Cucurbit yellow stunting disorder virus (CYSDV)
A Viral Biorealm page on the family Cucurbit yellow stunting disorder virus (CYSDV)
Baltimore Classification
Group IV: (+) sense single-stranded RNA viruses
Higher order categories
Order: Unassigned
Family: Closteroviridae
Genus: Crinivirus
Description and Significance
Cucurbit yellow stunting disorder virus, CYSDV, can infect members of the family Cucurbitaceae, including all types of melons, summer and winter squash, pumpkins, gourds, and cucumbers [1]. CYSDV symptoms develop first in older leaves and mimic water stress. Intervenial chlorosis, a yellowing between the veins, streaks the leaves. Eventually the entire leaf becomes yellow except for the veins, which remain green [2]. In certain varieties, small green spots may develop on the leaves as well. As the plant’s internal transport system breaks down, it begins to drop older leaves in attempt to preserve itself. Without enough leaves, the plant’s strength dwindles and it no longer can support or nourish its fruit. As a result, the fruits are smaller, not as sweet, and don’t ship or store as well [1]. Consequently, CYSDV has significant economic implications on national and international agriculture. However, control is difficult because there is no chemical or biological control suitable to fight the virus. Increasing water and fertilizer, and early season insecticide application (to reduce the virus’s vector population) may help, but these remedies compromise the producer’s ability to grow a sustainable crop and are incredibly costly [1].
Genome Structure
Genetic variability in CYSDV is unusually low compared with other members of the family Closteroviridae. Although two genetic groups have been differentiated, the so-called Eastern and Western CYSDV subpopulations. [2]
Virion Structure of CYSDV
CYSDV virus particles are flexous rods 750-800 nm in length. The virus ecapsidates 2 molecules of (+)sense ssRNA, designated RNA1 and RNA2 [2].
Reproductive Cycle of CYSDV in a Host Cell
Virus penetrates into the host cell.
Uncoating, and release of the viral genomic RNA into the cytoplasm.
The viral RNA is translated.
Negative-sense complementary ssRNAs are synthesized using the genomic RNAs as a templates.
New genomic RNAs are synthesized using the negative-sense RNAs as templates.
Formation of new virus particles.
Viral Ecology & Pathology
References
[1] McGinley, Susan. 2010. "New virus attacks melons, cucumbers, and squash." Western Farm Press. http://westernfarmpress.com/new-virus-attacks-melons-cucumbers-and-squash-0. Date accessed: 6 Sept. 2010.
[2] Auguilar, Juan M. et al. Resistance to Cucurbit yellow stunting disorder virus in Cucumber. Plant Diseases. 90.5 (2006): 583.
Page authored by Sally Wilson for BIOL 375 Virology, September 2010
