1
|
Battersby JL, Stevens DA, Coutts RHA, Havlíček V, Hsu JL, Sass G, Kotta-Loizou I. The Expanding Mycovirome of Aspergilli. J Fungi (Basel) 2024; 10:585. [PMID: 39194910 DOI: 10.3390/jof10080585] [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: 06/27/2024] [Revised: 08/08/2024] [Accepted: 08/14/2024] [Indexed: 08/29/2024] Open
Abstract
Mycoviruses are viruses that infect fungi and are widespread across all major fungal taxa, exhibiting great biological diversity. Since their discovery in the 1960s, researchers have observed a myriad of fungal phenotypes altered due to mycoviral infection. In this review, we examine the nuanced world of mycoviruses in the context of the medically and agriculturally important fungal genus, Aspergillus. The advent of RNA sequencing has revealed a previous underestimate of viral prevalence in fungi, in particular linear single-stranded RNA viruses, and here we outline the diverse viral families known to date that contain mycoviruses infecting Aspergillus. Furthermore, we describe these novel mycoviruses, highlighting those with peculiar genome structures, such as a split RNA dependent RNA polymerase gene. Next, we delineate notable mycovirus-mediated phenotypes in Aspergillus, in particular reporting on observations of mycoviruses that affect their fungal host's virulence and explore how this may relate to virus-mediated decreased stress tolerance. Furthermore, mycovirus effects on microbial competition and antifungal resistance are discussed. The factors that influence the manifestation of these phenotypes, such as temperature, fungal life stage, and infection with multiple viruses, among others, are also evaluated. In addition, we attempt to elucidate the molecular mechanisms that underpin these phenotypes, examining how mycoviruses can be targets, triggers, and even suppressors of RNA silencing and how this can affect fungal gene expression and phenotypes. Finally, we highlight the potential therapeutic applications of mycoviruses and how, in an approach analogous to bacteriophage therapy, their ability to produce hypovirulence in Aspergillus might be used to attenuate invasive aspergillosis infections in humans.
Collapse
Affiliation(s)
- Josephine L Battersby
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- Department of Clinical, Pharmaceutical and Biological Science, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - David A Stevens
- California Institute for Medical Research, San Jose, CA 95128, USA
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Robert H A Coutts
- Department of Clinical, Pharmaceutical and Biological Science, University of Hertfordshire, Hatfield AL10 9AB, UK
| | - Vladimír Havlíček
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 00 Prague, Czech Republic
- Department of Analytical Chemistry, Palacky University, 17. Listopadu 2, 779 00 Olomouc, Czech Republic
| | - Joe L Hsu
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gabriele Sass
- California Institute for Medical Research, San Jose, CA 95128, USA
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
- Department of Clinical, Pharmaceutical and Biological Science, University of Hertfordshire, Hatfield AL10 9AB, UK
| |
Collapse
|
2
|
Spada M, Pugliesi C, Fambrini M, Pecchia S. Challenges and Opportunities Arising from Host- Botrytis cinerea Interactions to Outline Novel and Sustainable Control Strategies: The Key Role of RNA Interference. Int J Mol Sci 2024; 25:6798. [PMID: 38928507 PMCID: PMC11203536 DOI: 10.3390/ijms25126798] [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: 05/31/2024] [Revised: 06/18/2024] [Accepted: 06/18/2024] [Indexed: 06/28/2024] Open
Abstract
The necrotrophic plant pathogenic fungus Botrytis cinerea (Pers., 1794), the causative agent of gray mold disease, causes significant losses in agricultural production. Control of this fungal pathogen is quite difficult due to its wide host range and environmental persistence. Currently, the management of the disease is still mainly based on chemicals, which can have harmful effects not only on the environment and on human health but also because they favor the development of strains resistant to fungicides. The flexibility and plasticity of B. cinerea in challenging plant defense mechanisms and its ability to evolve strategies to escape chemicals require the development of new control strategies for successful disease management. In this review, some aspects of the host-pathogen interactions from which novel and sustainable control strategies could be developed (e.g., signaling pathways, molecules involved in plant immune mechanisms, hormones, post-transcriptional gene silencing) were analyzed. New biotechnological tools based on the use of RNA interference (RNAi) are emerging in the crop protection scenario as versatile, sustainable, effective, and environmentally friendly alternatives to the use of chemicals. RNAi-based fungicides are expected to be approved soon, although they will face several challenges before reaching the market.
Collapse
Affiliation(s)
- Maria Spada
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Claudio Pugliesi
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Marco Fambrini
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Susanna Pecchia
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
- Interdepartmental Research Center Nutrafood “Nutraceuticals and Food for Health”, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| |
Collapse
|
3
|
Hua H, Zhang X, Liu L, Wu X. A Novel Strain of Fusarium oxysporum Alternavirus 1 Isolated from Fusarium oxysporum f. sp. melonis Strain T-BJ17 Confers Hypovirulence and Increases the Sensitivity of Its Host Fungus to Difenoconazole and Pydiflumetofen. Viruses 2024; 16:901. [PMID: 38932193 PMCID: PMC11209391 DOI: 10.3390/v16060901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 05/30/2024] [Accepted: 05/30/2024] [Indexed: 06/28/2024] Open
Abstract
In the current study, a novel strain of Fusarium oxysporum alternavirus 1 (FoAV1) was identified from the Fusarium oxysporum f. sp. melonis (FOM) strain T-BJ17 and was designated as Fusarium oxysporum alternavirus 1-FOM (FoAV1-FOM). Its genome consists of four dsRNA segments of 3515 bp (dsRNA1), 2663 bp (dsRNA2), 2368 bp (dsRNA3), and 1776 bp (dsRNA4) in length. Open reading frame 1 (ORF1) in dsRNA1 was found to encode a putative RNA-dependent RNA polymerase (RdRp), whose amino acid sequence was 99.02% identical to that of its counterpart in FoAV1; while ORF2 in dsRNA2, ORF3 in dsRNA3, and ORF4 in dsRNA4 were all found to encode hypothetical proteins. Strain T-BJ17-VF, which was verified to FoAV1-FOM-free, was obtained using single-hyphal-tip culture combined with high-temperature treatment to eliminate FoAV1-FOM from strain T-BJ17. The colony growth rate, ability to produce spores, and virulence of strain T-BJ17 were significantly lower than those of T-BJ17-VF, while the dry weight of the mycelial biomass and the sensitivity to difenoconazole and pydiflumetofen of strain T-BJ17 were greater than those of T-BJ17-VF. FoAV1-FOM was capable of 100% vertical transmission via spores. To our knowledge, this is the first time that an alternavirus has infected FOM, and this is the first report of hypovirulence and increased sensitivity to difenoconazole and pydiflumetofen induced by FoAV1-FOM infection in FOM.
Collapse
Affiliation(s)
| | | | | | - Xuehong Wu
- College of Plant Protection, China Agricultural University, Haidian District, Beijing 100193, China (X.Z.); (L.L.)
| |
Collapse
|
4
|
Xu X, Li J, Hai D, Wang Y, Li J, Zha Y. Complete genome sequence of a novel alternavirus isolated from the phytopathogenic fungus Colletotrichum fioriniae. Arch Virol 2024; 169:79. [PMID: 38519762 DOI: 10.1007/s00705-024-06010-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 02/04/2024] [Indexed: 03/25/2024]
Abstract
A novel double-strand RNA (dsRNA) mycovirus, named "Colletotrichum fioriniae alternavirus1" (CfAV1), was isolated from the strain CX7 of Colletotrichum fioriniae, the causal agent of walnut anthracnose. The complete genome of CfAV1 is composed of three dsRNA segments: dsRNA1 (3528 bp), dsRNA2 (2485 bp), and dsRNA3 (2481 bp). The RNA-dependent RNA polymerase (RdRp) is encoded by dsRNA1, while both dsRNA2 and dsRNA3 encode hypothetical proteins. Based on multiple sequence alignments and phylogenetic analysis, CfAV1 is identified as a new member of the family Alternaviridae. This is the first report of an alternavirus that infects the phytopathogenic fungus C. fioriniae.
Collapse
Affiliation(s)
- Xiaowen Xu
- Hubei Academy of Forestry, Wuhan, 430074, Hubei Province, People's Republic of China.
| | - Jincang Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, People's Republic of China
| | - Du Hai
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei Province, People's Republic of China
| | - Yixun Wang
- Hubei Academy of Forestry, Wuhan, 430074, Hubei Province, People's Republic of China
| | - Jinying Li
- Hubei Academy of Forestry, Wuhan, 430074, Hubei Province, People's Republic of China
| | - Yuping Zha
- Hubei Academy of Forestry, Wuhan, 430074, Hubei Province, People's Republic of China.
| |
Collapse
|
5
|
Jiang Y, Liu X, Tian X, Zhou J, Wang Q, Wang B, Yu W, Jiang Y, Hsiang T, Qi X. RNA interference of Aspergillus flavus in response to Aspergillus flavus partitivirus 1 infection. Front Microbiol 2023; 14:1252294. [PMID: 38033556 PMCID: PMC10682719 DOI: 10.3389/fmicb.2023.1252294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/19/2023] [Indexed: 12/02/2023] Open
Abstract
RNA interference (RNAi) is one of the important defense responses against viral infection, but its mechanism and impact remain unclear in mycovirus infections. In our study, reverse genetics and virus-derived small RNA sequencing were used to show the antiviral responses of RNAi components in Aspergillus flavus infected with Aspergillus flavus partitivirus 1 (AfPV1). qRT-PCR revealed that AfPV1 infection induced the expression of the RNAi components in A. flavus compared with noninfected A. flavus. Knock mutants of each RNAi component were generated, but the mutants did not exhibit any obvious phenotypic changes compared with the A. flavus parental strain. However, after AfPV1 inoculation, production of AfPV1 was significantly less than in the parental strain. Furthermore, sporulation was greater in each AfPV1-infected mutant compared with the AfPV1-infected parental A. flavus. We also investigated the sensitivity of virus-free and AfPV1-infected RNAi mutants and the parental strain to cell wall stress, osmotic stress, genotoxic stress, and oxidative stress. The mutants of DCLs and AGOs infected by AfPV1 displayed more changes than RDRP mutants in response to the first three stresses. Small RNA sequencing analysis suggested that AfPV1 infection reduced the number of unique reads of sRNA in A. flavus, although there were many vsiRNA derived from the AfPV1 genome. GO term and KEGG pathway analyses revealed that the functions of sRNA affected by AfPV1 infection were closely related to vacuole production. These results provide a better understanding of the functional role of RNAi in the impact of AfPV1 on the hypovirulence of A. flavus.
Collapse
Affiliation(s)
- Yinhui Jiang
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Xiang Liu
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Xun Tian
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Jianhong Zhou
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Qinrong Wang
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Bi Wang
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Wenfeng Yu
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| | - Yanping Jiang
- Department of Dermatology, The Affiliated Hospital, Guizhou Medical University, Guiyang, China
| | - Tom Hsiang
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
| | - Xiaolan Qi
- Key Laboratory of Endemic and Ethnic Diseases, Ministry of Education, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Molecular Biology of Guizhou Province, Guizhou Medical University, Guiyang, China
| |
Collapse
|
6
|
Andika IB, Tian M, Bian R, Cao X, Luo M, Kondo H, Sun L. Cross-Kingdom Interactions Between Plant and Fungal Viruses. Annu Rev Virol 2023; 10:119-138. [PMID: 37406341 DOI: 10.1146/annurev-virology-111821-122539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The large genetic and structural divergences between plants and fungi may hinder the transmission of viruses between these two kingdoms to some extent. However, recent accumulating evidence from virus phylogenetic analyses and the discovery of naturally occurring virus cross-infection suggest the occurrence of past and current transmissions of viruses between plants and plant-associated fungi. Moreover, artificial virus inoculation experiments showed that diverse plant viruses can multiply in fungi and vice versa. Thus, virus cross-infection between plants and fungi may play an important role in the spread, emergence, and evolution of both plant and fungal viruses and facilitate the interaction between them. In this review, we summarize current knowledge related to cross-kingdom virus infection in plants and fungi and further discuss the relevance of this new virological topic in the context of understanding virus spread and transmission in nature as well as developing control strategies for crop plant diseases.
Collapse
Affiliation(s)
- Ida Bagus Andika
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China;
| | - Mengyuan Tian
- 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;
| | - Xinran Cao
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China;
| | - Ming Luo
- College of Agronomy, Xinjiang Agricultural University, Urumqi, China
| | - 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;
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan;
| |
Collapse
|
7
|
Kelani AA, Bruch A, Rivieccio F, Visser C, Krüger T, Weaver D, Pan X, Schäuble S, Panagiotou G, Kniemeyer O, Bromley MJ, Bowyer P, Barber AE, Brakhage AA, Blango MG. Disruption of the Aspergillus fumigatus RNA interference machinery alters the conidial transcriptome. RNA (NEW YORK, N.Y.) 2023; 29:1033-1050. [PMID: 37019633 PMCID: PMC10275271 DOI: 10.1261/rna.079350.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 03/23/2023] [Indexed: 06/18/2023]
Abstract
The RNA interference (RNAi) pathway has evolved numerous functionalities in eukaryotes, with many on display in Kingdom Fungi. RNAi can regulate gene expression, facilitate drug resistance, or even be altogether lost to improve growth potential in some fungal pathogens. In the WHO fungal priority pathogen, Aspergillus fumigatus, the RNAi system is known to be intact and functional. To extend our limited understanding of A. fumigatus RNAi, we first investigated the genetic variation in RNAi-associated genes in a collection of 217 environmental and 83 clinical genomes, where we found that RNAi components are conserved even in clinical strains. Using endogenously expressed inverted-repeat transgenes complementary to a conditionally essential gene (pabA) or a nonessential gene (pksP), we determined that a subset of the RNAi componentry is active in inverted-repeat transgene silencing in conidia and mycelium. Analysis of mRNA-seq data from RNAi double-knockout strains linked the A. fumigatus dicer-like enzymes (DclA/B) and RNA-dependent RNA polymerases (RrpA/B) to regulation of conidial ribosome biogenesis genes; however, surprisingly few endogenous small RNAs were identified in conidia that could explain this broad change. Although RNAi was not clearly linked to growth or stress response defects in the RNAi knockouts, serial passaging of RNAi knockout strains for six generations resulted in lineages with diminished spore production over time, indicating that loss of RNAi can exert a fitness cost on the fungus. Cumulatively, A. fumigatus RNAi appears to play an active role in defense against double-stranded RNA species alongside a previously unappreciated housekeeping function in regulation of conidial ribosomal biogenesis genes.
Collapse
Affiliation(s)
- Abdulrahman A Kelani
- Junior Research Group RNA Biology of Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Alexander Bruch
- Junior Research Group RNA Biology of Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Flora Rivieccio
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
- Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Corissa Visser
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
- Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Thomas Krüger
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Danielle Weaver
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, United Kingdom
| | - Xiaoqing Pan
- Junior Research Group RNA Biology of Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Sascha Schäuble
- Department of Microbiome Dynamics, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Gianni Panagiotou
- Department of Microbiome Dynamics, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
- Department of Medicine and State Key Laboratory of Pharmaceutical Biotechnology, University of Hong Kong, Hong Kong, China
| | - Olaf Kniemeyer
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| | - Michael J Bromley
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, United Kingdom
| | - Paul Bowyer
- Manchester Fungal Infection Group, Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, United Kingdom
| | - Amelia E Barber
- Junior Research Group Fungal Informatics, Friedrich Schiller University, 07745 Jena, Germany
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
- Department of Microbiology and Molecular Biology, Institute of Microbiology, Friedrich Schiller University, 07743 Jena, Germany
| | - Matthew G Blango
- Junior Research Group RNA Biology of Fungal Infections, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (Leibniz-HKI), 07745 Jena, Germany
| |
Collapse
|
8
|
Pielhop TP, Popp C, Fricke S, Knierim D, Margaria P, Maiß E. Molecular characterization of two new alternaviruses identified in members of the fungal family Nectriaceae. Arch Microbiol 2023; 205:129. [PMID: 36947239 PMCID: PMC10033562 DOI: 10.1007/s00203-023-03477-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/23/2023]
Abstract
Since the first report in 2009, at least ten additional viruses have been identified and assigned to the proposed virus family Alternaviridae. Here we report two new mycoviruses tentatively assigned to this family, both identified as members of the fungal family Nectriaceae, which were isolated from surface-disinfected apple roots (Malus x domestica, Borkh.) affected by apple replant disease (ARD). ARD is a highly complex, worldwide-occurring disease resulting from plant reactions to a disturbed (micro)-biome and leads to high economic losses every year. The first alternavirus characterized in this study was identified in a Dactylonectria torresensis isolate. The virus was tentatively named dactylonectria torresensis alternavirus 1 (DtAV1) as the first member of the proposed new species Alternavirus dactylonectriae. The second virus was identified in an isolate of Ilyonectria robusta and was tentatively named ilyonectria robusta alternavirus 1 (IrAV1) as the first member of the proposed new species Alternavirus ilyonectriae. Full genomic sequences of the viruses were determined and are presented. Further, we found hints for putative components of a methyl transferase machinery using in silico approaches. This putative protein domain is encoded by segment 2. However, this result only establishes the basis for subsequent studies in which the function must be confirmed experimentally in vitro. Thus, this is the first study where a function is predicted to all three genomic segments within the group of the alternaviruses. These findings provide further insights into the virome of ARD-associated fungi and are therefore another brick in the wall of understanding the complexity of the disease.
Collapse
Affiliation(s)
- Tom P Pielhop
- Institute of Horticultural Production Systems, Department Phytomedicine, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany.
| | - Carolin Popp
- Institute of Horticultural Production Systems, Department Phytomedicine, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Sebastian Fricke
- Institute of Horticultural Production Systems, Department Phytomedicine, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| | - Dennis Knierim
- Leibniz Institute DSMZ, German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7 B, 38124, Braunschweig, Germany
| | - Paolo Margaria
- Leibniz Institute DSMZ, German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7 B, 38124, Braunschweig, Germany
| | - Edgar Maiß
- Institute of Horticultural Production Systems, Department Phytomedicine, Leibniz University Hannover, Herrenhäuser Str. 2, 30419, Hannover, Germany
| |
Collapse
|
9
|
Wingfield LK, Jitprasitporn N, Che-alee N. Isolation and characterization of halophilic and halotolerant fungi from man-made solar salterns in Pattani Province, Thailand. PLoS One 2023; 18:e0281623. [PMID: 36780513 PMCID: PMC9925087 DOI: 10.1371/journal.pone.0281623] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 01/27/2023] [Indexed: 02/15/2023] Open
Abstract
The present study explored culturable halophilic and halotolerant fungi from man-made solar salterns in Pattani Province, Thailand. A total of 24 fungal isolates were discovered and characterized using morphological and molecular identification. Production of extracellular enzymes, secondary metabolites and mycoviruses was examined. Growth was observed in salinity and temperature ranges between 0%-20% and 28-40°C, respectively. Growth in different environmental conditions confirmed the halophilic or halotolerant nature of some strains. Fungal isolates were phylogenetically classified into seven different genera belonging to Aspergillus, Cladosporium, Curvularia, Diaporthe, Ectophoma, Fusarium and Penicillium. An enzymatic production test revealed that thirteen isolates could produce proteases and amylases at different levels. The presence of mycoviruses was detected in three isolates. Seventeen of the 24 isolates produced antimicrobial metabolites. The majority of these active isolates were identified as Aspergillus and Penicillium species. Crude extracts of the fungal mycelia and culture broths from these isolates had an inhibitory effect on both Gram-positive and Gram-negative bacteria and human pathogenic fungi. Research into fungi from saline environments could reveal fungal strains of biotechnological and industrial interest.
Collapse
Affiliation(s)
- Lakkhana Kanhayuwa Wingfield
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
- * E-mail:
| | - Ninadia Jitprasitporn
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Nureeda Che-alee
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| |
Collapse
|
10
|
Zhang X, Wu C, Hua H, Cai Q, Wu X. Characterization of the First Alternavirus Identified in Fusarium avenaceum, the Causal Agent of Potato Dry Rot. Viruses 2023; 15:145. [PMID: 36680185 PMCID: PMC9864086 DOI: 10.3390/v15010145] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/03/2023] Open
Abstract
A novel virus with a double-stranded RNA (dsRNA) genome was isolated from Fusarium avenaceum strain GS-WW-224, the causal agent of potato dry rot. The virus has been designated as Fusarium avenaceum alternavirus 1 (FaAV1). Its genome consists of two dsRNA segments, 3538 bp (dsRNA1) and 2477 bp (dsRNA2) in length, encoding RNA-dependent RNA polymerase (RdRp) and a hypothetical protein (HP), respectively. The virions of FaAV1 are isometric spherical and approximately 30 nm in diameter. Multiple sequence alignments and phylogenetic analyses based on the amino acid sequences of RdRp and HP indicated that FaAV1 appears to be a new member of the proposed family Alternaviridae. No significant differences in colony morphology and spore production were observed between strains GS-WW-224 and GS-WW-224-VF, the latter strain being one in which FaAV1 was eliminated from strain GS-WW-224. Notably, however, the dry weight of mycelial biomass of GS-WW-224 was higher than that of mycelial biomass of GS-WW-224-VF. The depth and the width of lesions on potato tubers caused by GS-WW-224 were significantly greater, relative to GS-WW-224-VF, suggesting that FaAV1 confers hypervirulence to its host, F. avenaceum. Moreover, FaAV1 was successfully transmitted horizontally from GS-WW-224 to ten other species of Fusarium, and purified virions of FaAV1 were capable of transfecting wounded hyphae of the ten species of Fusarium. This is the first report of an alternavirus infecting F. avenaceum and conferring hypervirulence.
Collapse
Affiliation(s)
| | | | | | | | - Xuehong Wu
- College of Plant Protection, China Agricultural University, Haidian District, Beijing 100193, China
| |
Collapse
|
11
|
Lutz T, Langer G, Heinze C. Complete genome sequence of a novel alternavirus infecting the fungus Ilyonectria crassa. Arch Virol 2023; 168:34. [PMID: 36609790 PMCID: PMC9825354 DOI: 10.1007/s00705-022-05652-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/30/2022] [Indexed: 01/09/2023]
Abstract
A novel dsRNA mycovirus named Ilyonectria crassa alternavirus 1 (IcAV1) was found in Ilyonectria crassa isolate NW-FVA 1829. The fungus was isolated from an ash (Fraxinus excelsior L.) necrotic trunk disc infected with Hymenoscyphus fraxineus [(T. Kowalski) Baral, Queloz, Hosoya] causing ash dieback. The complete genome of IcAV1 is composed of three segments, each containing a single ORF on the positive-sense RNA. The extreme 5' UTRs of dsRNA 1 (3604 bp), dsRNA 2 (2547 bp), and dsRNA 3 (2518 bp) share a conserved hexadecamer sequence (5'-GGCTGTGTGTTTAGTT-3') and are capped. The 3' UTRs are polyadenylated. In silico analysis showed that the viral RdRP is encoded on dsRNA 1 and the capsid-protein subunits are encoded on dsRNA 3. Maximum-likelihood analysis of the aa sequence of the viral RdRP showed that IcAV1 clusters with alternaviruses from Fusarium spp., while the type member of the proposed family "Alternaviridae", Alternaria alternata virus 1 (AaV1), formed a clade together with Stemphylium lycopersici mycovirus (SlV). The function of the protein encoded on segment 2 is unknown. Based on its genome organization and its phylogenetic position, IcAV1 is suggested to be a new member of the proposed family "Alternaviridae". This is the first report of a mycovirus infecting I. crassa.
Collapse
Affiliation(s)
- Tobias Lutz
- Institute of Plant Science and Microbiology, Molecular Phytopathology, University of Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany
| | - Gitta Langer
- Nordwestdeutsche Forstliche Versuchsanstalt, Grätzelstr. 2, 37079, Göttingen, Germany
| | - Cornelia Heinze
- Institute of Plant Science and Microbiology, Molecular Phytopathology, University of Hamburg, Ohnhorststr. 18, 22609, Hamburg, Germany.
| |
Collapse
|
12
|
Ahmad MM, Qamar F, Saifi M, Abdin MZ. Natural inhibitors: A sustainable way to combat aflatoxins. Front Microbiol 2022; 13:993834. [PMID: 36569081 PMCID: PMC9773886 DOI: 10.3389/fmicb.2022.993834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/31/2022] [Indexed: 12/13/2022] Open
Abstract
Among a few hundred mycotoxins, aflatoxins had always posed a major threat to the world. Apart from A. flavus, A. parasiticus, and A. nomius of Aspergillus genus, which are most toxin-producing strains, several fungal bodies including Fusarium, Penicillium, and Alternaria that can biosynthesis aflatoxins. Basically, there are four different types of aflatoxins (Aflatoxin B1 (AFB1), Aflatoxin B2 (AFB2), Aflatoxin G1 (AFG1), Aflatoxin G2 (AFG2)) are produced as secondary metabolites. There are certainly other types of aflatoxins found but they are the by-products of these toxins. The fungal agents generally infect the food crops during harvesting, storing, and/or transporting; making a heavy post-harvest as well as economic loss in both developed and developing countries. And while ingesting the crop products, these toxins get into the dietary system causing aflatoxicosis, liver cirrhosis, etc. Therefore, it is imperative to search for certain ways to control the spread of infections and/or production of these toxins which may also not harm the crop harvest. In this review, we are going to discuss some sustainable methods that can effectively control the spread of infection and inhibit the biosynthesis of aflatoxins.
Collapse
Affiliation(s)
- Malik M. Ahmad
- Department of Agriculture, Integral Institute of Agricultural Science and Technology (IIAST), Integral University, Lucknow, India
| | - Firdaus Qamar
- CTPD, Department of Biotechnology, School of Chemical and Life Sciences, New Delhi, India
| | - Monica Saifi
- CTPD, Department of Biotechnology, School of Chemical and Life Sciences, New Delhi, India
| | - Malik Zainul Abdin
- CTPD, Department of Biotechnology, School of Chemical and Life Sciences, New Delhi, India,*Correspondence: Malik Zainul Abdin,
| |
Collapse
|
13
|
Similar Characteristics of siRNAs of Plant Viruses Which Replicate in Plant and Fungal Hosts. BIOLOGY 2022; 11:biology11111672. [PMID: 36421386 PMCID: PMC9687825 DOI: 10.3390/biology11111672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022]
Abstract
Simple Summary RNA silencing in fungi was shown to confer antiviral defense against plant viruses. In this study, using high-throughput sequencing and bioinformatic analyses, we showed that small interfering RNAs (siRNAs) of cucumber mosaic virus and tobacco mosaic virus (TMV) which replicated in phytopathogenic fungi Rhizoctonia solani and Fusarium graminearum had similarities with viral siRNAs produced in plant hosts in regard to the size distributions, proportion of plus and minus senses, and nucleotide preference for the 5′ termini. Additionally, our results also determined that both F. graminearum DCL1 and DCL2 were involved in the production of TMV siRNAs. Thus, the fungal RNA silencing machineries have adaptive capabilities to recognize and process the genome of invading plant viruses. Abstract RNA silencing is a host innate antiviral mechanism which acts via the synthesis of viral-derived small interfering RNAs (vsiRNAs). We have previously reported the infection of phytopathogenic fungi by plant viruses such as cucumber mosaic virus (CMV) and tobacco mosaic virus (TMV). Furthermore, fungal RNA silencing was shown to suppress plant virus accumulation, but the characteristics of plant vsiRNAs associated with the antiviral response in this nonconventional host remain unknown. Using high-throughput sequencing, we characterized vsiRNA profiles in two plant RNA virus–fungal host pathosystems: CMV infection in phytopathogenic fungus Rhizoctonia solani and TMV infection in phytopathogenic fungus Fusarium graminearum. The relative abundances of CMV and TMV siRNAs in the respective fungal hosts were much lower than those in the respective experimental plant hosts, Nicotiana benthamiana and Nicotiana tabacum. However, CMV and TMV siRNAs in fungi had similar characteristics to those in plants, particularly in their size distributions, proportion of plus and minus senses, and nucleotide preference for the 5′ termini of vsiRNAs. The abundance of TMV siRNAs largely decreased in F. graminearum mutants with a deletion in either dicer-like 1 (dcl1) or dcl2 genes which encode key proteins for the production of siRNAs and antiviral responses. However, deletion of both dcl1 and dcl2 restored TMV siRNA accumulation in F. graminearum, indicating the production of dcl-independent siRNAs with no antiviral function in the absence of the dcl1 and dcl2 genes. Our results suggest that fungal RNA silencing recognizes and processes the invading plant RNA virus genome in a similar way as in plants.
Collapse
|
14
|
Rodriguez Coy L, Plummer KM, Khalifa ME, MacDiarmid RM. Mycovirus-encoded suppressors of RNA silencing: Possible allies or enemies in the use of RNAi to control fungal disease in crops. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:965781. [PMID: 37746227 PMCID: PMC10512228 DOI: 10.3389/ffunb.2022.965781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 09/21/2022] [Indexed: 09/26/2023]
Abstract
Plants, fungi, and many other eukaryotes have evolved an RNA interference (RNAi) mechanism that is key for regulating gene expression and the control of pathogens. RNAi inhibits gene expression, in a sequence-specific manner, by recognizing and deploying cognate double-stranded RNA (dsRNA) either from endogenous sources (e.g. pre-micro RNAs) or exogenous origin (e.g. viruses, dsRNA, or small interfering RNAs, siRNAs). Recent studies have demonstrated that fungal pathogens can transfer siRNAs into plant cells to suppress host immunity and aid infection, in a mechanism termed cross-kingdom RNAi. New technologies, based on RNAi are being developed for crop protection against insect pests, viruses, and more recently against fungal pathogens. One example, is host-induced gene silencing (HIGS), which is a mechanism whereby transgenic plants are modified to produce siRNAs or dsRNAs targeting key transcripts of plants, or their pathogens or pests. An alternative gene regulation strategy that also co-opts the silencing machinery is spray-induced gene silencing (SIGS), in which dsRNAs or single-stranded RNAs (ssRNAs) are applied to target genes within a pathogen or pest. Fungi also use their RNA silencing machinery against mycoviruses (fungal viruses) and mycoviruses can deploy virus-encoded suppressors of RNAi (myco-VSRs) as a counter-defence. We propose that myco-VSRs may impact new dsRNA-based management methods, resulting in unintended outcomes, including suppression of management by HIGS or SIGS. Despite a large diversity of mycoviruses being discovered using high throughput sequencing, their biology is poorly understood. In particular, the prevalence of mycoviruses and the cellular effect of their encoded VSRs are under-appreciated when considering the deployment of HIGS and SIGS strategies. This review focuses on mycoviruses, their VSR activities in fungi, and the implications for control of pathogenic fungi using RNAi.
Collapse
Affiliation(s)
- Lorena Rodriguez Coy
- Australian Research Council Research Hub for Sustainable Crop Protection, Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Kim M. Plummer
- Australian Research Council Research Hub for Sustainable Crop Protection, Department of Animal, Plant and Soil Sciences, La Trobe University, Bundoora, VIC, Australia
| | - Mahmoud E. Khalifa
- Botany and Microbiology Department, Faculty of Science, Damietta University, Damietta, Egypt
| | - Robin M. MacDiarmid
- BioProtection, The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
15
|
Schalamun M, Schmoll M. Trichoderma - genomes and genomics as treasure troves for research towards biology, biotechnology and agriculture. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:1002161. [PMID: 37746224 PMCID: PMC10512326 DOI: 10.3389/ffunb.2022.1002161] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 08/25/2022] [Indexed: 09/26/2023]
Abstract
The genus Trichoderma is among the best studied groups of filamentous fungi, largely because of its high relevance in applications from agriculture to enzyme biosynthesis to biofuel production. However, the physiological competences of these fungi, that led to these beneficial applications are intriguing also from a scientific and ecological point of view. This review therefore summarizes recent developments in studies of fungal genomes, updates on previously started genome annotation efforts and novel discoveries as well as efforts towards bioprospecting for enzymes and bioactive compounds such as cellulases, enzymes degrading xenobiotics and metabolites with potential pharmaceutical value. Thereby insights are provided into genomes, mitochondrial genomes and genomes of mycoviruses of Trichoderma strains relevant for enzyme production, biocontrol and mycoremediation. In several cases, production of bioactive compounds could be associated with responsible genes or clusters and bioremediation capabilities could be supported or predicted using genome information. Insights into evolution of the genus Trichoderma revealed large scale horizontal gene transfer, predominantly of CAZyme genes, but also secondary metabolite clusters. Investigation of sexual development showed that Trichoderma species are competent of repeat induced point mutation (RIP) and in some cases, segmental aneuploidy was observed. Some random mutants finally gave away their crucial mutations like T. reesei QM9978 and QM9136 and the fertility defect of QM6a was traced back to its gene defect. The Trichoderma core genome was narrowed down to 7000 genes and gene clustering was investigated in the genomes of multiple species. Finally, recent developments in application of CRISPR/Cas9 in Trichoderma, cloning and expression strategies for the workhorse T. reesei as well as the use genome mining tools for bioprospecting Trichoderma are highlighted. The intriguing new findings on evolution, genomics and physiology highlight emerging trends and illustrate worthwhile perspectives in diverse fields of research with Trichoderma.
Collapse
Affiliation(s)
- Miriam Schalamun
- Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
| | - Monika Schmoll
- Department of Microbiology and Ecosystem Science, Division of Terrestrial Ecosystem Research, University of Vienna, Vienna, Austria
| |
Collapse
|
16
|
Characterization of a novel alternavirus infecting the fungal pathogen Fusarium solani. Virus Res 2022; 317:198817. [DOI: 10.1016/j.virusres.2022.198817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/13/2022] [Accepted: 05/18/2022] [Indexed: 11/20/2022]
|
17
|
Shimura H, Kim H, Matsuzawa A, Akino S, Masuta C. Coat protein of partitiviruses isolated from mycorrhizal fungi functions as an RNA silencing suppressor in plants and fungi. Sci Rep 2022; 12:7855. [PMID: 35551196 PMCID: PMC9098641 DOI: 10.1038/s41598-022-11403-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 04/19/2022] [Indexed: 12/11/2022] Open
Abstract
Orchid seeds depend on colonization by orchid mycorrhizal (OM) fungi for their germination; therefore, the orchids and OM fungi have long maintained a close relationship (e.g., formation of the hyphal mass structure, peloton) during their evolution. In the present study, we isolated new partitiviruses from OM fungi; partitivirus were separately found in different subcultures from the same fungi. Partitiviruses have been believed to lack an RNA silencing suppressor (RSS), which is generally associated with viral pathogenicity, because most partitiviruses isolated so far are latent in both plants and fungi. However, we found that the coat protein (CP) of our partitiviruses indeed had RSS activity, which differed among the virus isolates from OM fungi; one CP showed RSS activity in both plants and fungi, while another CP showed no activity. The family Partitiviridae include viruses isolated from plants and fungi, and it has been suggested that these viruses may occasionally be transmitted between plant and fungal hosts. Given that there are several reports showing that viruses can adapt to nonhost using strong RSS, we here discussed the idea that partitiviruses may be better able to migrate between the orchid and fungus probably through the pelotons formed in the orchid cells, if host RNA silencing is suppressed by partitivirus RSS.
Collapse
Affiliation(s)
- Hanako Shimura
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan.
| | - Hangil Kim
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan
| | - Akihiko Matsuzawa
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan
| | - Seishi Akino
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan
| | - Chikara Masuta
- Research Faculty of Agriculture, Hokkaido University, Kita-ku, Kita 9, Nishi 9, Sapporo, 060-8589, Japan.
| |
Collapse
|
18
|
Zhang Y, Shi N, Wang P, Zhu Q, Yang G, Huang B. Molecular characterization of a novel alternavirus infecting the entomopathogenic fungus Cordyceps chanhua. Arch Virol 2022; 167:1467-1470. [PMID: 35412147 DOI: 10.1007/s00705-022-05446-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/08/2022] [Indexed: 11/24/2022]
Abstract
In this study, a novel double-stranded (ds) RNA mycovirus, named Cordyceps chanhua alternavirus 1 (CcAV1), was detected in the entomogenous fungus Cordyceps chanhua in China and characterized. The complete genome of CcAV1 is composed of three dsRNA segments: dsRNA 1 (3,512 bp), dsRNA 2 (2,655 bp), and dsRNA 3 (2,415 bp). Each of the three dsRNAs possesses a single open reading frame (ORF). dsRNA 1 encodes a putative RNA-dependent RNA polymerase (RdRp), and dsRNA 2 and dsRNA 3 encode hypothetical protein 1 (HP 1) and hypothetical protein 2 (HP 2), respectively. The predicted amino acid sequences of the putative RdRp, HP 1, and HP 2 had the highest identity of 66.99%, 49.30%, and 56.91%, respectively, to those of Aspergillus foetidus dsRNA mycovirus. A maximum-likelihood phylogenetic tree based on RdRp amino acid sequences showed that CcAV1 clustered with members of the proposed family "Alternaviridae". Hence, we propose that Cordyceps chanhua alternavirus 1 is a novel member of the proposed family "Alternaviridae".
Collapse
Affiliation(s)
- Yuxiang Zhang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Najie Shi
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Ping Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Qiuyan Zhu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China
| | - Guogen Yang
- School of Plant Protection, Anhui Agricultural University, Hefei, 230036, China
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, 230036, China.
| |
Collapse
|
19
|
Lee MD, Creagh JW, Fredericks LR, Crabtree AM, Patel JS, Rowley PA. The Characterization of a Novel Virus Discovered in the Yeast Pichia membranifaciens. Viruses 2022; 14:v14030594. [PMID: 35337001 PMCID: PMC8951182 DOI: 10.3390/v14030594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/24/2022] [Accepted: 02/26/2022] [Indexed: 02/05/2023] Open
Abstract
Mycoviruses are widely distributed across fungi, including the yeasts of the Saccharomycotina subphylum. This manuscript reports the first double-stranded RNA (dsRNA) virus isolated from Pichia membranifaciens. This novel virus has been named Pichia membranifaciens virus L-A (PmV-L-A) and is a member of the Totiviridae. PmV-L-A is 4579 bp in length, with RNA secondary structures similar to the packaging, replication, and frameshift signals of totiviruses that infect Saccharomycotina yeasts. PmV-L-A was found to be part of a monophyletic group within the I-A totiviruses, implying a shared ancestry between mycoviruses isolated from the Pichiaceae and Saccharomycetaceae yeasts. Energy-minimized AlphaFold2 molecular models of the PmV-L-A Gag protein revealed structural conservation with the Gag protein of Saccharomyces cerevisiae virus L-A (ScV-L-A). The predicted tertiary structure of the PmV-L-A Pol and other homologs provided a possible mechanism for totivirus RNA replication due to structural similarities with the RNA-dependent RNA polymerases of mammalian dsRNA viruses. Insights into the structure, function, and evolution of totiviruses gained from yeasts are essential because of their emerging role in animal disease and their parallels with mammalian viruses.
Collapse
Affiliation(s)
- Mark D. Lee
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (M.D.L.); (J.W.C.); (L.R.F.); (A.M.C.); (J.S.P.)
| | - Jack W. Creagh
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (M.D.L.); (J.W.C.); (L.R.F.); (A.M.C.); (J.S.P.)
| | - Lance R. Fredericks
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (M.D.L.); (J.W.C.); (L.R.F.); (A.M.C.); (J.S.P.)
| | - Angela M. Crabtree
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (M.D.L.); (J.W.C.); (L.R.F.); (A.M.C.); (J.S.P.)
| | - Jagdish Suresh Patel
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (M.D.L.); (J.W.C.); (L.R.F.); (A.M.C.); (J.S.P.)
- Center for Modeling Complex Interactions, University of Idaho, Moscow, ID 83844, USA
| | - Paul A. Rowley
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA; (M.D.L.); (J.W.C.); (L.R.F.); (A.M.C.); (J.S.P.)
- Correspondence:
| |
Collapse
|
20
|
Non-detection of mycoviruses in amphibian chytrid fungus (Batrachochytrium dendrobatidis) from Australia. Fungal Biol 2021; 126:75-81. [PMID: 34930560 DOI: 10.1016/j.funbio.2021.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 10/18/2021] [Accepted: 10/25/2021] [Indexed: 11/04/2022]
Abstract
Mycoviruses may influence the pathogenicity of disease-causing fungi. Although mycoviruses have been found in some chytrid fungi, limited testing has not detected them in Batrachochytrium dendrobatidis (Bd), the cause of the devastating amphibian disease, chytridiomycosis. Here we conducted a survey for mycovirus presence in 38 Bd isolates from Australia (n = 31), Brazil (n = 5) and South Korea (n = 2) with a combination of modern high-throughput sequencing and conventional dsRNA cellulose chromatography. Mycoviruses were not detected in any isolates. This result was unexpected, given the long evolutionary history of Bd, as well as the high prevalence of mycoviruses in related fungal species. Given our widespread sampling in Australia and the limited number of Bd introductions, we suggest that mycoviruses are uncommon or absent from Australian Bd. Testing more isolates from regions where Bd originated, as well as regions with high diversity or low fungal virulence may identify mycoviruses that could aid in disease control.
Collapse
|
21
|
Wu CF, Aoki N, Takeshita N, Fukuhara T, Chiura HX, Arie T, Kotta-Loizou I, Okada R, Komatsu K, Moriyama H. Unique Terminal Regions and Specific Deletions of the Segmented Double-Stranded RNA Genome of Alternaria Alternata Virus 1, in the Proposed Family Alternaviridae. Front Microbiol 2021; 12:773062. [PMID: 34745080 PMCID: PMC8570381 DOI: 10.3389/fmicb.2021.773062] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
Alternaria alternata virus 1 (AaV1) has been identified in the saprophytic fungus Alternaria alternata strain EGS 35-193. AaV1 has four genomic double-stranded (ds)RNA segments (dsRNA1-4) packaged in isometric particles. The 3' end of each coding strand is polyadenylated (36-50nt), but the presence of a cap structure at each 5' end has not previously been investigated. Here, we have characterized the AaV1 genome and found that it has unique features among the mycoviruses. We confirmed the existence of cap structures on the 5' ends of the AaV1 genomic dsRNAs using RNA dot blots with anti-cap antibodies and the oligo-capping method. Polyclonal antibodies against purified AaV1 particles specifically bound to an 82kDa protein, suggesting that this protein is the major capsid component. Subsequent Edman degradation indicated that the AaV1 dsRNA3 segment encodes the major coat protein. Two kinds of defective AaV1 dsRNA2, which is 2,794bp (844 aa) in length when intact, appeared in EGS 35-193 during subculturing, as confirmed by RT-PCR and northern hybridization. Sequence analysis revealed that one of the two defective dsRNA2s contained a 231bp deletion, while the other carried both the 231bp deletion and an additional 465bp deletion in the open reading frame. Both deletions occurred in-frame, resulting in predicted proteins of 767 aa and 612 aa. The fungal isolates carrying virions with the defective dsRNA2s showed impaired growth and abnormal pigmentation. To our best knowledge, AaV1 is the first dsRNA virus to be identified with both 5' cap and 3'poly(A) structures on its genomic segments, as well as the specific deletions of dsRNA2.
Collapse
Affiliation(s)
- Chien-Fu Wu
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Nanako Aoki
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Naoki Takeshita
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Toshiyuki Fukuhara
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Hiroshi X Chiura
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Tsutomu Arie
- Laboratory of Plant Pathology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, United Kingdom
| | - Ryo Okada
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Ken Komatsu
- Laboratory of Plant Pathology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Hiromitsu Moriyama
- Laboratory of Molecular and Cellular Biology, Tokyo University of Agriculture and Technology, Fuchu, Japan
| |
Collapse
|
22
|
Molecular Characterization of the First Alternavirus Identified in Fusarium oxysporum. Viruses 2021; 13:v13102026. [PMID: 34696456 PMCID: PMC8538667 DOI: 10.3390/v13102026] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 01/25/2023] Open
Abstract
A novel mycovirus named Fusarium oxysporum alternavirus 1(FoAV1) was identified as infecting Fusarium oxysporum strain BH19, which was isolated from a fusarium wilt diseased stem of Lilium brownii. The genome of FoAV1 contains four double-stranded RNA (dsRNA) segments (dsRNA1, dsRNA 2, dsRNA 3 and dsRNA 4, with lengths of 3.3, 2.6, 2.3 and 1.8 kbp, respectively). Additionally, dsRNA1 encodes RNA-dependent RNA polymerase (RdRp), and dsRNA2- dsRNA3- and dsRNA4-encoded hypothetical proteins (ORF2, ORF3 and ORF4), respectively. A homology BLAST search, along with multiple alignments based on RdRp, ORF2 and ORF3 sequences, identified FoAV1 as a novel member of the proposed family "Alternaviridae". Evolutionary relation analyses indicated that FoAV1 may be related to alternaviruses, thus dividing the family "Alternaviridae" members into four clades. In addition, we determined that dsRNA4 was dispensable for replication and may be a satellite-like RNA of FoAV1-and could perhaps play a role in the evolution of alternaviruses. Our results provided evidence for potential genera establishment within the proposed family "Alternaviridae". Additionally, FoAV1 exhibited biological control of Fusarium wilt. Our results also laid the foundations for the further study of mycoviruses within the family "Alternaviridae", and provide a potential agent for the biocontrol of diseases caused by F. oxysporum.
Collapse
|
23
|
Degola F, Spadola G, Forgia M, Turina M, Dramis L, Chitarra W, Nerva L. Aspergillus Goes Viral: Ecological Insights from the Geographical Distribution of the Mycovirome within an Aspergillus flavus Population and Its Possible Correlation with Aflatoxin Biosynthesis. J Fungi (Basel) 2021; 7:833. [PMID: 34682254 PMCID: PMC8538035 DOI: 10.3390/jof7100833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 09/14/2021] [Accepted: 10/03/2021] [Indexed: 12/13/2022] Open
Abstract
Microbial multi-level interactions are essential to control the success of spreading and survival of most microbes in natural environments. Phytopathogenic mycotoxigenic fungal species, such as Aspergillus flavus, represent an important issue in food safety. Usually, non-toxigenic strains are exploited for biocontrol strategies to mitigate infections by toxigenic strains. To comprehend all the biological variables involved in the aflatoxin biosynthesis, and to possibly evaluate the interplay between A. flavus toxigenic and non-toxigenic strains during intraspecific biocompetition, the "virological" perspective should be considered. For these reasons, investigations on mycoviruses associated to A. flavus populations inhabiting specific agroecosystems are highly desirable. Here, we provide the first accurate characterization of the novel mycovirome identified within an A. flavus wild population colonizing the maize fields of northern Italy: a selection of A. flavus strains was biologically characterized and subjected to RNAseq analysis, revealing new mycoviruses and a peculiar geographic pattern distribution in addition to a 20% rate of infection. More interestingly, a negative correlation between viral infection and aflatoxin production was found. Results significantly expanded the limited existent data about mycoviruses in wild A. flavus, opening new and intriguing hypotheses about the ecological significance of mycoviruses.
Collapse
Affiliation(s)
- Francesca Degola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy; (G.S.); (L.D.)
| | - Giorgio Spadola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy; (G.S.); (L.D.)
| | - Marco Forgia
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135 Torino, Italy; (M.F.); (M.T.); (W.C.)
| | - Massimo Turina
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135 Torino, Italy; (M.F.); (M.T.); (W.C.)
| | - Lucia Dramis
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/A, 43124 Parma, Italy; (G.S.); (L.D.)
| | - Walter Chitarra
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135 Torino, Italy; (M.F.); (M.T.); (W.C.)
- Council for Agricultural Research and Economics—Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015 Conegliano, Italy
| | - Luca Nerva
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135 Torino, Italy; (M.F.); (M.T.); (W.C.)
- Council for Agricultural Research and Economics—Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015 Conegliano, Italy
| |
Collapse
|
24
|
Transcriptional Responses of Sclerotinia sclerotiorum to the Infection by SsHADV-1. J Fungi (Basel) 2021; 7:jof7070493. [PMID: 34206246 PMCID: PMC8303302 DOI: 10.3390/jof7070493] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 12/13/2022] Open
Abstract
The infection by a single-stranded DNA virus, Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), causes hypovirulence, a reduced growth rate, and other colony morphological changes in its host Sclerotinia sclerotiorum strain DT-8. However, the mechanisms of the decline are still unclear. Using digital RNA sequencing, a transcriptome analysis was conducted to elucidate the phenotype-related genes with expression changes in response to SsHADV-1 infection. A total of 3110 S. sclerotiorum differentially expressed genes (DEGs) were detected during SsHADV-1 infection, 1741 of which were up-regulated, and 1369 were down-regulated. The identified DEGs were involved in several important pathways. DNA replication, DNA damage response, carbohydrate and lipid metabolism, ribosomal assembly, and translation were the affected categories in S. sclerotiorum upon SsHADV-1 infection. Moreover, the infection of SsHADV-1 also suppressed the expression of antiviral RNA silencing and virulence factor genes. These results provide further detailed insights into the effects of SsHADV-1 infection on the whole genome transcription in S. sclerotiorum.
Collapse
|
25
|
Kotta-Loizou I. Mycoviruses and their role in fungal pathogenesis. Curr Opin Microbiol 2021; 63:10-18. [PMID: 34102567 DOI: 10.1016/j.mib.2021.05.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/03/2021] [Accepted: 05/17/2021] [Indexed: 12/11/2022]
Abstract
Nowadays, the focus of mycovirology research has expanded from plant pathogenic fungi and mycovirus mediated hypovirulence to include insect and human pathogenic fungi together with a range of mycovirus mediated phenotypes, such as hypervirulence, control of endophytic traits, regulation of metabolite production and drug resistance. In fungus-mycovirus-environmental interactions, the environment and both abiotic and biotic factors play crucial roles in whether and how mycovirus mediated phenotypes are manifest. Mycovirus infections result in alterations in the host transcriptome profile, via protein-protein interactions and triggering of antiviral RNA silencing in the fungus. These alterations, in combination with the environmental factors, may result in desirable phenotypic traits for the host, for us and in some cases for both.
Collapse
Affiliation(s)
- Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom.
| |
Collapse
|
26
|
Residual Effects Caused by a Past Mycovirus Infection in Fusarium circinatum. FORESTS 2020. [DOI: 10.3390/f12010011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mycoviruses are known to be difficult to cure in fungi but their spontaneous loss occurs commonly. The unexpected disappearance of mycoviruses can be explained by diverse reasons, from methodological procedures to biological events such as posttranscriptional silencing machinery. The long-term effects of a virus infection on the host organism have been well studied in the case of human viruses; however, the possible residual effect on a fungus after the degradation of a mycovirus is unknown. For that, this study analyses a possible residual effect on the transcriptome of the pathogenic fungus Fusarium circinatum after the loss of the mitovirus FcMV1. The mycovirus that previously infected the fungal isolate was not recovered after a 4-year storage period. Only 14 genes were determined as differentially expressed and were related to cell cycle regulation and amino acid metabolism. The results showed a slight acceleration in the metabolism of the host that had lost the mycovirus by the upregulation of the genes involved in essential functions for fungal development. The analysis also revealed a weak expression in the annotated genes of the RNA silencing machinery. To our knowledge, this is the first time that a potential residual effect on the host transcriptome caused by the past infection of a mycovirus is reported.
Collapse
|
27
|
Lax C, Tahiri G, Patiño-Medina JA, Cánovas-Márquez JT, Pérez-Ruiz JA, Osorio-Concepción M, Navarro E, Calo S. The Evolutionary Significance of RNAi in the Fungal Kingdom. Int J Mol Sci 2020; 21:E9348. [PMID: 33302447 PMCID: PMC7763443 DOI: 10.3390/ijms21249348] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/18/2022] Open
Abstract
RNA interference (RNAi) was discovered at the end of last millennium, changing the way scientists understood regulation of gene expression. Within the following two decades, a variety of different RNAi mechanisms were found in eukaryotes, reflecting the evolutive diversity that RNAi entails. The essential silencing mechanism consists of an RNase III enzyme called Dicer that cleaves double-stranded RNA (dsRNA) generating small interfering RNAs (siRNAs), a hallmark of RNAi. These siRNAs are loaded into the RNA-induced silencing complex (RISC) triggering the cleavage of complementary messenger RNAs by the Argonaute protein, the main component of the complex. Consequently, the expression of target genes is silenced. This mechanism has been thoroughly studied in fungi due to their proximity to the animal phylum and the conservation of the RNAi mechanism from lower to higher eukaryotes. However, the role and even the presence of RNAi differ across the fungal kingdom, as it has evolved adapting to the particularities and needs of each species. Fungi have exploited RNAi to regulate a variety of cell activities as different as defense against exogenous and potentially harmful DNA, genome integrity, development, drug tolerance, or virulence. This pathway has offered versatility to fungi through evolution, favoring the enormous diversity this kingdom comprises.
Collapse
Affiliation(s)
- Carlos Lax
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Ghizlane Tahiri
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - José Alberto Patiño-Medina
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, Morelia, Michoacán CP 58030, Mexico;
| | - José T. Cánovas-Márquez
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - José A. Pérez-Ruiz
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Macario Osorio-Concepción
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Eusebio Navarro
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain; (C.L.); (G.T.); (J.T.C.-M.); (J.A.P.-R.); (M.O.-C.); (E.N.)
| | - Silvia Calo
- School of Natural and Exact Sciences, Pontificia Universidad Católica Madre y Maestra, 51033 Santiago de los Caballeros, Dominican Republic
| |
Collapse
|
28
|
A Novel Mycovirus Evokes Transcriptional Rewiring in the Fungus Malassezia and Stimulates Beta Interferon Production in Macrophages. mBio 2020; 11:mBio.01534-20. [PMID: 32873760 PMCID: PMC7468202 DOI: 10.1128/mbio.01534-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Malassezia species represent the most common fungal inhabitant of the mammalian skin microbiome and are natural skin commensal flora. However, these fungi are also associated with a variety of clinical skin disorders. Recent studies have reported associations of Malassezia with Crohn’s disease and pancreatic cancer, further implicating this fungal genus in inflammatory and neoplastic disease states. Because M. sympodialis has lost genes involved in RNA interference (RNAi), we hypothesized Malassezia could harbor dsRNA mycoviruses. Indeed, we identified a novel mycovirus of the totivirus family in several Malassezia species and characterized the MsMV1 mycovirus of M. sympodialis. We found conditions that lead to curing of the virus and analyzed isogenic virus-infected/virus-cured strains to determine MsMV1 genetic and pathogenic impacts. MsMV1 induces a strong overexpression of transcription factors and ribosomal genes, while downregulating cellular metabolism. Moreover, MsMV1 induced a significantly higher level of beta interferon expression in cultured macrophages. This study sheds light on the mechanisms of pathogenicity of Malassezia, focusing on a previously unidentified novel mycovirus. Mycoviruses infect fungi, and while most persist asymptomatically, there are examples of mycoviruses having both beneficial and detrimental effects on their host. Virus-infected Saccharomyces and Ustilago strains exhibit a killer phenotype conferring a growth advantage over uninfected strains and other competing yeast species, whereas hypovirus-infected Cryphonectria parasitica displays defects in growth, sporulation, and virulence. In this study, we identify a double-stranded RNA (dsRNA) mycovirus in five Malassezia species. Sequence analysis reveals it to be a totivirus with two dsRNA segments: a larger 4.5-kb segment with genes encoding components for viral replication and maintenance, and a smaller 1.4-kb segment encoding a novel protein. Furthermore, transcriptome sequencing (RNA-seq) of virus-infected versus virus-cured Malassezia sympodialis revealed an upregulation of dozens of ribosomal components in the cell, suggesting the virus modifies the transcriptional and translational landscapes of the cell. Given that Malassezia is the most abundant fungus on human skin, we assessed the impact of the mycovirus in a murine epicutaneous infection model. Although infection with virus-infected strains was not associated with an increased inflammatory response, we did observe enhanced skin colonization in one of two virus-infected M. sympodialis strains. Noteworthy, beta interferon expression was significantly upregulated in bone marrow-derived macrophages when challenged with virus-infected, compared to virus-cured, M. sympodialis, suggesting that the presence of the virus can induce an immunological response. Although many recent studies have illuminated how widespread mycoviruses are, there are relatively few in-depth studies about their impact on disease caused by the host fungus. We describe here a novel mycovirus in Malassezia and its possible implications in pathogenicity.
Collapse
|
29
|
A Novel Virus Alters Gene Expression and Vacuolar Morphology in Malassezia Cells and Induces a TLR3-Mediated Inflammatory Immune Response. mBio 2020; 11:mBio.01521-20. [PMID: 32873759 PMCID: PMC7468201 DOI: 10.1128/mbio.01521-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Malassezia is the most dominant fungal genus on the human skin surface and is associated with various skin diseases including dandruff and seborrheic dermatitis. Among Malassezia species, Malassezia restricta is the most widely observed species on the human skin. In the current study, we identified a novel dsRNA virus, named MrV40, in M. restricta and characterized the sequence and structure of the viral genome along with an independent satellite dsRNA viral segment. Moreover, expression of genes involved in ribosomal synthesis and programmed cell death was altered, indicating that virus infection affected the physiology of the fungal host cells. Our data also showed that the viral nucleic acid from MrV40 induces a TLR3-mediated inflammatory immune response in bone marrow-derived dendritic cells, indicating that a viral element likely contributes to the pathogenicity of Malassezia. This is the first study to identify and characterize a novel mycovirus in Malassezia. Most fungal viruses have been identified in plant pathogens, whereas the presence of viral particles in human-pathogenic fungi is less well studied. In the present study, we observed extrachromosomal double-stranded RNA (dsRNA) segments in various clinical isolates of Malassezia species. Malassezia is the most dominant fungal genus on the human skin surface, and species in this group are considered etiological factors of various skin diseases including dandruff, seborrheic dermatitis, and atopic dermatitis. We identified novel dsRNA segments, and our sequencing results revealed that the virus, named MrV40, belongs to the Totiviridae family and contains an additional satellite dsRNA segment encoding a novel protein. The transcriptome of virus-infected Malassezia restricta cells was compared to that of virus-cured cells, and the results showed that transcripts involved in ribosomal biosynthesis were downregulated and those involved in energy production and programmed cell death were upregulated. Moreover, transmission electron microscopy revealed significantly larger vacuoles in virus-infected M. restricta cells, indicating that MrV40 infection dramatically altered M. restricta physiology. Our analysis also revealed that viral nucleic acid from MrV40 induced a TLR3 (Toll-like receptor 3)-mediated inflammatory immune response in bone marrow-derived dendritic cells, suggesting that a viral element contributes to the pathogenicity of Malassezia.
Collapse
|
30
|
Abstract
Mycoviruses, just as the fungal endophytes they infect, are ubiquitous biological entities on Earth. Mycoviruses constitute a diverse group of viruses, and metagenomic approaches have-through recent discoveries of been mycoviruses-only recently began to provide evidence of this astonishing diversity. The current review presents (1) various mycoviruses which infect fungal endophytes and forest pathogens, (2) their presumed origins and interactions with fungi, plants and the environment, (3) high-throughput sequencing techniques that can be used to explore the horizontal gene transfer of mycoviruses, and (4) how the hypo- and hypervirulence induced by mycoviral infection is relevant to the biological control of pathogenic fungi.
Collapse
Affiliation(s)
- Abu Bakar Siddique
- Department of Ecology and Environmental Sciences (EMG), Umeå University, Umeå, Sweden.
| |
Collapse
|
31
|
Takahashi-Nakaguchi A, Shishido E, Yahara M, Urayama SI, Sakai K, Chibana H, Kamei K, Moriyama H, Gonoi T. Analysis of an Intrinsic Mycovirus Associated With Reduced Virulence of the Human Pathogenic Fungus Aspergillus fumigatus. Front Microbiol 2020; 10:3045. [PMID: 32010101 PMCID: PMC6978690 DOI: 10.3389/fmicb.2019.03045] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/17/2019] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is an airborne fungal pathogen that causes severe infections with invasive growth in immunocompromised patients. Several mycoviruses have recently been isolated from A. fumigatus strains, but there are presently no reports of mycoviral-mediated reduction or elimination of fungal pathogenicity in vertebrate models. Here, we report the biological features of a novel mycovirus, A. fumigatus chrysovirus 41362 (AfuCV41362), isolated from the hypovirulent A. fumigatus strain IFM 41362. The AfuCV41362 genome is comprised of four dsRNAs, each of which contains a single ORF (ORF1-4). ORF1 encodes a protein with sequence similarity to RNA-dependent RNA polymerases of viruses in the family Chrysoviridae, while ORF3 encodes a putative capsid protein. Viral RNAs are expressed primarily during the germination stage, and RNA-seq analysis of virus-infected A. fumigatus at the germination stage suggested that the virus suppressed expression of several pathogenicity-associated host genes, including hypoxia adaptation and nitric oxide detoxification genes. In vitro functional analysis revealed that the virus-infected strain had reduced tolerance to environmental stressors. Virus-infected A. fumigatus strain IFM 41362 had reduced virulence in vivo compared to the virus-free strain in a mouse infection model. Furthermore, introduction of the mycovirus to a natively virus-free KU A. fumigatus strain induced virus-infected phenotypes. To identify mycovirus genes responsible for the reduced virulence of A. fumigatus, each viral ORF was ectopically expressed in the virus-free KU strain. Ectopic expression of the individual ORFs only nominally reduced virulence of the host fungus in a mouse infection model. However, we found that ORF3 and ORF4 reduced tolerance to environmental stresses in in vitro analysis. Based on these results, we suggest that the AfuCV41362 mycovirus ORF3 and ORF4 reduce fungal virulence by suppressing stress tolerance together with other viral genes, rather than alone.
Collapse
Affiliation(s)
| | - Erika Shishido
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Misa Yahara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | | | - Kanae Sakai
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Hiroji Chibana
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Katsuhiko Kamei
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | | | - Tohru Gonoi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| |
Collapse
|
32
|
Fungal Epigenetic Engineering. Fungal Biol 2020. [DOI: 10.1007/978-3-030-41870-0_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
33
|
Buscaino A. Chromatin-Mediated Regulation of Genome Plasticity in Human Fungal Pathogens. Genes (Basel) 2019; 10:E855. [PMID: 31661931 PMCID: PMC6896017 DOI: 10.3390/genes10110855] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/18/2019] [Accepted: 10/25/2019] [Indexed: 12/20/2022] Open
Abstract
Human fungal pathogens, such as Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans, are a public health problem, causing millions of infections and killing almost half a million people annually. The ability of these pathogens to colonise almost every organ in the human body and cause life-threating infections relies on their capacity to adapt and thrive in diverse hostile host-niche environments. Stress-induced genome instability is a key adaptive strategy used by human fungal pathogens as it increases genetic diversity, thereby allowing selection of genotype(s) better adapted to a new environment. Heterochromatin represses gene expression and deleterious recombination and could play a key role in modulating genome stability in response to environmental changes. However, very little is known about heterochromatin structure and function in human fungal pathogens. In this review, I use our knowledge of heterochromatin structure and function in fungal model systems as a road map to review the role of heterochromatin in regulating genome plasticity in the most common human fungal pathogens: Candida albicans, Aspergillus fumigatus and Cryptococcus neoformans.
Collapse
Affiliation(s)
- Alessia Buscaino
- University of Kent, School of Biosciences, Kent Fungal Group, Canterbury Kent CT2 7NJ, UK.
| |
Collapse
|
34
|
Sutela S, Poimala A, Vainio EJ. Viruses of fungi and oomycetes in the soil environment. FEMS Microbiol Ecol 2019; 95:5542194. [DOI: 10.1093/femsec/fiz119] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/30/2019] [Indexed: 12/17/2022] Open
Abstract
ABSTRACTSoils support a myriad of organisms hosting highly diverse viromes. In this minireview, we focus on viruses hosted by true fungi and oomycetes (members of Stamenopila, Chromalveolata) inhabiting bulk soil, rhizosphere and litter layer, and representing different ecological guilds, including fungal saprotrophs, mycorrhizal fungi, mutualistic endophytes and pathogens. Viruses infecting fungi and oomycetes are characterized by persistent intracellular nonlytic lifestyles and transmission via spores and/or hyphal contacts. Almost all fungal and oomycete viruses have genomes composed of single-stranded or double-stranded RNA, and recent studies have revealed numerous novel viruses representing yet unclassified family-level groups. Depending on the virus–host combination, infections can be asymptomatic, beneficial or detrimental to the host. Thus, mycovirus infections may contribute to the multiplex interactions of hosts, therefore likely affecting the dynamics of fungal communities required for the functioning of soil ecosystems. However, the effects of fungal and oomycete viruses on soil ecological processes are still mostly unknown. Interestingly, new metagenomics data suggest an extensive level of horizontal virus transfer between plants, fungi and insects.
Collapse
Affiliation(s)
- Suvi Sutela
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Anna Poimala
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
| | - Eeva J Vainio
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland
| |
Collapse
|
35
|
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: 40] [Impact Index Per Article: 8.0] [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.
Collapse
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
| |
Collapse
|
36
|
Thapa V, Roossinck MJ. Determinants of Coinfection in the Mycoviruses. Front Cell Infect Microbiol 2019; 9:169. [PMID: 31179246 PMCID: PMC6542947 DOI: 10.3389/fcimb.2019.00169] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/06/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Vaskar Thapa
- Department of Plant Pathology and Environmental Microbiology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States
| | - Marilyn J Roossinck
- Department of Plant Pathology and Environmental Microbiology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA, United States
| |
Collapse
|
37
|
Chun J, So KK, Ko YH, Kim JM, Kim DH. Comparative Transcriptomic Analysis of MAPK-Mediated Regulation of Sectorization in Cryphonectria parasitica. Mol Cells 2019; 42:363-375. [PMID: 31091557 PMCID: PMC6530638 DOI: 10.14348/molcells.2019.0019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 02/21/2019] [Indexed: 11/27/2022] Open
Abstract
Fungal sectorization is a complex trait that is still not fully understood. The unique phenotypic changes in sporadic sectorization in mutants of CpBck1, a mitogen-activated protein kinase kinase kinase (MAPKKK) gene, and CpSlt2, a mitogen-activated protein kinase (MAPK) gene, in the cell wall integrity pathway of the chestnut blight fungus Cryphonectria parasitica have been previously studied. Although several environmental and physiological factors cause this sectoring phenotype, genetic variants can also impact this complex morphogenesis. Therefore, RNA sequencing analysis was employed to identify candidate genes associated with sectorization traits and understand the genetic mechanism of this phenotype. Transcriptomic analysis of CpBck1 and CpSlt2 mutants and their sectored progeny strains revealed a number of differentially expressed genes (DEGs) related to various cellular processes. Approximately 70% of DEGs were common between the wild-type and each of CpBck1 and CpSlt2 mutants, indicating that CpBck1 and CpSlt2 are components of the same MAPK pathway, but each component governs specific sets of genes. Functional description of the DEGs between the parental mutants and their sectored progenies revealed several key pathways, including the biosynthesis of secondary metabolites, translation, amino acid metabolism, and carbohydrate metabolism; among these, pathways for secondary metabolism and translation appeared to be the most common pathway. The results of this comparative study provide a better understanding of the genetic regulation of sector formation and suggest that complex several regulatory pathways result in interplays between secondary metabolites and morphogenesis.
Collapse
Affiliation(s)
- Jeesun Chun
- Institute for Molecular Biology and Genetics, Chonbuk National University, Chonbuk 54896,
Korea
| | - Kum-Kang So
- Institute for Molecular Biology and Genetics, Chonbuk National University, Chonbuk 54896,
Korea
| | - Yo-Han Ko
- Department of Bioactive Material Sciences, Chonbuk National University, Chonbuk 54896,
Korea
| | - Jung-Mi Kim
- Department of Bio-Environmental Chemistry, Institute of Life Science and Natural Resources, Wonkwang University, Chonbuk 54538,
Korea
| | - Dae-Hyuk Kim
- Institute for Molecular Biology and Genetics, Chonbuk National University, Chonbuk 54896,
Korea
- Department of Bioactive Material Sciences, Chonbuk National University, Chonbuk 54896,
Korea
- Department of Molecular Biology, Chonbuk National University, Chonbuk 54896,
Korea
| |
Collapse
|
38
|
van de Sande WWJ, Vonk AG. Mycovirus therapy for invasive pulmonary aspergillosis? Med Mycol 2019; 57:S179-S188. [PMID: 30816971 DOI: 10.1093/mmy/myy073] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/21/2018] [Indexed: 12/13/2022] Open
Abstract
With the current revived interest in the use of bacteriophages for the treatment of bacterial infections, the study of mycoviruses as novel therapeutic solutions for invasive aspergillosis is the logical next step. Although ssRNA, dsRNA, and ssDNA mycoviruses have been identified, the majority of characterised mycoviruses have dsRNA genomes. Prevalence of dsRNA mycoviruses in Aspergillus spp. varies, and mycoviruses can have different effects on their fungal hosts: hypovirulence, hypervirulence, or a killer phenotype. Therapeutically, extracellular transmission of the mycovirus is essential. DsRNA mycoviruses lack an extracellular phase; however, a single ssDNA mycovirus with homologues in Aspergillus genomes has been described with an extracellular mode of transmission. Mycoviruses can induce hypovirulence or a killer phenotype, and both can be exploited therapeutically. Mycoviruses inducing hypovirulence have been used to control chestnut blight, however for aspergillosis no such mycovirus has been identified yet. Mycovirus encoded killer toxins or anti-idiotypic antibodies and killer peptides derived from these have been demonstrated to control fungal infections including aspergillosis in animals. This indicates that mycoviruses inducing both phenotypes could be exploited therapeutically as long as the right mycovirus has been identified.
Collapse
Affiliation(s)
- Wendy W J van de Sande
- ErasmusMC, Department of Medical Microbiology and Infectious Diseases, Wytemaweg 80, 3015 CE Rotterdam, The Netherlands
| | - Alieke G Vonk
- ErasmusMC, Department of Medical Microbiology and Infectious Diseases, Wytemaweg 80, 3015 CE Rotterdam, The Netherlands
| |
Collapse
|
39
|
Zhang X, Xie Y, Zhang F, Sun H, Zhai Y, Zhang S, Yuan H, Zhou L, Gao F, Li H. Complete genome sequence of an alternavirus from the phytopathogenic fungus Fusarium incarnatum. Arch Virol 2019; 164:923-925. [DOI: 10.1007/s00705-018-04128-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/23/2018] [Indexed: 10/27/2022]
|
40
|
Je M, Kim H, Son HS. Analysis of the codon usage pattern of the RdRP gene of mycovirus infecting Aspergillus spp. Virol J 2019; 16:10. [PMID: 30651145 PMCID: PMC6335760 DOI: 10.1186/s12985-019-1115-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/01/2019] [Indexed: 12/21/2022] Open
Abstract
Background Mycoviruses that infect fungi generally do not have a significant effect on the host and, instead, reduce the toxicity of the fungi. However, recent studies have shown that polymycovirus-1, a mycovirus that infects Aspergillus species known to cause disease in humans, is related to increased virulence of the fungus. Methods Comparative analysis was performed of RdRP gene codon usage patterns of Aspergillus fumigatus polymycovirus-1 (AfuPmV-1) and other mycoviruses known to infect Aspergillus spp. to examine the genetic characteristics of AfuPmV-1. In addition, codon usage analysis was performed to determine whether the nucleotide composition and codon usage characteristics of AfuPmV-1 were also present in other polymycoviruses and hypervirulence-related mycoviruses. Phylogenetic analysis was also performed to investigate their evolutionary relationship. Results Analysis of nucleotide composition indicated that AfuPmV-1 had the highest GC content among analyzed mycoviruses and relative synonymous codon usage analysis indicated that all of the codons preferred by AfuPmV-1 ended with C or G, while codons ending with A or U were not observed. Moreover, the effective number of codons, the codon adaptation index, and correspondence analysis showed that AfuPmV-1 had greater codon preference compared with other mycoviruses and that AfuPmV-1 had relatively high adaptability to humans and fungi. These results were generally similar among polymycoviruses. Conclusions The codon usage pattern of AfuPmV-1 differs from other mycoviruses that infect Aspergillus spp. This difference may be related to the hypervirulence effect of AfuPmV-1. Analysis of AfuPmV-1 codon usage patterns could contribute to the identification and prediction of virulence effects of mycoviruses with similar genetic characteristics.
Collapse
Affiliation(s)
- Mikyung Je
- SNU Bioinformatics Institute, Interdisciplinary Graduate Program in Bioinformatics, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.,Laboratory of Computational Biology & Bioinformatics, Institute of Public Health and Environment, Graduate School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea
| | - Hayeon Kim
- Department of Biomedical Laboratory Science, Kyungdong University, 815 Gyeonhwon-ro, Munmak, Wonju, Gangwondo, 24695, Korea
| | - Hyeon S Son
- SNU Bioinformatics Institute, Interdisciplinary Graduate Program in Bioinformatics, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea. .,Laboratory of Computational Biology & Bioinformatics, Institute of Public Health and Environment, Graduate School of Public Health, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.
| |
Collapse
|
41
|
Ejmal MA, Holland DJ, MacDiarmid RM, Pearson MN. A novel chrysovirus from a clinical isolate of Aspergillus thermomutatus affects sporulation. PLoS One 2018; 13:e0209443. [PMID: 30571748 PMCID: PMC6301774 DOI: 10.1371/journal.pone.0209443] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/05/2018] [Indexed: 12/15/2022] Open
Abstract
A clinical isolate of Aspergillus thermomutatus (Teleomorph: Neosartorya pseudofischeri) was found to contain ~35 nm isometric virus-like particles associated with four double-stranded (ds) RNA segments, each of which coded for a single open reading frame. The longest dsRNA element (3589 nt) encodes a putative RNA-dependent RNA polymerase (1114 aa), the second longest dsRNA element (2772 nt) encodes a coat protein (825 aa), and the other two dsRNAs (2676 nt, 2514 nt) encode hypothetical proteins of 768 aa and 711 aa, respectively. Phylogenetic analysis of the amino acid sequences showed 41-60% similarity to the proteins coded by the dsRNAs of the most closely related virus, Penicillium janczewskii chrysovirus 2, indicating that it is a new species based on the International Committee on Taxonomy of Viruses criteria for the genus Chrysovirus. This is the first virus reported from A. thermomutatus and was tentatively named Aspergillus thermomutatus chrysovirus 1. A virus free line of the fungal isolate, cured by cycloheximide treatment, produced large numbers of conidia but no ascospores at both 20°C and 37°C, whereas the virus infected line produced ten-fold fewer conidia at 20°C and a large number of ascospores at both temperatures. The effects of the virus on fungal sporulation have interesting implications for the spread of the fungus and possible use of the virus as a biological control agent.
Collapse
Affiliation(s)
- Mahjoub A. Ejmal
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
| | - David J. Holland
- Infectious Diseases Unit, Division of Medicine, Staff Centre, Middlemore Hospital, Auckland, New Zealand
| | - Robin M. MacDiarmid
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Michael N. Pearson
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
| |
Collapse
|
42
|
Chrysoviruses in Magnaporthe oryzae. Viruses 2018; 10:v10120697. [PMID: 30544784 PMCID: PMC6315753 DOI: 10.3390/v10120697] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 01/07/2023] Open
Abstract
Magnaporthe oryzae, the fungus that causes rice blast, is the most destructive pathogen of rice worldwide. A number of M. oryzae mycoviruses have been identified. These include Magnaporthe oryzae. viruses 1, 2, and 3 (MoV1, MoV2, and MoV3) belonging to the genus, Victorivirus, in the family, Totiviridae; Magnaporthe oryzae. partitivirus 1 (MoPV1) in the family, Partitiviridae; Magnaporthe oryzae. chrysovirus 1 strains A and B (MoCV1-A and MoCV1-B) belonging to cluster II of the family, Chrysoviridae; a mycovirus related to plant viruses of the family, Tombusviridae (Magnaporthe oryzae. virus A); and a (+)ssRNA mycovirus closely related to the ourmia-like viruses (Magnaporthe oryzae. ourmia-like virus 1). Among these, MoCV1-A and MoCV1-B were the first reported mycoviruses that cause hypovirulence traits in their host fungus, such as impaired growth, altered colony morphology, and reduced pigmentation. Recently we reported that, although MoCV1-A infection generally confers hypovirulence to fungi, it is also a driving force behind the development of physiological diversity, including pathogenic races. Another example of modulated pathogenicity caused by mycovirus infection is that of Alternaria alternata chrysovirus 1 (AaCV1), which is closely related to MoCV1-A. AaCV1 exhibits two contrasting effects: Impaired growth of the host fungus while rendering the host hypervirulent to the plant, through increased production of the host-specific AK-toxin. It is inferred that these mycoviruses might be epigenetic factors that cause changes in the pathogenicity of phytopathogenic fungi.
Collapse
|
43
|
Botella L, Hantula J. Description, Distribution, and Relevance of Viruses of the Forest Pathogen Gremmeniella abietina. Viruses 2018; 10:v10110654. [PMID: 30463286 PMCID: PMC6267220 DOI: 10.3390/v10110654] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 01/29/2023] Open
Abstract
The European race of the ascomycetous species Gremmeniella abietina (Lagerberg) Morelet includes causal agents of shoot blight and stem canker of several conifers in Europe and North America, which are known to host a diverse virome. GaRV6 is the latest and sixth mycovirus species reported within G. abietina. Before its description, one victorivirus and one gammapartitivirus species were described in biotype A, two mitoviruses in both biotypes A and B and a betaendornavirus in biotype B. Possible phenotypic changes produced by mycoviruses on G. abietina mycelial growth have been reported in Spanish mitovirus-free and GaRV6-hosting G. abietina isolates, which had higher growth rates at the optimal temperature of 15 °C, but no other major differences have been observed between partitivirus-like dsRNA and dsRNA-free isolates. In this review, we reappraise the diversity of viruses found in G. abietina so far, and their relevance in clarifying the taxonomy of G. abietina. We also provide evidence for the presence of two new viruses belonging to the families Fusariviridae and Endornaviridae in Spanish isolates.
Collapse
Affiliation(s)
- Leticia Botella
- Phytophthora Research Centre, Department of Forest Protection and Wildlife Management, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic.
| | - Jarkko Hantula
- Forest Health and Biodiversity, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland.
| |
Collapse
|
44
|
de Lima JGS, Teixeira DG, Freitas TT, Lima JPMS, Lanza DCF. Evolutionary origin of 2A-like sequences in Totiviridae genomes. Virus Res 2018; 259:1-9. [PMID: 30339789 DOI: 10.1016/j.virusres.2018.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/28/2018] [Accepted: 10/15/2018] [Indexed: 12/20/2022]
Abstract
In recent years there has been a significant increase in the number of new species potentially belonging to the Totiviridae family. Most of these new viruses have not yet been covered by the Committee on Taxonomy of Viruses (ICTV) official classification. In this study, a phylogenetic analysis including new sequences of Totiviridae candidates revealed a clade including Giardiavirus and a great diversity of new totiviruses, which infect arthropods, protozoa and mollusc. This expanded Giardiavirus clade comprises two monophyletic groups, one of them including Giardia lamblia virus (GLV) grouped with viruses that infect arthropods and vertebrates (GLV-like group), and the other includes the previously proposed Artivirus group (IMNV-like group). A screening of the members of the GLV-like group in search of genomic elements already described in IMNV-like group revealed the existence of sites with a high propensity to become 2 A-like oligopeptides, mainly in a specific subgroup of arthropod viruses, suggesting that these viruses preserved ancestral characteristics. The existence of these "pseudo 2 A-sites" associated to phylogenetic reconstruction indicates that these sequences appear at a decisive stage for viral evolution. If they are changed to functional 2 A-like sequences, an irreversible route to increase the genome complexity will be initiated.
Collapse
Affiliation(s)
- Juliana G S de Lima
- Applied Molecular Biology Lab - LAPLIC, Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Postgraduate Program in Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Diego G Teixeira
- Laboratory of Metabolic Systems and Bioinformatics - LASIS, Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Postgraduate Program in Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Tiago T Freitas
- Applied Molecular Biology Lab - LAPLIC, Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Postgraduate Program in Science, Technology and Innovation, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - João P M S Lima
- Laboratory of Metabolic Systems and Bioinformatics - LASIS, Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Postgraduate Program in Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Daniel C F Lanza
- Applied Molecular Biology Lab - LAPLIC, Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Postgraduate Program in Biochemistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil; Postgraduate Program in Science, Technology and Innovation, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
| |
Collapse
|
45
|
Ejmal MA, Holland DJ, MacDiarmid RM, Pearson MN. The Effect of Aspergillus Thermomutatus Chrysovirus 1 on the Biology of Three Aspergillus Species. Viruses 2018; 10:E539. [PMID: 30279352 PMCID: PMC6213286 DOI: 10.3390/v10100539] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/25/2018] [Accepted: 09/29/2018] [Indexed: 12/16/2022] Open
Abstract
This study determined the effects of Aspergillus thermomutatus chrysovirus 1 (AthCV1), isolated from Aspergillus thermomutatus, on A. fumigatus, A. nidulans and A. niger. Protoplasts of virus-free isolates of A. fumigatus, A. nidulans and A. niger were transfected with purified AthCV1 particles and the phenotype, growth and sporulation of the isogenic AthCV1-free and AthCV1-infected lines assessed at 20 °C and 37 °C and gene expression data collected at 37 °C. AthCV1-free and AthCV1-infected A. fumigatus produced only conidia at both temperatures but more than ten-fold reduced compared to the AthCV1-infected line. Conidiation was also significantly reduced in infected lines of A. nidulans and A. niger at 37 °C. AthCV1-infected lines of A. thermomutatus and A. nidulans produced large numbers of ascospores at both temperatures, whereas the AthCV1-free line of the former did not produce ascospores. AthCV1-infected lines of all species developed sectoring phenotypes with sclerotia produced in aconidial sectors of A. niger at 37 °C. AthCV1 was detected in 18% of sclerotia produced by AthCV1-infected A. niger and 31% of ascospores from AthCV1-infected A. nidulans. Transcriptome analysis of the naturally AthCV1-infected A. thermomutatus and the three AthCV1-transfected Aspergillus species showed altered gene expression as a result of AthCV1-infection. The results demonstrate that AthCV1 can infect a range of Aspergillus species resulting in reduced sporulation, a potentially useful attribute for a biological control agent.
Collapse
Affiliation(s)
- Mahjoub A Ejmal
- School of Biological Sciences, the University of Auckland, Auckland 1142 New Zealand.
| | - David J Holland
- Infectious Diseases Unit, Division of Medicine, Middlemore Hospital, Auckland 1640, New Zealand.
| | - Robin M MacDiarmid
- School of Biological Sciences, the University of Auckland, Auckland 1142 New Zealand.
- Plant and Food Research, Auckland 1142, New Zealand.
| | - Michael N Pearson
- School of Biological Sciences, the University of Auckland, Auckland 1142 New Zealand.
| |
Collapse
|
46
|
Novel Partitivirus Enhances Virulence of and Causes Aberrant Gene Expression in Talaromyces marneffei. mBio 2018; 9:mBio.00947-18. [PMID: 29895639 PMCID: PMC6016240 DOI: 10.1128/mbio.00947-18] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Talaromyces marneffei is the most important thermal dimorphic fungus causing systemic mycosis in Southeast Asia. We report the discovery of a novel partitivirus, Talaromyces marneffeipartitivirus-1 (TmPV1). TmPV1 was detected in 7 (12.7%) of 55 clinical T. marneffei isolates. Complete genome sequencing of the seven TmPV1 isolates revealed two double-stranded RNA (dsRNA) segments encoding RNA-dependent RNA polymerase (RdRp) and capsid protein, respectively. Phylogenetic analysis showed that TmPV1 occupied a distinct clade among the members of the genus Gammapartitivirus Transmission electron microscopy confirmed the presence of isometric, nonenveloped viral particles of 30 to 45 nm in diameter, compatible with partitiviruses, in TmPV1-infected T. marneffei Quantitative reverse transcription-PCR (qRT-PCR) demonstrated higher viral load of TmPV1 in the yeast phase than in the mycelial phase of T. marneffei Two virus-free isolates, PM1 and PM41, were successfully infected by purified TmPV1 using protoplast transfection. Mice challenged with TmPV1-infected T. marneffei isolates showed significantly shortened survival time (P < 0.0001) and higher fungal burden in organs than mice challenged with isogenic TmPV1-free isolates. Transcriptomic analysis showed that TmPV1 causes aberrant expression of various genes in T. marneffei, with upregulation of potential virulence factors and suppression of RNA interference (RNAi)-related genes. This is the first report of a mycovirus in a thermally dimorphic fungus. Further studies are required to ascertain the mechanism whereby TmPV1 enhances the virulence of T. marneffei in mice and the potential role of RNAi-related genes in antiviral defense in T. marneffeiIMPORTANCETalaromyces marneffei (formerly Penicillium marneffei) is the most important thermal dimorphic fungus in Southeast Asia, causing highly fatal systemic penicilliosis in HIV-infected and immunocompromised patients. We discovered a novel mycovirus, TmPV1, in seven clinical isolates of T. marneffei TmPV1 belongs to the genus Gammapartitivirus of the family Partitiviridae We showed that TmPV1 enhanced the virulence of T. marneffei in mice, with shortened survival time and higher fungal burden in the organs of mice challenged with TmPV1-infected T. marneffei isolates than in those of mice challenged with virus-free isogenic isolates. Transcriptomics analysis showed that TmPV1 altered the expression of genes involved in various cellular processes in T. marneffei, with upregulation of potential virulence factors and suppression of RNAi machinery which may be involved in antiviral defense. This is the first report of a mycovirus in a thermal dimorphic fungus. The present results offer insights into mycovirus-fungus interactions and pathogenesis of thermal dimorphic fungi.
Collapse
|
47
|
Abstract
The ecological modes of fungi are shaped not only by their intrinsic features and the environment in which they occur, but also by their interactions with diverse microbes. Here we explore the ecological and genomic features of diverse bacterial endosymbionts-endohyphal bacteria-that together are emerging as major determinants of fungal phenotypes and plant-fungi interactions. We first provide a historical perspective on the study of endohyphal bacteria. We then propose a functional classification of three main groups, providing an overview of their genomic, phylogenetic, and ecological traits. Last, we explore frontiers in the study of endohyphal bacteria, with special attention to those facultative and horizontally transmitted bacteria that associate with some of the most diverse lineages of fungi. Overall, our aim is to synthesize the rich literature from nearly 50 years of studies on endohyphal bacteria as a means to highlight potential applications and new research directions.
Collapse
|
48
|
Yu J, Lee KM, Cho WK, Park JY, Kim KH. Differential Contribution of RNA Interference Components in Response to Distinct Fusarium graminearum Virus Infections. J Virol 2018; 92:e01756-17. [PMID: 29437977 PMCID: PMC5899199 DOI: 10.1128/jvi.01756-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/02/2018] [Indexed: 01/14/2023] Open
Abstract
The mechanisms of RNA interference (RNAi) as a defense response against viruses remain unclear in many plant-pathogenic fungi. In this study, we used reverse genetics and virus-derived small RNA profiling to investigate the contributions of RNAi components to the antiviral response against Fusarium graminearum viruses 1 to 3 (FgV1, -2, and -3). Real-time reverse transcription-quantitative PCR (qRT-PCR) indicated that infection of Fusarium graminearum by FgV1, -2, or -3 differentially induces the gene expression of RNAi components in F. graminearum Transcripts of the DICER-2 and AGO-1 genes of F. graminearum (FgDICER-2 and FgAGO-1) accumulated at lower levels following FgV1 infection than following FgV2 or FgV3 infection. We constructed gene disruption and overexpression mutants for each of the Argonaute and dicer genes and for two RNA-dependent RNA polymerase (RdRP) genes and generated virus-infected strains of each mutant. Interestingly, mycelial growth was significantly faster for the FgV1-infected FgAGO-1 overexpression mutant than for the FgV1-infected wild type, while neither FgV2 nor FgV3 infection altered the colony morphology of the gene deletion and overexpression mutants. FgV1 RNA accumulation was significantly decreased in the FgAGO-1 overexpression mutant. Furthermore, the levels of induction of FgAGO-1, FgDICER-2, and some of the FgRdRP genes caused by FgV2 and FgV3 infection were similar to those caused by hairpin RNA-induced gene silencing. Using small RNA sequencing analysis, we documented different patterns of virus-derived small interfering RNA (vsiRNA) production in strains infected with FgV1, -2, and -3. Our results suggest that the Argonaute protein encoded by FgAGO-1 is required for RNAi in F. graminearum, that FgAGO-1 induction differs in response to FgV1, -2, and -3, and that FgAGO-1 might contribute to the accumulation of vsiRNAs in FgV1-infected F. graminearumIMPORTANCE To increase our understanding of how RNAi components in Fusarium graminearum react to mycovirus infections, we characterized the role(s) of RNAi components involved in the antiviral defense response against Fusarium graminearum viruses (FgVs). We observed differences in the levels of induction of RNA silencing-related genes, including FgDICER-2 and FgAGO-1, in response to infection by three different FgVs. FgAGO-1 can efficiently induce a robust RNAi response against FgV1 infection, but FgDICER genes might be relatively redundant to FgAGO-1 with respect to antiviral defense. However, the contribution of this gene in the response to the other FgV infections might be small. Compared to previous studies of Cryphonectria parasitica, which showed dicer-like protein 2 and Argonaute-like protein 2 to be important in antiviral RNA silencing, our results showed that F. graminearum developed a more complex and robust RNA silencing system against mycoviruses and that FgDICER-1 and FgDICER-2 and FgAGO-1 and FgAGO-2 had redundant roles in antiviral RNA silencing.
Collapse
Affiliation(s)
- Jisuk Yu
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
| | - Kyung-Mi Lee
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
| | - Won Kyong Cho
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
| | - Ju Yeon Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| |
Collapse
|
49
|
Complete Genome Sequence of a Fusarium graminearum Double-Stranded RNA Virus in a Newly Proposed Family, Alternaviridae. GENOME ANNOUNCEMENTS 2018; 6:6/8/e00064-18. [PMID: 29472334 PMCID: PMC5824011 DOI: 10.1128/genomea.00064-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We describe here a double-stranded RNA mycovirus, termed Fusarium graminearum alternavirus 1 (FgAV1/AH11), from the isolate AH11 of the phytopathogenic fungus F. graminearum. Phylogenetic analysis showed that FgAV1/AH11 belongs to a newly proposed family, Alternaviridae. This is the first report of a mycovirus in the family Alternaviridae that infects F. graminearum.
Collapse
|
50
|
Calkins SS, Elledge NC, Mueller KE, Marek SM, Couger MB, Elshahed MS, Youssef NH. Development of an RNA interference (RNAi) gene knockdown protocol in the anaerobic gut fungus Pecoramyces ruminantium strain C1A. PeerJ 2018; 6:e4276. [PMID: 29404209 PMCID: PMC5796279 DOI: 10.7717/peerj.4276] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/29/2017] [Indexed: 12/25/2022] Open
Abstract
Members of the anaerobic gut fungi (AGF) reside in rumen, hindgut, and feces of ruminant and non-ruminant herbivorous mammals and reptilian herbivores. No protocols for gene insertion, deletion, silencing, or mutation are currently available for the AGF, rendering gene-targeted molecular biological manipulations unfeasible. Here, we developed and optimized an RNA interference (RNAi)-based protocol for targeted gene silencing in the anaerobic gut fungus Pecoramyces ruminantium strain C1A. Analysis of the C1A genome identified genes encoding enzymes required for RNA silencing in fungi (Dicer, Argonaute, Neurospora crassa QDE-3 homolog DNA helicase, Argonaute-interacting protein, and Neurospora crassa QIP homolog exonuclease); and the competency of C1A germinating spores for RNA uptake was confirmed using fluorescently labeled small interfering RNAs (siRNA). Addition of chemically-synthesized siRNAs targeting D-lactate dehydrogenase (ldhD) gene to C1A germinating spores resulted in marked target gene silencing; as evident by significantly lower ldhD transcriptional levels, a marked reduction in the D-LDH specific enzymatic activity in intracellular protein extracts, and a reduction in D-lactate levels accumulating in the culture supernatant. Comparative transcriptomic analysis of untreated versus siRNA-treated cultures identified a few off-target siRNA-mediated gene silencing effects. As well, significant differential up-regulation of the gene encoding NAD-dependent 2-hydroxyacid dehydrogenase (Pfam00389) in siRNA-treated C1A cultures was observed, which could possibly compensate for loss of D-LDH as an electron sink mechanism in C1A. The results demonstrate the feasibility of RNAi in anaerobic fungi, and opens the door for gene silencing-based studies in this fungal clade.
Collapse
Affiliation(s)
- Shelby S Calkins
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Nicole C Elledge
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.,Current affiliation: University of Texas A&M Corpus Christi, Department of Life Sciences, Marine Biology Program, USA
| | - Katherine E Mueller
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Stephen M Marek
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, USA
| | - M B Couger
- High Performance Computing Center, Oklahoma State University, Stillwater, OK, USA
| | - Mostafa S Elshahed
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| | - Noha H Youssef
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
| |
Collapse
|