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As the 2005 Clean
Air Act deadline approaches for phasing out all use of the pesticide
methyl bromide, NC State’s Plant Nematode Genetics Group is zeroing
in on a non-toxic alternative for protecting crops, animals and humans
from the largest and most destructive phylum in the animal kingdom—Nematoda.
Plant-parasitic nematodes, the world’s most successful and prolific
parasites, are usually smaller than the head of a pin. Yet they are
second only to drought as a currently unmanageable crop killer. They
cause $100 billion a year in agricultural losses worldwide, including
more than $5 billion in the U.S. The situation is no better for humans,
companion animals and livestock, with billions afflicted with chronic
infection by parasitic nematodes, and many of those suffering death
from associated anemia or dehydration. The health problems are much
more severe in the developing world, but even Americans and their
animals contract pinworms, hookworms, heartworms and whipworms—all
nematodes.
Dr. Charles Opperman and Dr. David Bird, plant pathologists and leaders
of the Plant Nematode Genetics Group in the College of Agriculture
and Life Sciences, have been working together for seven years to design
control strategies that are safe for both the host and the environment,
but devastating for parasitic nematodes. Until now, the major means
of nematode control has been the application of chemical nematicides
such as methyl bromide—highly toxic compounds often known to
cause more harm to farmers and the environment than to nematodes.
In one of the Plant Nematode Genetics Group’s most promising
efforts, Opperman and his laboratory are sequencing the genome of
a nematode-lethal bacterium, Pasturia penetrans, in an international
collaboration with scientists at Rothamsted Experiment Station in
the United Kingdom. “This is a great, naturally occurring biocontrol
agent that leaves no chemical residue in plants for humans to ingest,”
Opperman explains. “But it only reproduces on nematodes, which
is a severe limitation in scaling up for manufacturing.”
It is also very specific in its host range—or number of nematode
targets. Opperman hopes that by sequencing and then manipulating the
organism’s genes, he can expand the host range and make the bacteria
easy to grow at industrial scale. He expects to have the entire sequence
of the bacterium by the end of this year. Having the sequence will
tell him which genes control the bacterium’s growth and make
it toxic. In a complementary project, Bird’s laboratory is now
in the second year of a $2.6 million grant from the National Science
Foundation to discover and characterize targets in the nematode.
“The new age of genomics has ushered in biology research that
was previously experimentally impossible,” says Bird. “In
addition to genetics and biochemistry techniques, we are now using
every tool of genomics to try to move away from chemicals toward a
more environmentally sound means of nematode control.”
For
more information, please visit
http://www.pngg.org
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