A proposed new family, Ophioviridae, to contain the Ophiovirus genus

ANNA MARIA VAIRA, JOHN V. DA GRAÇA, SELMA GAGO-ZACHERT, MARIA LAURA GARCIA, JOSÉ GUERRA, OSCAR GRAU, ROBERT G. MILNE, PEDRO MORENO, TOSHIYUKI MORIKAWA, TOMOHIDE NATSUAKI, VALERIA TOROK, MARTIN VERBEEK, H. JOSEF VETTEN

USA

Congreso; 9th Report of the International Committee on Taxonomy of Viruses; 2005

International Committee on Taxonomy of Viruses

Ophioviruses are ssRNA negative-sense viruses infecting plants. The genome is 11.3-12.5 kb in size and consists of three or four segments. The virions are naked filamentous nucleocapsids about 3 nm in diameter forming kinked circles that can collapse to form pseudolinear duplex structures. The genus contains five species: Citrus psorosis virus (CPsV), Lettuce ring necrosis virus (LRNV), Mirafiori lettuce big-vein virus (MLBVV), Ranunculus white mottle virus (RWMV) and Tulip mild mottle mosaic virus (TMMMV). A tentative species is also listed: Freesia ophiovirus (FOV). Ophiovirus-specific primers, based on a highly conserved sequence of RNA 1, have been tested by RT-PCR with all ophiovirus species and with FOV. In all cases a 136 bp fragment is amplified. CPsV has a tripartite genome. MLBVV and LRNV genomes possess a fourth segment. RdRp aa sequences show similarity with Paramyxoviridae, Rhabdoviridae, Bornaviridae and Filoviridae, and Varicosavirus.  The RdRp aa sequence also contains a motif typical of Orthomyxoviridae, Arenaviridae and Bunyaviridae. Phylogenetic reconstructions using RdRp conserved sequences reinforce the taxonomic relatedness of ophiovirus species and suggest their separation as a monophyletic group: the newly proposed family Ophioviridae.