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