Bacillus thuringiensis (Bt) is a Gram-positive, soil-dwelling bacterium, which produces the Cry toxin. The Cry toxin has insecticidal action which has led to its use as a pesticide, and in more recent years its introduction into genetically modified crops using Bt genes. Description: Isolated from Bt spores. Alternative Names: Cry1Ab protein, BtCry1Ab protein, Bacillus thuringiensis protein, CRY1AB protein, CRY1, Bacillus thuringiensis crystal 1Ab Protein, Bacillus thuringiensis crystal 1Ab