Biotechnology is the use of living systems and organisms to develop or make useful products. It harnesses cellular and biomolecular processes to develop technologies and products that help improve our health and lives.
Modern biotechnology provides breakthrough solutions and technologies to combat debilitating and rare diseases, reduce our environmental footprint, feed the hungry, use less and cleaner energy, and have safer and more efficient industrial manufacturing processes.
Humans have been using biotechnology to improve the quality of life, especially in the areas of food production and health.
Red biotechnology is applied to medical processes, some examples are the designing of organisms to produce antibiotics and the engineering of genetic cures through genomic manipulation. White biotechnology is applied to industrial process and green biotechnology is applied to agricultural processes.
Applications of Biotechnology in agriculture
The green revolution succeeded in increasing yield of crop due to use of improved varieties of crops and use of agrochemicals, i.e., fertilizers and pesticides. However, for farmers in the developing world, agrochemicals are often too expensive, and further increase in yield with existing varieties is not possible using conventional farming processes.
Further, to increase the crop production,manure, fertilizers, pesticides, etc. This method, cannot increase the yield of crop to an appreciable re solution of this problem is use of genetically modified crops.
Genes of plants, bacteria, fungi and animals have been changed by manipulations for various purposes, therefore, organisms are called Genetically Modified Organisms (GMO). The behaviour of a GMO depends on the nature of genes transferred, nature of host such plant, as bacterium, animal, etc.
Genetically modified crops using Biotechnology:
GM crops contain and express one or more useful foreign genes or transgenes. The technique of GM crops has two advantages, first, any gene from any organism or a synthetic gene can be incorporated and second, change in genotype is precisely controlled.
Some applications of genetically modified crops and examples of Biotechnology are :
– They can help to reduce the use of chemical pesticides.
– They are more tolerant to abiotic stresses (cold, drought, salt, heat, etc.).
– They have helped to reduce post-harvest losses.
– They prevent early exhaustion of fertility of soil.
– They enhance nutritional value of food, e.g., vitamin- A enriched rice.
– They are herbicide resistant, i.e., herbicides (weed killers) do not harm the GM crops. They also are disease resistant.
– They have been used to create alternative resources to industries in the form of starches, fuels and pharmaceuticals.
Production of transgenic plants using Ti plasmid in Biotechnology
The vector used to introduce new genes into plant cells is most often a plasmid from the soil bacterium Agrobacterium tumefaciens. This bacterium is called natural genetic engineer because genes carried by its plasmid produce effect in several parts of the plant. Its plasmid is called Ti plasmid (Tumour inducing plasmid), so called because in nature, it induces tumors in broad leaf plants such as tomato, tobacco and soyabean. For using Ti plasmid as a vector, researchers have eliminated its tumour causing properties while keeping its ability to transfer DNA into plant cells. The part of Ti plasmid transferred into plant cell DNA, is called the T-DNA.
Production of insect resistant plants using Biotechnology in Agriculture
The bacterium Bacillus thuringiensis (Bt) has family of different proteins which naturally produce chemicals harmful to selective insects, most notably the larvae of moths and butterflies, beetles, cotton bollworms and flies, and harmless to other forms of life.
B. thuringiensis forms some protein crystals. These crystals contain a toxic insecticidal protein.
This toxin does not kill the Bacillus (bacterium) because it exists as inactive protoxins in them. But, once an insect ingests, it is converted into an active form of toxin due to the alkaline of the alimentary canal.
The toxin molecules attach themselves to specific locations on the cadherin-like proteins present on the epithelial cells of the midge and ion channels are formed which allow the flow of potassium. Regulation of potassium concentration is essential and if left unchecked causes death of cells. The death of such cells creates gaps in the brush border membrane. The gaps then allow bacteria and (Bt) spores to enter the body cavity resulting in the death of the organism.
Through genetic engineering Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants. The choice of genes depends upon the crop and targeted pest, as most Bt toxins are insect-group specific. The toxin is coded by a gene named cry. Two cry genes cry I Errand cry II Ab have been incorporated in cotton.
The genetically modified crop is called Bt cotton as it contains Bt toxin genes against cotton bollworms. Similarly, cry I Ab has been introduced in Bt corn to protect the same from corn borer. B. thuringiensis has been used since world war I, particularly in Europe, to control some insect pests.
In India, Bt cotton has been enveloped in controversies due to its supposed links with seed monopolies and farmer suicides. However, the link between the introduction of Bt Cotton to India and a surge in farmer suicides has been refuted by other studies, with farmer suicides actually having fallen since the introduction of Bt cotton. Bt cotton accounts for majority of cotton grown in India.
Production of pest resistant plants using using Biotechnology
Many nematodes live in plants and animals including human beings. A nematode Meloidogyne incognita infests the roots of tobacco plants and causes a great reduction in yield. A novel strategy is adopted to prevent this infection that was based on the process of RNA interference (RNAi).
RNA interference (RNAi) is the phenomenon of inhibiting activity of a gene by synthesis of RNA molecules complementary to the mRNA. The normal (in vivo synthesized) mRNA of a gene is said to be “sense” because it carries the codons that are “read” during translation. Generally, the complement to the mRNA “sense” strand will not contain a sequence of codons that can be translated to produce a functional protein; thus, this complementary strand is called “anti-sense RNA”. The anti-sense RNA and mRNA molecules will anneal to form duplex RNA molecules (or double stranded RNA) and the duplex RNA molecules can not be translated. Thus, the presence of anti-sense RNA will block translation of the mRNA of the affected gene.
Different steps involved in making tobacco plant resistant to nematode are as following :
– Double-stranded RNAs are processed into approximately 21-23 nucleotide RNAs. An RNase enzyme, called Dicer, cuts the dsRNA molecules (from a virus, transposon, or through transformation) into small interfering RNAs (si RNAs).
– Each siRNA complexes with ribonudeases (distinct from Dicer) to form an RNA-induced silencing complex (RISC).
– The sRNA unwinds and RISC is activated.
– The activated RISC targets complementary mRNA molecules. The si RNA strands act as guides where the RISCs cut the transcripts. This destroys the mRNA.
– When mRNA of the parasite is destroyed no proteins are synthesized. It results in the death of the parasite (nematode) in the transgenic host. Thus, the transgenic plant gets itself protected from the parasite.
You can read further articles on Biotechnology in the other sections of this blog to understand careers in Biotechnology.