CUET Preparation Today
Which of the following in NOT true for Bt toxin? (A) It is produced by Bacillus thuringiensis Choose the correct answer from the options given below: |
(A) and (C) (A) and (B) (A) and (D) (B) and (D) |
(B) and (D) |
The correct answer is Option (4) → (B) and (D) Bacillus thuringiensis (Bt) is a bacterium that produces proteins called Bt toxins, which are toxic to certain insects. These toxins have been utilized in biotechnology to create pest-resistant plants, reducing the need for chemical insecticides. One such example is Bt cotton, where the Bt toxin gene is cloned from the bacterium and expressed in the plant. Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes). The Bt toxins are produced in the form of protein crystals during a specific phase of B. thuringiensis growth. These crystals contain an inactive form of the toxin, known as protoxins. Interestingly, the toxin does not harm the bacterium itself because the toxin is in its inactive form. A nematode Meloidegyne incognitia infects the roots of tobacco plants and causes a great reduction in yield. A novel strategy was adopted to prevent this infestation which was based on the process of RNA interference (RNAi . |
