Previous Year Question
Mon 863 is a variety of maize. It was in the news for the following reason
It is a genetically modified dwarf variety which is resistant to drought
It is a genetically modified variety which is pest resistant
It is a genetically modified variety with ten times higher protein content than regular maize crop
It is a genetically modified variety used exclusively for bio-fuel production
Correct Answer: B
Detailed Solution
What is MON 863?
MON 863 is a genetically modified maize line or transformation event originally developed by Monsanto.
It was developed principally to protect maize against corn rootworms.
Corn rootworms include the larvae of beetles belonging to the genus Diabrotica. These larvae feed upon maize roots and damage the root system.
Root damage reduces the plant’s ability to absorb water and nutrients and increases the risks of lodging and yield reduction.
Basis of its insect resistance:
MON 863 contains the cry3Bb1 gene obtained from the soil bacterium Bacillus thuringiensis.
This gene enables the maize plant to produce the insecticidal Cry3Bb1 protein.
When a targeted corn-rootworm larva feeds on the relevant plant tissue, the protein becomes active in its digestive system and damages the cells lining its midgut.
Feeding subsequently stops and the larva eventually dies.
This is an example of a plant-incorporated protectant, as the insect-controlling protein is produced by the plant itself.
Testing the options:
Option (a) is incorrect: MON 863 was not developed to produce dwarf plants or confer drought resistance.
Option (b) is correct: Its principal trait was protection against coleopteran pests, especially corn rootworms.
Option (c) is incorrect: It was not engineered to contain ten times more protein than conventional maize.
Option (d) is incorrect: It was not developed exclusively for biofuel production.
Important fact: “Pest-resistant” does not mean resistance to every insect pest. MON 863 was specifically designed principally for controlling corn rootworms.