Totivirus

Totivirus
	Saccharomyces cerevisiae virus L-A capsid protein structure and homodimer of the gag capsid protei
Virus classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Orthornavirae
Phylum:	Duplornaviricota
Class:	Chrymotiviricetes
Order:	Ghabrivirales
Family:	Orthototiviridae
Genus:	Totivirus
Synonyms
	Saccharomyces cerevisiae virus group;

Last updated October 10, 2025

Totivirus is a genus of double-stranded RNA viruses in the family Orthototiviridae . Fungi serve as natural hosts. The name of the group derives from Latin toti which means undivided or whole. There are 32 species in this genus.^[2]^[3]

Structure

Viruses in the genus Totivirus are non-enveloped, with icosahedral symmetry, and T=2 architecture. The diameter is around 40 nm.^[2]

Genome

Genome of genus totivirus

Totiviruses have a genome of 4700–6700 nucleotides in length and only a single copy of the genome is present in the particle. The nucleic acid content of a totivirus capsid is one segment of linear double stranded RNA. The genome contains two large overlapping open reading frames (ORFs). These open reading frames (ORFs) code for a capsid protein (CP) and an RNA-dependent RNA polymerase (RdRp). The 5' end of the positive strand of the dsRNA genome has no cap and is very structured. Totiviruses contain a long 5' untranslated region (5' UTR) which functions as an internal ribosome entry site (IRES). Totiviruses can have satellite RNAs encoding a toxin.^[2]^[4]

Life cycle

Viral replication is cytoplasmic. Entry into the host cell is achieved by virus remains intracellular. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. Translation takes place by -1 ribosomal frameshifting. The virus exits the host cell by cell-to-cell movement. Fungi Saccharomyces cerevisiae and smut serve as the natural host. The virus is transmitted during cell division, sporogenesis, and cell fusion.^[2]

Taxonomy

The genus Totivirus contains the following species:^[3]

References

↑ "Minutes of the Sixth Meeting of the ICTV, Sendai, 5 September 1984" (PDF). International Committee on Taxonomy of Viruses (ICTV). 5 September 1984. Retrieved 11 February 2020.
1 2 3 4 "Viral Zone". ExPASy. Retrieved 15 June 2015.
1 2 "Virus Taxonomy: 2024 Release". International Committee on Taxonomy of Viruses. Retrieved 8 March 2025.
↑ "Totiviridae". International Committee on Taxonomy of Viruses. Retrieved 11 September 2025.

External links

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[1] "Minutes of the Sixth Meeting of the ICTV, Sendai, 5 September 1984" (PDF). International Committee on Taxonomy of Viruses (ICTV). 5 September 1984. Retrieved 11 February 2020.

[ViralZone-2] 1 2 3 4 "Viral Zone". ExPASy. Retrieved 15 June 2015.

[ICTV-3] 1 2 "Virus Taxonomy: 2024 Release". International Committee on Taxonomy of Viruses. Retrieved 8 March 2025.

[4] "Totiviridae". International Committee on Taxonomy of Viruses. Retrieved 11 September 2025.

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