The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Naoyuki Matsumoto - One of the best experts on this subject based on the ideXlab platform.
-
An endornavirus from a hypovirulent strain of the violet root rot fungus, Helicobasidium mompa.
Virus Research, 2006Co-Authors: Hideki Osaki, Naoyuki Matsumoto, Hitoshi Nakamura, Atsuko Sasaki, Koji YoshidaAbstract:We determined the complete nucleotide (nt) sequence (16,614 nt) of a large double-stranded (ds) RNA (referred to as L1 dsRNA), previously identified as the hypovirulence factor from strain V670 of the violet root rot fungus, Helicobasidium mompa. The positive-strand of L1 dsRNA contained a long open reading frame (ORF) potentially encoding a protein of 5,373 amino acids (molecular mass 603,080 Da) with conserved motifs characteristic of RNA-dependent RNA polymerase (RdRp) and helicase. The ORF is the longest so far reported in the fungal kingdom. The putative RdRp and helicase were shown to be related to putative RdRps and helicases of members of the genus Endornavirus. As is the case with endornaviruses, the coding (sense) strand of L1 dsRNA contained a discontinuity (nick) at nt position 2,552. A region between the RdRp and helicase domains of the polyprotein also had an amino acid sequence, resembling UDP glycosyltransferases (UGTs) in Oryza sativa endornavirus and Phytophthora endornavirus 1. Regions in the L1 dsRNA-encoded protein presumed to contain putative helicase, UGT and RdRp motifs were present at comparable positions to those in other endornaviruses. L1 dsRNA of H. mompa strain V670 was assigned to the genus Endornavirus, and here, we designate it as H. mompa endornavirus 1-670 (HmEV1-670). This represents the first report of a fungal endornavirus whose complete nucleotide sequence has been determined.
-
Horizontal transmission and host-virulence attenuation of totivirus in violet root rot fungus Helicobasidium mompa
Journal of General Plant Pathology, 2005Co-Authors: Kouichi Suzaki, Satoko Kanematsu, Ken Ichi Ikeda, Naoyuki Matsumoto, Atsuko Sasaki, Kouji YoshidaAbstract:Monokaryotic strains of Helicobasidium mompa were used as vectors of a mycovirus between various H. mompa isolates to examine the transmissibility of one of the mycoviruses, totivirus ( HmTV1–17 virus ) in the hypovirulent isolate V17 of H. mompa . The isolates that acquired HmTV1–17 virus were also examined for any alteration in the virulence. Twelve dikaryotic isolates of H. mompa , belonging to 11 mycelial compatibility groups (MCGs) and being mycelially incompatible with isolate V17, were used as recipients of HmTV1–17 virus . Two monokaryotic isolates that were mycelially incompatible with isolate V17 and all of the recipients were also used as vectors of HmTV1-17 virus between isolate V17 and the recipients. When isolate V17 and recipients were directly paired on plate media, HmTV1-17 virus was transmitted from isolate V17 into 2 of the 12 recipients (i.e., 2 of the 11 MCGs). Two monokaryotic strains were paired with isolate V17, and the monokaryotic strains that acquired HmTV1-17 virus were then used as new virus donors. When the monokaryotic strains containing HmTV1-17 virus were paired with the 12 recipients, HmTV1-17 virus was transmitted into 7 of the 12 recipients from the monokaryotic strains (i.e., 7 of 11 MCGs). Based on these results, we concluded that monokaryotic strains could act as vectors to transmit HmTV1-17 virus into H. mompa isolates. When four of the H. mompa isolates that acquired HmTV1-17 virus were used to inoculate apple rootstock Malus prunifolia , the virulence of all of the isolates was attenuated from that of their parental isolates. Moreover, because the DNA fingerprints of the fungal isolates that acquired HmTV1-17 virus were the same as those of their parental isolates, the infection with HmTV1-17 virus is considered the cause of virulence attenuation of H. mompa .
-
Nucleotide sequence of a mitochondrial RNA virus from the plant pathogenic fungus, Helicobasidium mompa Tanaka.
Virus Research, 2005Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Hitoshi Nakamura, Koji YoshidaAbstract:Abstract A double-stranded (ds) RNA (2411 bp) from a strain V18 of the violet root rot basidiomycetous fungus, Helicobasidium mompa was sequenced. Using the fungal mitochondrial genetic code in which UGA codes for tryptophan, the positive strand of V18 dsRNA was found to contain a long open-reading frame with the potential to encode a protein of 700 amino acids (molecular mass 79,805 Da), including conserved motifs characteristic of RNA-dependent RNA polymerase (RDRP). This putative RDRP was shown to be related to putative RDRPs of several fungal mitochondrial viruses. It is proposed that V18 dsRNA is assigned to the genus Mitovirus in the family Narnaviridae and designated as H. mompa mitovirus 1-18 (HmMV1-18). Like other mitoviruses, HmMV1-18 RNA can be folded into potentially stable stem-loop structures at both the 5′- and 3′-termini, and both terminal sequences have inverted complementarity with the potential to form panhandle structure. BLAST analysis indicates that the RDRP encoded by HmMV1-18 is more closely related to those encoded by mitochondrial viruses of some ascomycetes than to that of the unassigned RsM2-1A1 dsRNA in the basidiomycetous Rhizoctonia solani . HmMV1-18 is the first member of the genus Mitovirus from basidiomycete fungi.
-
dynamics of double stranded rna segments in a Helicobasidium mompa clone from a tulip tree plantation
FEMS Microbiology Ecology, 2005Co-Authors: Ken Ichi Ikeda, Masao Arakawa, Hitoshi Nakamura, Toshiyuki Koiwa, Naoyuki MatsumotoAbstract:Eighty-three isolates of the violet root rot fungus, Helicobasidium mompa, were collected in a tulip tree plantation and analyzed for the dynamics of double-stranded (ds) RNA for five years. They were divided into eight mycelial compatibility groups (MCGs). Prevalent MCGs 60 and 68 included 61 and 11 isolates, respectively. Electrophoretic profiles of dsRNA in the first year collection of MCG 60 contained no or a single large dsRNA (more than 10 kb) with or without small dsRNAs (ca. 2.0–2.5 kb). Additional dsRNA fragments, i.e., a middle dsRNA (ca. 8.0 kb) or another type of small dsRNAs, became evident within MCG 60 isolates with time. Northern hybridization revealed the relatedness of all large and middle dsRNA fragments within MCG 60 but small fragments of dsRNA were variable. Large dsRNA fragment differed from that in other MCGs even in the same field. Correlation between specific dsRNA fragments and hypovirulence was not observed. Possible explanations for the accumulation of dsRNA fragments during the growth of disease patch by MCG 60 are discussed in terms of their internal changes such as evolution of novel dsRNA fragments from pre-existing viruses or fungal genomic DNA and horizontal transmissions.
-
characterization of double stranded rna elements in the violet root rot fungus Helicobasidium mompa
Fungal Biology, 2004Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Yoshihiro OhtsuAbstract:Double-stranded (ds) RNA of various types was detected by electrophoresis in 23 of 25 isolates of Helicobasidium mompa. These dsRNAs varied in size from ca. 2 kbp to more than 10 kbp. dsRNAs from an isolate V1 had two distinct nucleotide sequences for putative RNA-dependent RNA polymerase (RDRP). Their complete sequences revealed that V1 dsRNA1 was 2247 bp in length, with a single ORF that encoded a 706-amino acid residue polypeptide with a predicted molecular mass of 82.6 kDa, and that V1 dsRNA3 was 1776 bp in length, with a single ORF that encoded a 538-amino acid residue polypeptide with a predicted molecular mass of 62.6 kDa. RDRP-conserved motifs were identified in both predicted amino acid sequences. Phylogenetic analysis indicated that V1 dsRNA1 was most closely related to Fusarium poae virus 1, while V1 dsRNA3 was most closely related to Helicobasidium mompa 70 virus. These results indicate coinfection of isolate V1 by two distinct partitiviruses.
Hitoshi Nakamura - One of the best experts on this subject based on the ideXlab platform.
-
An endornavirus from a hypovirulent strain of the violet root rot fungus, Helicobasidium mompa.
Virus Research, 2006Co-Authors: Hideki Osaki, Naoyuki Matsumoto, Hitoshi Nakamura, Atsuko Sasaki, Koji YoshidaAbstract:We determined the complete nucleotide (nt) sequence (16,614 nt) of a large double-stranded (ds) RNA (referred to as L1 dsRNA), previously identified as the hypovirulence factor from strain V670 of the violet root rot fungus, Helicobasidium mompa. The positive-strand of L1 dsRNA contained a long open reading frame (ORF) potentially encoding a protein of 5,373 amino acids (molecular mass 603,080 Da) with conserved motifs characteristic of RNA-dependent RNA polymerase (RdRp) and helicase. The ORF is the longest so far reported in the fungal kingdom. The putative RdRp and helicase were shown to be related to putative RdRps and helicases of members of the genus Endornavirus. As is the case with endornaviruses, the coding (sense) strand of L1 dsRNA contained a discontinuity (nick) at nt position 2,552. A region between the RdRp and helicase domains of the polyprotein also had an amino acid sequence, resembling UDP glycosyltransferases (UGTs) in Oryza sativa endornavirus and Phytophthora endornavirus 1. Regions in the L1 dsRNA-encoded protein presumed to contain putative helicase, UGT and RdRp motifs were present at comparable positions to those in other endornaviruses. L1 dsRNA of H. mompa strain V670 was assigned to the genus Endornavirus, and here, we designate it as H. mompa endornavirus 1-670 (HmEV1-670). This represents the first report of a fungal endornavirus whose complete nucleotide sequence has been determined.
-
Nucleotide sequence of a mitochondrial RNA virus from the plant pathogenic fungus, Helicobasidium mompa Tanaka.
Virus Research, 2005Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Hitoshi Nakamura, Koji YoshidaAbstract:Abstract A double-stranded (ds) RNA (2411 bp) from a strain V18 of the violet root rot basidiomycetous fungus, Helicobasidium mompa was sequenced. Using the fungal mitochondrial genetic code in which UGA codes for tryptophan, the positive strand of V18 dsRNA was found to contain a long open-reading frame with the potential to encode a protein of 700 amino acids (molecular mass 79,805 Da), including conserved motifs characteristic of RNA-dependent RNA polymerase (RDRP). This putative RDRP was shown to be related to putative RDRPs of several fungal mitochondrial viruses. It is proposed that V18 dsRNA is assigned to the genus Mitovirus in the family Narnaviridae and designated as H. mompa mitovirus 1-18 (HmMV1-18). Like other mitoviruses, HmMV1-18 RNA can be folded into potentially stable stem-loop structures at both the 5′- and 3′-termini, and both terminal sequences have inverted complementarity with the potential to form panhandle structure. BLAST analysis indicates that the RDRP encoded by HmMV1-18 is more closely related to those encoded by mitochondrial viruses of some ascomycetes than to that of the unassigned RsM2-1A1 dsRNA in the basidiomycetous Rhizoctonia solani . HmMV1-18 is the first member of the genus Mitovirus from basidiomycete fungi.
-
dynamics of double stranded rna segments in a Helicobasidium mompa clone from a tulip tree plantation
FEMS Microbiology Ecology, 2005Co-Authors: Ken Ichi Ikeda, Masao Arakawa, Hitoshi Nakamura, Toshiyuki Koiwa, Naoyuki MatsumotoAbstract:Eighty-three isolates of the violet root rot fungus, Helicobasidium mompa, were collected in a tulip tree plantation and analyzed for the dynamics of double-stranded (ds) RNA for five years. They were divided into eight mycelial compatibility groups (MCGs). Prevalent MCGs 60 and 68 included 61 and 11 isolates, respectively. Electrophoretic profiles of dsRNA in the first year collection of MCG 60 contained no or a single large dsRNA (more than 10 kb) with or without small dsRNAs (ca. 2.0–2.5 kb). Additional dsRNA fragments, i.e., a middle dsRNA (ca. 8.0 kb) or another type of small dsRNAs, became evident within MCG 60 isolates with time. Northern hybridization revealed the relatedness of all large and middle dsRNA fragments within MCG 60 but small fragments of dsRNA were variable. Large dsRNA fragment differed from that in other MCGs even in the same field. Correlation between specific dsRNA fragments and hypovirulence was not observed. Possible explanations for the accumulation of dsRNA fragments during the growth of disease patch by MCG 60 are discussed in terms of their internal changes such as evolution of novel dsRNA fragments from pre-existing viruses or fungal genomic DNA and horizontal transmissions.
-
a comparative study of the violet root rot fungi Helicobasidium brebissonii and h mompa from japan
Fungal Biology, 2004Co-Authors: Hitoshi Nakamura, Masao Arakawa, Ken Ichi Ikeda, Tomoya Akahira, Naoyuki MatsumotoAbstract:A violet root rot fungus recently found in Japan was identified as Helicobasidium brebissonii. The fungus was compared with another violet root rot fungus, H. mompa, which is distributed throughout Japan, in terms of morphological characteristics of the basidiospores and the conidial state, sequences of rDNA ITS regions, and pathogenicity on carrot, sweet potato and apple rootstock. The two species were clearly discriminated by these features and the taxonomic status of both species is discussed.
-
hypovirulent strain of the violet root rot fungus Helicobasidium mompa
Journal of General Plant Pathology, 2003Co-Authors: Ken Ichi Ikeda, Hitoshi Nakamura, Naoyuki MatsumotoAbstract:The hyphal tip was isolated from 13 weakly or moderately virulent strains of Helicobasidium mompa to remove double-stranded (ds) RNAs and demonstrate their role as the hypovirulence factor. All of 829 hyphal tip subcultures retained dsRNAs. However, strain v670 containing two large fragments (≫10 kb) and one small fragment (ca. 2.3 kb) of dsRNA lost the largest fragment in 3 of 63 subcultures analyzed. One of the three subcultures (v670hti) was used to inoculate carrots to regain virulence compared to the parental strain v670. When isolate v670hti was paired with v670, the largest fragment was reintroduced to v670hti, and its virulence was diminished. Northern blot analysis with two probes hybridizing dsRNA fragments in most H. mompa strains revealed that the largest fragment involved in hypovirulence was different from two other fragments that are common in Japan. These results indicate that the largest dsRNA fragment in strain v670 is associated with hypovirulence in H. mompa.
Hideki Osaki - One of the best experts on this subject based on the ideXlab platform.
-
An endornavirus from a hypovirulent strain of the violet root rot fungus, Helicobasidium mompa.
Virus Research, 2006Co-Authors: Hideki Osaki, Naoyuki Matsumoto, Hitoshi Nakamura, Atsuko Sasaki, Koji YoshidaAbstract:We determined the complete nucleotide (nt) sequence (16,614 nt) of a large double-stranded (ds) RNA (referred to as L1 dsRNA), previously identified as the hypovirulence factor from strain V670 of the violet root rot fungus, Helicobasidium mompa. The positive-strand of L1 dsRNA contained a long open reading frame (ORF) potentially encoding a protein of 5,373 amino acids (molecular mass 603,080 Da) with conserved motifs characteristic of RNA-dependent RNA polymerase (RdRp) and helicase. The ORF is the longest so far reported in the fungal kingdom. The putative RdRp and helicase were shown to be related to putative RdRps and helicases of members of the genus Endornavirus. As is the case with endornaviruses, the coding (sense) strand of L1 dsRNA contained a discontinuity (nick) at nt position 2,552. A region between the RdRp and helicase domains of the polyprotein also had an amino acid sequence, resembling UDP glycosyltransferases (UGTs) in Oryza sativa endornavirus and Phytophthora endornavirus 1. Regions in the L1 dsRNA-encoded protein presumed to contain putative helicase, UGT and RdRp motifs were present at comparable positions to those in other endornaviruses. L1 dsRNA of H. mompa strain V670 was assigned to the genus Endornavirus, and here, we designate it as H. mompa endornavirus 1-670 (HmEV1-670). This represents the first report of a fungal endornavirus whose complete nucleotide sequence has been determined.
-
Nucleotide sequence of a mitochondrial RNA virus from the plant pathogenic fungus, Helicobasidium mompa Tanaka.
Virus Research, 2005Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Hitoshi Nakamura, Koji YoshidaAbstract:Abstract A double-stranded (ds) RNA (2411 bp) from a strain V18 of the violet root rot basidiomycetous fungus, Helicobasidium mompa was sequenced. Using the fungal mitochondrial genetic code in which UGA codes for tryptophan, the positive strand of V18 dsRNA was found to contain a long open-reading frame with the potential to encode a protein of 700 amino acids (molecular mass 79,805 Da), including conserved motifs characteristic of RNA-dependent RNA polymerase (RDRP). This putative RDRP was shown to be related to putative RDRPs of several fungal mitochondrial viruses. It is proposed that V18 dsRNA is assigned to the genus Mitovirus in the family Narnaviridae and designated as H. mompa mitovirus 1-18 (HmMV1-18). Like other mitoviruses, HmMV1-18 RNA can be folded into potentially stable stem-loop structures at both the 5′- and 3′-termini, and both terminal sequences have inverted complementarity with the potential to form panhandle structure. BLAST analysis indicates that the RDRP encoded by HmMV1-18 is more closely related to those encoded by mitochondrial viruses of some ascomycetes than to that of the unassigned RsM2-1A1 dsRNA in the basidiomycetous Rhizoctonia solani . HmMV1-18 is the first member of the genus Mitovirus from basidiomycete fungi.
-
characterization of double stranded rna elements in the violet root rot fungus Helicobasidium mompa
Fungal Biology, 2004Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Yoshihiro OhtsuAbstract:Double-stranded (ds) RNA of various types was detected by electrophoresis in 23 of 25 isolates of Helicobasidium mompa. These dsRNAs varied in size from ca. 2 kbp to more than 10 kbp. dsRNAs from an isolate V1 had two distinct nucleotide sequences for putative RNA-dependent RNA polymerase (RDRP). Their complete sequences revealed that V1 dsRNA1 was 2247 bp in length, with a single ORF that encoded a 706-amino acid residue polypeptide with a predicted molecular mass of 82.6 kDa, and that V1 dsRNA3 was 1776 bp in length, with a single ORF that encoded a 538-amino acid residue polypeptide with a predicted molecular mass of 62.6 kDa. RDRP-conserved motifs were identified in both predicted amino acid sequences. Phylogenetic analysis indicated that V1 dsRNA1 was most closely related to Fusarium poae virus 1, while V1 dsRNA3 was most closely related to Helicobasidium mompa 70 virus. These results indicate coinfection of isolate V1 by two distinct partitiviruses.
-
Cloning and Characterization of a Totivirus Double-stranded RNA from the Plant Pathogenic Fungus, Helicobasidium mompa Tanaka
Virus Genes, 2003Co-Authors: Kinya Nomura, Hideki Osaki, Toru Iwanami, Naoyuki Matsumoto, Yoshihiro OhtsuAbstract:Virus-like particles (VLPs, named HmTV1-17), about 40 nm in diameter were found in the violet root rot fungus Helicobasidium mompa Tanaka strain No. 17, which had been isolated from an apple tree. Purified preparations of HmTV1-17 contained two species of double-stranded RNA (dsRNA), designated 17L and 17S. cDNAs were constructed from HmTV1-17 genomic dsRNAs purified using CF-11 cellulose column chromatography. The sequences of 17L and 17S cDNA comprised 5207 and 2096 bp, respectively. Although 17S has no large open reading flame (ORF) on either strand, 17L has two large overlapping ORFs. The 5′ located ORF1 encodes the coat protein (CP, 788 amino acids), whereas the gene product of ORF2, which is in the −1 frame relative to ORF1, shows the typical features of a RNA dependent RNA polymerase (RDRP, 845 amino acids). Phylogenetic analysis based on RDRP showed that HmTV1-17 is closely related to Sphaeropsis sapinea SsRV1, a member of the genus Totivirus from filamentous fungus S. sapinea .
-
Detection of a Double-Stranded RNA Virus from a Strain of the Violet Root Rot Fungus Helicobasidium mompa Tanaka
Virus Genes, 2002Co-Authors: Hideki Osaki, Kinya Nomura, Satoko Kanematsu, Toru Iwanami, Ikuko Okabe, Naoyuki Matsumoto, Atsuko Sasaki, Yoshihiro OhtsuAbstract:Three double-stranded (ds) RNA species ( ca . 1.30, 1.27 and 1.23×10^6) were isolated by CF-11 cellulose chromatography from a strain of the violet root rot fungus Helicobasidium mompa recovered from apple roots. Purified virion preparations contained isometric particles about 25nm in diameter, and also the same three species of dsRNA isolated from total extracts by CF-11 cellulose chromatography. The molecular mass of the coat protein was about 67K when estimated by SDS-PAGE. The largest dsRNA (referred to as dsRNA1) contains a single, long open reading frame of 1794 nucleotides that encodes a putative polypeptide containing 598 amino acid residues with a molecular mass of 69.9K. This polypeptide contains amino acid sequence motifs conserved in putative RNA-dependent RNA polymerases of RNA viruses. Phylogenetic analysis revealed similarities to RNA-dependent RNA polymerases from Atkinsonella hypoxylon 2H virus, a member of the family Partitiviridae .
Koji Yoshida - One of the best experts on this subject based on the ideXlab platform.
-
An endornavirus from a hypovirulent strain of the violet root rot fungus, Helicobasidium mompa.
Virus Research, 2006Co-Authors: Hideki Osaki, Naoyuki Matsumoto, Hitoshi Nakamura, Atsuko Sasaki, Koji YoshidaAbstract:We determined the complete nucleotide (nt) sequence (16,614 nt) of a large double-stranded (ds) RNA (referred to as L1 dsRNA), previously identified as the hypovirulence factor from strain V670 of the violet root rot fungus, Helicobasidium mompa. The positive-strand of L1 dsRNA contained a long open reading frame (ORF) potentially encoding a protein of 5,373 amino acids (molecular mass 603,080 Da) with conserved motifs characteristic of RNA-dependent RNA polymerase (RdRp) and helicase. The ORF is the longest so far reported in the fungal kingdom. The putative RdRp and helicase were shown to be related to putative RdRps and helicases of members of the genus Endornavirus. As is the case with endornaviruses, the coding (sense) strand of L1 dsRNA contained a discontinuity (nick) at nt position 2,552. A region between the RdRp and helicase domains of the polyprotein also had an amino acid sequence, resembling UDP glycosyltransferases (UGTs) in Oryza sativa endornavirus and Phytophthora endornavirus 1. Regions in the L1 dsRNA-encoded protein presumed to contain putative helicase, UGT and RdRp motifs were present at comparable positions to those in other endornaviruses. L1 dsRNA of H. mompa strain V670 was assigned to the genus Endornavirus, and here, we designate it as H. mompa endornavirus 1-670 (HmEV1-670). This represents the first report of a fungal endornavirus whose complete nucleotide sequence has been determined.
-
Nucleotide sequence of a mitochondrial RNA virus from the plant pathogenic fungus, Helicobasidium mompa Tanaka.
Virus Research, 2005Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Hitoshi Nakamura, Koji YoshidaAbstract:Abstract A double-stranded (ds) RNA (2411 bp) from a strain V18 of the violet root rot basidiomycetous fungus, Helicobasidium mompa was sequenced. Using the fungal mitochondrial genetic code in which UGA codes for tryptophan, the positive strand of V18 dsRNA was found to contain a long open-reading frame with the potential to encode a protein of 700 amino acids (molecular mass 79,805 Da), including conserved motifs characteristic of RNA-dependent RNA polymerase (RDRP). This putative RDRP was shown to be related to putative RDRPs of several fungal mitochondrial viruses. It is proposed that V18 dsRNA is assigned to the genus Mitovirus in the family Narnaviridae and designated as H. mompa mitovirus 1-18 (HmMV1-18). Like other mitoviruses, HmMV1-18 RNA can be folded into potentially stable stem-loop structures at both the 5′- and 3′-termini, and both terminal sequences have inverted complementarity with the potential to form panhandle structure. BLAST analysis indicates that the RDRP encoded by HmMV1-18 is more closely related to those encoded by mitochondrial viruses of some ascomycetes than to that of the unassigned RsM2-1A1 dsRNA in the basidiomycetous Rhizoctonia solani . HmMV1-18 is the first member of the genus Mitovirus from basidiomycete fungi.
Yoshihiro Ohtsu - One of the best experts on this subject based on the ideXlab platform.
-
characterization of double stranded rna elements in the violet root rot fungus Helicobasidium mompa
Fungal Biology, 2004Co-Authors: Hideki Osaki, Kinya Nomura, Naoyuki Matsumoto, Yoshihiro OhtsuAbstract:Double-stranded (ds) RNA of various types was detected by electrophoresis in 23 of 25 isolates of Helicobasidium mompa. These dsRNAs varied in size from ca. 2 kbp to more than 10 kbp. dsRNAs from an isolate V1 had two distinct nucleotide sequences for putative RNA-dependent RNA polymerase (RDRP). Their complete sequences revealed that V1 dsRNA1 was 2247 bp in length, with a single ORF that encoded a 706-amino acid residue polypeptide with a predicted molecular mass of 82.6 kDa, and that V1 dsRNA3 was 1776 bp in length, with a single ORF that encoded a 538-amino acid residue polypeptide with a predicted molecular mass of 62.6 kDa. RDRP-conserved motifs were identified in both predicted amino acid sequences. Phylogenetic analysis indicated that V1 dsRNA1 was most closely related to Fusarium poae virus 1, while V1 dsRNA3 was most closely related to Helicobasidium mompa 70 virus. These results indicate coinfection of isolate V1 by two distinct partitiviruses.
-
Cloning and Characterization of a Totivirus Double-stranded RNA from the Plant Pathogenic Fungus, Helicobasidium mompa Tanaka
Virus Genes, 2003Co-Authors: Kinya Nomura, Hideki Osaki, Toru Iwanami, Naoyuki Matsumoto, Yoshihiro OhtsuAbstract:Virus-like particles (VLPs, named HmTV1-17), about 40 nm in diameter were found in the violet root rot fungus Helicobasidium mompa Tanaka strain No. 17, which had been isolated from an apple tree. Purified preparations of HmTV1-17 contained two species of double-stranded RNA (dsRNA), designated 17L and 17S. cDNAs were constructed from HmTV1-17 genomic dsRNAs purified using CF-11 cellulose column chromatography. The sequences of 17L and 17S cDNA comprised 5207 and 2096 bp, respectively. Although 17S has no large open reading flame (ORF) on either strand, 17L has two large overlapping ORFs. The 5′ located ORF1 encodes the coat protein (CP, 788 amino acids), whereas the gene product of ORF2, which is in the −1 frame relative to ORF1, shows the typical features of a RNA dependent RNA polymerase (RDRP, 845 amino acids). Phylogenetic analysis based on RDRP showed that HmTV1-17 is closely related to Sphaeropsis sapinea SsRV1, a member of the genus Totivirus from filamentous fungus S. sapinea .
-
Detection of a Double-Stranded RNA Virus from a Strain of the Violet Root Rot Fungus Helicobasidium mompa Tanaka
Virus Genes, 2002Co-Authors: Hideki Osaki, Kinya Nomura, Satoko Kanematsu, Toru Iwanami, Ikuko Okabe, Naoyuki Matsumoto, Atsuko Sasaki, Yoshihiro OhtsuAbstract:Three double-stranded (ds) RNA species ( ca . 1.30, 1.27 and 1.23×10^6) were isolated by CF-11 cellulose chromatography from a strain of the violet root rot fungus Helicobasidium mompa recovered from apple roots. Purified virion preparations contained isometric particles about 25nm in diameter, and also the same three species of dsRNA isolated from total extracts by CF-11 cellulose chromatography. The molecular mass of the coat protein was about 67K when estimated by SDS-PAGE. The largest dsRNA (referred to as dsRNA1) contains a single, long open reading frame of 1794 nucleotides that encodes a putative polypeptide containing 598 amino acid residues with a molecular mass of 69.9K. This polypeptide contains amino acid sequence motifs conserved in putative RNA-dependent RNA polymerases of RNA viruses. Phylogenetic analysis revealed similarities to RNA-dependent RNA polymerases from Atkinsonella hypoxylon 2H virus, a member of the family Partitiviridae .