M. J. Adams & J. F. Antoniw - Plant Pathogen Interactions Division, Rothamsted Research, Harpenden, Herts, U.K.
A. A. Brunt - Department of Microbiology and Plant Pathology, Horticulture Research International, Wellesbourne, U.K.
T. Candresse - Equipe de Virologie, UMR GD2P, Villenave d’Ornon, France
G. D. Foster - School of Biological Sciences, University of Bristol, Bristol, U.K.
G. P. Martelli - Dipartimento di Protezione delle Piante e Microbiologia Applicata, Bari, Italy
R. G. Milne - Istituto di Virologia Vegetale CNR, Torino, Italy
C. M. Fauquet - ILTAB, Danforth Plant Science Center, St Louis, Missouri, U.S.A.
The new plant virus family Flexiviridae is described. The family is named because its members have flexuous virions and it includes the existing genera Allexivirus, Capillovirus, Carlavirus, Foveavirus, Potexvirus, Trichovirus and Vitivirus, plus the new genus Mandarivirus together with some related viruses not assigned to any genus. The family is justified from phylogenetic analyses of the polymerase and coat protein (CP) sequences. To help to define suitable molecular criteria for demarcation of species, a complete set of pairwise comparisons was made using the nucleotide (nt) and amino acid (aa) sequences of each fully-sequenced gene from every available accession in the family. Based on the distributions and on inspection of the data, it was concluded that, as a general rule, distinct species have less than ca. 72% identical nt or 80% identical aa between their entire CP or replication protein genes.
