Plasmid-like dynamics of persistent RNA viruses in the host fungal population.

Unlike the well-known acute or chronic animal and plant RNA viruses, most fungal RNA viruses (RNA mycoviruses) have a persistent life cycle. They lack an extracellular infection route and coexist with their hosts for a lifetime. RNA mycoviruses affect various biological properties of host fungi and are widespread across all major fungal groups.

Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses (ICTV) from the Fungal and Protist Viruses Subcommittee, 2025.

The Fungal and Protist Viruses Subcommittee (SC) of the International Committee on Taxonomy of Viruses (ICTV) has received a total of eight taxonomic proposals for the 2024 annual cycle. The extent of proposed changes varied, including nomenclatural updates, creation of new taxa and reorganization of established taxa. Following the ICTV procedures, all proposals were reviewed and voted upon by the members of the Executive Committee with ratification in March 2025.

"Paraxenoviridae", a putative family of globally distributed marine bacteriophages with double-stranded RNA genomes.

Metatranscriptome sequencing dramatically expanded the known diversity of the global RNA virome and, in particular, suggested several new candidate phyla in riboviruses. Using a double-stranded RNA (dsRNA) sequencing, here we report five complete, bisegmented RNA genomes of a putative phylum group, paraxenoviruses, identified from marine environments. Phylogenetic analysis of the RNA-directed RNA polymerases of paraxenoviruses demonstrated their affinity with the ribovirus order Durnavirales within the class Duplopiviricetes of the phylum Pisuviricota.

"Paraxenoviridae", a putative family of ubiquitous marine bacteriophages with double-stranded RNA genomes.

F ragmented and primer L igated D sRNA S equencing (FLDS) was used to reconstruct five complete, bisegmented RNA genomes of paraxenoviruses, a group of viruses that was previously identified in the ocean and that based on the analysis of partial genomes was proposed to represent a putative new phylum within the kingdom of the realm . Phylogenetic analysis of the RNA-directed RNA polymerases of paraxenoviruses demonstrated their affinity with the ribovirus order within the class of the phylum . The order includes families that consists of well-characterized dsRNA bacteriophages and less thoroughly studied that are also suspected to infect bacteria.

Characterization of the mycovirus Aspergillus sulphureus partitivirus 1.

Fungi are frequently infected with viruses called mycoviruses. Some mycoviruses have shown potential as biocontrol agents because they can weaken the virulence of fungal plant pathogens. Intensive research has been conducted on the diversity of viruses infecting plant pathogens and the functions of such viruses.

Characterization of a multi-segmented rod-shaped mycovirus within the order Martellivirales largely accommodating plant viruses.

The order Martellivirales in the Riboviria realm includes seven established families. The viruses in this order have a single-stranded positive-sense RNA genome and infect animals, plants, or fungi. In this study, we characterized Aspergillus flavus vivivirus 1 (AfViV1), an RNA virus infecting Aspergillus flavus that presumably belongs to the proposed "Viviviridae" family in the Martellivirales order.

Rediscovery of viomellein as an antibacterial compound and identification of its biosynthetic gene cluster in dermatophytes.

Fungi produce a wide variety of compounds, especially those that exhibit biological activity. Such compounds may aid the survival of fungi in the environment or may contribute to host infection for pathogenic species. Regarding dermatophytes, which affect a large number of patients worldwide, studies on metabolites that exhibit biological activity are scarce.

Molecular characterization of a polymycovirus in Leptosphaeria biglobosa.

Leptosphaeria biglobosa is a phytopathogenic ascomycete of Brassica napus that causes phoma stem canker/blackleg. A new double-stranded RNA (dsRNA) mycovirus from this fungus has been fully characterized. The virus genome has five dsRNA segments, ranging in length from 1,180 bp to 2,402 bp.

Mycoviruses from Aspergillus fungi involved in fermentation of dried bonito.

Fungi are exploited for fermentation of foods such as cheese, Japanese sake, and soy sauce. However, the diversity of viruses that infect fungi involved in food fermentation is poorly understood. Fermented dried bonito ("katsuobushi") is one of the most important processed marine products in Japan.

Greetings from virologists to mycologists: A review outlining viruses that live in fungi.

Viruses are genetic elements that parasitize self-replicating cells. Therefore, organisms parasitized by viruses are not limited to animals and plants but also include microorganisms. Among these, viruses that parasitize fungi are known as mycoviruses.

New lineages of RNA viruses from clinical isolates of revealed by fragmented and primer-ligated dsRNA sequencing (FLDS) analysis.

is a species in the order Mucorales that is known to cause mucormycosis, but it is poorly understood as a host of viruses. Here, we examined 25 clinical strains of for viral infection with a conventional double-stranded RNA (dsRNA) assay using agarose gel electrophoresis (AGE) and the recently established fragmented and primer-ligated dsRNA sequencing (FLDS) protocol. By AGE, five virus-infected strains were detected.

Molecular and biological characterization of a novel partitivirus from Talaromyces pinophilus.

Talaromyces spp. have a worldwide distribution, are ecologically diverse and have been isolated from numerous different substrates. Talaromyces spp.

Double-stranded RNA sequencing reveals distinct riboviruses associated with thermoacidophilic bacteria from hot springs in Japan.

Metatranscriptome sequencing expanded the known diversity of the bacterial RNA virome, suggesting that additional riboviruses infecting bacterial hosts remain to be discovered. Here we employed double-stranded RNA sequencing to recover complete genome sequences of two ribovirus groups from acidic hot springs in Japan. One group, denoted hot spring riboviruses (HsRV), consists of viruses with distinct RNA-directed RNA polymerases (RdRPs) that seem to be intermediates between typical ribovirus RdRPs and viral reverse transcriptases.

Molecular and biological characterization of a partitivirus from .

is a thermo-tolerant, ubiquitous fungus commonly found in food products, indoor environments, soil and clinical samples. It is a well-known biocontrol agent used against phytopathogenic fungi and its metabolites have many industrial applications. Rare reports of related human infections have been found in the medical literature.

Distinct groups of RNA viruses associated with thermoacidophilic bacteria.

Recent massive metatranscriptome mining substantially expanded the diversity of the bacterial RNA virome, suggesting that additional groups of riboviruses infecting bacterial hosts remain to be discovered. We employed full length double-stranded (ds) RNA sequencing for identification of riboviruses associated with microbial consortia dominated by bacteria and archaea in acidic hot springs in Japan. Whole sequences of two groups of multisegmented riboviruses genomes were obtained.

Experimental verification of strain-dependent relationship between mycovirus and its fungal host.

Mycoviruses are viruses that infect fungi. Unlike mammalian infectious viruses, their life cycle does not generally have an extracellular stage, and a symbiosis-like relationship is maintained between virus and host fungi. Recently, mycoviruses have been reported to show effects on host fungi, altering biological properties such as growth rate, virulence, drug resistance, and metabolite production.

Discovery, Genomic Sequence Characterization and Phylogenetic Analysis of Novel RNA Viruses in the Turfgrass Pathogenic spp. in Japan.

Turfgrass used in various areas of the golf course has been found to present anthracnose disease, which is caused by spp. To obtain potential biological agents, we identified four novel RNA viruses and obtained full-length viral genomes from turfgrass pathogenic spp. in Japan.

Efficient elimination of RNA mycoviruses in species using RdRp-inhibitors ribavirin and 2'-C-methylribonucleoside derivatives.

RNA viruses in fungi (mycoviruses) are model systems for understanding the relationships between eukaryotic microorganisms and RNA viruses. To reveal the effects of mycoviruses on host fungi, it is essential to compare the phenotypes between isogenic fungal isolates with or without RNA virus infection. Since active entry machinery for RNA mycoviruses has never been identified, introducing mycoviruses to fungi is a difficult and time-consuming process.

NeoRdRp: A Comprehensive Dataset for Identifying RNA-dependent RNA Polymerases of Various RNA Viruses from Metatranscriptomic Data.

RNA viruses are distributed throughout various environments, and most have recently been identified by metatranscriptome sequencing. However, due to the high nucleotide diversity of RNA viruses, it is still challenging to identify novel RNA viruses from metatranscriptome data. To overcome this issue, we created a dataset of RNA-dependent RNA polymerase (RdRp) domains that are essential for all RNA viruses belonging to Orthornavirae.

Intracellular production of reactive oxygen species and a DAF-FM-related compound in Aspergillus fumigatus in response to antifungal agent exposure.

Fungi are ubiquitously present in our living environment and are responsible for crop and infectious diseases. Developing new antifungal agents is constantly needed for their effective control. Here, we investigated fungal cellular responses to an array of antifungal compounds, including plant- and bacteria-derived antifungal compounds.

Eukaryotic Microbial RNA Viruses-Acute or Persistent? Insights into Their Function in the Aquatic Ecosystem.

Isolated RNA viruses mainly parasitize eukaryotes. RNA viruses either expand horizontally by infecting hosts (acute type) or coexist with the host and are vertically inherited (persistent type). The significance of persistent-type RNA viruses in environmental viromes (the main hosts are expected to be microbes) was only recently reported because they had previously been overlooked in virology.