How do GM crops resist pests and diseases?

GM crops resist pests and diseases through genetic modifications that enhance their natural defences or produce pest-killing substances.

Genetically Modified (GM) crops are plants whose DNA has been altered using genetic engineering techniques. These modifications are designed to improve the crop's resistance to pests and diseases, thereby increasing yield and reducing the need for chemical pesticides.

One common method of enhancing pest resistance in GM crops is through the introduction of a gene from the bacterium Bacillus thuringiensis (Bt). This bacterium produces a protein that is toxic to many insects. When this gene is inserted into the crop's DNA, the plant begins to produce the Bt toxin, effectively turning the plant into a pest-killing machine. Insects that eat the GM crop ingest the toxin and die, reducing the need for chemical pesticides.

Disease resistance in GM crops is often achieved by introducing genes that produce substances which interfere with the disease-causing organism's ability to infect the plant. For example, some GM crops have been engineered to produce proteins that block the action of disease-causing viruses. When a virus tries to infect the plant, these proteins prevent the virus from replicating, thereby stopping the disease in its tracks.

Another approach is to enhance the plant's natural defences. All plants have an immune system that helps them fight off infections. By identifying and strengthening these natural defence genes, scientists can create GM crops that are better equipped to resist diseases.

In addition to these methods, GM crops can also be engineered to tolerate harsh environmental conditions, such as drought or high salinity, which can make them more resistant to disease. For example, a plant that is able to tolerate drought is less likely to be weakened and made vulnerable to disease.

In conclusion, GM crops resist pests and diseases through a combination of enhanced natural defences, production of pest-killing substances, and improved tolerance to environmental stressors.