Résumé
The amino acid composition of the virion capsid protein is a criterion that has been used in viral taxonomy for over 20 years. Using correspondence analysis and hierarchical ascending classification, we have been able to derive taxonomic schemes from this criterion that are consistent, over a large corpus, with those adopted by the International Committee for Taxonomy of Viruses.The aim of the present study is to apply this method to the available data on plant viruses in rigid rods. Our typology, based on the amino acid composition of the capsid, uses distance calculations between viruses, and makes it possible to calculate distances between class centres or between virus and class centre. It should be noted that some rod-shaped viruses are very labile and are only found in infected plants at very low concentrations. In such cases, however, it is possible to obtain small quantities of purified capsid protein. Analysis of this protein could provide relatively reliable criteria for classifying viruses and identifying new groups.