Notes on Family: Secoviridae

icosahedra

Contents

Members of this Family
General Description
Morphology
Genome
Genera in the Family
All Known Sequences
Curated Sequences

General Description

This family contains all the plant-infecting members of the order Picornavirales. The viruses included all have icosahedral particles and monopartite or bipartite genomes, which are translated as polyproteins for subsequent processing.

Morphology

Virions isometric, icosahedral, not enveloped and about 30 nm in diameter.

Genome

Mono- or bi-partite with linear, single-stranded positive sense RNA. Total genome 9000-12000 nucleotides long. The 5'-terminus has a genome-linked protein (VPg) and a poly (A) tract is present almost invariably at the 3'-end. The genomic RNA(s) have a large open reading frame which is translated into a polyprotein for subsequent processing.

Genera in the Family

Classification into genera depends upon genome organisation and some biological properties, supported by phylogenetic analysis. The current genera are:
GenusRNAsRNA2
polyprotein
(kDa)
Nos of coat proteinsVectorOther features
Subfamily Comovirinae:
Comovirus21302Beetles
Fabavirus21302Aphids
Nepovirus2135-1901Nematodes
Other genera:
Cheravirus2100-1103Nematodes
Sadwavirus21712Nematodes?
Sequivirus1-3AphidsRequires helper virus for transmission. Genome may lack a 3'-polyA tail.
Torradovirus21343Whiteflies? Extra partially overlapping ORF at 5'-end of RNA2
Waikavirus1-3BeetlesTwo small additional ORFs at 3'-end