Flexiviridae

The Flexiviridae were a new family of viruses in the 2004 classification of viruses, but have since the 2009 classification been split into the three new families Alphaflexiviridae, Betaflexiviridae and Gammaflexiviridae. These have in turn been subsumed under the new order Tymovirales along with the old family Tymoviridae by the International Committee on Taxonomy of Viruses based on molecular phylogenetic systematic analyses of proteins (RNA polymerase and viral coat). The viruses are positive-sense ssRNA viruses, placing them in Group IV of the Baltimore classification. These viruses are filamentous and named for being highly flexible. Members of these families are readily transmitted mechanically and have other vectors of transmission. Species tend to be confined to a single host plant, many species preferring woody hosts, but a diversity of angiosperm hosts are known to the Flexiviridae. Viral aggregates are known to form in the cytoplasm of plant cells.