2. ā¢ Definition of Tissue culture
ā¢ Definition of Plant Biotechnology
ā¢ General steps of tissue culture process
ā¢ Aims of modern Plant Biotechnology
ā¢ Impact of Plant Biotechnology
ā¢ Practical Applications in the Field
Contents
3. Plant Tissue culture
ā¢ It is the process of producing
plants from tissue of the
desired plant in an artificial
nutrient medium under
controlled conditions.
The Product = a plant exactly similar to the mother
plant in all aspects
4.
5. Plant biotechnology
Plant biotechnology is a process to produce a genetically
modified plant by removing genetic information from an
organism, manipulating it in the laboratory and then
transferring it into a plant to change certain of its
characteristics (a process to produce useful or
beneficial plants).
The Product = a plant genetically modified than
the mother plant in some aspects
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8. Today, biotechnology is being used as a tool to give plants new traits
that benefit agricultural production, the environment, and human
nutrition and health.
9. The goal of plant breeding is to combine desirable traits
from different varieties of plants to produce plants of
superior quality.
10. It chiefly involves the introduction of foreign genes into economically
important plant species, resulting in crop improvement and
the production of novel products in plants.
ļØ This approach to improving crop production has been very
successful over the years.
ļØ For example, it would be beneficial to cross a tomato plant that
bears sweeter fruit with one that exhibits increased disease
resistance.
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18. ā¢ UVA radiations contribute up to 95% of the total
UV exposure and are known to induce cell
damage, leading to apoptosis.
ā¢ Since the beneficial effects of ascorbic acid on
human health are well known, a new tomato
genotype, highly rich in ascorbic acid, has been
recently obtained.
ā¢ we compared the effects of ascorbic acid and
hydrophilic DHO4 extracts in protecting human
keratinocytes exposed to UVA stress.
19. Results:
The hydrophilic extracts from the DHO4 genotype
have anti-proliferative activity on human
cancer cells whereas they don't affect the
growth of normal cells due to the high
concentration of vitamin C that acts as free
radical scavenger.
20. ļ¶Disease Resistance
ā¢ Vaccines for plants contain dead
or weakened strains of plant
viruses to turn on the plantās
immune system
ā¢ Transgenic plants express viral
proteins to confer immunity
Practical Applications in the Field
21. ļ¶Insect Control
ā¢ Bacillus thuringiensis (Bt) produces a protein that is toxic
to plant pests
ā¢ Transgenic plants contain the gene for the Bt toxin and
have a built-in defense against these plant pests
Practical Applications in the Field
22. ļ¶Weed Management
ā¢ Herbicide resistance
Weed-infested
soybean plot
Transgenic soybean
plot after Roundup
treatment
Practical Applications in the Field
23. Practical Applications in the Field
ļ¶Safe Storage
ā¢ avidin-blocks the availability of biotin for insects.
ļ¶Stronger fibers
ā¢ Increase strength of cotton fiber by 60%
24. ļ¶Enhanced Nutrition
ā¢ Golden rice that is genetically modified to produce
large amounts of beta carotene
ā¢ QPM: Maize with increased nutritive value
Practical Applications in the Field
25. ļ¶ Future Transgenic Products
ā¢ to generate caffeine free coffee beans.
Practical Applications in the Field
26. ļ¶The Future: From Pharmaceuticals to Fuel
ā¢ Plant-based petroleum for fuels
ā¢ Biofuel ā fuel derived from biomass
Practical Applications in the Field
Editor's Notes
Historically, the agricultural industry has relied on the use of fungicides worth $5.8 billion for control of fungal diseases worldwide. Infections can lead to reduced growth rate, poor crop yield, and low crop quality. Fortunately, farmers can protect their crops by stimulating a plantās natural defenses against disease by injecting plants with a vaccine which turns on the plants version of an immune system, making it resistant to the real virus. Vaccinating an entire field of crops is no easy task and because of advancements in biotechnology is no longer always necessary. Many plants are inherently resistant to invading pathogens. Breeding for resistance to fungal, viral and other pathogenic microorganisms through traditional methods requires crossing closely related species, one of which has a gene or genes for resistance, but such resistant species often do not exist. Another approach using biotechnology involves taking a gene from the disease causing organism and inserting it into the plant so that the plant becomes protected. For example, researchers have recently inserted a gene from the tobacco mosaic virus (TMV) into tobacco plants. The gene produces a protein found on the surface of the tobacco mosaic virus and, like a vaccine, turns on the plantās immune system. The development of transgenic disease resistant plants has also revitalized the once ravaged papaya industry in Hawaii. Researchers at Cornell University characterized the papaya ringspot virus (PRSV). The researchers were able to use recombinant DNA techniques to isolate and clone a gene from the papaya virus in the laboratory that encodes the coat proteins of the virus. This isolated gene was then transferred into cells of the papaya plant. These genetically modified papaya plants were resistant to PRSV and subsequently were responsible for rejuvenating the $45 million dollar papaya industry that had experienced a 50% decline in production due to the destruction of the papaya ringspot virus. This picture is an aerial view of a field trial in Hawaii showing healthy transgenic papaya trees surrounded by papaya trees severely infected by PRSV.
An estimated $8 billion is used annually worldwide on chemical pesticides for control of insects that damage plants and affect human health and ecological systems. These pesticides are nonspecific, affecting all insects including beneficial ones. Pesticide poisoning is often reported in farm workers and due to the recalcitrance of pesticides, they are found in our foods and in ecosystems worldwide, far from the site of the pesticide applications. In agriculture, an estimated 30% of this market can be served by insect-protected plants, which produce a protein from a soil bacteria, Bacillus thuringiensis (Bt) whose spores contain a crystalline (Cry) protein. In the insect gut, the Cry protein breaks down to release a toxin that binds to and creates pores in the intestinal lining of the insect resulting in ion imbalance, paralysis of the digestive system, and after a few days, insect death. Crop breeders have not been able to breed high enough levels of caterpillar resistance into corn or cotton by traditional methods. With biotechnology methods, breeders have been able to insert a gene from Bt into cotton and corn to produce a protein that protects the plant against certain economically damaging insects. When caterpillars bore into the stalks and ears of corn or feed on the flowers and buds of cotton plants containing the Bt transgene, it ingests the toxin from the Cry protein and dies within in a few days. The Bacillus thuringiensis bacteria have been used as an insecticide spray by organic and conventional farmers for over 50 years and is harmless to humans and many beneficial insects. However, it can be only marginally effective when applied as a spray because it breaks down quickly and often does not get to where the insects are feeding. In the US, 30% of total agricultural insecticide use is on cotton. The National Center for Food and Agricultural Policy estimates that the use of Bt cotton will result in a reduction of 1,200 metric tons of active ingredient of insecticide. Most of the alternative insecticides have a wider spectrum of activity than Bt and are more harmful to the environment and non-target organisms like beneficial insects. Bt insect resistant crops are currently on the market for corn and cotton and have shown to not only reduce dependency on chemical pesticides, but also improve yield and profits for farmers. Click on the animation to visualize the affects of the Bt toxin on insects.
Scientists who use genetic engineering techniques for food production have the same goal as traditional breeders: making our food supply safer for consumers and the environment and less expensive to produce. An estimated 5.5 million farmers grow transgenic crops on 130 million acres in about 15 countries, led by the US and Canada. Virtually all of the biotech crops on the market today were developed to reduce crop damage by weeds, diseases, and insects. Anyone who grows a garden or maintains a lawn knows the importance of weed management. Weeds reduce the yield and quality of plants and may also contaminate the product, so most large-scale growers use herbicides. Many herbicides on the market control only certain types of weeds, and are approved for use only on certain crops at specific growth stages. Residues of some herbicides remain in the soil for a year or more, so that farmers must pay close attention to the herbicide history of a field when planning what to plant there. The rationale for herbicide-resistant crops is that the crop can be planted directly into the field, allowed to germinate with any weeds already present, and then treated with an herbicide that kills only weeds. The most common herbicide tolerant crops have been designed to be unaffected by the broad-spectrum herbicide called RoundupĀ® (Monsanto). This herbicide works by blocking an enzyme required for photosynthesis. Roundup is a broad-spectrum herbicide that kills nearly all kinds of plants EXCEPT those that have a transgene that allows them to be tolerant of the herbicide. Through genetic engineering, scientists have created transgenic crops that express an alternate EPSPS gene from bacteria which allows the plant to use an alternative chemical pathway for photosynthesis. Therefore, a farmer can apply a single herbicide treatment to a field of these transgenic crops. The use of herbicide resistant crops reduces soil erosion and compaction because growers drive over the field fewer times. Recent data indicate that their use also results in a substantial reduction of herbicides. Farmers who plant herbicide-resistant crops are generally able to control weeds with chemicals that are milder and more environmentally friendly than typical herbicides. This approach has been especially successful in cotton and soybean crops. Approximately 70% of all soybean and cotton crops are grown with transgenes for weed management.
Of all the potential benefits of biotechnology, nothing is more important that the opportunity to save millions of people from the crippling effects of malnutrition. One potential weapon against malnutrition is Golden rice. Golden rice is a transgenic rice that contains beta-carotene and other carotenoids needed for production of Vitamin A, essential in the prevention of blindess. According to recent estimates, 500,000 children in the world will eventually become blind because of vitamin A deficiency. Currently, health workers in developing countries carry doses of vitamin A from village to village in an effort to prevent blindness. Simply adding the nutrient to the food supply is much more efficient and effective. Another example is the production of Quality Protein Maize (QPM) which is a corn product that has 90% the nutritive value of milk. Several hundred million people in underdeveloped countries rely on maize as their principal daily food. Unfortunately maize has one significant flaw; it lacks the full range of amino acids, namely lysine and tryptophan, needed to produce proteins. Therefore diets high in maize produce a condition known as wet malnutrition where a person is receiving sufficient calories, but his or her body malfunctions due to a lack of protein. This makes conventional maize is a poor quality food staple unless consumed as part of a varied diet which is beyond the means of most people in the developing world. Researchers have introduced and adapted QPM maize with increased levels of the two amino acids, lysine and tryptophan, that makes more of maizeās protein useful to humans. According to a recent study, the heights and weights of children whose diets included QPM as their main starchy staple increased more than 20% faster than those of children who ate conventional maize. To date most QPM is produced by traditional crossbreeding methods. However, researchers have recently identified three gene loci implicated in controlling the levels of a protein synthesis factor correlated with lysine levels. Transgenic QPM could be produced at a significantly faster rate and reduced cost. Click on the link to watch a video and discover how QPM is being used to alleviate malnutrition in Haiti.
Whether you are for or against genetically modified food, one thing is clear: Biotech companies and university laboratories are cooking up new ideas for GM foods all the time. Click on the Biotech Crop Database to see a list of genetically modified plants by species. As previously mentioned, RNA interference (RNAi) is a new technology that is described in detail in the first. RNAi is being explored as a way to create the next wave of genetically modified foods. For example, scientists have identified the genes that lead to the production of caffeine in coffee beans and tea leaves. The demand for decaffeinated coffee is increasing because the stimulatory effects of caffeine can adversely affect sensitive individuals by triggering palpitations, increased blood pressure, and insomnia. Transgenic plants have been constructed that repress expression of genes leading to caffeine production by RNA interference. The caffeine content of these plants is reduced by up to 70% indicating that it could be feasible to produce coffee beans that are intrinsically deficient in caffeine. The U.S. Department of Agriculture lists 7,516 field tests on new GM foods currently underway. It remains unclear which if any of these foods will pass the strict series of tests that stand between the laboratories and our supermarket shelves. Nevertheless, it's fun to sneak a peak into the future. Click on the animation to find out about the next wave of genetically modified foods.
