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Robert H A Coutts - One of the best experts on this subject based on the ideXlab platform.
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multiplex detection of aspergillus fumigatus Mycoviruses
Viruses, 2018Co-Authors: Selin Ozkankotiloglu, Robert H A CouttsAbstract:Mycoviruses are viruses that naturally infect and replicate in fungi. They are widespread in all major fungal groups including plant and animal pathogenic fungi. Several dsRNA Mycoviruses have been reported in Aspergillus fumigatus. Multiplex polymerase chain reaction (PCR) amplification is a version of PCR that enables amplification of different targets simultaneously. This technique has been widely used for detection and differentiation of viruses especially plant viruses such as those which infect tobacco, potato and garlic. For rapid detection, multiplex RT-PCR was developed to screen new isolates for the presence of A. fumigatus Mycoviruses. Aspergillus fumigatus chrysovirus (AfuCV), Aspergillus fumigatus partitivirus (AfuPV-1), and Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1) dsRNAs were amplified in separate reactions using a mixture of multiplex primer pairs. It was demonstrated that in the presence of a single infection, primer pair mixtures only amplify the corresponding single virus infection. Mixed infections using dual or triple combinations of dsRNA viruses were also amplified simultaneously using multiplex RT-PCR. Up until now, methods for the rapid detection of Aspergillus Mycoviruses have been restricted to small scale dsRNA extraction approaches which are laborious and for large numbers of samples not as sensitive as RT-PCR. The multiplex RT-PCR assay developed here will be useful for studies on determining the incidence of A. fumigatus Mycoviruses. This is the first report on multiplex detection of A. fumigatus Mycoviruses.
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Mycoviruses in aspergilli a comprehensive review
Frontiers in Microbiology, 2017Co-Authors: Ioly Kottaloizou, Robert H A CouttsAbstract: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 characterised Mycoviruses to date will be analysed 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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profile and functional analysis of small rnas derived from aspergillus fumigatus infected with double stranded rna Mycoviruses
BMC Genomics, 2017Co-Authors: Robert H A Coutts, Selin Ozkan, Irina Mohorianu, Ping Xu, Tamas DalmayAbstract:Abstract Background Mycoviruses are viruses that naturally infect and replicate in fungi. Aspergillus fumigatus, an opportunistic pathogen causing fungal lung diseases in humans and animals, was recently shown to harbour several different types of Mycoviruses. A well-characterised defence against virus infection is RNA silencing. The A. fumigatus genome encodes essential components of the RNA silencing machinery, including Dicer, Argonaute and RNA-dependent RNA polymerase (RdRP) homologues. Active silencing of double-stranded (ds)RNA and the generation of small RNAs (sRNAs) has been shown for several Mycoviruses and it is anticipated that a similar mechanism will be activated in A. fumigatus isolates infected with Mycoviruses. Results To investigate the existence and nature of A. fumigatus sRNAs, sRNA-seq libraries of virus-free and virus-infected isolates were created using Scriptminer adapters and compared. Three dsRNA viruses were investigated: Aspergillus fumigatus partitivirus-1 (AfuPV-1, PV), Aspergillus fumigatus chrysovirus (AfuCV, CV) and Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1, NK) which were selected because they induce phenotypic changes such as coloration and sectoring. The dsRNAs of all three viruses, which included two conventionally encapsidated ones PV and CV and one unencapsidated example NK, were silenced and yielded characteristic vsiRNAs together with co-incidental silencing of host fungal genes which shared sequence homology with the viral genomes. Conclusions Virus-derived sRNAs were detected and characterised in the presence of virus infection. Differentially expressed A. fumigatus microRNA-like (miRNA-like) sRNAs and small interfering RNAs (siRNAs) were detected and validated. Host sRNA loci which were differentially expressed as a result of virus infection were also identified. To our knowledge, this is the first study reporting the sRNA profiles of A. fumigatus isolates.
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the effects of dsrna Mycoviruses on growth and murine virulence of aspergillus fumigatus
Fungal Genetics and Biology, 2011Co-Authors: Muhammad Faraz Bhatti, Atif Jamal, Michael A Petrou, Timothy C Cairns, Elaine Bignell, Robert H A CouttsAbstract:Some isolates of the opportunistic human pathogenic fungus Aspergillus fumigatus are known to be infected with Mycoviruses. The dsRNA genomes of two of these Mycoviruses, which include a chrysovirus and a partitivirus, have been completely sequenced and an RT-PCR assay for the viruses has been developed. Through curing virus-infected A. fumigatus isolates by cycloheximide treatment and transfecting virus-free isolates with purified virus, as checked by RT-PCR, isogenic virus-free and virus-infected lines of the fungus were generated whose phenotypes and growth have been directly compared. Mycovirus infection of A. fumigatus with either the chrysovirus or the partitivirus resulted in significant aberrant phenotypic alterations and attenuation of growth of the fungus but had no effect on susceptibility to common antifungals. Chrysovirus infection of A. fumigatus caused no significant alterations to murine pathogenicity.
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Molecular characterisation of two novel double-stranded RNA elements from Phlebiopsis gigantea
Virus Genes, 2009Co-Authors: Zisis Kozlakidis, Caroline V. Hacker, Dominic Bradley, Atif Jamal, Xiyu Phoon, Joan Webber, Clive M. Brasier, Kenneth W. Buck, Robert H A CouttsAbstract:The incomplete sequences of two large, 10–12 kbp, double-stranded RNAs (dsRNAs) found in the TW-2 isolate of the saprophytic fungus, Phlebiopsis gigantea (Pg) are reported. Both PgV-TW2 dsRNA1 and dsRNA2 potentially encode fusion proteins which are apparently expressed by a translational frameshifting mechanism. The C-terminal region of both predicted proteins was 21% identical and contained the eight motifs conserved in RNA-dependent RNA polymerases of dsRNA Mycoviruses and had highest similarity with members of the family Totiviridae , but possibly do not form virions. The remainder of the N-terminal protein sequences predicted from the PgV-TW2 dsRNA1 and dsRNA2 sequences and the 3′-terminal nucleotide sequences of both dsRNAs had no homology with one another or any sequence in the database suggesting that individually both may be members of novel families of Mycoviruses.
Daohong Jiang - One of the best experts on this subject based on the ideXlab platform.
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Viruses of the plant pathogenic fungus Sclerotinia sclerotiorum.
Advances in Virus Research, 2020Co-Authors: Daohong Jiang, Yanping Fu, Li Guoqing, Said A GhabrialAbstract:Abstract Sclerotinia sclerotiorum is a notorious plant fungal pathogen with a broad host range including many important crops, such as oilseed rape, soybean, and numerous vegetable crops. Hypovirulence-associated Mycoviruses have attracted much attention because of their potential as biological control agents for combating plant fungal diseases and for use in fundamental studies on fungal pathogenicity and other properties. This chapter describes several Mycoviruses that were isolated from hypovirulent strains except for strain Sunf-M, which has a normal phenotype. These viruses include the geminivirus-like mycovirus Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), Sclerotinia debilitation-associated RNA virus (SsDRV), Sclerotinia sclerotiorum RNA virus L (SsRV-L), Sclerotinia sclerotiorum hypovirus 1 (SsHV-1), Sclerotinia sclerotiorum mitoviruses 1 and 2 (SsMV-1, SsMV-2), and Sclerotinia sclerotiorum partitivirus S (SsPV-S). Unlike many other fungi, incidences of mixed infections with two or more Mycoviruses in S. sclerotiorum are particularly high and very common. The interaction between SsDRV and S. sclerotiorum is likely to be unique. The significance of these Mycoviruses to fungal ecology and viral evolution and the potential for biological control of Sclerotinia diseases using Mycoviruses are discussed.
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discovery of two Mycoviruses by high throughput sequencing and assembly of mycovirus derived small silencing rnas from a hypovirulent strain of sclerotinia sclerotiorum
Frontiers in Microbiology, 2019Co-Authors: Qianqian Wang, Shufen Cheng, Jiasen Cheng, Yanping Fu, Tao Chen, Xueqiong Xiao, Daohong JiangAbstract:: Sclerotinia sclerotiorum, an important phytopathogenic fungus, harbors rich diversity of Mycoviruses. Lately, more Mycoviruses can be successfully and accurately discovered by deep sequencing, especially those that could not be detected by traditional double-stranded RNA (dsRNA) extraction. Previously, we reported that the hypovirulent S. sclerotiorum strain SZ-150 is coinfected by Sclerotinia sclerotiorum hypovirus 1 (SsHV1) and its related satellite RNA. Here, aside from SsHV1, we detected two other Mycoviruses, Sclerotinia sclerotiorum botybirnavirus 3 (SsBV3/SZ-150) and Sclerotinia sclerotiorum mycotymovirus 1 (SsMTV1/SZ-150), coinfecting strain SZ-150, by deep sequencing and assembly of mycovirus-derived small RNAs and determined their full-length genomes. The genome of SsBV3/SZ-150 was found to be composed of two linear dsRNA segments, 6,212, and 5,880 bp in size, respectively. Each dsRNA segment of SsBV3/SZ-150 contains a large open reading frame (ORF) encoding RNA-dependent RNA polymerase (RdRp) and a hypothetical protein. The whole genome of SsBV3/SZ-150 shares more than 95% sequence identity with Botrytis porri botybirnavirus 1 (BpBV1) at the nucleotide (nt) or amino acid level. Thus, SsBV3/SZ-150 was assumed to be a strain of BpBV1. The genome of SsMTV1/SZ-150 consists of 6,391 nt excluding the poly(A) tail. SsMTV1/SZ-150 was predicted to contain a large ORF that encodes a putative replication-associated polyprotein (RP) with three conserved domains of viral RNA methyltransferase, viral RNA helicase, and RdRp. Phylogenetic analyses suggest that SsMTV1/SZ-150 is related, albeit distantly, to members of the family Tymoviridae. Analysis of the small RNAs derived from SsBV3/SZ-150 and SsMTV1/SZ-150 revealed that small-RNA lengths mainly range from 20 to 24 nt, with a peak at 22 nt, and the most abundant 5'-terminal nucleotide is uridine, suggesting that the Dicer 2 and Argonaute 1, two key components in the RNA inference pathway, may play important roles in the resistance to mycoviral infection in S. sclerotiorum. Neither SsBV3/SZ-150 nor SsMTV1/SZ-150 is a causal agent of hypovirulence in strain SZ-150.
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50-plus years of fungal viruses.
Virology, 2015Co-Authors: Said A Ghabrial, Daohong Jiang, José R Castón, Max L Nibert, Nobuhiro SuzukiAbstract:Mycoviruses are widespread in all major taxa of fungi. They are transmitted intracellularly during cell division, sporogenesis, and/or cell-to-cell fusion (hyphal anastomosis), and thus their life cycles generally lack an extracellular phase. Their natural host ranges are limited to individuals within the same or closely related vegetative compatibility groups, although recent advances have established expanded experimental host ranges for some Mycoviruses. Most known Mycoviruses have dsRNA genomes packaged in isometric particles, but an increasing number of positive- or negative-strand ssRNA and ssDNA viruses have been isolated and characterized. Although many Mycoviruses do not have marked effects on their hosts, those that reduce the virulence of their phytopathogenic fungal hosts are of considerable interest for development of novel biocontrol strategies. Mycoviruses that infect endophytic fungi and those that encode killer toxins are also of special interest. Structural analyses of Mycoviruses have promoted better understanding of virus assembly, function, and evolution.
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prevalence and diversity of Mycoviruses infecting the plant pathogen ustilaginoidea virens
Virus Research, 2015Co-Authors: Yinhui Jiang, Guoqing Li, Daohong Jiang, Tingting Zhang, Qili Li, Tom Hsiang, Junbin HuangAbstract:Rice false smut caused by Ustilaginoidea virens is a destructive disease in many rice-growing areas. Mycoviruses have been described in many fungal species, but there is little information regarding Mycoviruses in U. virens. In this study, double-stranded (ds) RNA banding patterns were assessed in 198 wild-type isolates of U. virens obtained from different geographical regions in China. The presence of viral infections was unusually common in U. virens: 188 of the 198 isolates contained dsRNA elements with viral characteristics, and the presence of mixed infections with two or more related or unrelated Mycoviruses was commonly detected. The GX-1 isolate contained four dsRNA Mycoviruses: Ustilaginoidea virens RNA virus 1 (UvRV1) belonging to Totiviridae, Ustilaginoidea virens RNA virus 4 (UvRV4) belonging to an unclassified family which includes the Curvularia thermal tolerance virus, and the last two probably belonging to Partitiviridae. Biological comparisons of virus-free and infected fungal isolates revealed that UvRV1 strain GX-1 and UvRV4 were likely cryptic, since the infected strains did not show apparent symptoms or debilitation. Northern blotting experiments revealed that UvRV1 strain GX-1 and UvRV4 were frequently found in U. virens, irrespective of the place of origin, and similarly sized dsRNA bands were not always of similar sequence. Thus, our findings suggest that Mycoviruses infecting U. virens in China are widespread and highly diverse.
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new insights into Mycoviruses and exploration for the biological control of crop fungal diseases
Annual Review of Phytopathology, 2014Co-Authors: Daohong JiangAbstract:Mycoviruses are viruses that infect fungi. A growing number of novel Mycoviruses have expanded our knowledge of virology, particularly in taxonomy, ecology, and evolution. Recent progress in the study of Mycoviruses has comprehensively improved our understanding of the properties of Mycoviruses and has strengthened our confidence to explore hypovirulence-associated Mycoviruses that control crop diseases. In this review, the advantages of using hypovirulence-associated Mycoviruses to control crop diseases are discussed, and, as an example, the potential for Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) to control the stem rot of rapeseed (Brassica napus) is also introduced. Fungal vegetative incompatibility is likely to be the key factor that limits the wide utilization of Mycoviruses to control crop diseases; however, there are suggested strategies for resolving this problem.
Satoko Kanematsu - One of the best experts on this subject based on the ideXlab platform.
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natural infection of the soil borne fungus rosellinia necatrix with novel Mycoviruses under greenhouse conditions
Virus Research, 2016Co-Authors: Hajime Yaegashi, Satoko KanematsuAbstract:Abstract Fungi are an important component of the soil ecosystem. Mycoviruses have numerous potential impacts on soil fungi, including phytopathogenic fungal species. However, the diversity and ecology of Mycoviruses in soil fungi is largely unexplored. Our previous work has shown that the soil-borne phytopathogenic fungus Rosellinia necatrix was infected with several novel Mycoviruses after growing for 2–3 years in an apple orchard. In this study, we investigated whether natural infection of R. necatrix with Mycoviruses occurs under limited conditions. Virus-free R. necatrix isolates were grown in a small bucket containing soil samples for a short time (1.5–4.5 months) under greenhouse conditions. Screening of dsRNA Mycoviruses among 365 retrieved isolates showed that four, including 6–31, 6–33, 6–35, and 7–11, harbored virus-like dsRNAs. Molecular characterization of the dsRNAs revealed that three retrieved isolates, 6–31, 6–33, and 6–35 were infected with a novel endornavirus and isolate 7–11 is infected with a novel partitivirus belonging to the genus Alphapartitivirus. These novel Mycoviruses had no overt biological impact on R. necatrix. Overall, this study indicates that natural infections of R. necatrix with new Mycoviruses can occur under experimental soil conditions.
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differential inductions of rna silencing among encapsidated double stranded rna Mycoviruses in the white root rot fungus rosellinia necatrix
Journal of Virology, 2016Co-Authors: Hajime Yaegashi, Takeo Shimizu, Satoko KanematsuAbstract:UNLABELLED: RNA silencing acts as a defense mechanism against virus infection in a wide variety of organisms. Here, we investigated inductions of RNA silencing against encapsidated double-stranded RNA (dsRNA) fungal viruses (Mycoviruses), including a partitivirus (RnPV1), a quadrivirus (RnQV1), a victorivirus (RnVV1), a mycoreovirus (RnMyRV3), and a megabirnavirus (RnMBV1) in the phytopathogenic fungus Rosellinia necatrix Expression profiling of RNA silencing-related genes revealed that a dicer-like gene, an Argonaute-like gene, and two RNA-dependent RNA polymerase genes were upregulated by RnMyRV3 or RnMBV1 infection but not by other virus infections or by constitutive expression of dsRNA in R. necatrix Massive analysis of viral small RNAs (vsRNAs) from the five Mycoviruses showed that 19- to 22-nucleotide (nt) vsRNAs were predominant; however, their ability to form duplexes with 3' overhangs and the 5' nucleotide preferences of vsRNAs differed among the five Mycoviruses. The abundances of 19- to 22-nt vsRNAs from RnPV1, RnQV1, RnVV1, RnMyRV3, and RnMBV1 were 6.8%, 1.2%, 0.3%, 13.0%, and 24.9%, respectively. Importantly, the vsRNA abundances and accumulation levels of viral RNA were not always correlated, and the origins of the vsRNAs were distinguishable among the five Mycoviruses. These data corroborated diverse interactions between encapsidated dsRNA Mycoviruses and RNA silencing. Moreover, a green fluorescent protein (GFP)-based sensor assay in R. necatrix revealed that RnMBV1 infection induced silencing of the target sensor gene (GFP gene and the partial RnMBV1 sequence), suggesting that vsRNAs from RnMBV1 activated the RNA-induced silencing complex. Overall, this study provides insights into RNA silencing against encapsidated dsRNA Mycoviruses. IMPORTANCE: Encapsidated dsRNA fungal viruses (Mycoviruses) are believed to replicate inside their virions; therefore, there is a question of whether they induce RNA silencing. Here, we investigated inductions of RNA silencing against encapsidated dsRNA Mycoviruses (a partitivirus, a quadrivirus, a victorivirus, a mycoreovirus, and a megabirnavirus) in Rosellinia necatrix We revealed upregulation of RNA silencing-related genes in R. necatrix infected with a mycoreovirus or a megabirnavirus but not with other viruses, which was consistent with the relatively high abundances of vsRNAs from the two Mycoviruses. We also showed common and different molecular features and origins of the vsRNAs from the five Mycoviruses. Furthermore, we demonstrated the activation of RNA-induced silencing complex by Mycoviruses in R. necatrix Taken together, our data provide insights into an RNA silencing pathway against encapsidated dsRNA Mycoviruses which is differentially induced among encapsidated dsRNA Mycoviruses; that is, diverse replication strategies exist among encapsidated dsRNA Mycoviruses.
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Mycoviruses and virocontrol
Uirusu, 2010Co-Authors: Sotaro Chiba, Hideki Kondo, Satoko Kanematsu, Nobuhiro SuzukiAbstract:: Viruses are widespread in all major groups of fungi. The transmission of fungal viruses occurs intracellularly during cell division, sporogenesis, and cell fusion. They apparently lack an extracellular route for infection. Recent searches of the collections of field fungal isolates have detected an increasing number of novel viruses and lead to discoveries of novel genome organizations, expression strategies and virion structures. Those findings enhanced our understanding of virus diversity and evolution. The majority of fungal viruses have dsRNA genomes packaged in spherical particles, while ssRNA Mycoviruses, possessing or lacking the ability to form particles, have increasingly been reported. This review article discusses the current status of mycovirus studies and virocontrol (biocontrol) of phytopathogenic fungi using viruses that infect them and reduce their virulence. Selected examples of virocontrol-associated systems include the chestnut/chestnut blight/hypovirus and fruit trees/white root rot fungus/Mycoviruses. Natural dissemination and artificial introduction of hypovirulent fungal strains efficiently contributed to virocontrol of chestnut blight in European forests. Attempts to control white root rot with hypovirulence-conferring Mycoviruses are now being made in Japan.
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Extending the fungal host range of a partitivirus and a mycoreovirus from Rosellinia necatrix by inoculation of protoplasts with virus particles.
Phytopathology, 2010Co-Authors: Satoko Kanematsu, Atsuko Sasaki, Mari Onoue, Yuri OikawaAbstract:ABSTRACT The potential host range of Mycoviruses is poorly understood because of the lack of suitable inoculation methods. Recently, successful transfection has been reported for somatically incompatible fungal isolates with purified virus particles of two Mycoviruses, the partitivirus RnPV1-W8 (RnPV1) and the mycoreovirus RnMyRV3/W370 (MyRV3), from the white root rot fungus Rosellinia necatrix (class Sordariomycetes, subclass Xylariomycetidae). These studies examined and revealed the effect of the Mycoviruses on growth and pathogenicity of R. necatrix. Here, we extended the experimental host range of these two Mycoviruses using a transfection approach. Protoplasts of other phytopathogenic Sordariomycetous fungi—Diaporthe sp., Cryphonectria parasitica, Valsa ceratosperma (Sordariomycetidae), and Glomerella cingulata (Hypocreomycetidae)—were inoculated with RnPV1 and MyRV3 viral particles. The presence of double-stranded RNA viral genomes in regenerated mycelia of Diaporthe sp., C. parasitica, and V. cerat...
Donald L. Nuss - One of the best experts on this subject based on the ideXlab platform.
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Mycoviruses rna silencing and viral rna recombination
Advances in Virus Research, 2011Co-Authors: Donald L. NussAbstract:In contrast to viruses of plants and animals, viruses of fungi, Mycoviruses, uniformly lack an extracellular phase to their replication cycle. The persistent, intracellular nature of the mycovirus life cycle presents technical challenges to experimental design. However, these properties, coupled with the relative simplicity and evolutionary position of the fungal host, also provide opportunities for examining fundamental aspects of virus–host interactions from a perspective that is quite different from that pertaining for most plant and animal virus infections. This chapter presents support for this view by describing recent advances in the understanding of antiviral defense responses against one group of Mycoviruses for which many of the technical experimental challenges have been overcome, the hypoviruses responsible for hypovirulence of the chestnut blight fungus Cryphonectria parasitica. The findings reveal new insights into the induction and suppression of RNA silencing as an antiviral defense response and an unexpected role for RNA silencing in viral RNA recombination.
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Hypovirulence: Mycoviruses at the fungal–plant interface
Nature Reviews Microbiology, 2005Co-Authors: Donald L. NussAbstract:This review provides an overview of the Mycoviruses that are associated with the attenuation of fungal pathogenesis that is known as hypovirulence. The taxonomy and genome organization of hypoviruses are outlined. These viruses are in the taxonomic family Hypoviridae , which cause hypovirulence of the chestnut blight fungus Cryphonectria parasitica . The development of hypovirus reverse genetics systems is described. Hypovirus diversity has been exploited to identify symptom determinants and modulate fungal–plant pathogenic interactions. Potentially, Mycoviruses could be used to explore the origins, evolution and functions of RNA silencing in fungi. These viruses could also be used to probe the signal transduction pathways that underpin fungal pathogenesis. Hypovirus-mediated modulation of the host transcriptome has been analysed using microarrays, which has confirmed hypovirus-mediated alterations of host functions including G-protein signalling, and has revealed a link between mitochondrial and viral hypovirulence. Finally, the prospects for engineering hypoviruses to improve their suitability for biological control of fungal diseases of plants are discussed. Whereas most Mycoviruses lead 'secret lives', some reduce the ability of their fungal hosts to cause disease in plants. This property, known as hypovirulence, has attracted attention owing to the importance of fungal diseases in agriculture and the limited strategies that are available for the control of these diseases. Using one pathogen to control another is appealing, both intellectually and ecologically. The recent development of an infectious cDNA-based reverse genetics system for members of the Hypoviridae mycovirus family has enabled the analysis of basic aspects of this fascinating virus–fungus–plant interaction, including virus–host interactions, the mechanisms underlying fungal pathogenesis, fungal signalling pathways and the evolution of RNA silencing. Such systems also provide a means for engineering Mycoviruses for enhanced biocontrol potential.
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hypovirulence Mycoviruses at the fungal plant interface
Nature Reviews Microbiology, 2005Co-Authors: Donald L. NussAbstract:Whereas most Mycoviruses lead 'secret lives', some reduce the ability of their fungal hosts to cause disease in plants. This property, known as hypovirulence, has attracted attention owing to the importance of fungal diseases in agriculture and the limited strategies that are available for the control of these diseases. Using one pathogen to control another is appealing, both intellectually and ecologically. The recent development of an infectious cDNA-based reverse genetics system for members of the Hypoviridae mycovirus family has enabled the analysis of basic aspects of this fascinating virus–fungus–plant interaction, including virus–host interactions, the mechanisms underlying fungal pathogenesis, fungal signalling pathways and the evolution of RNA silencing. Such systems also provide a means for engineering Mycoviruses for enhanced biocontrol potential.
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Hypovirulence: Mycoviruses at the fungal–plant interface
Nature Reviews Microbiology, 2005Co-Authors: Donald L. NussAbstract:Whereas most Mycoviruses lead 'secret lives', some reduce the ability of their fungal hosts to cause disease in plants. This property, known as hypovirulence, has attracted attention owing to the importance of fungal diseases in agriculture and the limited strategies that are available for the control of these diseases. Using one pathogen to control another is appealing, both intellectually and ecologically. The recent development of an infectious cDNA-based reverse genetics system for members of the Hypoviridae mycovirus family has enabled the analysis of basic aspects of this fascinating virus–fungus–plant interaction, including virus–host interactions, the mechanisms underlying fungal pathogenesis, fungal signalling pathways and the evolution of RNA silencing. Such systems also provide a means for engineering Mycoviruses for enhanced biocontrol potential.
Selin Ozkan - One of the best experts on this subject based on the ideXlab platform.
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profile and functional analysis of small rnas derived from aspergillus fumigatus infected with double stranded rna Mycoviruses
BMC Genomics, 2017Co-Authors: Robert H A Coutts, Selin Ozkan, Irina Mohorianu, Ping Xu, Tamas DalmayAbstract:Abstract Background Mycoviruses are viruses that naturally infect and replicate in fungi. Aspergillus fumigatus, an opportunistic pathogen causing fungal lung diseases in humans and animals, was recently shown to harbour several different types of Mycoviruses. A well-characterised defence against virus infection is RNA silencing. The A. fumigatus genome encodes essential components of the RNA silencing machinery, including Dicer, Argonaute and RNA-dependent RNA polymerase (RdRP) homologues. Active silencing of double-stranded (ds)RNA and the generation of small RNAs (sRNAs) has been shown for several Mycoviruses and it is anticipated that a similar mechanism will be activated in A. fumigatus isolates infected with Mycoviruses. Results To investigate the existence and nature of A. fumigatus sRNAs, sRNA-seq libraries of virus-free and virus-infected isolates were created using Scriptminer adapters and compared. Three dsRNA viruses were investigated: Aspergillus fumigatus partitivirus-1 (AfuPV-1, PV), Aspergillus fumigatus chrysovirus (AfuCV, CV) and Aspergillus fumigatus tetramycovirus-1 (AfuTmV-1, NK) which were selected because they induce phenotypic changes such as coloration and sectoring. The dsRNAs of all three viruses, which included two conventionally encapsidated ones PV and CV and one unencapsidated example NK, were silenced and yielded characteristic vsiRNAs together with co-incidental silencing of host fungal genes which shared sequence homology with the viral genomes. Conclusions Virus-derived sRNAs were detected and characterised in the presence of virus infection. Differentially expressed A. fumigatus microRNA-like (miRNA-like) sRNAs and small interfering RNAs (siRNAs) were detected and validated. Host sRNA loci which were differentially expressed as a result of virus infection were also identified. To our knowledge, this is the first study reporting the sRNA profiles of A. fumigatus isolates.
