• The applications of biotechnology include therapeutics, diagnostics, genetically modified crops for agriculture, transgenic animals, processed food, bioremediation, waste treatment and energy production.
BIOTECHNOLOGICAL APPLICATION IN AGRICULTURE
• Traditional methods of crop improvement like selection, hybridisation etc. involve the whole genome. These methods are tedious time consuming and results are not always satisfactory.
• However the latest biotechnological methods involves transfer of one or more beneficial genes from one plant to other.
• Plants, bacteria, fungi and animals whose genes have been altered are called Genetically Modifi ed Organisms (GMO).
• Genetic modifi cations has :
• made crops more tolerant to abiotic stresses [cold, drought, salt and heat.
• reduced reliance on chemical pesticide (pest-resistant crop).
• helped to reduce post harvest losses.
• increased effi ciency of mineral usage by plant to prevent early exhaustion of fertility of soil.
• enhanced nutritional value of food, e.g.,- vitamin A enriched golden rice.
• Genetically modifi ed crop or transgenic crop are prepared by transferring genes from one plants to other. Such genes are known as transgene and plant in which foreign genes are introduced are known as transgenic crops.
• Biotechnological techniques improve crop yield by the following ways :
Increase in Photosynthetic yield
• Genetic manipulation in RUBISCO (Ribulose 1,5-biphosphate) which is an important enzyme of photosynthesis are also utilized for increasing crop yield. RUBISCO act as carboxylase and oxygenase both. 25% of the fi xed CO2 is photorespired. Genetic alteration in RUBISCO gene inhibits its oxygenase activity. One such gene controlling RUBISCO enzyme has been transferred from pea plant to tobacco plant to increase photosynthetic process and crop yield.
Herbicide Tolerance
• Herbicides are chemicals which kill the weeds. When these chemicals are sprayed in the field, they not only kill the weeds but also damage the crop plants. By biotechnological techniques transgenic crop plants are developed which are resistant to herbicides and not damaged on exposure of herbicides. Some herbicide resistant crops produced by genetic engineering are—tomato, potato, tobacco, soyabean, cotton, corn, oil seed, rape, sugarbeet, petunia, etc.
• Herbicide tolerance in these plant can be achieved by (a) Overproduction of those enzymes which are inactivated by herbicides; (b) Inducing mutation resulting in the production of enzymes which are less sensitive to the herbicide; (c) Introduction of such enzymes which cause detoxifi cation of herbicides. Several such enzymes have been identified in plants as well as in microbes and transferred into the crop plants to produce transgenic plants resistant to herbicides.
