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How do genetically modified crops produce their own pesticides?

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A step-by-step diagram shows donor DNA and vector DNA cut with restriction enzymes to create overhangs, mixed and sealed with ligase to form recombinant DNA, which is introduced into bacterial cells. The recombinant DNA replicates as the cells divide, producing clones. — biotechnology Steps involved in the engineering of a recombinant DNA molecule.

Genetically modified crops produce their own pesticides through the application of genetic engineering to incorporate specific genes from the soil-dwelling bacterium Bacillus thuringiensis (Bt).

These crops are engineered to express proteins that are toxic to specific insect pests. When a susceptible insect consumes parts of the plant containing these proteins, the toxin acts by blocking the insect's digestive system, which leads to the pest's death by starvation or digestive rupture.1

This technology allows crops such as corn, cotton, potatoes, and rice to defend themselves against targeted pests, such as various caterpillars, beetles, and fly larvae, without the need for external applications of broad-spectrum chemical insecticides. Because these Bt proteins target specific digestive mechanisms found only in certain insects, they are generally considered nontoxic to humans and other mammals, who lack the necessary enzymes to activate the toxin crystals.12