Family: Tomosaviridae (Interim Report)

This is a summary page created by the ICTV Report Editors using information from associated Taxonomic Proposals and the Master Species List.

Edited by: Luisa Rubino
Posted: March 2025

Summary

The family Tomosaviridae includes ssRNA(+) satellite viruses of plants (Table 1 Tomosaviridae). The family Tomosaviridae was established in 2025 (Master Species List #40).

Table 1 Tomosaviridae. Characteristics of members of the family Tomosaviridae.

Characteristic	Description
Example	satellite tobacco mosaic virus (M25782), species Virtovirus tabaci
Virion	Capsids with T=1 symmetry (diameter 16 nm), constructed from 60 copies of capsid protein that has jelly-roll topology
Genome	ssRNA(+) of 1.1 kb (Figure 1 Tomosaviridae)
Replication	Satellite virus dependent on members of the genus Tobamovirus, family Virgaviridae. Involves helper virus replicase and tomosavirus (+)-strand and (-) strand transcripts.
Translation	Cap-independent translation initiation involving a conserved 3′-terminal stem-loop structure
Host range	Plants
Taxonomy	Realm Riboviria, order Tombendovirales: 1 genus 1 species (Figure 2 Tomosaviridae)

Figure 1 Tomosaviridae. Genome organisation of satellite tobacco mosaic virus, a member of the family Tomosaviridae. Boxes indicate open reading frames as annotated on GenBank accession M25782.

Figure 2 Tomosaviridae. Taxonomy of the family Tomosaviridae.

Derivation of names

Tomosaviridae: from tobacco mosaic virus and satellite

Virtovirus: from virgavirus (helper virus) and tobacco