Genus Rymovirus

Type Species	Ryegrass mosaic virus	(RGMV)

Virion Properties

Virions are flexuous filaments 690-720 11-15  nm in size. Virion density in CsCl is 1.325  g/cm³ (for Ryegrass mosaic virus, RGMV). Virion S_20w is 165-166S for most members. Virions contain a single molecule of linear positive sense ssRNA with a 3-poly(A) terminus. Virion RNA is about 9-10  kb in size (Mr 2.7 10⁶). Rymoviruses have a single CP with Mr 29.2 10³ (RGMV). No lipid or carbohydrate are reported.

Genome Organization and Replication

The rymoviruses presumably have a genome organization and replication strategy typical of viruses in the family Potyviridae.

Antigenic Properties

Most rymoviruses are moderately immunogenic. No serological relationships among member viruses have been found except for a weak reaction between Oat necrotic mottle virus (ONMV) and WSMV (genus Tritimovirus).

Biological Properties

Host Range

Most rymoviruses have limited but widespread host ranges within the family Graminae but some have relatively narrow host ranges.

Transmission

Transmission by eriophyid mites and mechanical transmission have been reported for most members.

List of Species Demarcating Criteria in the Genus

	Genome sequence relatedness. CP amino acid sequence identity less than approximately 80%, Nucleotide sequence identity less than 85% over whole genome, Different polyprotein cleavage sites.
	Natural host range. Host range may be related to species but usually not helpful in identifying species. May delineate strains.
	Pathogenicity and cytopathology. Different inclusion body morphology, Lack of cross-protection, Seed transmissibility, or lack thereof, Some aspects of host reaction may be useful (e.g., resistance genes, different responses in key host species).
	Mode of transmission. Different primary vectors, but vector species not of use in identification to virus species.
	Antigenic properties. serological differences.

List of Species in the Genus

Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names, CMI/AAB description number ( ), and assigned abbreviations ( ) are:

Species in the Genus

Agropyron mosaic virus (118)		(AgMV)
Hordeum mosaic virus		(HoMV)
Oat necrotic mottle virus (169)		(ONMV)
Ryegrass mosaic virus (86)	[Y09854, AF035818]	(RGMV)

Tentative Species in the Genus

Spartina mottle virus	(SpMV)