Published: Thursday, June 19, 2008 at 4:30 a.m.
Last Modified: Thursday, June 19, 2008 at 2:27 p.m.
KENT PORTER / The Press Democrat
Grape grower Richard Rued, checking vines Wednesday, says Pierce's
disease is a persistent problem in his Dry Creek vineyards. The
tell-tale sign of the infection is stunted vine growth when compared
with others, at left, which are growing normally.
Researchers trying to save the California wine industry from the
dreaded Pierce's disease have made a series of promising discoveries
they hope will lead to a cure for the vineyard scourge.
They've
cracked the genetic code of the bacterium that causes Pierce's disease
and have used the information to engineer grapevines impervious to the
disease.
"Those plants are quite resistant . . . in our initial
studies, so it seems to work as we had hoped," said Steven Lindow, a
professor of plant biology at UC Berkeley.
Lindow's discovery is
one of the most promising of several breakthroughs made by researchers
trying to protect California's $19 billion wine industry from the most
deadly threat since the phylloxera epidemic.
Pierce's disease has
been around since the 1800s, but in the late 1990s a little bug called
the glassy winged sharpshooter proved more effective than any prior
insect at moving the disease-causing bacterium around vineyards. It
spread Pierce's Disease to hundreds of acres of vineyards in Kern
County in 2001, killing them all. The industry has been on red alert
ever since, warning that its spread northward was likely.
"It's a
real threat," said Nick Frey, president of the Sonoma County Winegrape
Commission. "If it got established in Sonoma County and was indeed
effective at moving (the bacterium) around vineyards, it could put
people out of the grape business."
The disease is already in
Sonoma County, but is spread by the blue-green sharpshooter, which is
less of a threat because it doesn't fly as far or eat as much as its
glassy winged cousin.
To better understand and combat the
disease, the state in 2001 established the Pierce's disease/Glassy
Winged Sharpshooter Board, an industry group that advises the state
secretary of agriculture how to spend the millions of dollars raised
every year by an assessment on grape growers.
The board earlier
this month lowered the assessment on growers from $1.50 per $1,000 of
crop to $1. The reduction was meant to reflect economic difficulties
for some growers hurt by spring frosts, and for all facing higher
costs, especially gasoline.
The main reason the assessments
declined is because the board decided the time has come to focus the
research on turning scientific breakthroughs into solutions the
industry can use, said Steve McIntyre. His business, Monterey Pacific,
is one of the largest grape growers in the state.
McIntyre said Lindow's research is some of the most promising and could change the state's fight against the disease.
Lindow
appears to have figured out how to disrupt the bacteria's "cell-to-cell
communication," slowing the spread through the grapevines, McIntyre
said.
It's exciting research because bacteria plague all kinds of
crops, and this research could provide key insights that could help
other industries, as well.
Lindow said he has figured out how to
isolate a molecule that disease-causing bacteria use to signal one
another. In essence, when it gets too crowded in a vine, the bacteria
communicate with one another, slowing down their growth rate. This
gives them time to spread to other areas of the vine with more food.
Lindow
realized that if a bacterium could be tricked into thinking the vine is
already filled with other bacteria, then it would automatically shut
down.
"We're trying to confuse it into thinking it's crowded when it isn't," he said.
Now
the trick is to partner with a company that can effectively help turn
these scientific discoveries into a marketable cure for Pierce's
disease, McIntyre said.
This could take the form of another
bacterium that transfers the signal molecule into an existing vine, a
spray that the vines absorb, or the creation of vines genetically
modified to resist the bacterium, Lindow said.
The breakthrough is an example of how decoding genomes is living up to the hype.
"We're pretty pleased," Lindow said. "Molecular biology is pretty fantastic these days."
You can reach Staff Writer Kevin McCallum at 521-5207 or kevin.mccallum@pressdemocrat.com.
