Xylella fastidiosa
| Xylella fastidiosa | |
|---|---|
| Scientific classification | |
| Kingdom: | Bacteria |
| Phylum: | Proteobacteria |
| Class: | Gamma Proteobacteria |
| Order: | Xanthomonadales |
| Family: | Xanthomonadaceae |
| Genus: | Xylella |
| Species: | X. fastidiosa |
| Binomial name | |
| Xylella fastidiosa Wells et al., 1987 |
|
Xylella fastidiosa is a Gammaproteobacteria that is an important plant pathogen that causes several plant diseases, including phoney peach disease in the southern United States, oleander leaf scorch and Pierce's disease (named after Newton Barris Pierce (b. 1856, d. 1916; became 60 years old), California's first professional plant pathologist) in California and Texas, and citrus X disease in Brazil.
Contents |
[edit] Pierce's disease
Pierce's disease was discovered in 1892 by Newton Barris Pierce near Anaheim. It became a real threat for California's wine industry and overall economy when the Glassy-winged sharpshooter, native from South East United States, was discovered in the Temecula Valley in California in 1996. It triggered a unique effort from growers, administrators, policy makers and researchers to work together in finding a solution for this immense threat. No cure has yet been found,[1] but the understanding of Xylella fastidiosa and Glassy-Winged SharpShooter Biology have exponentially increased since 2000, date when the California Department of Food and Agriculture in collaboration with different Universities such as University of California, Davis; University of California, Berkeley, University of California, Riverside started to focus their research on this pest. The research explores the different aspects of the disease propagation from the vector to the host plant and within the host plant, to the impact of the disease on California's economy. All researchers working on Pierce's Disease meet annually in San Diego mid-December to discuss the breakthrough in their field. All proceedings from this Symposium can be found on the Pierce's Disease website[2], website developed and managed by the Public Intellectual Property Resource for Agriculture (PIPRA)[3].
There are no resistant Vitis vinifera varieties, and Chardonnay and Pinot Noir are especially sensitive, although muscadine grapes have a natural resistance.[1] Pierce's disease is presently found in the south eastern United States, Mexico, Costa Rica, and Venezuela and possibly other parts of Central and South America. There are isolated hot spots of the disease near creeks in Napa and Sonoma in northern California.[1]
Currently work is underway at U.C. Davis to breed PD resistance into Vitis vinifera. The first generation was 50 percent high quality vinifera genes, the next 75 percent, the third 87 percent and the fourth 94 percent. In the spring of 2007 seedlings that are 94 percent vinifera were planted. [4]
When a vine becomes infected, the bacterium causes a gel to form in the xylem tissue of the vine, preventing water from being drawn through the vine. Leaves on vines with Pierce's disease will turn yellow and brown and eventually drop off the vine. Shoots will also die. After 1 to 5 years, the vine itself will die. The proximity of vineyards to citrus orchards compounds the threat because citrus is not only a host for the sharpshooter eggs, but it is also a popular overwintering site for the insect. Likewise, oleander is a common landscaping plant in California, and it also serves as a reservoir for Xylella.
[edit] Oleander leaf scorch
Oleander leaf scorch is a disease of landscape oleanders (Oleander nerium) caused by a strain of X. fastidiosa and has become prevalent in California and Arizona, USA. The disease is transmitted by another sharpshooter (Homalodisca liturata), a leafhopper.
[edit] Genome sequencing
The genome sequencing of X. fastidiosa was realized by a pool of over 30 research labs in the State of São Paulo, Brazil, and funded by this State's Science Foundation (FAPESP). "Genomic medicine and developing countries: creating a room of their own". Nature Reviews Genetics 9 (6): 487–493. Jun 2008. doi:10.1038/nrg2379. PMID 18487990.
[edit] References
- Public Intellectual Property Resource for Agriculture Pierce's Disease Website
- APHIS. 2002. Glassy-winged Sharpshooter and Pierce's Disease in California
- Univ. of Arizona. 2006 Oleander leaf scorch
- Wells, J. M., B. C. Raju, H. Y. Hung, W. G. Weisburg, L. M. Parl and D. Beemer (1987). "Xylella fastidiosa gen. nov., sp. nov.: Gram-negative, xylem-limited, fastidious plant bacteria related to Xanthomonas spp.". International Journal of Systematic Bacteriology 37: 136–143. doi:10.1099/00207713-37-2-136.
- Footnotes
- ^ a b c winepros.com.au. Oxford Companion to Wine. "Pierce's disease". http://www.winepros.com.au/jsp/cda/reference/oxford_entry.jsp?entry_id=2428.
- ^ PIPRA Pierce's Disease website. "Pierce's disease". http://www.piercesdisease.org.
- ^ Public Intellectual Property Resource for Agriculture. "PIPRA". http://www.pipra.org.
- ^ PD/GWSS Board Newsletter http://www.pdgwss.net/News/PD_Newsletter_Spring07.pdf
|
||||||||||||||||||||||||||
