BIOTECHNOLOGY: AND ITS APPLICATION


APPLICATIONS OF BIOTECHNOLOGY:-

  1. Agriculture
  2. Therapeutics (Medicine)
  3. Diagnostics
  4. Energy production
  5. Bioremediation
  6. Processed food 
It deals with the industrial-scale production of biopharmaceuticals and biologicals using genetically modified microbes, fungi, plants, and animals. Let us now learn how human beings have used biotechnology to improve the quality of human life, especially in the field of food production and health.

Agriculture

Three options can be thought for increasing food production:–
  • Agro-chemical-based agriculture:- Based on chemical fertilizers and chemical pesticides. By this, we can increase production but quality decreases.
  • Organic farming/agriculture:- Chemical-free agriculture. Based on biofertilizers and biopesticides. 
  • Genetically engineered crop-based agriculture:- For this desired gene is transferred in the plant. Now these plants are called Genetic Modified (GM)/ Transgenic plant/ Tailor-made plants 


APPLICATIONS IN AGRICULTURE/USE OF TRANSGENIC PLANT


(1) Enhanced Nutritional Value of Food:-

e.g. Vitamin ‘A’ enriched rice.

In golden rice, some genes of the Daffodil plant and some genes of Erwinia bacteria have been transferred. These genes are responsible for the synthesis of beta (β) carotene. 

(2) To Reduce Post Harvest Losses

e.g.Flavr Savr Tomato

This transgenic tomato has a longer shelf life (delayed ripening). It was developed by antisense technology. By this technique, the activity of the polygalacturonase enzyme is inhibited. This enzyme is responsible for the ripening of fruit (it dissolves pectin and loosens the cell wall).


(3) To Increase Tolerance Against Abiotic Stresses

Abiotic stresses like - cold, drought, salt, heat 

(4) To Produce Biopharmaceutical Products 

Production of Hirudin in seeds of transgenic Brassica napus. Hirudin is a protein that prevents blood clotting. Its gene was chemically synthesized and was transferred into Brassica napus where hirudin accumulates in seeds. The hirudin is extracted and purified and used as medicine.


(5) To Produce Weedicide / Herbicide Resistance Plant 

Glyphosate (Weedicide) resistant plants have been developed. These plants cannot be killed by weedicide (like glyphosate) which kills all other weeds in the field. It helps to eliminate weeds from the field without the use of manual labor. But higher use of glyphosate will cause pollution.

(6) Increased Efficiency Of Mineral Usage By Plants 

This prevents early exhaustion of fertility of the soil. Genetically engineered plants can be made which will absorb minerals only in the required quantity which will help in maintaining soil fertility for a long time. 

(7) Pest-Resistant Crops

Pest-resistant plants increase yield and reduce reliance (dependence) on chemical pesticides. Two categories:- 
(a) Insect resistant plant 
(b) Nematode resistant plant

Insect-resistant plant:- 

Bt Plants/crop is the best example of insect-resistant plants.  In Bt plants, a special cry gene of Bacillus thuringiensis (Bt) bacteria has been transferred. Cry gene produces an insecticidal toxin that kills insects of three orders:-

 Lepidopterans:- Tobacco budworm, Armyworm, Cotton bollworm, corn borer 

Coleopterans:- Beetles 

Dipterans:- Flies, Mosquitoes




Once an insect ingests the inactive toxin, in the alkaline pH of the midgut of the insect crystalline protein is dissolved and the toxin is activated.  The activated toxin binds to the surface of midgut epithelial cells. Now, this toxin creates pores that cause cell swelling and lysis and eventually cause the death of the insect.


Most Bt toxins are insect-group specific. The choice of genes depends upon the crop and the targeted pest. The proteins encoded by the genes cryIAb:- controls corn borer. cryIAc and cryIIAb:- control the cotton bollworms
e.g. of BT plants are :
Bt cotton 
Bt corn 
Bt soybean 
Bt brinjal (produced in India)


Nematode resistant plant:-
Nematodes parasitize (cause disease) in both plants and animals including human beings. A nematode Meloidogyne incognita infects the roots of tobacco plants and causes a great reduction in yield. To prevent this nematode a novel strategy was adopted called RNA interference (RNAi). RNAi is a process of gene silencing. RNAi takes place in all eukaryotic organisms as a method of cellular defense.





Using the Agrobacterium vector (Ti plasmid), nematode-specific genes were introduced into the host plant. The introduction of DNA was such that it produced both sense and anti-sense RNA in the host plant cells. These two RNAs being complementary to each other, formed a double-stranded (dsRNA) that initiated RNAi. Thus, RNAi silenced the specific mRNA of the nematode. The consequence was that the parasite could not survive.

Naturally in eukaryotic cells, the source of this complementary RNA could be from:- An infection by viruses having RNA genomes or  Mobile genetic elements (transposons) that replicate via an RNA intermediate.


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