Learning the ABCs of Bt: ABC transporters and insect resistance to Bacillus thuringiensis provide clues to a crucial step in toxin mode of action

Abstract

Insecticidal crystal toxins from the bacterium Bacillus thuringiensis (Bt) kill insects via a complex mode of action resulting in the creation of cytolytic pores in the membrane of midgut epithelial cells. Recent genetic studies in four species of Lepidoptera have found mutations in an ABC transporter in strains that have evolved resistance to Cry1A toxins. This points to a novel role of ABC proteins in insertion of pores into the membrane, and suggests strategies to increase efficacy of and delay resistance to Bt toxins.