September 16, 2011

Pest Resistance to Genetically Engineered Crops Emerges

Genetic engineering (GE) in agricultural production has two possible goals: one is to produce a GE food with superior nutritional properties, while the other is to provide an agronomic benefit that improves crop development.  The The strategy behind the development of the well-known Bt corn, produced by Monsanto, is agronomic:to create a genetically engineered corn stock which contains a bacterial protein that is toxic to the rootworm; the stock essentially producing an insecticide that avoids the need for topical application of a pesticide to the field.   The current U.S. Department of Agriculture (USDA) estimate is that about 65% of the corn planted in the U.S. is Bt corn. A recent research report in PloS One provides the first account of rootworm resistance to the protein, with the consequence that the GE component of the corn is no longer effective.  The results, while preliminary and not yet widespread, are a reminder that genetic alterations, whether through breeding or engineering, function against a dynamic backdrop of evolving organisms, which could out maneuver a strategy that relies on the performance of a single protein. Monsanto replies that the use of Bt corn should occur against a backdrop of complementary tactics, such as crop rotation, possible supplementary GE crops, and attention to refuge requirements.  Since more GE crops are engineered for agronomic purposes than nutritional advantage, demonstrations of ineffectiveness are sure to draw attention, as the shelf life for the intervention is shortened, but the genetic modifications nonetheless persist in the food supply as biochemical artifacts.

No comments: