Résumé
About 40% of genetically modified crops contain the insecticidal trait engineered from the soil bacterium Bacillus thuringiensis. Plants produce an insectidal protein and it is important to understand how the interactions of this protein with soil influence its persistence and its biological properties. We have used various techniques to monitor the interactions of one such toxin, Cry1Aa with soils and minerals. We have investigated the persistence of the toxin as a function of soil properties and microbial activity and conclude that microbial decay is not the determinant factor in the observed decline of toxin in soil.