Biotechnology and its Applications

Lesson

Part 1 — how genetically modified crops can reduce losses and the use of chemical pesticides.

In this lesson you will

Explain the uses of genetically modified crops
Explain how Bt toxin protects cotton from insect pests
Explain how RNA interference protects tobacco from a nematode

Concept

Why genetically modified crops?

GM plants have been useful in many ways.

Table of benefits of genetically modified crops with examples
Benefit	Example
Tolerance to abiotic stresses	Cold, drought, salt, heat
Reduced reliance on chemical pesticides	Pest-resistant crops
Reduced post-harvest losses	Slower spoilage
Increased efficiency of mineral use	Prevents early exhaustion of soil fertility
Enhanced nutritional value	Golden rice, rich in vitamin A
Industrial uses	Tailor-made plants supplying starches, fuels and pharmaceuticals

Concept

Bt: a bacterial insecticide

Bacillus thuringiensis (Bt) forms protein crystals containing an insecticidal protein. Bt toxins kill certain insects — lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).

Table of cry genes and the pests they control
Bt gene	Controls
cryIAc, cryIIAb	Cotton bollworms
cryIAb	Corn borer

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