ARLINGTON, Va. -- An industry representative on the U.S.Department of Agriculture's Agricultural BiotechnologyResearch Advisory Committee (ABRAC) suggested last weekthat increased research into biotechnology-derived insecticidescould lead to a holistic approach to understanding and fightinginsect pests.
Pamela Marrone is president of Novo Nordisk subsidiaryEntotech Inc., which is developing both natural andrecombinant microbial pesticides in Davis, Calif. She saiddifferent genes for pesticide resistance are needed for differentproducts so that "growers don't just latch onto a (single) biotechproduct and treat it like chemicals, as a panacea, instead ofintegrating it" into a more holistic vision of agriculture.
Currently, plants are made resistant to insects and disease onlywith single genes for resistance, Marrone told BioWorld. "Ienvision the time you can clone the entire metabolic pathwayof a new insect control agent into a plant," she said.
To cope with insects or microbes that evolve ways to evadebiopesticides, a better understanding is needed of themolecular mechanics of viruses, nematodes and fungi. "We stilldon't know ... how Bt (Bacillus thuringiensis) works on insects(despite) 40 years of research," Marrone told BioWorld. Alsopoorly understood is why some viruses are broad-spectrumwhile others are very specific, she said.
New modes of action for biopesticides provide anotherarmamentarium that could keep pests at bay, Marrone said.Currently, most biopesticides attack the nervous system orinterfere with molting.
"How do the pest insects find their hosts and why do they laytheir eggs on certain plants and not others?" she asked. "If youcould find out what the insect cues into, you could engineer aplant to inhibit or to delete the cue."
Research is needed to make insect control agents morepractical, said Marrone. Economical systems for scale-up needto be developed, and shelf life must be improved, she added.
As for plants, tissue-specific promoters could alleviate safetyproblems and public concerns, said Marrone. For example, toattack the corn root worm, "why have a gene in the rest of theplant, when you could just target the root?" she asked.
The other industry representative on the committee who wasat the meeting, James Lauderdale of The Upjohn Co., addressedconcerns about animal biotechnology. "Understanding microbialor animal genome to enhance metabolism of phosphorus isgoing to do two practical things: increase the efficiency of leanmeat production and decrease the load on the environmentfrom the spread of the manure," he said.
The current Journal of the American Society of Animal Sciencereported that pigs fed Aspergillus niger, containing the enzymephytase, became more efficient metabolizers, said Lauderdale.
"They cloned it into tobacco seeds, fed the tobacco seeds intoswine and chickens, and increased production," said RudyWodzinski, of the Department of Molecular Biology andMicrobiology of the University of Central Florida.
"I think it opens up this whole area of how do you deliver anenzyme or other beneficial products," said Wodzinski. "Whatare you going to use as a vector? Whether microbe or plantseed, it doesn't matter."
-- David Holzman Washington Editor
(c) 1997 American Health Consultants. All rights reserved.