BOTANY Higher Secondary Second Year - Textbooks Online

introducing Bt toxin gene in cotton for the development of resistance
against pests in this major cash crop of India. Widespread use of
insecticides, fungicides and pesticides for crop protection undoubtedly
has damaging effects on the environment and hence it is important to
improve the control of pests and diseases by genetic means. Genetic
modification of plants is an attempt for ecofriendly measures against
environmental degradation.
Through genetic modification, the oil-producing soya bean was tailored
to produce a wide range of industrial lubricants, cosmetic compounds and
detergents that are biodegradable. A whole new area of biotechnology
has been opened up and plants are made to synthesize many novel substances
including functional human antibody fragments.
Practical application of genetic transformation
By genetic manipulation, it is possible to obtain plants with insecticidal
property. Thus, application of chemical pesticides to the crop plants
is reduced.
Genetic manipulation is also carried out in crops for making desirable
storage proteins, vitamins, amino acids and for the suppression of
antinutritional protein synthesis.
Plants are made to produce large amount of secondary metabolites
having high commercial value.
Losses during storage and transport of some crops can be as high as
80 per cent. This is mainly due to biological activities - bruising,
heat and cold damage in soft fruits and vegetables. In tomato the
enzyme polygalactronase breaks down cell wall constituents, thus
leading to softening of the fruit during ripening. By inhibiting the
polygalactronase by antisense genes the tomato can remain dormant
fresh until mature and be transported in a firm solid state. Antisense
RNA is a RNA molecule capable of controlling and expression of
particular enzymes which are involved in ripening processes.
Genetic manipulation of flower and leaf colour, abundance of flowers,
perfume and shape are now the major targets for decorative plant
industries.
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