RESUMO
The family Hadakaviridae, including the genus Hadakavirus, accommodates capsidless viruses with a 10- or 11-segmented positive-sense (+) RNA genome. Currently known hosts are ascomycetous filamentous fungi. Although phylogenetically related to polymycovirids with a segmented double-stranded RNA genome and certain encapsidated picorna-like viruses, hadakavirids are distinct in their lack of a capsid ('hadaka' means naked in Japanese) and their consequent inability to be pelleted by conventional ultracentrifugation; they show ribonuclease susceptibility in host tissue homogenates. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Hadakaviridae, which is available at ictv.global/report/hadakaviridae.
Assuntos
Ascomicetos , Vírus de RNA , Vírus , Vírus de RNA/genética , Genoma Viral , Vírus/genética , Proteínas do Capsídeo/genética , Replicação Viral , Vírion/genéticaRESUMO
Aspergillus foetidus virus (AfV) contains at least two icosahedral particle types named AfV-fast (-F) and AfV-slow (-S), based on relative electrophoretic mobility. AfV-F is a quadripartite double-stranded RNA (dsRNA) virus, and AfV-S contains AfV-S1, which is a member of the genus Victorivirus in the family Totiviridae, and AfV-S2, which may be a satellite RNA or satellite virus and is described here. Analysis of the complete AfV-S2 nucleotide sequence reveals it to be significantly similar to an unclassified RNA from the fungus Rosellinia necatrix and distantly related to the RNA-dependent RNA polymerases of several single-stranded RNA genomes.
Assuntos
Aspergillus/virologia , Vírus de RNA/genética , RNA de Cadeia Dupla/genética , RNA Satélite/genética , RNA Viral/genética , Análise de Sequência de DNA , Aspergillus/genética , Análise por Conglomerados , Dados de Sequência Molecular , Filogenia , Vírus de RNA/isolamento & purificação , RNA de Cadeia Dupla/isolamento & purificação , RNA Satélite/isolamento & purificação , Homologia de Sequência do Ácido NucleicoRESUMO
Virus infection of Aspergillus foetidus was documented over 40 years ago and was one of the first mycovirus infections described in a filamentous fungus. The virus, named Aspergillus foetidus virus (AfV), contains at least two types of icosahedral particles, called AfV-fast (-F) and AfV-slow (-S) virions, based on their relative electrophoretic mobilities. Here, we report the complete nucleotide sequence of the AfV-F genome isolated from virions purified from the prototype isolate of the fungus. The AfV-F double-stranded (ds) RNA genome is tetra-segmented, and the plus strands of each of the four segments, but not the minus strands, are polyadenylated. The organisation and sequences of the four AfV-F dsRNAs are similar to those described for Alternaria alternata virus 1, which we propose is a member of an emerging mycovirus genus ("Alternavirus") and family ("Alternaviridae"), which also includes AfV-F.
Assuntos
Aspergillus/virologia , Totivirus/genética , Totivirus/isolamento & purificação , Sequência de Bases , Genoma Viral , Dados de Sequência Molecular , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Totivirus/classificação , Proteínas Virais/genéticaRESUMO
A collection of clinical and environmental isolates of the opportunistic human pathogen, Aspergillus fumigatus, were screened for the presence of mycoviruses and 6.6 % of 366 isolates contained dsRNA segments ranging in size from ~1.0 to 4.0 kbp. The dsRNAs were categorised into three different groups comprising bipartite dsRNAs, quadripartite dsRNAs, representative isolates of which have both been sequenced, and an uncharacterised mycovirus, whose genome apparently consists of four dsRNAs 1-2.5 kbp in size. Here, we describe dsRNA incidence in the A. fumigatus isolates examined, their provenance and also note that on occasion individual isolates were infected with two groups of different dsRNAs.
Assuntos
Aspergilose/microbiologia , Aspergillus fumigatus/virologia , Vírus de RNA/isolamento & purificação , Microbiologia Ambiental , Genoma Viral , Humanos , Vírus de RNA/classificação , Vírus de RNA/genética , RNA de Cadeia Dupla/genética , RNA Viral/genéticaRESUMO
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.
