Corn, potato, soybeans and cotton are four types of genetically modified organisms, or GMOs, that have built-in pesticides, according to the University of Kentucky College of Agriculture, Food and Environment. The "built-in" pesticide is Bacillus thuringiensis.
Bacillus thuringiensis is a spore-forming soil bacterium derived from the family Bacillus cerus. There are approximately 200 Bt strains. The B. cerus family naturally produces various protein crystals that are toxic to certain insects. Bt does not cause food poisoning, reports the University of California, San Diego.
The European corn borer, the southwestern corn borer, the tobacco budworm, the pink bollworm and the cotton bollworm are insects susceptible to the toxic effects of Bt GMOs. When a susceptible insect consumes a Bt GMO, the Bt toxins dissolve in the high pH of the insect's gut, and the toxins bind to the gut wall within minutes. The gut wall breaks down, spores and bacteria proliferate throughout the insect's body, and the insect dies.
Bt GMOs contain an inserted genetic trait, that is, a Bt protein and a promoter sequence of genetic material. The promoter sequence results in Bt proteins occurring in certain parts of an organism, throughout a whole organism in differing concentrations, or only at certain times during the organism's maturation.
Potential risks of Bt GMOs include resistance on the part of normally affected insects and potential cross-contamination of genes. While the latter is unproven, it is possible in theory, states the University of California, San Diego.