2. What are GMO’s?
Genetically Modified Organisms are organisms that
have been genetically altered to carry and/or produce
a certain necessary gene. This is done by inserting the
required gene into the organism’s DNA.
There are three types of GMO’s: animals, plants and
bacteria
We focused on bacteria.
3. How are GMO’s made?
A specific gene is chosen and then extracted from DNA
using a restriction enzyme.
This gene is then inserted into a bacterium. Since these
are single celled organisms the gene only has to be
inserted once and because bacteria multiply quickly,
they are an ideal candidate for mass production of a
specific gene.
4. Why is it relevant to society?
GM bacteria are relevant to society, because they are a
fast and easy way to make a lot of a selected gene.
They can be used to cure and prevent sicknesses,
to create medicines, to improve the
environment in numerous ways and to help
in many other ways.
5. Benefits of GM Bacteria
In the Environment- Possible control of weeds and use of GMOs that
reduce the use of toxic chemicals, GMOs to decontaminate toxic waste sites,
GMOs in environmental friendly power
In Farms- Improved nutrition for people, increased environmental
protection through the reduced use of pesticides, and increased quality and
quantity of yields, as well as increased farm profitability through reduced
costs and new product opportunities
6. Degradation of oil spill : gene that synthesize lipase (fat
digesting enzyme) from animal is inserted into bacteria
Used to clean oil spill that cause water pollution.
Nitrogen fixation : producing bacteria that can fix
nitrogen to increase crops production.
Anti-freezing bacteria (transgenic) is sprayed to the
plants to prevent the ice formation.
Eg : tomatoes, strawberries
7. Transgenic plant
transgenic plant: plants that has useful foreign
genes from another species.
Has desirable improved characteristics
- e.g: Pests and herbicides resistance, delay
ripening, improve flavour
8. 1985
1992
1988
1994
1998
1996
1999
2000
1st transgenic plants produced
Particle bombardment developed
GM crops considered substantially equivalent to hybrid varieties
Flavr-Savr tomato is released
Herbicide- and insect-resistant crops approved for cultivation
4.3 million acres of GM crops planted
GM food is dangerous (UK TV)
Monarch butterfly paper causes uproar
GM corn is excluded from its baby food
Greenpeace starts anti-GM campaign
75 million acres of GM crops planted
Golden rice with ß-carotene developed
McDonald’s rejects GM potatoes
10. Important Traits for Crop Improvement
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
11. Insect Resistance
Delayed Fruit Ripening
Nutritional Enhancing
Herbicide Resistance
Virus Resistance
The big five successful traits
12. Resistance to herbicide
Gene for herbicide resistance can be inserted into a crop plant’s chromosomal
DNA
Herbicides will have no effect on the transgenic crop plants and only destroy the
weeds
13. 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 (bar gene) that
produce a protein that inactivates the herbicide.
Herbicide Resistance
14. 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.
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
(acetolactate synthase), and transferring the mutated gene
into crop plants.
Herbicide Resistance
15. Roundup Ready™ Soybeans
A problem in agriculture is the reduced growth of crops imposed by
the presence of unwanted weeds. Herbicides such as Roundup and
Liberty Link 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.
16. Insect resistance
a) Toxic crystal protein from Bacillus thuringensis
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
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.
17. Insect Resistance
Corn hybrid with a Bt gene Corn hybrid susceptible to European
corn borer
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.
18. δ -endotoxin gene (Cry gene) of Bacillus thuriengenesis
GENE FOR Bt TOXIN WAS TRANSFERRED
TO OBTAIN BT TRANSGENIC PLANTS
PLANT SYNTHESIZES INACTIVE PROTOXIN
PROTEINASE
DIGESTION IN
INSECT GUT
MAKES THE
ACTIVE TOXIN
Toxin binds a receptor on the gut epithelial cells, forms a channel
on the membrane. This causes electrolyte leakage and insect death
INSECT FEEDS ON
TRANSGENIC PLANT
19. 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
Delayed Fruit Ripening
20. What happened to the Flavr Savr tomato?
i. Produced by blocking the polygalacturonase (PG) gene, which is
involved in spoilage. PG is an enzyme that breaks down pectin, which
is found in plant cell walls.
ii. Plants were transformed with the anti-sense PG gene, which is mRNA
that base pair with mRNA that the plant produces, essentially blocking
the gene from translation.
iii. First genetically modified organism to be approved by the FDA, in
1994.
iv. Tomatoes were delicate, did not grow well in Florida, and cost much
more than regular tomatoes.
v. Calgene was sold to Monsanto after Monsanto filed a patent-
infringement lawsuit against Calgene, and the Flavr Savr tomato left the
market.
Delayed Fruit Ripening
24. The disadvantages of genetically modified
crops are:
Proteins produced by GM organisms may cause allergies and other diseases
Persistent release of insecticidal proteins by GMO’s may disrupt the
biological activity of the soil.
Horizontal transfer of antibiotic resistant genes from transgenic crops to
bacteria
The genetically modified crops may eliminate the indigenous varieties
through competition for minerals and nutrients
Environmental risk of crop developed using GMO’s
Genetically modified crops may turn benign organisms into destructive
pests.
