Narnavirus

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

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]

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 two species:[1]

References

  1. ^ a b "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 16 May 2021.
  2. ^ a b c "Viral Zone". ExPASy. Retrieved 15 June 2015.
  3. ^ Espino-Vázquez AN; Bermúdez-Barrientos JR; Cabrera-Rangel JF; Córdova-López G; Cardoso-Martínez F; Martínez-Vázquez A; Camarena-Pozos DA; Mondo SJ; Pawlowska TE; Abreu-Goodger C; Partida-Martínez LP. (2020). "Narnaviruses: Novel players in fungal–bacterial symbioses". The ISME Journal. 14 (7): 1743–1754. doi:10.1038/s41396-020-0638-y. PMC 7305303. PMID 32269378.
  4. ^ "Narnaviridae - Positive Sense RNA Viruses - Positive Sense RNA Viruses (2011) - ICTV". talk.ictvonline.org. Archived from the original on 31 August 2018. Retrieved 15 June 2021.
  5. ^ Dolja, V. V.; Koonin, E. V. (2012). "Capsid-Less RNA Viruses". ELS. doi:10.1002/9780470015902.a0023269. ISBN 978-0-470-01617-6.