Transfer of insecticidal Cry proteins from stacked Bt crops along the food chain

Insect-resistant genetically modified (GM) crops express genes encoding insecticidal crystalline (Cry) proteins from the bacterium Bacillus thuringiensis (Bt). One concern of the use of such GM crops is their potential to adversely affect valued non-target organisms. This includes natural enemies that contribute to sustainable pest management. Herbivores ingesting the plant-produced Cry proteins can pass them on to their natural enemies. In general, Cry proteins are diluted when transferred from plant to herbivore to natural enemies. Different Cry proteins, however, may reveal a different behavior in the food-chain due to differences in expression in the plant tissue and mode of feeding, digestion, and excretion rates of herbivores and natural enemies. The aim of our research is to develop a general model of the Bt protein transfer through the arthropod food web. We are currently investigating how different Cry proteins expressed simultaneously in one GM plant (so called stacked Bt proteins) are transferred to herbivores and predators. Stacked Bt cotton and stacked Bt maize were selected as model plants. First results of different Cry proteins quantified using immunological (ELISA) technique in plants, herbivores, and arthropod natural enemies will be presented.