Write a short note on Bt crops.

Hint: Genetically Modified Organisms or GMO are those microbes (like bacteria and fungi), plants and animals, whose genes are modified and altered by human manipulation. GMO has several uses in all aspects of our day to day life. Bt cotton is an example of GMO crops.

Complete Answer:
Genetically modified organisms have several applications like reducing the reliance on chemical pesticides which are toxic to our health, reduce post harvest losses, making plants more resistant to abiotic stresses, increasing the nutritional value of foods, enhancing the efficiency of mineral uptake by plants, along with supplying modified resources to several industries.

Bt toxin is named after the bacterium Bacillus thuringiensis, since it is produced by the bacterium itself. This is one of the main GMO produced in India successfully. The commercially accepted Bt crops mostly include cotton and corn. The Bt toxin is being expressed in plants by cloning the bacteria’s strain, in order to provide insect resistance without insecticides.

The bacterium produces specific proteins called ‘cry proteins’ that are fatal to insects. When the insect tries to feed on the genetically modified plant, the toxin is converted into an active form, which is due to the alkaline nature of the gut, which solubilise those crystallised toxins. When this binds to the midgut epithelium, they create pores on them, and hence ultimately leading to their death.

Note: The Bt toxin or the protein exists as inactive protoxin in the plant, and that is the reason due to which it does not harm the plant itself. And the vulnerable insects are lepidopterans, coleopterans, and dipterans.