Events like the September 2000 discovery of biologically engineered corn in fast food tortillas have focused media attention and stirred controversy about genetically modified organisms. While new approaches in agricultural biotechnology have improved crop quality and yield, the incorporation of genes from other organisms into food plants has raised concerns about possible health risks and environmental consequences. A new report from the American Academy of Microbiology (AAM) looks at the case of a bacterium called Bacillus thuringiensis (Bt) and its use in agriculture in a careful examination of what we know--and what we need to know--about transgenic plants.
The document, "100 Years of Bacillus thuringiensis: A Critical Scientific Assessment," follows the experience with Bt since it was discovered over 100 years ago as a cause of disease in Japanese silkworms. Bt insecticides, made of bacterial spores and protein crystals, have been applied to crops in spray products since the 1940s. In 1987, researchers discovered that the insecticidal crystal protein (ICP) genes from Bt could be introduced into plants to produce pest-resistant crops. It is now estimated that 12 million hectares, or about 29,652,000 acres, of insect-protected crops with Bt ICPs are planted worldwide each year. Corn and cotton are most common, but the release of Bt rice, soybeans, canola and some fruits and vegetables is expected soon.
Bt crops, the report says, have many positive effects. Reducing insect damage with insecticidal proteins reduces fungal toxins in the food supply, while better crops improve farmers' livelihood. Replacing chemical pesticides has reduced toxic hazards to the environment and to farm-workers. Yet concerns related to Bt crops include the potential for harm to organisms other than the insects targeted by Bt, the development of Bt-resistant insects, the possibility of toxicity or allergenic properties in Bt crops or their pollen, and the consequences of gene flow to related wild plants or other organisms.
The report details the issues, assesses current scientific knowledge, and compares Bt technology to alternatives. It presents the conclusions of twenty-five (25) scientists with expertise in plant biology, microbiology, entomology and ecology brought together in November of 2001 for 21/2 days of in-depth discussion of Bt technology and its intended and unintended outcomes. Specific recommendations are made for future research, evaluation and environmental monitoring, scientific coordination and exchange, and public education.
The American Academy of Microbiology is an honorific leadership group within the American Society for Microbiology (ASM) whose mission is to recognize excellence and foster knowledge in the microbiological sciences. Its programs include convening critical issues colloquia and developing consensus-building position papers that provide expert scientific opinion on current and emerging issues in microbiology.
A full copy of the report can be found online at http://www.asmusa.org/acasrc/pdfs/Btreport.pdf.
Materials provided by American Society For Microbiology. Note: Content may be edited for style and length.
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