RIVERSIDE, Calif. -- A research team led by University of California, Riversides Leonard Nunney, a professor of biology, has received a grant of $1.75 million from the U.S. Department of Agriculture to battle a bioterrorist less than half an inch long and bearing a lethal weapon that is microscopic in size.

Nunneys team will study Xylella, a pathogen that has potential, along with its vector, the glassy-winged sharpshooter, to wipe out Californias grape, peach and almond industry, as well as much of the states ornamental bushes and trees. In time, the states citrus industry also could be destroyed by the sharpshooter and the Xylella pathogen.

Xylella causes damaging diseases in a wide range of economically important crops, said Nunney, who also is director of the Graduate Research Unit in Evolution and Ecology at UCR. The North American varieties of Xylella attack grapes, almonds, and peaches, and have devastated the ornamental oleander bushes that line Southern California freewaysat enormous replacement cost.

There are four main Xylella subspecies, three in North America and one in South America. The South American variety feeds on citrus. But it has not yet crossed our border, Nunney said.

Among the North American varieties, subspecies fastidiosa, the one that causes Pierces disease, is found on grapes and almonds; subspecies sandyi on oleanders, day lilies, magnolias, and jacarandas; subspecies multiplex on almonds, brittlebushes, sages, olives, oaks, plums, and peaches.

There are several puzzles about this bacterium, Nunney said. If you find Xylella on a certain plant, you cant predict what else it might be found on. Most bacteria will attack a group of related organisms. If they attack a peach tree, they might also attack apricots. But with Xylella theres little phylogenet
'"/>

Contact: Iqbal Pittalwala
iqbal@ucr.edu
951-827-6050
University of California - Riverside
4-Jun-2007