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Written by G. Akhtar - Dr. R. M. Balal - M.
A. Shahid - T. Abbas - A. Akram
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Biotechnology is not applied in the field of
medical but also has a significant role in agriculture. The processes and
methods of agriculture have been refined by the use of biotechnology to
increment the productivity. Biotechnology has also revolutionized research
activities in the area of agriculture which includes the following: (i) plant
cell, tissue and organ Culture(ii) genetic engineering leading to
transformation followed by regeneration of plants to give genetically modified
plants carrying desirable, traits like disease resistance, insect resistance
and herbicide resistance; eventually this may also be used for increasing
photosynthetic efficiency, nitrogen fixing ability, improved storage proteins,
hybrid crops, crops for food processing etc. The development of genetically
modified foods and other agricultural biotechnology products has generated
significant public debate. The potential for creating foods enhanced for health
benefits or increasing crop yields was tantalizing, but there was also widespread
concern about the technology’s health and environmental risks. The Pew
Initiative on Food and Biotechnology spotlighted policy issues arising from
these discussions and served as a credible, honest broker, bringing together
people with differing viewpoints to examine the opportunities and challenges of
agricultural biotechnology.
Green biotechnology is biotechnology applied
to agricultural processes. An example would be the selection and domestication
of plants via micropropagation. Another example is the designing of transgenic
plants to grow under specific environments in the presence (or absence) of
chemicals. One hope is that green biotechnology might produce more
environmentally friendly solutions than traditional industrial agriculture. An
example of this is the engineering of a plant to express a pesticide, thereby
ending the need of external application of pesticides. An example of this would
be Bt corn. Whether or not green biotechnology products such as this are
ultimately more environmentally friendly is a topic of considerable debate.
Ornamental plants are grown as flowering
plants in the gardens or as houseplants. Their most common features are flowers
and others are leaves, bark, stem, and fruits of different color, size and
fragrance. These are used for decoration of office, garden, house, roadside or
any thing and place due to their decorative purposes and keep the people close
to nature. Flowers of some ornamental plants are also used for extraction of
valuable essential oils. Due to these reasons demand of ornamental plants is
increasing with the passage of time and plant breeder are trying to produce new
varieties of different attractive colors, more fragrance, longer vase life and
resistance against pests and diseases but it is a very tedious process and
takes many years to produce genetic modification.
Genetic engineering in combination with plant
tissue culture is an efficient way of producing genetic modification in
ornamental plants through alteration in genetic material by artificial means
and is different from the traditional breeding because it does not need
selection and pollination in the field, which takes many years to produce
genetic modification with very little success. In this technique desired genes
is isolated from a plant and transferred in the plant to produce desired
characters. There are two methods of gene transfer first is vector
mediated transfer and second is direct gene transfer. In vector-mediated method
of transformation a vector Agrobacterium is used, which a soil bacterium is
causing outgrowths (galls) on the plants. This bacterium transferred the genes
in the root cells of the plants to produce gall. Due to this ability it is used
as vector. The gene of interest is isolated and transferred in the DNA (Deoxyribonucleic
acid) of Agrobacterium, which infect the desired plant cell and transferred the
desired gene in the plant cell. In the direct transfer method desired genes are
transferred in the plant with out the use of vector. It has different methods
like electroporation of protoplast, in this method pores are made in the
protoplast membrane and through these pores plasmid DNA transferred in the
protoplast, which is used to regenerate the plants. Microinjection, in this
foreign DNA is transferred in the nucleus of protoplast by injection pipette of
0.2 mm diameter and protoplast is cultured to produce plants. Laser microbeam,
in this UV-laser microbeams are used to produce pores in the membranes and DNA
from the solution is entered in the cell through these pores. Electroporation
into embryos, DNA is delivered in the embryos by electroporation. Particle
bombardment, this is most desired used method of transferred because it can
deliver DNA in cells, tissue or organs. In this method DNA particles are coated
with gold or tungston and transferred by a gene gun, which accelerate particles
to penetrate into the tissue.
Plant tissue culture also has very important
role in the production of genetically modified plants because after the
transferred cell or tissue are need to regenerate into new plant and production
of more plants from that genetically modified plant. There are different direct
and indirect regeneration techniques of plant tissue culture. In direct
techniques direct shoots and roots are developed from the explants e.g.
meristem culture, in which meristem is used to shoot and roots. Nodal culture,
in this node is used to produce plants. In indirect methods first callus and
then from callus shoots and roots are developed e.g. leaf, ovule, anther, petal
and cell culture. After gene transfer in the cells or tissue of desired, callus
is produced from these transformed cell which further form somatic embryos then
shoot and roots. From this single plant many plants produced by mass
propagation through plant tissue culture techniques.
Flower color is most important and attractive
trait of ornamental plants. People want variation in flower color of different
ornamental plants. To fulfill the growing need of different colored ornamental
plants, genetic engineering is playing is role and successfully genetic
modifications have been in many ornamental plants like rose, gerbera, petunia,
chrysanthemum, carnation, torenia and lisianthus by inducing changes in
anthocyanin (a class of flavonoids produces pink, red, violet and blue color in
flowers) and Carotenoids (a class of isoprenoids produces yellow, orange and
red color in flowers). Flower fragrance is also a very important trait to
increase the value of ornamental plants. Fragrance of flowers is due to
volatile compounds, which are secondary metabolites such as terpenoids,
phenylpropanoids and derivatives of fatty acids. Few genes have been identified
which directly involved in production of fragrance in the flowers of ornamental
plants. As linalool synthase (lis) gene responsible for the production of
fragrance was introduced in petunia and carnation but it does not produce
olfactorally detectable changes in the fragrance of these flowers. Vase life is
also desirable character of ornamental plants. Work has been done on genetic
modification of many ornamental plants to increase their vase life like
carnation, petunia and carnation etc. Insects and diseases cause major losses
to ornamental plants. Different fungal, bacterial and viral pathogens attacked
on the ornamental plants and in response to their attack chitinases and
glucanases are produced in the plants. So the over production of chitinases and
glucanases by genetic modification can produce resistance in the plants. More
resistance has produced in against fungus in petunia and against blackspot in
roses by genetic modification. From more than 30 years cry gene of Bacillus
thuringiensis has been using for creating resistance in plants.
There is a great need of genetic modification
in ornamental plants in our country to fulfill the growing needs and to earn a
lot of by their export. It is a need of day to expand the work on genetic
modification because we invest a lot of to import ornamental plants. Now work
has been started to developed protocols for invitro regeneration of different
ornamental plants (rose, gladiolus, carnation etc) in plant tissue culture,
which is a step in this response. For this our government should develop more
high quality lab. and private sector should also involved in this work, more
short courses should arranged to produce skilled labour.
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