Notes on Genus: Citrivirus
flexuous filaments
Type member: Citrus leaf blotch virus
Contents
General Description
The genus
Citrivirus is one of is one of the genera in the family
Betaflexiviridae. In genome organisation it particularly resembles the genus
Trichovirus but has a much larger coat protein that is phylogenetically distinct and much more closely related to foveaviruses, together with longer virions. There are no known vectors. The name is from the type (and only) member Citrus leaf bloch virus.
Morphology
Virions filamentous and flexuous, not enveloped, 960 nm long and 12 nm in diameter.
Genome
Monopartite, linear, single stranded, positive sense RNA, 8747 nucleotides long. The 3' terminus has a poly(A) tract and the 5' terminus has a methylated nucleotide cap.
Genus Genomic Organization
The genome is translated by means of 3 ORFs. The largest ORF (ORF1) is involved in replication, while ORF2 (putative movement protein) and ORF3 (coat protein) are expressed from subgenomic mRNAs. Unlike trichoviruses, the coat protein ORF does not overlap with that of the movement protein.
Type Member Genomic Organization
The genome is believed to be translated by means of three open reading frames:
- 227 kDa polyprotein: putative replicase
- 40 kDa Movement protein
- 41 kDa Coat protein