Virology Division News
Arch Virol 145/8 (2000)
Revised proposal for naming geminiviruses
C. M. Fauquet
, D. P. Maxwell
, B. Gronenborn
and J. Stanley
ILTAB/Donald Danforth Plant Science Center, St. Louis, Missouri, U.S.A.
Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin, U.S.A.
CNRS, Institut des Sciences Végétales, Gif sur Yvette, France
John Innes Centre, Norwich, U.K.
Geminiviruses are plant viruses that belong to the family Geminiviridae and have circular,
single-stranded DNA genomes packaged within geminate particles. The genome organiza-
tion and biological properties of geminiviruses allow them to be divided into four genera [1,
4, 6, 11]. Those that have a monopartite genome and that are transmitted by leafhopper
insect vectors to monocotyledonous plants are members of the genus Mastrevirus, of which
Maize streak virus is the type species. The genus Curtovirus comprises viruses that have a
monopartite genome and are transmitted by leafhoppers to dicotyledonous plants; Beet
curly top virus is the type species. The genus Topocuvirus has only one member (also the
type species): Tomato pseudo-curly top virus, which has a monopartite genome and is
transmitted by tree hoppers to dicotyledonous plants. The fourth genus, Begomovirus,
includes viruses that are transmitted by whiteflies to dicotyledonous plants; Bean golden
yellow mosaic virus is the type species. These viruses have bipartite genomes (A and B
components), with some exceptions (e.g., Tomato yellow leaf curl virus, Cotton leaf curl
virus, Tomato leaf curl virus…) for which no B components have been found.
Infection by geminiviruses can cause significant yield losses to many crop plants through-
out the world . Because of their economic importance and the relative ease with which their
DNA genomes can be cloned, many geminiviruses are now being characterized. Yet, at
present, virologists have no definitive guidelines for naming geminiviruses. Traditionally,
viruses are named according to the host, the symptoms produced, and/or geographical origin
(e.g., Wheat dwarf virus and African cassava mosaic virus), but it is becoming increasingly
difficult or even impossible to name new geminiviruses because different species often cause
similar symptoms in the same crop (e.g., Tomato yellow leaf curl viruses from Thailand,
Israel, and Sardinia). Naming is especially difficult when different species infect the same
crop in the same geographical region (e.g., the tomato leaf curl viruses in India). Moreover,
many isolates are now being characterized within a given virus species, adding a level of
complexity to the system. This complexity is compounded by the recent discovery that recom-
bination between species of geminiviruses happens relatively frequently .