina, Diaporthe longicolla, Rhizoctonia solani, and Sclerotinia sclerotiorum, a high-throughput sequencing-based metatranscriptomic approach was used to detect viral sequences. Total RNA and double-stranded RNA (dsRNA) from mycelia and RNA from samples enriched for virus particles were sequenced. Sequence data were assembled de novo, and contigs with predicted amino acid sequence similarities to viruses in the nonredundant protein database were selected. The analysis identified 72 partial or complete genome segments representing 66 previously undescribed mycoviruses. Using primers specific for each viral contig, at least one fungal isolate was identified that contained each virus. The novel mycoviruses showed affinity with 15 distinct lineages: Barnaviridae, Benyviridae, Chrysoviridae, Endornaviridae, Fusariviridae, Hypoviridae, Mononegavirales, Narnaviridae, Ophioviridae, Ourmiavirus, Partitiviridae, Tombusviridae, Totiviridae, Tymoviridae, and Virgaviridae More than half of the viral sequences were predicted to be members of the Mitovirus genus in the family Narnaviridae, which replicate within mitochondria. Five viral sequences showed strong affinity with three families (Benyviridae, Ophioviridae, and Virgaviridae) that previously contained no mycovirus species. The genomic information provides insight into the diversity and taxonomy of mycoviruses and coevolution of mycoviruses and their fungal hosts. IMPORTANCE Plant-pathogenic fungi reduce crop yields, which affects food security worldwide. Plant host resistance is considered a sustainable disease management option but may often be incomplete or lacking for some crops to certain fungal pathogens or strains. In addition, the rising issues of fungicide resistance demand alternative strategies to reduce the negative impacts of fungal pathogens. Those fungus-infecting viruses (mycoviruses) that attenuate fungal virulence may be welcome additions for mitigation of plant diseases. By high-throughput sequencing of the RNAs from 275 isolates of five fungal plant pathogens, 66 previously undescribed mycoviruses were identified. In addition to identifying new potential biological control agents, these results expand the grand view of the diversity of mycoviruses and provide possible insights into the importance of intracellular and extracellular transmission in fungus-virus coevolution.
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Marzano SYL, Domier LL. Reprint of “Novel mycoviruses discovered from metatranscriptomics survey of soybean phyllosphere phytobiomes”. Virus Res 2016; 219:11-21. [DOI: 10.1016/j.virusres.2016.05.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/30/2015] [Accepted: 11/01/2015] [Indexed: 10/21/2022]
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Marzano SYL, Domier LL. Novel mycoviruses discovered from metatranscriptomics survey of soybean phyllosphere phytobiomes. Virus Res 2016; 213:332-342. [PMID: 26547008 DOI: 10.1016/j.virusres.2015.11.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/30/2015] [Accepted: 11/01/2015] [Indexed: 11/25/2022]
Abstract
Mycoviruses can be beneficial to plants in that they can debilitate pathogenic fungi thereby reducing the severity of associated plant diseases. Studies to date have focused primarily on culturable fungi that represent a fraction of natural fungal populations. The nonculturable fungi, however, can harbor diverse populations of mycoviruses that reduce plant disease or enhance resistance to abiotic stress. Metatranscriptome analysis of field-grown plant samples using high-throughput sequencing offers the possibility of unbiased detection and quantification of mycoviruses regardless of the culturability of their fungal hosts together with the complete associated microbial consortia. In this study, we describe the fungal viromes of the phyllosphere of production soybean fields in Illinois, USA by analyzing the metatranscriptomes of thousands of soybean leaf samples collected during the 2008 and 2009 growing seasons. The analyses identified 25 partial genome sequences that represented at least 22 mycovirus genomes, only one of which had been described previously. The novel mycovirus genomes showed similarity to 10 distinct lineages including the genera Alphapartitivirus, Botybirnavirus, Endornavirus, Mitovirus, Mycoflexivirus, Ourmiavirus, Totivirus, Victorivirus, family Tombusviridae, order Mononegavirales, and the recently proposed genus Gemycircularvirus. The present study adds to the wealth of mycoviruses associated with plant phytobiomes and establishes groundwork needed for further characterization of the viruses.
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Affiliation(s)
| | - Leslie L Domier
- Department of Crop Sciences, University of Illinois, Urbana, IL, USA; United States Department of Agriculture-Agricultural Research Service, Urbana, IL, USA.
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Li K, Zheng D, Cheng J, Chen T, Fu Y, Jiang D, Xie J. Characterization of a novel Sclerotinia sclerotiorum RNA virus as the prototype of a new proposed family within the order Tymovirales. Virus Res 2015; 219:92-99. [PMID: 26603216 DOI: 10.1016/j.virusres.2015.11.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/12/2015] [Accepted: 11/14/2015] [Indexed: 11/18/2022]
Abstract
Recent studies have shown that Sclerotinia sclerotiorum, an important plant pathogen fungus, harbors diverse mycoviruses. A new mycovirus, tentatively named as Sclerotinia sclerotiorum deltaflexivirus 1 (SsDFV1), was isolated from a S. sclerotiorum strain AX19 containing multiple dsRNA elements. The complete genome of SsDFV1 was shown to be 8178 nucleotides long excluding the poly (A) tail. SsDFV1 has a large putative open reading frame (ORF1) and three smaller ORFs (2-4). ORF1 encodes a putative methyltransferase-helicase-RdRp polyprotein of 2075 amino acids. ORFs (2-4) encode three putative small hypothetical proteins (<40kDa) with unknown biological functions. No evidence for a coat protein encoded by SsDFV1 was obtained. Multiple alignment suggested that three conserved domains, RdRp, methyltransferase, and helicase, from SsDFV1 have lower identity (approximately 25%) with all the reported viruses of four approved families, Alphaflexiviridae, Betaflexiviridae, Gammaflexiviridae and Tymoviridae in the order Tymovirales. Moreover, a phylogenetic tree also suggested that the SsDFV1 could not be phylogenetically placed in any of the approved families, and forms a separated cluster distinct from other known viruses. Therefore, these combined results suggest that SsDFV1 could represent a new positive-sense single-stranded RNA virus with some unique molecular features, and we propose to create a tentative family Deltaflexiviridae that accommodates SsDFV1.
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Affiliation(s)
- Kunfei Li
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Dan Zheng
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Jiasen Cheng
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Tao Chen
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Yanping Fu
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Daohong Jiang
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China
| | - Jiatao Xie
- State Key Laboratory of Agriculture Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China; Provincial Key Laboratory of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, People's Republic of China.
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45
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Affiliation(s)
- Moonil Son
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Korea
| | - Jisuk Yu
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Korea
- * E-mail:
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Characterization of a Novel Megabirnavirus from Sclerotinia sclerotiorum Reveals Horizontal Gene Transfer from Single-Stranded RNA Virus to Double-Stranded RNA Virus. J Virol 2015; 89:8567-79. [PMID: 26063429 DOI: 10.1128/jvi.00243-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/01/2015] [Indexed: 01/27/2023] Open
Abstract
UNLABELLED Mycoviruses have been detected in all major groups of filamentous fungi, and their study represents an important branch of virology. Here, we characterized a novel double-stranded RNA (dsRNA) mycovirus, Sclerotinia sclerotiorum megabirnavirus 1 (SsMBV1), in an apparently hypovirulent strain (SX466) of Sclerotinia sclerotiorum. Two similarly sized dsRNA segments (L1- and L2-dsRNA), the genome of SsMBV1, are packaged in rigid spherical particles purified from strain SX466. The full-length cDNA sequence of L1-dsRNA/SsMBV1 comprises two large open reading frames (ORF1 and ORF2), which encode a putative coat protein and an RNA-dependent RNA polymerase (RdRp), respectively. Phylogenetic analysis of the RdRp domain clearly indicates that SsMBV1 is related to Rosellinia necatrix megabirnavirus 1 (RnMBV1). L2-dsRNA/SsMBV1 comprises two nonoverlapping ORFs (ORFA and ORFB) encoding two hypothetical proteins with unknown functions. The 5'-terminal regions of L1- and L2-dsRNA/SsMBV1 share strictly conserved sequences and form stable stem-loop structures. Although L2-dsRNA/SsMBV1 is dispensable for replication, genome packaging, and pathogenicity of SsMBV1, it enhances transcript accumulation of L1-dsRNA/SsMBV1 and stability of virus-like particles (VLPs). Interestingly, a conserved papain-like protease domain similar to a multifunctional protein (p29) of Cryphonectria hypovirus 1 was detected in the ORFA-encoded protein of L2-dsRNA/SsMBV1. Phylogenetic analysis based on the protease domain suggests that horizontal gene transfer may have occurred from a single-stranded RNA (ssRNA) virus (hypovirus) to a dsRNA virus, SsMBV1. Our results reveal that SsMBV1 has a slight impact on the fundamental biological characteristics of its host regardless of the presence or absence of L2-dsRNA/SsMBV1. IMPORTANCE Mycoviruses are widespread in all major fungal groups, and they possess diverse genomes of mostly ssRNA and dsRNA and, recently, circular ssDNA. Here, we have characterized a novel dsRNA virus (Sclerotinia sclerotiorum megabirnavirus 1 [SsMBV1]) that was isolated from an apparently hypovirulent strain, SX466, of Sclerotinia sclerotiorum. Although SsMBV1 is phylogenetically related to RnMBV1, SsMBV1 is markedly distinct from other reported megabirnaviruses with two features of VLPs and conserved domains. Our results convincingly showed that SsMBV1 is viable in the absence of L2-dsRNA/SsMBV1 (a potential large satellite-like RNA or genuine genomic virus component). More interestingly, we detected a conserved papain-like protease domain that commonly exists in ssRNA viruses, including members of the families Potyviridae and Hypoviridae. Phylogenetic analysis based on the protease domain suggests that horizontal gene transfer might have occurred from an ssRNA virus to a dsRNA virus, which may provide new insights into the evolutionary history of dsRNA and ssRNA viruses.
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Liu R, Cheng J, Fu Y, Jiang D, Xie J. Molecular Characterization of a Novel Positive-Sense, Single-Stranded RNA Mycovirus Infecting the Plant Pathogenic Fungus Sclerotinia sclerotiorum. Viruses 2015; 7:2470-84. [PMID: 26008696 PMCID: PMC4452915 DOI: 10.3390/v7052470] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/10/2015] [Accepted: 05/12/2015] [Indexed: 01/16/2023] Open
Abstract
Recent studies have demonstrated that a diverse array of mycoviruses infect the plant pathogenic fungus Sclerotinia sclerotiorum. Here, we report the molecular characterization of a newly identified mycovirus, Sclerotinia sclerotiorum fusarivirus 1 (SsFV1), which was isolated from a sclerotia-defective strain JMTJ14 of S. sclerotiorum. Excluding a poly (A) tail, the genome of SsFV1 comprises 7754 nucleotides (nts) in length with 83 and 418 nts for 5'- and 3'-untranslated regions, respectively. SsFV1 has four non-overlapping open reading frames (ORFs): ORF1 encodes a 191 kDa polyprotein (1664 amino acid residues in length) containing conserved RNA-dependent RNA polymerase (RdRp) and helicase domains; the other three ORFs encode three putative hypothetical proteins of unknown function. Phylogenetic analysis, based on RdRp and Helicase domains, indicated that SsFV1 is phylogenetically related to Rosellinia necatrix fusarivirus 1 (RnFV1), Fusarium graminearum virus-DK21 (FgV1), and Penicillium roqueforti RNA mycovirus 1 (PrRV1), a cluster of an independent group belonging to a newly proposed family Fusarividae. However, SsFV1 is markedly different from FgV1 and RnFV1 in genome organization and nucleotide sequence. SsFV1 was transmitted successfully to two vegetatively incompatible virus-free strains. SsFV1 is not responsible for the abnormal phenotype of strain JMTJ14.
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Affiliation(s)
- Rong Liu
- State Key Laboratory of Agricultural Microbiology, The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology, The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yanping Fu
- State Key Laboratory of Agricultural Microbiology, The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology, The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology, The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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Liu L, Wang Q, Cheng J, Fu Y, Jiang D, Xie J. Molecular characterization of a bipartite double-stranded RNA virus and its satellite-like RNA co-infecting the phytopathogenic fungus Sclerotinia sclerotiorum. Front Microbiol 2015; 6:406. [PMID: 25999933 PMCID: PMC4422086 DOI: 10.3389/fmicb.2015.00406] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/19/2015] [Indexed: 11/13/2022] Open
Abstract
A variety of mycoviruses have been found in Sclerotinia sclerotiorum. In this study, we report a novel mycovirus S. sclerotiorum botybirnavirus 1 (SsBRV1) that was originally isolated from the hypovirulent strain SCH941 of S. sclerotiorum. SsBRV1 has rigid spherical virions that are ∼38 nm in diameter, and three double-stranded RNA (dsRNA) segments (dsRNA1, 2, and 3 with lengths of 6.4, 6.0, and 1.7 kbp, respectively) were packaged in the virions. dsRNA1 encodes a cap-pol fusion protein, and dsRNA2 encodes a polyprotein with unknown functions but contributes to the formation of virus particles. The dsRNA3 is dispensable and may be a satellite-like RNA of SsBRV1. Although phylogenetic analysis of the RdRp domain demonstrated that SsBRV1 is related to Botrytis porri RNA virus 1 (BpRV1) and Ustilago maydis dsRNA virus-H1, the structure proteins of SsBRV1 do not have any significant sequence similarities with other known viral proteins with the exception of those of BpRV1. SsBRV1 carrying dsRNA3 seems to have no obvious effects on the colony morphology, but can significantly reduce the growth rate and virulence of S. sclerotiorum. These findings provide new insights into the virus taxonomy, virus evolution and the interactions between SsBRV1 and the fungal hosts.
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Affiliation(s)
- Lijiang Liu
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Qihua Wang
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Yanping Fu
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
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