Notes on Genus: Maculavirus
Type member: Grapevine fleck virus
The genus Maculavirus
, one of three genera in the family Tymoviridae
, is a small group of phloem-limited isometric viruses which are not sap-transmissible and with no known vectors. Phylogenetic analysis indicates some relationship to the other genera in the family but the genome size is larger and members of the genus Tymovirus
are beetle-transmitted while those of the genus Marafivirus
are transmitted by leafhoppers.
Virions isometric (icosahedral), not enveloped, c.
30 nm in diameter.
Monopartite, linear, single stranded, positive sense RNA approx. 7.5 kb in size. The 3' terminus has a poly(A) tract.
Genus Genomic Organization
Only the type member has been fully sequenced and this is believed to have four ORFs. The largest is a replication protein and the three smaller ones overlap and are probably translated from two or more subgenomic RNAs.
Type Member Genomic Organization
The RNA is translated from four open reading frames:
|1 || 216 kDa ||Replication protein with methyltransferase and polymerase domains|
|2 || 24 kDa ||Coat protein|
|3 || 31 kDa ||proline rich; unknown function|
|4 || 16 kDa ||proline rich; unknown function|