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2-Plants: Vines should be protected against Pierce's Disease by GEbacteria



-------------------------------- GENET-news -------------------------------

TITLE:  Project shows promise for grape growers
SOURCE: Associated Press, by Daisy Nguyen / Seattle Post-Intelligencer, USA
        http://seattlepi.nwsource.com/printer/ap.asp?category=1501&slug=
        Wine%20Sharpshooter
DATE:   24 Aug 2004 

------------------- archive: http://www.genet-info.org/ -------------------


Project shows promise for grape growers

University of California-Riverside entomology professor Thomas Miller
holds a preserved glassy-winged sharpshooter Wednesday, Aug. 11, 2004, in
Riverside, Calif. Since the discovery five years ago that a ravenous
insect was spreading grape-killing Pierce's Disease in California, grape
growers have contributed millions of dollars to fund research projects
they hope can end the scourge. Researchers at UC-Riverside have been
working on a high-tech approach to neutralize the sharpshooter's
bacterial pathogen by introducing genetically engineered traits into the
natural insect population.
(AP Photo/Nick Ut)

RIVERSIDE, Calif. -- Since the discovery five years ago that a ravenous
insect was spreading grape-killing Pierce's Disease in California, grape
growers have contributed millions of dollars to fund research projects
they hope can end the scourge.

One project at the University of California, Riverside involves
introducing genetically altered bacteria into the plant. When the bug -
known as the glassy-winged sharpshooter - eats the material, it
neutralizes the pathogen that causes the disease.

The technique, however, alarms environmentalists opposed to using
genetically modified organisms, or GMOs, in nature.

In addition, some grape growers are concerned that even a slight change
to plants would taint classic grape varieties - Merlot, Chardonnay, Pinot
Noir, for example - that are prized by wine lovers.

"Growers say it's a marketing issue," said Ray Van Rein, a spokesman for
the California Department of Food and Agriculture Pierce's Disease
Control Program. "Even if the solution becomes available in the lab, it
won't make it into the field unless consumers find it palatable."

A major outbreak of Pierce's Disease was detected in 1999 when vineyards
in Temecula in San Diego County showed yellowing leaves and shriveled
young grapes.

The culprit was determined to be the sharpshooter, a half-inch flying
insect that can suck up and excrete about 30 times its body weight in
fluid from a plant.

Since then, sharpshooter infestations have decimated vineyards elsewhere
in Southern California but have been found in just a few spots in the
northern part of the state.

In June, however, alarms sounded when a colony of the insects was
discovered in Vacaville, about 30 miles from Napa Valley, the heart of
California wine country.

If left unchecked, the sharpshooter could cause major damage to
California's 880,000 acres of grape vines and paralyze the $2.3 billion
grape industry - the state's second-largest agriculture commodity behind
dairy.

"It's put the fear of God in us," said Ben Drake, who grows and manages
vineyards in Temecula.

Before the infestation, the region had 2,500 acres of vines, Drake said.
That number has since been reduced to 1,800.

Pierce's Disease is caused by a bacterium known as Xylella fastidiosa,
which sharpshooters spread as they feed. The bacteria infects and kills
plants by clogging the vessels that carry water and nutrients.

At UC Riverside, a research group led by Thomas A. Miller has isolated
another bacteria found inside the sharpshooter, called Alcaligenes, and
is genetically altering it.

In the technique called "symbiotic control," scientists inject the
altered bacterium into a plant. When the sharpshooter feeds on it, the
bacterium can kill Xylella, said Miller, an entomology professor.

"The way I envision it, it gives a grower a tool with which he can
protect the plant," he said.

The Environmental Protection Agency, which regulates most microorganisms,
has granted Miller permits to experiment outdoors. So far, he said
cautiously, his team of researchers have seen promising results.

"We've been warned by our sponsors not to be too enthusiastic too soon
because agriculture industries are plagued with false hopes all the
time," he said.

So far, the field tests have shown that altered Alcaligenes injected into
plants were not detected in grapes or soil. Still, Miller concedes a lot
more research needs to be done, and it will take time for the public to
get used to the idea.

In a review of research projects targeting Pierce's Disease, the National
Research Council of the National Academies concluded that such transgenic
approaches may be a long-term, expensive strategy.

Although scientifically appealing, the report said, regulatory and legal
hurdles along with public resistance to the release of GMOs would have to
be overcome.

Meanwhile, state agriculture officials and growers are settling on a
combination of tactics to fight sharpshooters, including using pesticides
and releasing natural enemies.

Drake, the grower who also chairs the California Association of Winegrape
Growers, has donated some vineyards for Miller to conduct his field test.

"I feel the research needs to go forward, and I think that as we move
forward, at some point the industry has to address GMOs and everything
else going on," Drake said.


---

On the Net:
http://www.cdfa.ca.gov/phpps/pdcp/




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