BIOTECHNOLOGY
It is the use of plants, animals and micro-organisms to create new products or processes. It includes
using bacteria or enzymes to make industrial processes work more efficiently and create less
pollution, or to clean up the environment.
One kind of biotechnology is gene technology, sometimes called "genetic engineering" or "genetic
modification", where the genetic material of living things is deliberately altered to enhance or remove
a particular trait and allow the organism to perform new functions. Genes within a species can be
modified, or genes can be moved from one species to another.
Biotechnological       Applications     in  Agri-            transferred to several plants such as
culture                                                      cotton.
                                                            Crystal proteins are produced by a gene
Plants, bacteria, fungi and animals whose                    called cry in Bacillus thuringiensis.
genes have been altered by manipulation are                 The protein coded by genes cryIAc and
called Genetically Modified Organisms                        cryIIAb control the cotton bollworms.
(GMO).                                                      The protein coded by gene cryIAb controls
Advantages of Genetic Modification in plants.                corn borer.
                                                        Pest resistant plants
    Made crops more tolerant to abiotic
     stresses (cold, drought, salt, heat)                   Several nematodes parasitize a wide
    Reduce reliance on chemical pesticides                  variety of plants and animals including
     (pest resistant crop)                                   human beings.
    Helped to reduce post-harvest losses.                  A nematode Meloidegyne incognitia
    Increased efficiency of mineral usage by                infects the root of tobacco plants and
     plants.                                                 causes a great reduction in yield.
    Enhanced nutritional values of food e.g.               Strategy based on RNA interference
     vitamin A enriched rice.                                (RNAi) prevents this infestation.
                                                            Process by which double-stranded RNA
Bt Cotton
                                                             (dsRNA)        directs    sequence-specific
    Some strains of Bacillus thuringiensis                  degradation of mRNA
     produce proteins that kill certain insects
                                                        Steps of RNA interference
     such as lepidopterans (tobacco budworm,
     armyworm), coleopterans (beetles) and                  Double stranded RNA is produced
     dipterans (flies, mosquitoes).                          endogenously or exogenously.
    Bacillus thuringiensis forms protein                   Using Agrobacterium vectors nematode
     crystals during a particular phase of their             specific genes were introduced into the
     growth. These crystals contain a toxic                  host plant (tobacco plant).
     insecticidal protein.                                  Introduction of DNA produces both sense
    These proteins are present in inactive                  and antisense RNA in the host.
     protoxin form, but become active toxin in              These two RNA’s being complementary to
     the alkaline pH of insect gut.                          each other formed a double stranded
    The activated toxin binds to the surface of             (dsRNA) that initiated RNAi.
     midgut epithelial cells and create pores               The dsRNA injected into the host plant
     that cause cell swelling and lysis and                  from outside called exogenous dsRNA.
     eventually cause death of insect
                                                            The dsRNAs are cleaved into 21-23 nt
    Specific Bt toxin genes were isolated form              segments (“small interfering RNAs”, or
     Bacillus thuringiensis and genetically                  siRNAs) by an enzyme called Dicer.
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