Notes on Genus: Tepovirus

flexuous filaments
flexuous filaments

Type member: Potato virus T


General Description

This genus in the family Betaflexiviridae currently contains a single species that was originally thought to be a possible member of the genus Trichovirus. This is supported by particle morphology and genome organisation but the replication protein is substantially smaller and phylogenetic analysis does not group it reliably with trichoviruses. The name is derived from the type (and only) member, Potato virus T.


Virions filamentous, flexuous, not enveloped, about 640 nm long and 12 nm in diameter with a pitch of 3.4 nm and between 9 and 10 subunits per turn of the primary helix. Particles are obliquely striated, and with rope-like features (depending on the negative staining method).

Virions composed of 5% nucleic acid.


Monopartite, linear, polyadenylated ssRNA of about 6.5 kb.

Genus Genomic Organization

The genome is translated by means of 3 slightly overlapping ORFs. The largest ORF (ORF1) is probably involved in replication, while ORF2 (putative movement protein) and ORF3 (coat protein) are expressed from subgenomic mRNAs.

Type Member Genomic Organization

The genome is believed to be translated by means of three open reading frames:
  1. 184.8 kDa polyprotein: putative replicase
  2. 40.5 kDa Movement protein
  3. 23.6 kDa Coat protein