Xylella fastidiosa

Xylella fastidiosa (also known as Pierce's disease) is a Gamma Proteobacteria that is an important plant pathogen, causing several plant diseases including phoney peach disease in the southern United States, oleander leaf scorch and Pierce's disease in California and Texas, and citrus X disease in Brazil.

Pierce's Disease
Pierce's disease is a disease affecting grapes. Pierce's disease has long been a scourge to California's vintners. In the 1880s, the disease infected over 40,000 acres (160 km²) of grapes around Anaheim, devastating vineyards. Over the years, California producers learned to cope with the disease. With the introduction of the glassy-winged sharpshooter from the southeastern U.S., however, the spread of Pierce's disease has increased dramatically.

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.

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.



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). The results were published in 2000 in Nature.