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Type Species |
(LBVV) |
Virions are rod-shaped with modal lengths of 320 to 360 nm and diameters of about 18 nm. The central canal is about 3 nm in diameter and an obvious helix is visible with a pitch of about 5 nm. Virions are very unstable, glutaraldehyde fixation is recommended to facilitate detection by electron microscopy. No envelope has been observed (Fig. 1).
Physicochemical and Physical Properties
Virus particles have a density in Cs2SO4 of approximately 1.27 g/cm3.
Virions contain dsRNA of two sizes, approximately 7 kbp and approximately 6.5 kbp.
Capsid protein has an Mr of approximately 48 103.
None reported.
None reported.
Genome Organization and Replication
Nothing is known about the genome organization.
Particles of Lettuce big-vein virus (LBVV) and of the tentative species, Tobacco stunt virus (TStV), react similarly with heterologous antiserum.
LBVV-like viruses are reported from hosts from up to 9 families. LBVV does not infect tobacco and TStV does not infect lettuce. Some hosts are common to both viruses.
Viruses are transmitted by chytrid fungi of the genus Olpidium and are thus soil- or water-borne. Mechanical transmission is possible, though sometimes difficult. No seed transmission has been reported.
List of Species Demarcation Criteria in the Genus
Not applicable.
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:
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Lettuce big-vein virus |
(LBVV) |
Tentative Species in the Genus
|
Tobacco stunt virus (313) |
(TStV) |
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Camellia yellow mottle virus |
(CYMoV) |
|
Freesia leaf necrosis virus |
(FLNV) |
Phylogenetic Relationships within the Genus
Not available.
Vari from varix, Latin, meaning abnormal dilatation or enlargement of a vein or artery and referring to the main symptom of the type species.
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