Bt stands for Bacillus thuringiensis. It is a bacterium which produces over 200 toxins, which are harmful to different insect species. Bt toxins are insecticidal to different larvae of beetles, butterflies and flies but are harmless to other life forms. The Bt toxin gene have been successfully inserted into the different variety of crops such as cotton, brinjal etc. to protect them from various insects which lead to mass destruction of crops and great loss to human income.
The Bt gene is isolated from the bacterium and is inserted in the crops which lead to the production of the cry protein, which is an endotoxin. When insects eat the plant, this cry protein gets dissolved due to high pH level of insect’s gut. These cry protein attach to the specific cadherin protein present inside the epithelial cell of insect which leads to unregulated flow of potassium ions inside the cell, which in turn leads to the death of the cells and ultimately death of insect.
However, it is completely safe for human consumption as in the human gut; it encounters the acidic environment due to which it cannot be activated. Bt technology is considered to be the friendly measure for farmers as it save a huge amount of money that is going to be spent on chemical insecticide.
But use of Bt crops is not approved in many parts of the world due to the integration of a foreign gene. Also there is a threat of contamination by the foreign gene in the genome of the plants of wild species.