Biotechnology — BIOLOGY STD 12 Science — Question

Examples of insect resistant transgenic crops are as follows:
(1) BT crops:

• Insect resistant transgenic plants contain either a gene from B. thuringiensis or the cowpea trypsin inhibitor gene.
• ‘cry’ gene present in B. thuringiensis produces a protein that forms crystalline inclusions in bacterial spores. When insect ingests it, because of high pH and the proteinase enzymes present in insect’s midgut, they are hydrolyzed to release the core toxic fragments.
• This toxin causes midgut paralysis and disruption of midgut cells of insect.
• Bt toxin activity has been against many species of insects within the orders of Lepidoptera, Diptera and Coleoptera.

(2) Transgenic tobacco:

• The gene of a-amylase inhibitor (aAl-Pv), isolated from adzuki bean (Phaseolus vulgaris) is transferred to tobacco.
• This gene works against pests like Zabrotes subfasciatus and Callosobruchus chinensis.