Notes on Genus: Sequivirus
Type member: Parsnip yellow fleck virus
This is one of the genera in the plant picornavirus family Secoviridae
and is also known as the parsnip yellow fleck virus group. Members of the genus are dependent for aphid transmission on a helper protein encoded by a separate helper virus. The name is derived from the Latin sequi
, to follow or accompany, to describe this dependent transmission. The helper virus for the type member, parsnip yellow fleck virus, is anthriscus yellows waikavirus.
Virions isometric (icosahedral) about 30 nm in diameter with no obvious structural features.
Monopartite, single-stranded positive-sense RNA about 10,000 nucleotides long. 3' terminus has no poly(A) tract. 5' terminus probably has a genome-linked protein (VPg).
Genus Genomic Organization
The sole (or major) translation product is a polyprotein, which is subsequently processed into a number of products, including three coat proteins.
Type Member Genomic Organization
The sole (or major) translation product is a polyprotein, in which several products or domains have been identified:
|P1 ||c. 40 kDa|| ||Unknown function|
|CP1 ||22.5 kDa||coat protein 1|
|CP2||26 kDa|| ||coat protein 2|
|CP3 ||31 kDa||coat protein 3|
|Pro||?|| ||Protease domain|
|Pol ||?||Polymerase domain|
|NTP||?|| ||NTP-binding domain|