Narnavirus

Narnavirus is a genus of positive-strand RNA viruses in the family Narnaviridae. Fungi serve as natural hosts. There are two species in this genus.^[1][2] Member viruses have been shown to be required for sexual reproduction of Rhizopus microsporus ("Narnaviruses decrease asexual reproduction, but together with Mycetohabitans, are required for sexual reproductive success. This fungal–bacterial-viral system represents an outstanding model to investigate three-way microbial symbioses and their evolution.").^[3] Narnaviruses have a naked RNA genome without a virion and derive their name from this feature.^[4]

Narnavirus
Narnaviruses have no capsid or viral envelope, RNA genome and RdRp form a naked ribonucleoprotein complex
Virus classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Orthornavirae
Phylum:	Lenarviricota
Class:	Amabiliviricetes
Order:	Wolframvirales
Family:	Narnaviridae
Genus:	Narnavirus
Species
See text

Virology

Structure

Narnaviruses have no true virion. They do not have structural proteins or a capsid.^[5]

Genome

Narnaviruses have nonsegmented, linear, positive-sense, single-stranded RNA genomes. The genome has one open reading frame which encodes the RNA-dependent RNA polymerase (RdRp). The genome is associated with the RdRp in the cytoplasm of the fungi host and forms a naked ribonucleoprotein complex.^[2]

Replication cycle

Viral replication is cytoplasmic. Replication follows the positive-strand RNA virus replication model. Positive-strand RNA virus transcription is the method of transcription. The virus exits the host cell by cell-to-cell movement. Fungi serve as the natural host. Transmission routes are parental and sexual.^[2]

Taxonomy

The genus has the following species, listed by scientific name and followed by the exemplar virus of the species:^[1][6]

• Narnavirus saccharomaior, Saccharomyces 23S RNA narnavirus
• Narnavirus saccharominor, Saccharomyces 20S RNA narnavirus