Quantification in Soil of 'Bacillus thuringiensis' var. 'kurstaki' delta-Endotoxin from Transgenic Plants

摘要

Transgenic plants that produce pesticidal proteins have the potential to release these products into the environment when the plants are incorporated into soil. This could result in novel exposure of soil organisms to these pesticidal proteins. There is a lack of knowledge about the fate and persistence of transgenic pesticidal products in the soil. A model system of transgenic cotton, which produces Bacillus thuringiensis kurstaki (delta)-endotoxin (Bt toxin), was used to address this issue. Methods were developed to quantify Btk toxin in soil and soil/plant litter by extraction of the Btk toxin with an aqueous buffer and quantification by ELISA. The highest recovery of Btk toxin from soil was obtained with a high salt, high pH buffer. The method was shown to be useful in tracking over time the persistence of both purified and transgenic Btk toxin in laboratory experiments.