Tomato yellow leaf curl virus, the intracellular
dynamics of a plant DNA virus
Yedidya Gafni
Department of Plant Genetics, A.R.O., The Volcani Center, Bet Dagan 50250,
Israel
|
| Summary |
Tomato yellow leaf curl virus
is a geminivirus, transmitted by whitefly (Bemisia tabaci) and
causing the most destructive disease of tomato throughout the
Mediterranean region, the Middle East and the tropical regions of Africa
and Central America. Affected plants produce either no fruits or a few
small fruits. Since it is an ssDNA virus which replicates in the host cell
nucleus, the molecular mechanisms involved in the viral nuclear import
have been the focus of our studies in recent years and results as well as
prospects will be discussed. |
| Taxonomy: |
Tomato yellow leaf curl virus
(TYLCV) is a ssDNA plant virus, a member of the family Geminiviridae,
of the genus Begomovirus. |
| Physical properties: |
TYLCV, like all members of Geminiviridae,
has geminate (twinned) particles, 18-20 nm in diameter, 30 nm
long, apparently consisting of two incomplete T = 1 icosahedra joined
together in a structure with 22 pentameric capsomers and 110 identical
protein subunits |
| Disease Symptoms: |
Symptoms become visible in tomato
in approximately 2-3 weeks after infection. Leaf symptoms include
chlorotic margins, small leaves that are cupped, thick and rubbery. The
majority (up to 90%) of flowers abscise after infection, and therefore few
fruits are produced. In Israel and elsewhere, weeds bridge the gap as
potential perennial host and source of the virus between tomato growing
seasons. |
| Disease control: |
Control of TYLCV is currently based
on insecticide treatments and/or physical barriers against the insect
vector (Bemisia tabaci), and on tomato breeding programs based on
introgression of resistance or tolerance from wild species to cultivated
tomato. |
| Useful websites: |
http://www.danforthcentre.org/iltab/geminiviridae/ |
|
Fig. 1 Particles of TYLCV. Electron micrograph of purified, negatively stained TYLCV particles. Bar = 100 nm.
|
Fig. 2 Tomato yellow leaf curl symptoms on tomato plant. Leaves show
yellowing on the edges accompanied by upward curling.
|
|
 |
Download
the full article |
|
