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Transgenic technology
Transgenic technology
Breeding method
Crop Improvement
Problems in Agriculture
1. Quantity
2. Quality
3. Stress Environment
4. Public acceptance
Important Traits
High crop yield
 High nutritional quality
 Abiotic stress tolerance
 Pest resistance
 Adaptation to inter-cropping
 Nitrogen Fixation
Insensitivity to photo-period
 Elimination of toxic compounds

Biotech goes global
Wide range of crops
16 Field Crops
14 Vegetables
16 Fruits
11 other crops
Alfalfa
Barley
Canola
Cassava
Clover
Cotton
Flax
Maize
Rice
Safflower
Sorghum
Soybean
Sugar Beet
Sugar Cane
Sunflower
Wheat
Broccoli
Cabbage
Carrot
Cauliflower
Cucumber
Eggplant
Lettuce
Onion
Pea/Bean
Pepper
Potato
Spinach
Squash
Tomato
Apple
Banana
Cantaloupe
Cherry
Citrus
Coconut
Grape
Kiwi
Mango
Melon
Papaya
Pineapple
Plum
Raspberry
Strawberry
Watermelon
Chicory
Cocoa
Coffee
Garlic
Lupins
Mustard
Oil Palm
Oilseed Poppy
Olive
Peanut
Tobacco
57 fruits, vegetables, field crops and other plants – ranging from lab
trials to commercial production
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Sorghum
Safflower
Clover
Sunflower
Cassava
Alfalfa
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Barley
Sugar cane
Wheat
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Flax
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Sugar beet
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Canola
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Rice
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Maize
Canada
United States
Australia
West Europe (15/15)
Argentina
Mexico
China
Japan
South Africa
Brazil
South Korea
Indonesia
Uruguay
Egypt
East Europe (7/12)
India
Colombia
Philippines
Paraguay
Chile
Honduras
Belize
Cuba
Thailand
Venezuela
Zimbabwe
Bolivia
Costa Rica
New Zealand
Malaysia
Pakistan
Morocco
Bangladesh
Kenya
Cotton
FIELD CROPS
by COUNTRY
Soybean
Field Crops by Country
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commercial Production
regulatory Approval
Field study
Lab / greenhouse
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The big five successful traits
 Herbicide Resistance
 Insect Resistance
 Virus Resistance
 Delayed Fruit Ripening
Hot Issue
1. Genetically Modified Food
2. Golden Rice
3. Molecular Farming
Roundup Ready™ Soybeans
A problem in agriculture is the reduced growth of crops imposed by the
presence of unwanted weeds. Herbicides such as RoundupTM and Liberty
LinkTM are able to kill a wide range of weeds and have the advantage of
breaking down easily. Development of herbicide resistant crops allows the
elimination of surrounding weeds without harm to the crops.
Herbicide Resistance
a)
Glyphosate Resistance
i. Glyphosate = “Roundup”, “Tumbleweed” = Systemic herbicide
ii. Marketed under the name Roundup, glyphosate inhibits the enzyme EPSPS
(S-enolpyruvlshikimate-3 phosphate – involved in chloroplast amino acid
synthesis), makes aromatic amino acids.
iii. The gene encoding EPSPS has been transferred from glyphosate-resistant E.
coli into plants, allowing plants to be resistant.
Glufosinate Resistance
i.
Glufosinate (the active ingredient being phosphinothricin) mimics the structure
of the amino acid glutamine, which blocks the enzyme glutamate synthase.
ii. Plants receive a gene from the bacterium Streptomyces that produce a protein
that inactivates the herbicide.
Herbicide Resistance
c) Bromoxynil Resistance
i. A gene encoding the enzyme bromoxynil nitrilase (BXN) is
transferred from Klebsiella pneumoniae bacteria to plants.
ii. Nitrilase inactivates the Bromoxynil before it kills the plant.
d) Sulfonylurea.
i. Kills plants by blocking an enzyme needed for synthesis of the
amino acids valine, leucine, and isoleucine.
ii. Resistance generated by mutating a gene in tobacco plants,
and transferring the mutated gene into crop plants.
Insect Resistance
Various insect resistant crops have been produced. Most of
these make use of the Cry gene in the bacteria Bacillus
thuringiensis (Bt); this gene directs the production of a protein
that causes paralysis and death to many insects.
Corn hybrid with a Bt gene
Corn hybrid susceptible to European
corn borer
Insect resistance
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Anti-Insect Strategy - Insecticides
a) Toxic crystal protein from Bacillus thuringensis
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Toxic crystals found during sporulation
Alkaline protein degrades gut wall of lepidopteran larvae
• Corn borer catepillars
• Cotton bollworm catepillars
• Tobacco hornworm catepillars
• Gypsy moth larvae
Sprayed onto plants – but will wash off
The Bt toxin isolated from Bacillus thuringiensis has been
used in plants. The gene has been placed in corn, cotton,
and potato, and has been marketed.
Insect resistance
b) Plant protease inhibitors have been explored since the
1990s:
i. Naturally produced by plants, are produced in response
to wounding.
ii. They inhibit insect digestive enzymes after insects
ingest them, causing starvation.
iii. Tobacco, potato, and peas have been engineered to
resist insects such as weevils that damage crops while
they are in storage
iv. Results have not been as promising as with Bt toxin,
because it is believed that insects evolved resistance to
protease inhibitors.
Virus Resistant Crops
Papaya infected with the papaya
ringspot virus
Virus resistance gene
introduced
The Freedom II squash has a
modified coat protein that confer
resistance to zucchini yellows
mosaic virus and watermelon
mosaic virus II.
Scientists are now trying to develop
crops with as many as five virus
resistance genes
Virus resistance
a) Chemicals are used to control the insect vectors of viruses, but
controlling the disease itself is difficult because the disease spreads
quickly.
b) Plants may be engineered with genes for resistance to viruses,
bacteria, and fungi.
c) Virus-resistant plants have a viral protein coat gene that is
overproduced, preventing the virus from reproducing in the host
cell, because the plant shuts off the virus’ protein coat gene in
response to the overproduction.
d) Coat protein genes are involved in resistance to diseases such as
cucumber mosaic virus, tobacco rattle virus, and potato virus X.
Virus resistance
e) Resistance genes for diseases such as fungal rust disease and
tobacco mosaic virus have been isolated from plants and may be
transferred to crop plants.
f) Yellow Squash and Zucchini
Seeds are available that are resistant to watermelon mottle virus,
zucchini yellow mosaic virus, and cucumber mosaic virus.
g) Potato.
a) Monsanto developed potatoes resistant to potato leaf roll virus and potato virus X,
which also contained a Bt toxin gene as a pesticide.
b) hain restaurants do not use genetically engineered potatoes due to public pressures.
h) Papaya
Varieties resistant to papaya ring spot virus have been developed.
First biotech plant product – Flav’r Sav’r
tomato
“Rot-Resistant Tomato”
Anti-sense gene  complementary to polygalacturonase (PG)
PG = pectinase  accelerates plant decay/rotting
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Delayed Fruit Ripening
a) Allow for crops, such as tomatoes, to have a higher shelf life.
b) Tomatoes generally ripen and become soft during shipment to a
store.
c) Tomatoes are usually picked and sprayed with the plant hormone
ethylene to induce ripening, although this does not improve taste
d) Tomatoes have been engineered to produce less ethylene so
they can develop more taste before ripening, and shipment to
markets.
Plant Biotechnology Revolution:
Genetically Engineered Foods.
 Foods that contain an added gene sequence
 Foods that have a deleted gene sequence
 Animal products from animals fed GM feed
 Products produced by GM organisms
Plant Biotechnology Revolution:
Genetically Engineered Foods.
1.
More than 60% of processed foods in the United States contain
ingredients from genetically engineered organisms.
2. 12 different genetically engineered plants have been approved in the
United States, with many variations of each plant, some approved
and some not.
3. Soybeans.
a) Soybean has been modified to be resistant to broad-spectrum
herbicides.
b) Scientists in 2003 removed an antigen from soybean called P34
that can cause a severe allergic response.
4. Corn
a) Bt insect resistance is the most common use of engineered corn,
but herbicide resistance is also a desired trait.
Plant Biotechnology Revolution:
Genetically Engineered Foods
4. Corn
a) Bt insect resistance is the most common use of engineered corn, but herbicide resistance
is also a desired trait.
b) Products include corn oil, corn syrup, corn flour, baking powder, and alcohol.
c) By 2002 about 32% of field corn in the United States was engineered.
5. Canola.
a) More than 60% of the crop in 2002 was genetically engineered; it is found in many
processed foods, and is also a common cooking oil.
6. Cotton.
a) More than 71% of the cotton crop in 2002 was engineered.
b) Engineered cottonseed oil is found in pastries, snack foods, fried foods, and peanut
butter.
7. Other Crops
Other engineered plants include papaya, rice, tomato, sugar beet, and red heart
chicory.
Golden Rice
Normal rice
Transgenic technology produced a type of rice that accumulates
beta-carotene in rice grains. Once inside the body, beta-carotene is
converted to vitamin A.
“Normal” rice
“Golden” rice
Plant Biotechnology Revolution:
Nutritionally Enhanced Plants
Golden Rice
1. More than one third of the world’s population relies on rice as a food
staple, so rice is an attractive target for enhancement.
2. Golden Rice was genetically engineered to produce high levels of
beta-carotene, which is a precursor to vitamin A. Vitamin A is needed
for proper eyesight.
3. Biotechnology company Syngenta, who owns the rights to Golden
Rice, is exploring commercial opportunities in the United States and
Japan. Monsanto will provide licenses to Golden Rice technology
royalty-free.
4. Other enhanced crops include iron-enriched rice and tomatoes with
three times the normal amount of beta-carotene
Pharmaceutical Production in Plants
Genetically modified plants have been used as “bioreactors” to produce
therapeutic proteins for more than a decade. A recent contribution by
transgenic plants is the generation of edible vaccines.
Edible vaccines are vaccines produced in plants that can be administered
directly through the ingestion of plant materials containing the vaccine. Eating
the plant would then confer immunity against diseases.
Edible vaccines produced by transgenic plants are
attractive for many reasons. The cost associated
with the production of the vaccine is low, especially
since the vaccine can be ingested directly, and
vaccine production can be rapidly up scaled should
the need arises. Edible vaccine is likely to reach
more individuals in developing countries.
The first human clinical trial took place in 1997.
Vaccine against the toxin from the bacteria E.coli
was produced in potato. Ingestion of this transgenic
potato resulted in satisfactory vaccinations and no
adverse effects.
Plant Biotechnology Revolution:
Molecular Farming
1.
2.
3.
4.
A new field where plants and animals are genetically
engineered to produce important pharmaceuticals, vaccines,
and other valuable compounds.
Plants may possibly be used as bioreactors to mass-produce
chemicals that can accumulate within the cells until they are
harvested.
Soybeans have been used to produce monoclonal antibodies
with therapeutic value for the treatment of colon cancer. Drugs
can also be produced in rice, corn, and tobacco plants
Plants have been engineered to produce human antibodies
against HIV and Epicyte Pharmaceuticals has begun clinical
trials with herpes antibodies produced in plants.
Plant Biotechnology Revolution:
Molecular Farming
5. Edible Vaccines
a) People in developing countries have limited access to many
vaccines.
b) Making plants that produce vaccines may be useful for
places where refrigeration is limited.
c) Potatoes have been studied using a portion of the E. coli
enterotoxin in mice and humans.
d) Other candidates for edible vaccines include banana and
tomato, and alfalfa, corn, and wheat are possible
candidates for use in livestock.
e) Edible vaccines may lead to the eradication of diseases
such as hepatitis B and polio.
Edible
Vaccines
One focus of current vaccine effort is on hepatitis B, a virus responsible for causing
chromic liver disease. Transgenic tobacco and potatoes were engineered to
express hepatitis B virus vaccine. During the past two years, vaccines against a
E.coli toxin, the respiratory syncytial virus, measles virus, and the Norwalk virus
have been successfully expressed in plants and delivered orally. These studies
have supported the potential of edible vaccines as preventive agents of many
diseases.
There is hope to produce edible vaccines in bananas, which are grown extensively
throughout the developing world.
Plant Biotechnology Revolution:
Biopolymers and Plants
a) Plant seeds may be a potential source for plastics that could be
produced and easily extracted.
b) A type of PHA (polyhydroxylalkanoate) polymer called “poly-betahydroxybutyrate”, or PHB, is produced in Arabidopsis, or mustard
plant.
c) PHB can be made in canola seeds by the transfer of three
genes from the bacterium Alicaligenes eutrophus, which codes
for enzymes in the PHB synthesis pathway.
d) Monsanto produces a polymer called PHBV through Alicaligenes
fermentation, which is sold under the name Biopol.
Areas of ongoing debate
Environment
 Human Health
 Food security
Socio-economic concerns
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Environment
Anti-GM
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Loss of biodiversity
Cross-pollination
Emergence of superweeds
and superbugs
Potential increase in use
of herbicides
*Opinions are generalized, and not all opponents or
proponents may hold all of these views.
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Pro-GM
Need to increase yields to
feed growing population
Possibility of reducing
need for pesticides,
fertilizers
Grow more food on same
amount of land
Human Health
Anti-GM
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Fear of unknown allergens
Spread of anti-biotic
resistance
Inadequate regulation of
new products
Pro-GM
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Greater regulations than
other foods
Potential benefits to
nutrition
• golden rice
• enhanced protein content
in corn
• soybean oil with less
saturated fat
Food Security
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Anti-GM
Need redistribution, not
just more
Farmers will not be able to
afford expensive seed
Developing countries
should not have to eat the
food others reject
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Pro-GM
Modified seeds will allow
farmers to grow more to
feed their family and to
sell, reducing the need for
food aid
Public-private cooperation
can transfer technology
Socio-economic concerns
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Corporations benefit, not
those in need
Products needed in
developing countries are
not being developed
because the market is not
profitable
It is wrong to patent life
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Patents needed because
new strains are intellectual
property
Publicly funded research
can benefit the public good