1
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Zhang J, Shi X, Liu W. Targeting wheat fusarium head blight with mycovirus-mediated VIGS. Trends Microbiol 2023; 31:1197-1198. [PMID: 37914620 DOI: 10.1016/j.tim.2023.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/12/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023]
Abstract
Fusarium head blight (FHB) caused by Fusarium graminearum occurs in wheat (Triticum aestivum) and threatens food production worldwide. Wheat lacks broad, durable FHB resistance. However, Zhang et al. developed a mycovirus-based virus-induced gene-silencing system in F. graminearum, providing efficient biocontrol of this devastating fungal disease.
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Affiliation(s)
- Junqi Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xuetao Shi
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
| | - Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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2
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Khan HA, Baig DI, Bhatti MF. An Overview of Mycoviral Curing Strategies Used in Evaluating Fungal Host Fitness. Mol Biotechnol 2023; 65:1547-1564. [PMID: 36841858 PMCID: PMC9963364 DOI: 10.1007/s12033-023-00695-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/11/2023] [Indexed: 02/27/2023]
Abstract
The number of novel mycoviruses is increasing at a high pace due to advancements in sequencing technologies. As a result, an uncountable number of mycoviral sequences are available in public sequence repositories. However, only genomic information is not sufficient to understand the impact of mycoviruses on their host biology. Biological characterization is required to determine the nature of mycoviruses (cryptic, hypervirulent, or hypovirulent) and to search for mycoviruses with biocontrol and therapeutic potential. Currently, no particular selective method is used as the gold standard against these mycoviral infections. Given the importance of curing, we present an overview of procedures used in preparation of isogenic lines, along with their benefits and drawbacks. We concluded that a combination of single-spore isolation and hyphal tipping is the best fit for preparation of isogenic lines. Furthermore, recent bioinformatic approaches should be introduced in the field of mycovirology to predict virus-specific antivirals to get robust results.
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Affiliation(s)
- Haris Ahmed Khan
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000 Pakistan
- Department of Biotechnology, University of Mianwali, Punjab, 42200 Pakistan
| | - Danish Ilyas Baig
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000 Pakistan
| | - Muhammad Faraz Bhatti
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, 44000 Pakistan
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3
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Wang P, Yang G, Shi N, Zhao C, Hu F, Coutts RHA, Kotta-Loizou I, Huang B. A novel partitivirus orchestrates conidiation, stress response, pathogenicity, and secondary metabolism of the entomopathogenic fungus Metarhizium majus. PLoS Pathog 2023; 19:e1011397. [PMID: 37216409 DOI: 10.1371/journal.ppat.1011397] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/01/2023] [Indexed: 05/24/2023] Open
Abstract
Mycoviruses are widely present in all major groups of fungi but those in entomopathogenic Metarhizium spp. remain understudied. In this investigation, a novel double-stranded (ds) RNA virus is isolated from Metarhizium majus and named Metarhizium majus partitivirus 1 (MmPV1). The complete genome sequence of MmPV1 comprises two monocistronic dsRNA segments (dsRNA 1 and dsRNA 2), which encode an RNA-dependent RNA polymerase (RdRp) and a capsid protein (CP), respectively. MmPV1 is classified as a new member of the genus Gammapartitivirus in the family Partitiviridae based on phylogenetic analysis. As compared to an MmPV1-free strain, two isogenic MmPV1-infected single-spore isolates were compromised in terms of conidiation, and tolerance to heat shock and UV-B irradiation, while these phenotypes were accompanied by transcriptional suppression of multiple genes involved in conidiation, heat shock response and DNA damage repair. MmPV1 attenuated fungal virulence since infection resulted in reduced conidiation, hydrophobicity, adhesion, and cuticular penetration. Additionally, secondary metabolites were significantly altered by MmPV1 infection, including reduced production of triterpenoids, and metarhizins A and B, and increased production of nitrogen and phosphorus compounds. However, expression of individual MmPV1 proteins in M. majus had no impact on the host phenotype, suggesting insubstantive links between defective phenotypes and a single viral protein. These findings indicate that MmPV1 infection decreases M. majus fitness to its environment and its insect-pathogenic lifestyle and environment through the orchestration of the host conidiation, stress tolerance, pathogenicity, and secondary metabolism.
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Affiliation(s)
- Ping Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Guogen Yang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Najie Shi
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Cheng Zhao
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Fenglin Hu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Robert H A Coutts
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
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4
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Tebbi CK. Mycoviruses in Fungi: Carcinogenesis of Fungal Agents May Not Always Be Mycotoxin Related. J Fungi (Basel) 2023; 9:jof9030368. [PMID: 36983536 PMCID: PMC10052198 DOI: 10.3390/jof9030368] [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: 02/01/2023] [Revised: 03/02/2023] [Accepted: 03/09/2023] [Indexed: 03/30/2023] Open
Abstract
Certain viruses have been found to induce diverse biological pathways to carcinogenesis, evidenced by the presence of viral gene products in some tumors. Despite the fact that many fungal agents contain mycoviruses, until recently, their possible direct effects on human health, including carcinogenesis and leukemogenesis, had not been explored. In this regard, most studies of fungal agents have rightly concentrated on their mycotoxin formation and effects. Recently, the direct role of yeasts and fungi in the etiology of cancers, including leukemia, have been investigated. While greater attention has been placed on the carcinogenic effects of Candida, the role of filamentous fungi in carcinogenesis has also been explored. Recent findings from studies using the enzyme-linked immunosorbent assay (ELISA) technique indicate that the plasma of patients with acute lymphoblastic leukemia (ALL) uniformly contains antibodies for a certain mycovirus-containing Aspergillus flavus, while controls are negative. The exposure of mononuclear leukocytes from patients with ALL in full remission, and long-term survivors, to the product of this organism was reported to result in the re-development of typical genetics and cell surface phenotypes characteristic of active ALL. Mycoviruses are known to be able to significantly alter the biological characteristics and functions of their host. The possible carcinogenic and leukemogenic role of mycoviruses, with and without their host, needs to be further investigated.
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Affiliation(s)
- Cameron K Tebbi
- Children's Cancer Research Group Laboratory, 13719 North Nebraska Avenue, Suite #108, Tampa, FL 33613-3305, USA
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5
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Variation with In Vitro Analysis of Volatile Profiles among Aspergillus flavus Strains from Louisiana. SEPARATIONS 2023. [DOI: 10.3390/separations10030157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Volatile organic compounds (VOCs) produced by A. flavus strains were first captured and identified to discern between non-aflatoxigenic and toxigenic phenotypes, and more recently to help with detecting fungal infection, but not with the goal of using VOCs produced by non-aflatoxigenic strains to inhibit growth and/or production of one or more mycotoxins (e.g., aflatoxin and cyclopiazonic acid) by toxigenic aspergilli. In this study, four Aspergillus strains from Louisiana (one non-aflatoxigenic and three toxigenic) were grown on various substrates and had their headspaces captured and analyzed by solid-phase microextraction/gas chromatography/mass spectroscopy (SPME/GC/MS), to find biocontrol and biomarker compounds. Here, we present a collection of nearly 100 fungus-related VOCs, many of which were substrate dependent. Thirty-one were produced across multiple replicates and the rest were observed in a single replicate. At least three VOCs unique to non-aflatoxigenic strain LA1 can be tested for biocontrol properties (e.g., euparone, 4-nonyne), and at least four VOCs unique to toxigenic strains LA2-LA4 can be explored as biomarkers (e.g., 2-heptanone, glycocyamidine) to detect their presence while infecting crops in the field or in storage.
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6
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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.
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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
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7
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Freeing Aspergillus fumigatus of Polymycovirus Infection Renders It More Resistant to Competition with Pseudomonas aeruginosa Due to Altered Iron-Acquiring Tactics. J Fungi (Basel) 2021; 7:jof7070497. [PMID: 34206595 PMCID: PMC8306778 DOI: 10.3390/jof7070497] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 12/31/2022] Open
Abstract
A virus-free (VF) A. fumigatus isolate has been shown to be resistant in competition with Pseudomonas as compared to the isogenic line infected with Aspergillus fumigatus polymycovirus 1 (AfuPmV-1), and this phenotype was apparently related to alterations in iron metabolism. Here we investigated further the mechanisms underpinning this phenotype. The extracellular siderophore profiles of five isogenic VF and virus-infected (VI) strains were sampled at 24, 31, 48, 54, and 72 h in submerged cultures and quantitatively examined by liquid chromatography and mass spectrometry. Intracellular profiles of conidia and cultures at the stationary growth phase were defined. VF A. fumigatus demonstrated the best fitness represented by the fastest onset of its exponential growth when grown on an iron-limited mineral medium. The exponential phase and transitional production phase of the extracellular triacetylfusarinine C (TafC) were achieved at 24 and 31 h, respectively, contrary to VI strains, which acted more slowly. As a result, the TafC reservoir was consumed sooner in the VF strain. Additionally, the VF strain had lower ferricrocin and higher hydroxyferricrocin content in the pellet during the stationary phase. All of these differences were significant (Kruskal–Wallis, p < 0.01). In our study, the siderophore reservoir of a VF strain was consumed sooner, improving the fitness of the VF strain in competition with P. aeruginosa.
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8
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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.
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Affiliation(s)
- Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom.
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9
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Tebbi CK, Badiga A, Sahakian E, Powers JJ, Achille AN, Patel S, Migone F. Exposure to a mycovirus containing Aspergillus Flavus reproduces acute lymphoblastic leukemia cell surface and genetic markers in cells from patients in remission and not controls. Cancer Treat Res Commun 2020; 26:100279. [PMID: 33348275 DOI: 10.1016/j.ctarc.2020.100279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/27/2020] [Accepted: 12/09/2020] [Indexed: 12/17/2022]
Abstract
The etiology of acute lymphoblastic leukemia (ALL) remains unknown. A recent "two-hit" model for the occurrence of precursor B cell acute lymphoblastic leukemia propose that this disease arises through a two-step process, including predisposing genetic mutation and exposure to infections. While several genetic mutations are proposed, no infection category has been suggested. We have isolated a certain Aspergillus Flavus from residence of an ALL patient. This organism contains mycovirus and does not produce aflatoxin. The supernatant of culture of this mycovirus containing Aspergillus Flavus (SAF) was tested on the PBMCs of ALL patients in remission and controls. Cell surface phenotypes and genetic markers were examined. The effects of its combination with Epstein-Barr virus (EBV) was also investigated. For the SAF, positive and negative controls were aflatoxin and culture of Mycocladus corymbifer, respectively. Controls for ALL were sickle cell patients undergoing exchange transfusion. Incubation of the PMBCs from ALL patients in remission, or controls, with SAF resulted in re-development of ALL cell surface phenotypes and genetic markers in ALL patients in remission and not controls. These differentiating effects were not seen with aflatoxin or culture of Mycocladus Corymbifer. Addition of EBV did not alter effects of SAF. Currently, there are no techniques to discriminately reproduce characteristic leukemic genetic markers and cell surface phenotypes in cells from ALL patients in remission and not controls. These studies may provide a test for recognition of ALL patients in remission and new prospects for the investigation of leukemogenesis.
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Affiliation(s)
- Cameron K Tebbi
- Florida Pediatric Hematology/Oncology and Children's Cancer Research Group Laboratory, 13719 North Nebraska Avenue, Tampa, Florida, 33613 USA.
| | - Aruna Badiga
- Children's Cancer Research Group Laboratory, 13719 North Nebraska Avenue, Tampa, Florida, 33613 USA
| | - Eva Sahakian
- Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, Florida, 33612 USA
| | - John J Powers
- Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, Florida, 33612 USA
| | - Alex N Achille
- Moffitt Cancer Center and Research Institute, 12902 Magnolia Drive, Tampa, Florida 33612 USA
| | - Saumil Patel
- Tampa General Hospital, 1 Tampa General Circle, Tampa, Florida, 33606 USA
| | - Felicia Migone
- Children's Cancer Research Group Laboratory, 13719 North Nebraska Avenue, Tampa, Florida, 33613 USA
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10
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Ninomiya A, Urayama SI, Suo R, Itoi S, Fuji SI, Moriyama H, Hagiwara D. Mycovirus-Induced Tenuazonic Acid Production in a Rice Blast Fungus Magnaporthe oryzae. Front Microbiol 2020; 11:1641. [PMID: 32765467 PMCID: PMC7379127 DOI: 10.3389/fmicb.2020.01641] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 06/24/2020] [Indexed: 11/13/2022] Open
Abstract
Fungi are a rich source of natural products with biological activities. In this study, we evaluated viral effects on secondary metabolism of the rice blast fungus Magnaporthe oryzae using an isolate of APU10-199A co-infected with three types of mycoviruses: a totivirus, a chrysovirus, and a partitivirus. Comparison of the secondary metabolite profile of APU10-199A with that of the strain lacking the totivirus and chrysovirus showed that a mycotoxin tenuazonic (TeA) acid was produced in a manner dependent on the mycoviruses. Virus reinfection experiments verified that TeA production was dependent on the totivirus. Quantitative reverse transcription PCR and RNA-sequencing analysis indicated the regulatory mechanism underlying viral induction of TeA: the totivirus activates the TeA synthetase gene TAS1 by upregulating the transcription of the gene encoding a Zn(II)2-Cys6-type transcription factor, TAS2. To our knowledge, this is the first report that confirmed mycovirus-associated regulation of secondary metabolism at a transcriptional level by viral reinfection. Because only treatment with dimethyl sulfoxide has been reported to trigger TeA production in this fungus without gene manipulation, our finding highlights the potential of mycoviruses as an epigenomic regulator of fungal secondary metabolism.
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Affiliation(s)
- Akihiro Ninomiya
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Syun-ichi Urayama
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan
| | - Rei Suo
- College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Shiro Itoi
- College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Shin-ichi Fuji
- Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan
| | - Hiromitsu Moriyama
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, Fuchu, Japan
| | - Daisuke Hagiwara
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Microbiology Research Center for Sustainability, University of Tsukuba, Tsukuba, Japan
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11
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Ejmal MA, Holland DJ, MacDiarmid RM, Pearson MN. A novel chrysovirus from a clinical isolate of Aspergillus thermomutatus affects sporulation. PLoS One 2018; 13:e0209443. [PMID: 30571748 PMCID: PMC6301774 DOI: 10.1371/journal.pone.0209443] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 12/05/2018] [Indexed: 12/15/2022] Open
Abstract
A clinical isolate of Aspergillus thermomutatus (Teleomorph: Neosartorya pseudofischeri) was found to contain ~35 nm isometric virus-like particles associated with four double-stranded (ds) RNA segments, each of which coded for a single open reading frame. The longest dsRNA element (3589 nt) encodes a putative RNA-dependent RNA polymerase (1114 aa), the second longest dsRNA element (2772 nt) encodes a coat protein (825 aa), and the other two dsRNAs (2676 nt, 2514 nt) encode hypothetical proteins of 768 aa and 711 aa, respectively. Phylogenetic analysis of the amino acid sequences showed 41-60% similarity to the proteins coded by the dsRNAs of the most closely related virus, Penicillium janczewskii chrysovirus 2, indicating that it is a new species based on the International Committee on Taxonomy of Viruses criteria for the genus Chrysovirus. This is the first virus reported from A. thermomutatus and was tentatively named Aspergillus thermomutatus chrysovirus 1. A virus free line of the fungal isolate, cured by cycloheximide treatment, produced large numbers of conidia but no ascospores at both 20°C and 37°C, whereas the virus infected line produced ten-fold fewer conidia at 20°C and a large number of ascospores at both temperatures. The effects of the virus on fungal sporulation have interesting implications for the spread of the fungus and possible use of the virus as a biological control agent.
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Affiliation(s)
- Mahjoub A. Ejmal
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
| | - David J. Holland
- Infectious Diseases Unit, Division of Medicine, Staff Centre, Middlemore Hospital, Auckland, New Zealand
| | - Robin M. MacDiarmid
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Michael N. Pearson
- School of Biological Sciences, the University of Auckland, Auckland, New Zealand
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12
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Nerva L, Chitarra W, Siciliano I, Gaiotti F, Ciuffo M, Forgia M, Varese GC, Turina M. Mycoviruses mediate mycotoxin regulation in Aspergillus ochraceus. Environ Microbiol 2018; 21:1957-1968. [PMID: 30289193 DOI: 10.1111/1462-2920.14436] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 09/24/2018] [Accepted: 09/27/2018] [Indexed: 12/30/2022]
Abstract
To date, no demonstration of a direct correlation between the presence of mycoviruses and the quantitative or qualitative modulation of mycotoxins has been shown. In our study, we transfected a virus-free ochratoxin A (OTA)-producing isolate of Aspergillus ochraceus with purified mycoviruses from a different A. ochraceus isolate and from Penicillium aurantiogriseum. Among the mycoviruses tested, only Aspergillus ochraceus virus (AoV), a partitivirus widespread in A. ochraceus, caused a specific interaction that led to an overproduction of OTA, which is regulated by the European Commission and is the second most important contaminant of food and feed commodities. Gene expression analysis failed to reveal a specific viral upregulation of the mRNA of genes considered to play a role in the OTA biosynthetic pathway. Furthermore, AoOTApks1, a polyketide synthase gene considered essential for OTA production, is surprisingly absent in the genome of our OTA-producing isolate. The possible biological and evolutionary implications of the mycoviral regulation of mycotoxin production are discussed.
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Affiliation(s)
- L Nerva
- Council for Agricultural Research and Economics - Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015, Conegliano (TV), Italy.,Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135, Torino, Italy
| | - W Chitarra
- Council for Agricultural Research and Economics - Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015, Conegliano (TV), Italy.,Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135, Torino, Italy
| | - I Siciliano
- Council for Agricultural Research and Economics - Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015, Conegliano (TV), Italy
| | - F Gaiotti
- Council for Agricultural Research and Economics - Research Centre for Viticulture and Enology CREA-VE, Via XXVIII Aprile 26, 31015, Conegliano (TV), Italy
| | - M Ciuffo
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135, Torino, Italy
| | - M Forgia
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135, Torino, Italy.,Mycotheca Universitatis Taurinensis (MUT), Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125, Torino, Italy
| | - G C Varese
- Mycotheca Universitatis Taurinensis (MUT), Department of Life Sciences and Systems Biology, University of Turin, Viale Mattioli 25, 10125, Torino, Italy
| | - M Turina
- Institute for Sustainable Plant Protection, CNR, Strada delle Cacce 73, 10135, Torino, Italy
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13
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Kotta-Loizou I, Coutts RHA. Mycoviruses in Aspergilli: A Comprehensive Review. Front Microbiol 2017; 8:1699. [PMID: 28932216 PMCID: PMC5592211 DOI: 10.3389/fmicb.2017.01699] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 08/23/2017] [Indexed: 12/31/2022] Open
Abstract
Fungi, similar to all species, are susceptible to viral infection. Aspergillus is arguably the most well studied fungal genus because of its medical, ecological and economical significance. Mycoviruses were initially detected in Aspergillus species almost 50 years ago and the field continues to be active today with ground-breaking discoveries. The aim of the present review is to cover the scientific progress in all aspects of mycovirology as exemplified by Aspergillus-focused research. Initially an overview of the population studies illustrating the presence of mycoviruses in numerous important Aspergillus species, such as A. niger, A. flavus, and A. fumigatus with be presented. Moreover the intricacies of mycovirus transmission, both inter- and intra-species, will be discussed together with the methodologies used to investigate viral dispersion in a laboratory setting. Subsequently, the genomic features of all molecularly characterized mycoviruses to date will be analyzed in depth. These include members of established viral families, such as Partitiviridae, Chrysoviridae and Totiviridae, but also more recent, novel discoveries that led to the proposal of new viral families, such as Polymycoviridae, Alternaviridae and, in the context of the present review, Exartaviridae. Finally, the major issue of phenotypic effects of mycoviral infection on the host is addressed, including aflatoxin production in A. flavus, together with growth and virulence in A. fumigatus. Although the molecular mechanisms behind these phenomena are yet to be elucidated, recent studies suggest that by implication, RNA silencing may be involved.
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Affiliation(s)
- Ioly Kotta-Loizou
- Department of Life Sciences, Imperial College LondonLondon, United Kingdom
| | - Robert H A Coutts
- Department of Biological and Environmental Sciences, University of HertfordshireHatfield, United Kingdom
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The RNA interference-virus interplay: tools of nature for gene modulation, morphogenesis, evolution and a possible mean for aflatoxin control. Appl Microbiol Biotechnol 2009; 83:611-5. [PMID: 19466405 DOI: 10.1007/s00253-009-2007-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 04/08/2009] [Accepted: 04/08/2009] [Indexed: 11/27/2022]
Abstract
This article points out, that viruses, in an interplay with RNA interference and as vehicles for intergenic and interspecies gene transfer, may work as agents for intracellular gene modulation, for steering of individual morphogenesis and as a driving force of evolution in the toolbox of nature. This is illustrated in particular in the light of a fungal double-stranded RNA virus that may be employed as a suitable agent for a biological control of aflatoxins, the most carcinogenic natural substances occurring in food and feedstuff.
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Cancer et environnement en Afrique. ONCOLOGIE 2007. [DOI: 10.1007/s10269-007-0636-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Aziz NH, Smyk B. Influence of UV radiation and nitrosamines on the induction of mycotoxins synthesis by nontoxigenic moulds isolated from feed samples. DIE NAHRUNG 2002; 46:118-21. [PMID: 12017988 DOI: 10.1002/1521-3803(20020301)46:2<118::aid-food118>3.0.co;2-#] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effects of UV radiation and nitrosamines on the induction of mycotoxin biosynthesis by some nontoxigenic moulds isolated from feed samples collected from Egypt and Poland was investigated. Nontoxigenic strains of Aspergillus flavus P-63, A. niger EN-200 and A. ochraceus P-157 synthesized mycotoxins (aflatoxins and ochratoxin, A) after exposure to near UV radiation for 120-210 min. Nitrosamines (DMNA and DENA) at 30 up to 1000 ppm induced the synthesis of aflatoxins by nontoxigenic species of A. flavus ES-255 and P-63 and A. niger EN 200. Near-UV radiation and nitrosamines had no influence on the induction of mycotoxin synthesis by Penicillium and Fusarium isolates. All nontoxigenic strains of Aspergilli which synthesized aflatoxins in the presence of 1000 ppm nitrosamines, also synthesized continuously aflatoxins during the next fifteen generations. Near-UV radiation and nitrosamines had a mutagenic effect on the induction of mycotoxins synthesis by nontoxigenic moulds.
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Affiliation(s)
- Nagy H Aziz
- National Center for Radiation Research and Technology, 3 Ahmed El Zumor St., 8th Sector, P.O. Box 29, Nasr City, Cairo, 113701 Nasr City Cairo, Egypt
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Varga J, Rinyu E, Kevei E, Tóth B, Kozakiewicz Z. Double-stranded RNA mycoviruses in species of Aspergillus sections Circumdati and Fumigati. Can J Microbiol 1998; 44:569-74. [PMID: 9734307 DOI: 10.1139/w98-038] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isolates (178) belonging to Aspergillus sections Fumigati, Candidi, Clavati, and Circumdati were tested for the presence of double-stranded RNA (dsRNA) genomes. Altogether, 5.6% of the Aspergillus strains examined were infected with dsRNAs. dsRNA segments indicative of mycovirus infection were observed for the first time in Neosartorya hiratsukae, Neosartorya quadricincta, Petromyces alliaceus, and Aspergillus clavatus strains. Correlation was not observed between ochratoxin production and dsRNA content of the strains. This is the first report on the detection of naturally occurring dsRNAs in Aspergillus species that are able to reproduce sexually. The detection of dsRNA in sexual aspergilli gave us a chance to examine the transmission of these segments through ascospores. A Neosartorya hiratsukae strain transmitted the dsRNAs efficiently through sexual spores, while the stromata embedding the asci in Petromyces alliaceus did not transmit one of the dsRNA segments. The 0.6-kb dsRNA segment that was present in the single-stromatal cultures was found to be located in the mitochondrial fraction of this strain. This observation indicates that some mechanisms exist in aspergilli to exclude cytoplasmically located dsRNA molecules from stromatal structures.
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Affiliation(s)
- J Varga
- Department of Microbiology, Attila József University, Szeged, Hungary.
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Elias KS, Cotty PJ. Incidence and stability of infection by double-stranded RNA genetic elements inAspergillussectionflaviand effects on aflatoxigenicity. ACTA ACUST UNITED AC 1996. [DOI: 10.1139/b96-090] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ninety-two isolates belonging to Aspergillus sect, flavi were analyzed for double-stranded (ds) RNA via standard cellulose chromatography. Double-stranded RNA infection was detected in fungal isolates that had been in culture for long periods (5 of 26 were infected) and in those recently isolated (5 of 66 were infected). The number of dsRNA genetic elements differed among infected isolates and no two isolates contained identical dsRNAs on the basis of electrophoretic migration in agarose gels. Addition of micronutrients to culture media affected both the amount of dsRNA produced and the number of dsRNA genetic elements detected. Attempts to cure six fungal isolates of dsRNA by serial single conidial transfer, chlorate selection for nitrogen-metabolism mutants, and cycloheximide treatment, met with variable results. The frequency at which serial single conidial transfer and nitrogen-metabolism mutant (nit) selection successfully cured six Aspergillus sect, flavi isolates varied from 11 to 100% and 0 to 100%, respectively. The cycloheximide treatment was effective at curing 40% of the dsRNA-infected isolates. Comparison of aflatoxin production prior to and after dsRNA curing indicated that infection by dsRNA did not influence aflatoxin production. However, aflatoxin production by two isolates (91-031B and 91-184G) was reduced by both single conidial transfer and induction of nit mutants. Keywords: aflatoxin, cycloheximide, mycovirus, nitrogen-metabolism mutant.
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Lemke PA, Davis ND, Creech GW. Direct visual detection of aflatoxin synthesis by minicolonies of Aspergillus species. Appl Environ Microbiol 1989; 55:1808-10. [PMID: 2504116 PMCID: PMC202954 DOI: 10.1128/aem.55.7.1808-1810.1989] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Single-spore colonies of Aspergillus flavus and Aspergillus parasiticus, grown for 4 to 5 days at 25 degrees C on a coconut extract agar containing sodium desoxycholate as a growth inhibitor, produced aflatoxin, readily detectable as blue fluorescent zones under long-wave (365 nm) UV light. Over 100 colonies per standard petri dish were scored for aflatoxin production by this procedure. Progeny from some strains remained consistently stable for toxin production after repeated subculture, whereas instability for toxin synthesis was revealed among progeny from other strains. Spore color markers were used to rule out cross-contamination in monitoring strains. A yellow-spored and nontoxigenic strain of A. flavus, reported previously to produce aflatoxin in response to cycloheximide treatment, proved to be toxin negative even after repeated exposure to cycloheximide. Extended series of progeny from another strain of A. flavus and from a strain of A. parasiticus were each compared by this plating procedure and by fluorometric analysis for aflatoxin when grown in a coconut extract broth. Both of these strains showed variation for toxin synthesis among their respective progeny, and specific progeny showed a good correlation for aflatoxin synthesis when examined by the two procedures.
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Affiliation(s)
- P A Lemke
- Department of Botany and Microbiology, Auburn University, Alabama 36849-5407
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Affiliation(s)
- G G Brown
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Abstract
Double-stranded (ds) RNAs associated with viruslike particles have been found in six isolates of Alternaria alternata which produce tentoxin. Isolates had from one to three dsRNAs ranging in size from 1.0 to 5.1 kilobase pairs. In two isolates the dsRNAs were associated with 30-nm particles. No dsRNA was detected in any of six other tentoxin-producing isolates or nine isolates which did not produce tentoxin.
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Affiliation(s)
- H S Shepherd
- Southern Regional Research Center, U.S. Department of Agriculture, New Orleans, Louisiana 70179
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5-Fluorouracil stimulation of naphthoquinone synthesis in Nectria haematococca (Berk. & Br.) Wr. Mycology 1988. [DOI: 10.1016/0147-5975(88)90014-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Abstract
In the field of natural peptides, beta-lactams, and related compounds, recent exciting developments are discussed. The increasing interest in this class of bioactive amino-acid derived structures has been attributed to the use of new directed screens (enzyme inhibition assays, beta-lactam detection, immunomodulator studies), new and improved applications (antibiotic, transplantation, and cancer chemotherapy), and advances in functional studies (DNA binding peptides, nucleotide complexones, cell wall and protein processing inhibitors). Peptides offer unique access to modifications and analog production by in vivo (directed biosynthesis) and in vitro procedures (enzymatic synthesis) due to their general linear precursors permitting point replacements. Of special interest are recent developments in the genetics of these compounds (cyclic peptides and beta-lactams), which will find applications in production methods in the near future.
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Affiliation(s)
- H Kleinkauf
- Institute of Biochemistry and Molecular Biology, Technical University of Berlin, West Germany
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