The family Closteroviridae revised

Recently obtained molecular and biological information has prompted the revision of the taxonomic structure of the family Closteroviridae. In particular, mealybug-transmitted species have been separated from the genus Closterovirus and accommodated in a new genus named Ampelovirus (from ampelos, Greek for grapevine). Thus, the family now comprises three genera. Their major properties are (i) Closterovirus: type species Beet yellows virus, genome monopartite, 15.5-19.3 kb in size, a 22-25 kDa major coat protein (CP), the gene encoding the divergent CP analogue (CPd) upstream of the CP cistron, transmission by aphids, a membership of 8 definitive and 4 tentative species; (ii) Ampelovirus: type species Grapevine leafroll virus 3, genome monopartite 16.9-19.5 kb in size, a 35-37 kDa major CP, a CPd cistron generally located downstream of the CP gene, transmission by pseudococcid and coccid mealybugs, a membership of 6 definitive and 5 tentative species; (iii) Crinivirus: type species Lettuce infectious yellows virus, genome essentially bipartite 15.3-19 kb in size, a 28-33 kDa CP, a CPd cistron downstream of the CP gene, transmission by whiteflies (Bemisia, Trialeurodes), a membership of 7 definitive and 3 tentative species. There are five unassigned species in the family.