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M. Carmen Cañizares - One of the best experts on this subject based on the ideXlab platform.
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Mycoviruses in biological control from basic research to field implementation
Phytopathology, 2019Co-Authors: Maria D Garciapedrajas, J L Sarmientovillamil, A G Jacquat, M. Carmen Cañizares, Jose Sebastian DambolenaAbstract:: Mycoviruses from plant pathogens can induce hypovirulence (reduced virulence) in their host fungi and have gained considerable attention as potential biocontrol tools. An increasing number of Mycoviruses that induce fungal hypovirulence, from a wide variety of taxonomic groups, are currently being reported. Successful application of these viruses in disease management is greatly dependent on their ability to spread in the natural populations of the pathogen. Mycoviruses generally lack extracellular routes of transmission. Hyphal anastomosis is the main route of horizontal Mycovirus transmission to other isolates, and conidia of vertical transmission to the progeny. Transmission efficiencies are influenced by both the fungal host and the infecting virus. Interestingly, artificial transfection methods have shown that potential biocontrol Mycoviruses often have the ability to infect a variety of fungi. This expands their possible use to the control of pathogens others than those where they were identified. Mycovirus research is also focused on gaining insights into their complex molecular biology and the molecular bases of fungus-virus interactions. This knowledge could be exploited to manipulate the Mycovirus and/or the host and generate combinations with enhanced properties in biological control. Finally, when exploring the use of Mycoviruses in field conditions, the pathogen life style and the characteristics of the disease and crops affected will deeply impact the specific challenges to overcome, and the development of biocontrol formulations and delivery methods.
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Horizontal and vertical transmission of the hypovirulence-associated Mycovirus Fusarium oxysporum f. sp. dianthi virus 1
European Journal of Plant Pathology, 2018Co-Authors: C.g. Lemus-minor, M. Carmen Cañizares, María D. García-pedrajas, Encarnación Pérez-artésAbstract:Mycovirus Fusarium oxysporum f. sp. dianthi virus 1 (FodV1) has been recently described infecting isolate Fod 116 of Fusarium oxysporum f. sp. dianthi (Fod). FodV1 is a new member of the family Chrysoviridae, and its genome consists of four dsRNA segments ranging from 2.6 to 3.5 kb. Presence of high levels of FodV1 in its original fungal host correlated with alteration of some phenotypic traits, including virulence. In this work we have analysed if FodV1 can be transferred horizontally to another Fod isolate by hyphal anastomosis, and vertically through conidiation, and if the Mycovirus accumulates in the recipient isolate at similar levels that those found in the donor one. Moreover, we have investigated if the new virus-infected isolate reproduces the same phenotypic alterations that the original virus-infected does. Results indicated that FodV1 transfers horizontally between compatible isolates by hyphal anastomosis, reaching a high level of accumulation in the recipient isolate, and vertically during sporogenesis. Presence of FodV1 in the new fungal host reduced the growth rate and altered the morphology of the colony on solid medium, and diminished the conidiation rate in liquid medium. More interestingly, FodV1 induced hypovirulence in its new fungal host. Results contained in this work constitute the basis for further research on the application of Mycovirus FodV1 to the control of Fusarium wilt diseases.
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Characterization of a novel single-stranded RNA Mycovirus related to invertebrate viruses from the plant pathogen Verticillium dahliae
Archives of Virology, 2018Co-Authors: M. Carmen Cañizares, Francisco J. López-escudero, Encarnación Pérez-artés, María D. García-pedrajasAbstract:Fungal viruses, also known as Mycoviruses, are widespread in all major groups of fungi. Mycoviruses from plant pathogens can reduce the virulence of their host fungus and have therefore potential as biological control agents. This has spurred the identification of novel Mycoviruses in plant pathogens, research which is greatly contributing to our understanding of these organisms. In this work, we report the characterization of a novel monopartite Mycovirus from Verticillium dahliae , the main causal agent of Verticillium wilt. This novel Mycovirus, which we termed Verticillium dahliae RNA virus 1 (VdRV1), was identified in three different isolates of V. dahliae collected in olive growing areas of the Guadalquivir valley, southern Spain. We determined that the VdRV1 genome is a positive (+) single-stranded (ss) RNA, 2631 nucleotides in length, containing two open reading frames. VdRV1 showed few similarities with known Mycoviruses, only with a group of unassigned (+) ssRNA Mycoviruses which are related to plant viruses classified within the family Tombusviridae . However, phylogenetic analysis revealed that VdRV1 and the unassigned (+) ssRNA Mycoviruses have a closer relationship with recently reported invertebrate viruses. This result indicates that as more viral sequences become available, the relationships of Mycoviruses with viruses from other hosts should be reexamined. Additionally, the work supports the hypothesis of a heterogeneous origin for Mycoviruses.
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Complete genome sequence of a novel dsRNA Mycovirus isolated from the phytopathogenic fungus Fusarium oxysporum f. sp. dianthi
Archives of Virology, 2015Co-Authors: Carlos G. Lemus-minor, M. Carmen Cañizares, María D. García-pedrajas, Encarnación Pérez-artésAbstract:A novel double-stranded RNA (dsRNA) Mycovirus, designated Fusarium oxysporum f. sp. dianthi Mycovirus 1 (FodV1), was isolated from a strain of the phytopathogenic fungus F. oxysporum f. sp. dianthi . The FodV1 genome had four dsRNA segments, designated, from the largest to the smallest one, dsRNA 1, 2 3, and 4. Each one of these segments contained a single open reading frame (ORF). dsRNA 1 (3555 bp) and dsRNA 3 (2794 bp) encoded a putative RNA-dependent RNA polymerase (RdRp) and a putative coat protein (CP), respectively. dsRNA 2 (2809 bp) and dsRNA 4 (2646 bp) contained ORFs encoding hypothetical proteins (named P2 and P4, respectively) with unknown functions. Analysis of its genomic structure, homology searches of the deduced amino acid sequences, and phylogenetic analysis all indicated that FodV1 is a new member of the family Chrysoviridae . This is the first report of the complete genomic characterization of a Mycovirus identified in the plant pathogen Fusarium oxysporum .
María D. García-pedrajas - One of the best experts on this subject based on the ideXlab platform.
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Horizontal and vertical transmission of the hypovirulence-associated Mycovirus Fusarium oxysporum f. sp. dianthi virus 1
European Journal of Plant Pathology, 2018Co-Authors: C.g. Lemus-minor, M. Carmen Cañizares, María D. García-pedrajas, Encarnación Pérez-artésAbstract:Mycovirus Fusarium oxysporum f. sp. dianthi virus 1 (FodV1) has been recently described infecting isolate Fod 116 of Fusarium oxysporum f. sp. dianthi (Fod). FodV1 is a new member of the family Chrysoviridae, and its genome consists of four dsRNA segments ranging from 2.6 to 3.5 kb. Presence of high levels of FodV1 in its original fungal host correlated with alteration of some phenotypic traits, including virulence. In this work we have analysed if FodV1 can be transferred horizontally to another Fod isolate by hyphal anastomosis, and vertically through conidiation, and if the Mycovirus accumulates in the recipient isolate at similar levels that those found in the donor one. Moreover, we have investigated if the new virus-infected isolate reproduces the same phenotypic alterations that the original virus-infected does. Results indicated that FodV1 transfers horizontally between compatible isolates by hyphal anastomosis, reaching a high level of accumulation in the recipient isolate, and vertically during sporogenesis. Presence of FodV1 in the new fungal host reduced the growth rate and altered the morphology of the colony on solid medium, and diminished the conidiation rate in liquid medium. More interestingly, FodV1 induced hypovirulence in its new fungal host. Results contained in this work constitute the basis for further research on the application of Mycovirus FodV1 to the control of Fusarium wilt diseases.
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Characterization of a novel single-stranded RNA Mycovirus related to invertebrate viruses from the plant pathogen Verticillium dahliae
Archives of Virology, 2018Co-Authors: M. Carmen Cañizares, Francisco J. López-escudero, Encarnación Pérez-artés, María D. García-pedrajasAbstract:Fungal viruses, also known as Mycoviruses, are widespread in all major groups of fungi. Mycoviruses from plant pathogens can reduce the virulence of their host fungus and have therefore potential as biological control agents. This has spurred the identification of novel Mycoviruses in plant pathogens, research which is greatly contributing to our understanding of these organisms. In this work, we report the characterization of a novel monopartite Mycovirus from Verticillium dahliae , the main causal agent of Verticillium wilt. This novel Mycovirus, which we termed Verticillium dahliae RNA virus 1 (VdRV1), was identified in three different isolates of V. dahliae collected in olive growing areas of the Guadalquivir valley, southern Spain. We determined that the VdRV1 genome is a positive (+) single-stranded (ss) RNA, 2631 nucleotides in length, containing two open reading frames. VdRV1 showed few similarities with known Mycoviruses, only with a group of unassigned (+) ssRNA Mycoviruses which are related to plant viruses classified within the family Tombusviridae . However, phylogenetic analysis revealed that VdRV1 and the unassigned (+) ssRNA Mycoviruses have a closer relationship with recently reported invertebrate viruses. This result indicates that as more viral sequences become available, the relationships of Mycoviruses with viruses from other hosts should be reexamined. Additionally, the work supports the hypothesis of a heterogeneous origin for Mycoviruses.
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Complete genome sequence of a novel dsRNA Mycovirus isolated from the phytopathogenic fungus Fusarium oxysporum f. sp. dianthi
Archives of Virology, 2015Co-Authors: Carlos G. Lemus-minor, M. Carmen Cañizares, María D. García-pedrajas, Encarnación Pérez-artésAbstract:A novel double-stranded RNA (dsRNA) Mycovirus, designated Fusarium oxysporum f. sp. dianthi Mycovirus 1 (FodV1), was isolated from a strain of the phytopathogenic fungus F. oxysporum f. sp. dianthi . The FodV1 genome had four dsRNA segments, designated, from the largest to the smallest one, dsRNA 1, 2 3, and 4. Each one of these segments contained a single open reading frame (ORF). dsRNA 1 (3555 bp) and dsRNA 3 (2794 bp) encoded a putative RNA-dependent RNA polymerase (RdRp) and a putative coat protein (CP), respectively. dsRNA 2 (2809 bp) and dsRNA 4 (2646 bp) contained ORFs encoding hypothetical proteins (named P2 and P4, respectively) with unknown functions. Analysis of its genomic structure, homology searches of the deduced amino acid sequences, and phylogenetic analysis all indicated that FodV1 is a new member of the family Chrysoviridae . This is the first report of the complete genomic characterization of a Mycovirus identified in the plant pathogen Fusarium oxysporum .
Encarnación Pérez-artés - One of the best experts on this subject based on the ideXlab platform.
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Horizontal and vertical transmission of the hypovirulence-associated Mycovirus Fusarium oxysporum f. sp. dianthi virus 1
European Journal of Plant Pathology, 2018Co-Authors: C.g. Lemus-minor, M. Carmen Cañizares, María D. García-pedrajas, Encarnación Pérez-artésAbstract:Mycovirus Fusarium oxysporum f. sp. dianthi virus 1 (FodV1) has been recently described infecting isolate Fod 116 of Fusarium oxysporum f. sp. dianthi (Fod). FodV1 is a new member of the family Chrysoviridae, and its genome consists of four dsRNA segments ranging from 2.6 to 3.5 kb. Presence of high levels of FodV1 in its original fungal host correlated with alteration of some phenotypic traits, including virulence. In this work we have analysed if FodV1 can be transferred horizontally to another Fod isolate by hyphal anastomosis, and vertically through conidiation, and if the Mycovirus accumulates in the recipient isolate at similar levels that those found in the donor one. Moreover, we have investigated if the new virus-infected isolate reproduces the same phenotypic alterations that the original virus-infected does. Results indicated that FodV1 transfers horizontally between compatible isolates by hyphal anastomosis, reaching a high level of accumulation in the recipient isolate, and vertically during sporogenesis. Presence of FodV1 in the new fungal host reduced the growth rate and altered the morphology of the colony on solid medium, and diminished the conidiation rate in liquid medium. More interestingly, FodV1 induced hypovirulence in its new fungal host. Results contained in this work constitute the basis for further research on the application of Mycovirus FodV1 to the control of Fusarium wilt diseases.
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Characterization of a novel single-stranded RNA Mycovirus related to invertebrate viruses from the plant pathogen Verticillium dahliae
Archives of Virology, 2018Co-Authors: M. Carmen Cañizares, Francisco J. López-escudero, Encarnación Pérez-artés, María D. García-pedrajasAbstract:Fungal viruses, also known as Mycoviruses, are widespread in all major groups of fungi. Mycoviruses from plant pathogens can reduce the virulence of their host fungus and have therefore potential as biological control agents. This has spurred the identification of novel Mycoviruses in plant pathogens, research which is greatly contributing to our understanding of these organisms. In this work, we report the characterization of a novel monopartite Mycovirus from Verticillium dahliae , the main causal agent of Verticillium wilt. This novel Mycovirus, which we termed Verticillium dahliae RNA virus 1 (VdRV1), was identified in three different isolates of V. dahliae collected in olive growing areas of the Guadalquivir valley, southern Spain. We determined that the VdRV1 genome is a positive (+) single-stranded (ss) RNA, 2631 nucleotides in length, containing two open reading frames. VdRV1 showed few similarities with known Mycoviruses, only with a group of unassigned (+) ssRNA Mycoviruses which are related to plant viruses classified within the family Tombusviridae . However, phylogenetic analysis revealed that VdRV1 and the unassigned (+) ssRNA Mycoviruses have a closer relationship with recently reported invertebrate viruses. This result indicates that as more viral sequences become available, the relationships of Mycoviruses with viruses from other hosts should be reexamined. Additionally, the work supports the hypothesis of a heterogeneous origin for Mycoviruses.
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Complete genome sequence of a novel dsRNA Mycovirus isolated from the phytopathogenic fungus Fusarium oxysporum f. sp. dianthi
Archives of Virology, 2015Co-Authors: Carlos G. Lemus-minor, M. Carmen Cañizares, María D. García-pedrajas, Encarnación Pérez-artésAbstract:A novel double-stranded RNA (dsRNA) Mycovirus, designated Fusarium oxysporum f. sp. dianthi Mycovirus 1 (FodV1), was isolated from a strain of the phytopathogenic fungus F. oxysporum f. sp. dianthi . The FodV1 genome had four dsRNA segments, designated, from the largest to the smallest one, dsRNA 1, 2 3, and 4. Each one of these segments contained a single open reading frame (ORF). dsRNA 1 (3555 bp) and dsRNA 3 (2794 bp) encoded a putative RNA-dependent RNA polymerase (RdRp) and a putative coat protein (CP), respectively. dsRNA 2 (2809 bp) and dsRNA 4 (2646 bp) contained ORFs encoding hypothetical proteins (named P2 and P4, respectively) with unknown functions. Analysis of its genomic structure, homology searches of the deduced amino acid sequences, and phylogenetic analysis all indicated that FodV1 is a new member of the family Chrysoviridae . This is the first report of the complete genomic characterization of a Mycovirus identified in the plant pathogen Fusarium oxysporum .
Hiromitsu Moriyama - One of the best experts on this subject based on the ideXlab platform.
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Analysis of an Intrinsic Mycovirus Associated With Reduced Virulence of the Human Pathogenic Fungus Aspergillus fumigatus.
Frontiers in Microbiology, 2020Co-Authors: Azusa Takahashi-nakaguchi, Syun-ichi Urayama, Hiromitsu Moriyama, Erika Shishido, Misa Yahara, Kanae Sakai, Hiroji Chibana, Katsuhiko Kamei, Tohru GonoiAbstract: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.
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Chrysoviruses in Magnaporthe oryzae
Viruses, 2018Co-Authors: Hiromitsu Moriyama, Tomoya Higashiura, Tuong Minh Le, Syun-ichi Urayama, Ken KomatsuAbstract: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.
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Genome sequence of a novel victorivirus identified in the phytopathogenic fungus Alternaria arborescens
Archives of Virology, 2016Co-Authors: Ken Komatsu, Motoichiro Kodama, Tohru Teraoka, Tsutomu Arie, Yukie Katayama, Toshiyuki Fukuhara, Tsutomu Omatsu, Tetsuya Mizutani, Hiromitsu MoriyamaAbstract:Strains of the phytopathogenic fungus Alternaria spp. have been found to contain a variety of double-stranded RNA (dsRNA) elements indicative of Mycovirus infection. Here, we report the molecular characterization of a novel dsRNA Mycovirus, Alternaria arborescens victorivirus 1 (AaVV1), from A. arborescens , the tomato pathotype of A. alternata . Using next-generation sequencing of dsRNA purified from an A. arborescens strain from the United States of America, we found that the AaVV1 genome is 5203 bp in length and contains two open reading frames (ORF1 and 2) that overlap at the tetranucleotide AUGA. Proteins encoded by ORF1 and ORF2 showed significant similarities to the coat protein (CP) and the RNA-dependent RNA polymerase (RdRp), respectively, of dsRNA Mycoviruses of the genus Victorivirus . Pairwise comparisons and phylogenetic analysis of the deduced amino acid sequences of both CP and RdRp indicated that AaVV1 is a member of a distinct species of the genus Victorivirus in the family Totiviridae .
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a dsrna Mycovirus magnaporthe oryzae chrysovirus 1 b suppresses vegetative growth and development of the rice blast fungus
Virology, 2014Co-Authors: Syun-ichi Urayama, Tohru Teraoka, Tsutomu Arie, Toshiyuki Fukuhara, Hirofumi Sakoda, Ryoko Takai, Yu Katoh, Hiromitsu MoriyamaAbstract:A double-stranded RNA (dsRNA) Mycovirus was found in isolate S-0412-II 2a of the rice blast fungus Magnaporthe oryzae. Sequence analysis of the five dsRNA segments (dsRNA1 through dsRNA5) revealed that this Mycovirus is closely related to Magnaporthe oryzae chrysovirus 1-A (MoCV1-A), tentatively classified as a member of the Chrysoviridae; therefore, it was named Magnaporthe oryzae chrysovirus 1-B (MoCV1-B). Virus particles were spherical and composed of the ORF1, ORF3 and ORF4 proteins. MoCV1-B-infected isolate S-0412-II 2a showed a more severe impaired phenotype than the MoCV1-A-infected isolate. In a virus-cured isolate, normal growth was restored, implied that MoCV1-B could be involved in this observed phenotype. An unanticipated result was the occurrence of a fungal isolate lacking dsRNA5. The nonessential dsRNA5 had higher sequence identity (96%) with dsRNA5 of MoCV1-A than with the other dsRNA segments (71-79%), indicating that dsRNA5 could be a portable genomic element between MoCV1-A and MoCV1-B.
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Mycoviruses related to chrysovirus affect vegetative growth in the rice blast fungus magnaporthe oryzae
Journal of General Virology, 2010Co-Authors: Syun-ichi Urayama, Yu Suzuki, Sachie Kato, Nanako Aoki, Minh Tuong Le, Tohru Teraoka, Tsutomu Arie, Toshiyuki Fukuhara, Hiromitsu MoriyamaAbstract:Mycoviruses causing impaired growth and abnormal pigmentation of the host were found in the rice blast fungus, Magnaporthe oryzae. Four dsRNAs, dsRNA 1 (3554 bp), dsRNA 2 (3250 bp), dsRNA 3 (3074 bp) and dsRNA 4 (3043 bp), were detected in isolate S-0412-II 1a of M. oryzae. By picking up single conidia of S-0412-II 1a, cured strains of the fungus were isolated that had completely lost the Mycovirus. The cured strains had normal mycelial growth and pigmentation, suggesting that this Mycovirus modulates host traits. The buoyant densities of isometric virus particles (∼35 nm diameter) containing these dsRNAs in CsCl ranged from 1.37 to 1.40 g cm−3. The single ORF (3384 nt) of dsRNA 1 encoded a gene product highly homologous to the viral RNA-dependent RNA polymerase of members of the family Chrysoviridae. It is noteworthy that Mycovirus S-0412-II 1a was detected not only in host cells but also in culture supernatant. Furthermore, abnormal aggregation of mycelia was observed after adding the Mycovirus-containing culture supernatant to an uninfected strain of M. oryzae and mycoviral dsRNAs were detectable from the aggregated mycelia. This novel dsRNA Mycovirus was named Magnaporthe oryzae chrysovirus 1.
Toshiyuki Fukuhara - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of a novel Mycovirus in alternaria alternata manifesting two sided effects down regulation of host growth and up regulation of host plant pathogenicity
Virology, 2018Co-Authors: Ryo Okada, Ken Komatsu, Tsutomu Arie, Syun-ichi Urayama, Toshiyuki Fukuhara, Shun Ichinose, Kana Takeshita, Atsushi Ishihara, Mayumi Egusa, Motoichiro KodamaAbstract:Abstract A double-stranded RNA (dsRNA) Mycovirus was detected in a strain of Alternaria alternata showing impaired growth phenotypes. The A. alternata strain is the Japanese pear pathotype, which produces a host-specific AK-toxin. Sequence analysis of the viral genome dsRNAs revealed that this Mycovirus consists of five dsRNAs and is evolutionarily related to members of the family Chrysoviridae; the virus was named Alternaria alternata chrysovirus 1 (AaCV1). AaCV1-ORF2 protein accumulated in dsRNA-high-titer sub-isolates with severely impaired phenotypes; heterologous AaCV1-ORF2 overexpression in Saccharomyces cerevisiae caused growth inhibition. In contrast to this yeast growth inhibition phenomenon, the dsRNA-high-titer isolates displayed enhanced pathogenicity against Japanese pear plants, in accordance with a 13-fold increase in AK-toxin level in one such isolate. These findings indicated that AaCV1 is a novel Mycovirus that exhibits two contrasting effects, impairing growth of the host fungus while rendering the host ‘hypervirulent’ to the plant.
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Genome sequence of a novel victorivirus identified in the phytopathogenic fungus Alternaria arborescens
Archives of Virology, 2016Co-Authors: Ken Komatsu, Motoichiro Kodama, Tohru Teraoka, Tsutomu Arie, Yukie Katayama, Toshiyuki Fukuhara, Tsutomu Omatsu, Tetsuya Mizutani, Hiromitsu MoriyamaAbstract:Strains of the phytopathogenic fungus Alternaria spp. have been found to contain a variety of double-stranded RNA (dsRNA) elements indicative of Mycovirus infection. Here, we report the molecular characterization of a novel dsRNA Mycovirus, Alternaria arborescens victorivirus 1 (AaVV1), from A. arborescens , the tomato pathotype of A. alternata . Using next-generation sequencing of dsRNA purified from an A. arborescens strain from the United States of America, we found that the AaVV1 genome is 5203 bp in length and contains two open reading frames (ORF1 and 2) that overlap at the tetranucleotide AUGA. Proteins encoded by ORF1 and ORF2 showed significant similarities to the coat protein (CP) and the RNA-dependent RNA polymerase (RdRp), respectively, of dsRNA Mycoviruses of the genus Victorivirus . Pairwise comparisons and phylogenetic analysis of the deduced amino acid sequences of both CP and RdRp indicated that AaVV1 is a member of a distinct species of the genus Victorivirus in the family Totiviridae .
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a dsrna Mycovirus magnaporthe oryzae chrysovirus 1 b suppresses vegetative growth and development of the rice blast fungus
Virology, 2014Co-Authors: Syun-ichi Urayama, Tohru Teraoka, Tsutomu Arie, Toshiyuki Fukuhara, Hirofumi Sakoda, Ryoko Takai, Yu Katoh, Hiromitsu MoriyamaAbstract:A double-stranded RNA (dsRNA) Mycovirus was found in isolate S-0412-II 2a of the rice blast fungus Magnaporthe oryzae. Sequence analysis of the five dsRNA segments (dsRNA1 through dsRNA5) revealed that this Mycovirus is closely related to Magnaporthe oryzae chrysovirus 1-A (MoCV1-A), tentatively classified as a member of the Chrysoviridae; therefore, it was named Magnaporthe oryzae chrysovirus 1-B (MoCV1-B). Virus particles were spherical and composed of the ORF1, ORF3 and ORF4 proteins. MoCV1-B-infected isolate S-0412-II 2a showed a more severe impaired phenotype than the MoCV1-A-infected isolate. In a virus-cured isolate, normal growth was restored, implied that MoCV1-B could be involved in this observed phenotype. An unanticipated result was the occurrence of a fungal isolate lacking dsRNA5. The nonessential dsRNA5 had higher sequence identity (96%) with dsRNA5 of MoCV1-A than with the other dsRNA segments (71-79%), indicating that dsRNA5 could be a portable genomic element between MoCV1-A and MoCV1-B.
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Mycoviruses related to chrysovirus affect vegetative growth in the rice blast fungus magnaporthe oryzae
Journal of General Virology, 2010Co-Authors: Syun-ichi Urayama, Yu Suzuki, Sachie Kato, Nanako Aoki, Minh Tuong Le, Tohru Teraoka, Tsutomu Arie, Toshiyuki Fukuhara, Hiromitsu MoriyamaAbstract:Mycoviruses causing impaired growth and abnormal pigmentation of the host were found in the rice blast fungus, Magnaporthe oryzae. Four dsRNAs, dsRNA 1 (3554 bp), dsRNA 2 (3250 bp), dsRNA 3 (3074 bp) and dsRNA 4 (3043 bp), were detected in isolate S-0412-II 1a of M. oryzae. By picking up single conidia of S-0412-II 1a, cured strains of the fungus were isolated that had completely lost the Mycovirus. The cured strains had normal mycelial growth and pigmentation, suggesting that this Mycovirus modulates host traits. The buoyant densities of isometric virus particles (∼35 nm diameter) containing these dsRNAs in CsCl ranged from 1.37 to 1.40 g cm−3. The single ORF (3384 nt) of dsRNA 1 encoded a gene product highly homologous to the viral RNA-dependent RNA polymerase of members of the family Chrysoviridae. It is noteworthy that Mycovirus S-0412-II 1a was detected not only in host cells but also in culture supernatant. Furthermore, abnormal aggregation of mycelia was observed after adding the Mycovirus-containing culture supernatant to an uninfected strain of M. oryzae and mycoviral dsRNAs were detectable from the aggregated mycelia. This novel dsRNA Mycovirus was named Magnaporthe oryzae chrysovirus 1.
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A novel Mycovirus associated with four double-stranded RNAs affects host fungal growth in Alternaria alternata.
Virus Research, 2009Co-Authors: Nanako Aoki, Motoichiro Kodama, Tohru Teraoka, Tsutomu Arie, Hiromitsu Moriyama, Toshiyuki FukuharaAbstract:Four double-stranded RNAs (dsRNAs), referred to as dsRNA 1 (3617 bp), dsRNA 2 (2794 bp), dsRNA 3 (2576 bp) and dsRNA 4 (1420 bp), were detected in the EGS 35-193 strain of Alternaria alternata at high concentration ( approximately 3 microg/g dried mycelium). This strain had an impaired growth phenotype. By exposing the strain to cycloheximide during hyphal tip isolation, we isolated strains which had normal mycelial growth and pigmentation, in which decreased levels of the dsRNAs were observed ( approximately 0.3 microg/g dried mycelium). These results indicate that this dsRNA Mycovirus might be involved in modulating traits of its fungal host, A. alternata. The buoyant density of isometric virus particles (about 33 nm in diameter) containing these dsRNAs in CsCl was 1.35-1.40 g/cm(3) depending on the size of the packaged dsRNAs. The dsRNA 1 encodes a single open reading frame (3447 nt) containing the conserved motifs of viral RNA-dependent RNA polymerase (RdRp), which is related to the ORF encoded by dsRNA 1 of Aspergillus Mycovirus 341. It is noteworthy that all of the coding strands of the four dsRNA genomes have 3'-poly (A) tails ranging from 33 to 50 nt in length. We named this novel dsRNA Mycovirus in the EGS 35-193 strain A. alternata virus-1 (AaV-1).
