The genus includes a single species, Bellflower veinal mottle virus; members of this species, like macluraviruses and arepaviruses, lack the P1 region present in most potyvirids. The HC-Pro lacks the conserved potyvirus aphid transmission motifs R/KITC and PTK. Isolates of bellflower veinal mottle virus share low (22–27%) nucleotide and amino acid sequence identities to macluraviruses.
The largest genus in the family contains viruses transmitted by aphids in a non-persistent manner.
Virions are flexuous filaments, 680–900 nm long and 11–13 nm wide, with helical symmetry and a pitch of about 3.4 nm. Particles of some viruses are longer in the presence of divalent cations than in the presence of EDTA.
Triticum mosaic virus (TriMV) is transmitted by the wheat curl mite (Aceria tosichella) and has an unusually long 5´-untranslated region. Vectors are unknown for the other members of the genus.
Virions of sugarcane streak mosaic virus (SCSMV) are flexuous filaments 890 nm×15 nm in size.
Ipomoviruses are distinguished from members of other genera by their mode of transmission being by whiteflies, and by their separate branching on phylogenetic analyses.
Virions are flexuous filaments 800–950 nm long.
Compared with other viruses in the family, members of the genus Bymovirus are distinct in having a divided (bipartite) genome and in being transmitted by the root-infecting parasite, Polymyxa graminis (Plasmodiophorales), a fungoid protist.
The genus includes a single species, members of which are distinguished from all other members of the family in that they encode a very large P1 protein (83.6 kDa) containing an AlkB domain, and are also phylogenetically distinct (Susaimuthu et al., 2008).
