Notes on Genus: Polemovirus

icosahedra
icosahedra

Type member: Poinsettia latent virus

Contents

General Description

This genus was created in 2007 and presently contains a single species. The name reflects the fact that it has a close relationship to members of the genus Polerovirus within the first three quarters of its genome but to members of the genus Sobemovirus in the last quarter. The virus is widespread, but symptomless in its host plant and its natural method of transmission is unknown.

Morphology

Virions are isometric (icosahedral), not enveloped, 34 nm in diameter.

Genome

Monopartite, linear, single stranded, positive sense RNA c. 4600 nucleotides long. The 3' terminus has neither a poly (A) tract nor a tRNA-like structure. The 5' terminus probably has a genome-linked protein (VPg).

Genus Genomic Organization

There are a total of four potential ORFs. The three at the 5'-end have sequence homology to members of the genus Polerovirus. The fourth (coat protein) ORF resembles that of members of the genus Sobemovirus.

Type Member Genomic Organization

Four open reading frames have been identified :
1. 30 kDa  unknown function, similar to polerovirus ORF0
2. 72 kDa Replication protein
3. 61 kDaPolymerase. Probably expressed as a larger protein entered earlier by frameshift from ORF2
4. 33 kDa Coat protein expressed from a subgenomic RNA