Notes on Family: Potyviridae

flexuous filaments

General Description

This family is characterised by its flexuous filamentous particles up to 900 nm in length and by the presence of characteristic inclusion bodies within infected plant cells. The genome or genome segments are translated into polyproteins which are subsequently processed by virus-encoded proteases into functional products.

Morphology

Virions filamentous, not enveloped. Of one (650-900 nm) or two (500-600 and 200-300 nm) lengths x 12-15 nm in diameter. Symmetry helical. Pitch of helix 3.4 nm.

Particles contain 5 % nucleic acid and 95 % protein.

Genomen

Linear, single stranded positive sense RNA. Genome monopartite or bipartite with total genome 8500-12000 nucleotides long. 3' terminus has a poly (A) tract. 5' terminus has (or probably has) a genome-linked protein (VPg).

RNA molecules are translated into polyproteins, which are subsequently processed into a number of structural and non-structural proteins.

Genera in the Family

Brambyvirus: monopartite, vector unknown; with AlkB domain in P1 protein
Bymovirus: bipartite, fungus transmission
Ipomovirus: monopartite, white fly transmission
Macluravirus: monopartite, aphid transmission, particles less than 700 nm long
Poacevirus: monopartite, mite transmission, small % nucleotide homology to rymoviruses and tritimoviruses and very long 5'-UTR
Potyvirus: monopartite, aphid transmission, particles more than 700 nm long
Rymovirus: monopartite, mite transmission (Abacarus hystrix)
Tritimovirus: monopartite, mite transmission (Aceria tulipae), small % nucleotide homology to rymoviruses