Biotechnology has many applications such as biopharmaceuticals, therapeutics, diagnostics, genetically modified crops, processed food, bioremediation, waste treatment, and energy production.
Biotechnology has 3 Critical Research Areas:
- Providing the best catalyst in the form of an improved organism, usually a microbe or enzyme.
- Creating optimal conditions through engineering for a catalyst to act.
- Downstream processing technologies to purify the protein/organic compound.
Applications in Agriculture
3 Options for Increasing Food Production
- Agro-chemical based agriculture: Uses fertilizers and pesticides. Expensive and causes environmental pollution.
- Organic agriculture: Expensive.
- Genetically engineered crop-based agriculture: Uses genetically modified crops. Genetically Modified Organisms (GMO) are plants, bacteria, fungi, and animals whose genes are altered by manipulation.
Advantages of Genetic Modification in Plants
- Makes crops more tolerant to abiotic stresses (cold, drought, salt, heat, etc.).
- Pest-resistant crops reduce the use of chemical pesticides.
- Reduces post-harvest losses.
- Increases efficiency of mineral usage by plants, preventing early exhaustion of soil fertility.
- Enhances nutritional value of food, e.g., Golden rice (Vitamin A-enriched rice).
- Creates tailor-made plants to supply alternative resources (starches, fuels, pharmaceuticals, etc.) to industries.
Pest Resistant Plants
- Act as bio-pesticides.
- Reduce the need for insecticides.
- Examples: Bt cotton, Bt corn, rice, tomato, potato, soybean, etc.
Bt Cotton
- Some strains of Bacillus thuringiensis have proteins that kill insects like coleopterans (beetles), lepidopterans (tobacco budworm, armyworm), and dipterans (flies, mosquitoes).
- B. thuringiensis forms an insecticidal protein (Bt toxin) crystal during a phase of their growth. It does not kill the Bacillus as it exists as inactive protoxins.
- When an insect ingests the toxin, it becomes active due to the alkaline pH of the gut, which solubilizes the crystals. The toxin binds to the surface of mid-gut epithelial cells, creating pores, causing cell swelling, lysis, and death of the insect.
- Bt toxin genes were isolated from B. thuringiensis and incorporated into crop plants such as cotton.
- Most Bt toxins are insect-group specific, coded by cry genes. For example, proteins encoded by cryIAc and cryIIAb genes control cotton bollworms, while the protein of cryIAb gene controls corn borer.
Nematode Resistance in Tobacco Plants
- A nematode, Meloidogyne incognita, infects the roots of tobacco plants, causing a reduction in yield.
- It can be prevented by RNA interference (RNAi) strategy.
- RNAi is a method of cellular defense in all eukaryotic organisms. It prevents translation of a specific mRNA (silencing) due to a complementary dsRNA molecule.
- The source of this complementary RNA is from an infection by RNA viruses or mobile genetic elements (transposons) that replicate via an RNA intermediate.
- Isolate nematode-specific genes (DNA) and introduce them into the host plant using Agrobacterium vectors. This produces both sense and anti-sense RNA in host cells, which are complementary, forming double-stranded (ds) RNA. This initiates RNAi, silencing the specific mRNA of the nematode, preventing the parasite from surviving in the transgenic host expressing specific interfering RNA.
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