Applications of Transgenic technology. Transgenic technology Breeding method Breeding method Crop Improvement Crop Improvement The Potential traits: The

Applications of Applications of Transgenic technologyTransgenic technology

Transgenic technologyTransgenic technology

Breeding methodBreeding method Crop Improvement Crop Improvement The Potential traits:The Potential traits:

1. controlling insects1. controlling insects

2. manipulating petal color, 2. manipulating petal color,

3. production of industrially important 3. production of industrially important compounds compounds

4. supporting plant growth in harsh conditions4. supporting plant growth in harsh conditions

Herbicide ResistanceHerbicide Resistance Insect ResistanceInsect Resistance

Virus ResistanceVirus Resistance Altered Oil ContentAltered Oil Content

Delayed Fruit Ripening Delayed Fruit Ripening Pollen ControlPollen Control

The big six traitsThe big six traits

Herbicides are a huge industry, with herbicide Herbicides are a huge industry, with herbicide use quadrupling between 1966 and 1991, so use quadrupling between 1966 and 1991, so plants that resist chemicals that kill them are a plants that resist chemicals that kill them are a growing need.growing need.

Critics claim that genetically engineered plants Critics claim that genetically engineered plants

will lead to more chemical use, and possible will lead to more chemical use, and possible development of weeds resistant to the chemicalsdevelopment of weeds resistant to the chemicals. .

Herbicide ResistanceHerbicide Resistance

a)a) Glyphosate ResistanceGlyphosate Resistance i.i. Glyphosate = “Roundup”, “Tumbleweed” = Systemic Glyphosate = “Roundup”, “Tumbleweed” = Systemic

herbicideherbicideii.ii. Marketed under the name Roundup, glyphosate inhibits the Marketed under the name Roundup, glyphosate inhibits the

enzyme EPSPS enzyme EPSPS (S-(S-eenolnolppyruvlyruvlsshikimate-3 hikimate-3 pphosphate – hosphate – involved in chloroplast amino acid synthesis)involved in chloroplast amino acid synthesis), makes , makes aromatic amino acids.aromatic amino acids.

iii.iii. The gene encoding EPSPS has been transferred from The gene encoding EPSPS has been transferred from glyphosate-resistant E. coli into plants, allowing plants to glyphosate-resistant E. coli into plants, allowing plants to be resistant. be resistant.

Glufosinate Resistance Glufosinate Resistance i.i. Glufosinate (the active ingredient being phosphinothricin) Glufosinate (the active ingredient being phosphinothricin)

mimics the structure of the amino acid glutamine, which mimics the structure of the amino acid glutamine, which blocks the enzyme glutamate synthase.blocks the enzyme glutamate synthase.

ii.ii. Plants receive a gene from the bacterium Streptomyces Plants receive a gene from the bacterium Streptomyces that produce a protein that inactivates the herbicidethat produce a protein that inactivates the herbicide . .


c) Bromoxynil Resistancec) Bromoxynil Resistance

i.i. A gene encoding the enzyme bromoxynil nitrilase (BXN) is A gene encoding the enzyme bromoxynil nitrilase (BXN) is transferred from transferred from Klebsiella pneumoniaeKlebsiella pneumoniae bacteria to plants. bacteria to plants.

ii.ii. Nitrilase inactivates the Bromoxynil before it kills the plant. Nitrilase inactivates the Bromoxynil before it kills the plant.

d) Sulfonyluread) Sulfonylurea..

i.i. Kills plants by blocking an enzyme needed for synthesis of Kills plants by blocking an enzyme needed for synthesis of the amino acids valine, leucine, and isoleucine. the amino acids valine, leucine, and isoleucine.

ii.ii. Resistance generated by mutating a gene in tobacco plants, Resistance generated by mutating a gene in tobacco plants, and transferring the mutated gene into crop plants. and transferring the mutated gene into crop plants.


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.

Insect resistanceInsect resistance

Anti-Insect Strategy - InsecticidesAnti-Insect Strategy - Insecticides• From From Bacillus thuringensisBacillus thuringensis

Toxic crystals found during sporulationToxic crystals found during sporulation Alkaline protein degrades gut wall of Alkaline protein degrades gut wall of

lepidopteran larvae lepidopteran larvae • Corn borer catepillarsCorn borer catepillars• Cotton bollworm catepillarsCotton bollworm catepillars• Tobacco hornworm catepillarsTobacco hornworm catepillars• Gypsy moth larvaeGypsy moth larvae

Sprayed onto plants – but will wash offSprayed onto plants – but will wash off

a)a) The Bt toxin isolated from The Bt toxin isolated from Bacillus thuringiensisBacillus thuringiensis has been has been used in plants. The gene has been placed in corn, cotton, used in plants. The gene has been placed in corn, cotton, and potato, and has been marketed. and potato, and has been marketed.

b)b) Plant protease inhibitors have been explored since the Plant protease inhibitors have been explored since the 1990s: 1990s:

i.i. Naturally produced by plants, are produced in response Naturally produced by plants, are produced in response to wounding. to wounding.

ii.ii. They inhibit insect digestive enzymes after insects They inhibit insect digestive enzymes after insects ingest them, causing starvation. ingest them, causing starvation.

iii.iii. Tobacco, potato, and peas have been engineered to Tobacco, potato, and peas have been engineered to resist insects such as weevils that damage crops while resist insects such as weevils that damage crops while they are in storage they are in storage

iv.iv. Results have not been as promising as with Bt toxin, Results have not been as promising as with Bt toxin, because it is believed that insects evolved resistance to because it is believed that insects evolved resistance to protease inhibitors. protease inhibitors.

Insect resistanceInsect resistance

Bt Corn

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.

a)a) Chemicals are used to control the insect vectors Chemicals are used to control the insect vectors of viruses, but controlling the disease itself is of viruses, but controlling the disease itself is difficult because the disease spreads quickly. difficult because the disease spreads quickly.

b)b) Plants may be engineered with genes for Plants may be engineered with genes for resistance to viruses, bacteria, and fungi. resistance to viruses, bacteria, and fungi.

c)c) Virus-resistant plants have a viral protein coat Virus-resistant plants have a viral protein coat gene that is overproduced, preventing the virus gene that is overproduced, preventing the virus from reproducing in the host cell, because the from reproducing in the host cell, because the plant shuts off the virus’ protein coat gene in plant shuts off the virus’ protein coat gene in response to the overproduction. response to the overproduction.

d)d) Coat protein genes are involved in resistance to Coat protein genes are involved in resistance to diseases such as cucumber mosaic virus, diseases such as cucumber mosaic virus, tobacco rattle virus, and potato virus X.tobacco rattle virus, and potato virus X.

Virus resistanceVirus resistance

e)e) Resistance genes for diseases such as fungal rust disease and Resistance genes for diseases such as fungal rust disease and tobacco mosaic virus have been isolated from plants and may tobacco mosaic virus have been isolated from plants and may be transferred to crop plants.be transferred to crop plants.

f)f) Yellow Squash and ZucchiniYellow Squash and Zucchini

Seeds are available that are resistant to watermelon mottle Seeds are available that are resistant to watermelon mottle virus, zucchini yellow mosaic virus, and cucumber mosaic virus, zucchini yellow mosaic virus, and cucumber mosaic virus. virus.

g) Potatog) Potato..

a)a) Monsanto developed potatoes resistant to potato leaf roll Monsanto developed potatoes resistant to potato leaf roll virus and potato virus X, which also contained a Bt toxin virus and potato virus X, which also contained a Bt toxin gene as a pesticide. gene as a pesticide.

b)b) hain restaurants do not use genetically engineered hain restaurants do not use genetically engineered potatoes due to public pressures. potatoes due to public pressures.

h) Papayah) Papaya

Varieties resistant to papaya ring spot virus have been Varieties resistant to papaya ring spot virus have been developed. developed.

Virus resistanceVirus resistance

Papaya infected with the papaya ringspot virus

Virus resistance gene introduced

Virus Resistant Crops

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

a)a)Done in plants by modifying an enzyme in the fatty acid Done in plants by modifying an enzyme in the fatty acid synthesis pathway (oils are lipids, which fatty acids are a synthesis pathway (oils are lipids, which fatty acids are a part of). part of).

b)b)Varieties of canola and soybean plants have been Varieties of canola and soybean plants have been genetically engineered to produce oils with better cooking genetically engineered to produce oils with better cooking and nutritional properties. and nutritional properties.

c)c) Genetically engineered plants may also be able to produce Genetically engineered plants may also be able to produce oils that are used in detergents, soaps, cosmetics, oils that are used in detergents, soaps, cosmetics, lubricants, and paints. lubricants, and paints.

Altered Oil ContentAltered Oil Content

Laurate canola oilLaurate canola oil

Canola plant modified with Canola plant modified with thioesterase gene obtained from thioesterase gene obtained from California bay laurel treeCalifornia bay laurel tree• Enzyme produces lauric acid (up to 40% Enzyme produces lauric acid (up to 40%

in oil from genetically modified (GM) in oil from genetically modified (GM) canola seeds)canola seeds)

Low saturated fat contentLow saturated fat content Heat tolerant Heat tolerant

• Does not break downDoes not break down• Excellent for high temperature cooking processesExcellent for high temperature cooking processes

a)a) Allow for crops, such as tomatoes, to have a Allow for crops, such as tomatoes, to have a higher shelf life. higher shelf life.

b)b) Tomatoes generally ripen and become soft Tomatoes generally ripen and become soft during shipment to a store. during shipment to a store.

c)c) Tomatoes are usually picked and sprayed with Tomatoes are usually picked and sprayed with the plant hormone ethylene to induce ripening, the plant hormone ethylene to induce ripening, although this does not improve taste.although this does not improve taste.

Delayed Fruit RipeningDelayed Fruit Ripening

d)d) Tomatoes have been engineered to produce less ethylene so Tomatoes have been engineered to produce less ethylene so they can develop more taste before ripening, and shipment to they can develop more taste before ripening, and shipment to markets. markets.

e)e) What happened to the Flavr Savr tomato? What happened to the Flavr Savr tomato? i.i.Produced by Calgene by blocking the polygalacturonase Produced by Calgene by blocking the polygalacturonase

(PG) gene, which is involved in spoilage. PG is an enzyme (PG) gene, which is involved in spoilage. PG is an enzyme that breaks down pectin, which is found in plant cell walls. that breaks down pectin, which is found in plant cell walls.

ii.ii.Plants were transformed with the anti-sense PG gene, Plants were transformed with the anti-sense PG gene, which is mRNA that base pair with mRNA that the plant which is mRNA that base pair with mRNA that the plant produces, essentially blocking the gene from translation. produces, essentially blocking the gene from translation.

iii.iii.First genetically modified organism to be approved by the First genetically modified organism to be approved by the FDA, in 1994. FDA, in 1994.

iv.iv.Tomatoes were delicate, did not grow well in Florida, and Tomatoes were delicate, did not grow well in Florida, and cost much more than regular tomatoes.cost much more than regular tomatoes.

v.v.Calgene was sold to Monsanto after Monsanto filed a Calgene was sold to Monsanto after Monsanto filed a patent-infringement lawsuit against Calgene, and the Flavr patent-infringement lawsuit against Calgene, and the Flavr Savr tomato left the market.Savr tomato left the market.

Delayed Fruit RipeningDelayed Fruit Ripening

The Flavr SavrTM TomatoThe Flavr SavrTM Tomato (First transgenic Plant Product)(First transgenic Plant Product)

How enzyme How enzyme is made?is made?

DNA

PRODUCED

Summary of Summary of Antisense Antisense mechanism:mechanism:

When A Cloned When A Cloned Antisense DNA Is Antisense DNA Is Added To The Added To The Original DNA:Original DNA:

First biotech plant product – Flav’r Sav’r tomato

First biotech plant product – Flav’r Sav’r tomato

Flavr-Savr tomatoFlavr-Savr tomato

““Rot-Resistant Tomato”Rot-Resistant Tomato” Calgen, Inc.Calgen, Inc. Anti-sense gene Anti-sense gene complementary to complementary to

polygalacturonase (PG)polygalacturonase (PG)• PG = pectinase PG = pectinase accelerates plant accelerates plant

decay/rottingdecay/rotting

a)a) Hybrid crops are created by crossing two distantly Hybrid crops are created by crossing two distantly related varieties of the same crop plant.related varieties of the same crop plant.

b)b) The method may generate plants with favorable The method may generate plants with favorable traits, such as tall soybean plants that make more traits, such as tall soybean plants that make more seeds and are resistant to environmental pressures. seeds and are resistant to environmental pressures.

c)c) For success, plant pollination must be controlled. For success, plant pollination must be controlled. This is usually done by removing the male flower This is usually done by removing the male flower parts by hand before pollen is released. Also, parts by hand before pollen is released. Also, sterilized plants have been genetically engineered sterilized plants have been genetically engineered with a gene from the bacteria Bacillus with a gene from the bacteria Bacillus amyloliqueifaciens (barnase gene). This gene is amyloliqueifaciens (barnase gene). This gene is dominant gene for male sterilitydominant gene for male sterility

Pollen ControlPollen Control

Genetic laser approachGenetic laser approach Targetting the expression of a gene encoding a cytotoxin by Targetting the expression of a gene encoding a cytotoxin by

placing it under the control of an ather specific promoter placing it under the control of an ather specific promoter (Promoter of TA29 gene)(Promoter of TA29 gene)

Expression of gene encoding ribonuclease (chemical Expression of gene encoding ribonuclease (chemical synthesized synthesized RNAse-T1RNAse-T1 from from Aspergillus oryzaeAspergillus oryzae and natural and natural gene gene barnasebarnase from from Bacillus amyloliquefaciensBacillus amyloliquefaciens))

RNAse RNAse production leads to precocious degeneration of tapetum production leads to precocious degeneration of tapetum cells, the arrest of microspore development and male sterility. cells, the arrest of microspore development and male sterility. It is a dominant nuclear encoded or genetic male sterile (GMS), It is a dominant nuclear encoded or genetic male sterile (GMS), although the majority of endogenous GMS is recessivealthough the majority of endogenous GMS is recessive

Success in oilseed rape, maize and several vegetative speciesSuccess in oilseed rape, maize and several vegetative species Used antisense or cosuppression of endogenous gene that are Used antisense or cosuppression of endogenous gene that are

essential for pollen formation or functionessential for pollen formation or function Reproducing a specific phenotype-premature callose wall Reproducing a specific phenotype-premature callose wall

dissolution around the microsporogenous cellsdissolution around the microsporogenous cells Reproducing mitocondrial dysfunction, a general phenotype Reproducing mitocondrial dysfunction, a general phenotype

observed in many CMSobserved in many CMS

Fertility restorationFertility restoration Restorer gene (RF) must be devised that can Restorer gene (RF) must be devised that can

suppress the action of the male sterility gene suppress the action of the male sterility gene (Barstar)(Barstar)

1.1. a specific inhibitor of barnasea specific inhibitor of barnase2.2. Also derived from B. amyloliquefaciensAlso derived from B. amyloliquefaciens3.3. Served to protect the bacterium from its own RNAse activity Served to protect the bacterium from its own RNAse activity

by forming a diffusion-dependent, extremely one to one by forming a diffusion-dependent, extremely one to one complex which is devoid of residual RNase activitycomplex which is devoid of residual RNase activity

The use of similar promoter to ensure that it would The use of similar promoter to ensure that it would be activated in tapetal cells at the same time and to be activated in tapetal cells at the same time and to maximize the chance that barstar molecule would maximize the chance that barstar molecule would accumulate in amounts at least equal to barnaseaccumulate in amounts at least equal to barnase

Inhibiting the male sterility gene by antisense. But Inhibiting the male sterility gene by antisense. But in the cases where the male sterility gene is itself in the cases where the male sterility gene is itself antisense, designing a restorer counterpart is more antisense, designing a restorer counterpart is more problematicproblematic

Production of 100% male sterile populationProduction of 100% male sterile population

When using a dominant GMS gene, a means to When using a dominant GMS gene, a means to produce 100% male sterile population is produce 100% male sterile population is required in order to produce a practical required in order to produce a practical pollination control systempollination control system

Linkage to a selectable markerLinkage to a selectable markerUse of a dominant selectable marker gene (bar) that Use of a dominant selectable marker gene (bar) that confers tolerance to glufosinate herbicideconfers tolerance to glufosinate herbicideTreatment at an early stage with glufosinate during Treatment at an early stage with glufosinate during female parent increase and hybrid seed production female parent increase and hybrid seed production phases eliminates 50% sensitive plantsphases eliminates 50% sensitive plants

Pollen lethalityPollen lethalityadd a second locus to female parent lines consisting of an add a second locus to female parent lines consisting of an RF gene linked to a pollen lethality gene (expressing with RF gene linked to a pollen lethality gene (expressing with a pollen specific promoter)a pollen specific promoter)

1.1.Plants such fruits are subject to frost damage at low Plants such fruits are subject to frost damage at low temperatures, as well as from loss of water. They can be temperatures, as well as from loss of water. They can be genetically engineered to resist these conditions, and genetically engineered to resist these conditions, and increase crop yields as a result. increase crop yields as a result.

2.2.To resist cold weather, cold-regulated (COR) genes are also To resist cold weather, cold-regulated (COR) genes are also called “antifreeze genes,”, which encode proteins that called “antifreeze genes,”, which encode proteins that protect plant cells from frost damage. protect plant cells from frost damage.

3.3.A transcription factor for a group of COR genes called “CBF” A transcription factor for a group of COR genes called “CBF” was patented as WeatherGard in 1997 by a group at was patented as WeatherGard in 1997 by a group at Michigan State University. The genes also provide drought Michigan State University. The genes also provide drought tolerance and tolerance to high-salt soils. tolerance and tolerance to high-salt soils.

4.4.All major crop species, including corn, soybean, and rice All major crop species, including corn, soybean, and rice contain CBF genes.contain CBF genes.

5.5.Genetically engineering plants with CBF genes survive Genetically engineering plants with CBF genes survive temperatures as much as 4 to 50C lower than non-temperatures as much as 4 to 50C lower than non-engineered plants. engineered plants.

Plant Biotechnology RevolutionPlant Biotechnology RevolutionCold and Drought Tolerance and WeatherGard Genes.Cold and Drought Tolerance and WeatherGard Genes.

Plant Biotechnology RevolutionPlant Biotechnology Revolution Genetically Engineered FoodsGenetically Engineered Foods..

Foods that contain an added gene sequenceFoods that contain an added gene sequence Foods that have a deleted gene sequenceFoods that have a deleted gene sequence Animal products from animals fed GM feedAnimal products from animals fed GM feed Products produced by GM organismsProducts produced by GM organisms

1.1.More than 60% of processed foods in the United States More than 60% of processed foods in the United States contain ingredients from genetically engineered organisms. contain ingredients from genetically engineered organisms.

2.2.12 different genetically engineered plants have been 12 different genetically engineered plants have been approved in the United States, with many variations of each approved in the United States, with many variations of each plant, some approved and some not. plant, some approved and some not.

3.3.Soybeans.Soybeans.a)a) Soybean has been modified to be resistant to broad-Soybean has been modified to be resistant to broad-

spectrum herbicides. spectrum herbicides. b)b) Scientists in 2003 removed an antigen from soybean Scientists in 2003 removed an antigen from soybean

called P34 that can cause a severe allergic response. called P34 that can cause a severe allergic response. 4.4.Corn Corn

a)a) Bt insect resistance is the most common use of Bt insect resistance is the most common use of engineered corn, but herbicide resistance is also a desired engineered corn, but herbicide resistance is also a desired traittrait. .

Plant Biotechnology RevolutionPlant Biotechnology Revolution Genetically Engineered FoodsGenetically Engineered Foods..

4. Corn 4. Corn a)a)Bt insect resistance is the most common use of engineered Bt insect resistance is the most common use of engineered

corn, but herbicide resistance is also a desired traitcorn, but herbicide resistance is also a desired trait. . b)b) Products include corn oil, corn syrup, corn flour, baking powder, Products include corn oil, corn syrup, corn flour, baking powder,

and alcohol.and alcohol. c)c) By 2002 about 32% of field corn in the United States was By 2002 about 32% of field corn in the United States was

engineered. engineered. 5.5.Canola. Canola.

a)a) More than 60% of the crop in 2002 was genetically engineered; it More than 60% of the crop in 2002 was genetically engineered; it is found in many processed foods, and is also a common cooking is found in many processed foods, and is also a common cooking oil.oil.

6.6.Cotton. Cotton. a)a) More than 71% of the cotton crop in 2002 was engineered. More than 71% of the cotton crop in 2002 was engineered. b)b) Engineered cottonseed oil is found in pastries, snack foods, fried Engineered cottonseed oil is found in pastries, snack foods, fried

foods, and peanut butter. foods, and peanut butter. 7.7.Other Crops Other Crops

Other engineered plants include papaya, rice, tomato, sugar Other engineered plants include papaya, rice, tomato, sugar beet, and red heart chicory. beet, and red heart chicory.

Plant Biotechnology RevolutionPlant Biotechnology Revolution Genetically Engineered FoodsGenetically Engineered Foods

Golden RiceGolden Rice1.1.More than one third of the world’s population relies on More than one third of the world’s population relies on

rice as a food staple, so rice is an attractive target for rice as a food staple, so rice is an attractive target for enhancement. enhancement.

2.2.Golden Rice was genetically engineered to produce Golden Rice was genetically engineered to produce high levels of beta-carotene, which is a precursor to high levels of beta-carotene, which is a precursor to vitamin A. Vitamin A is needed for proper eyesight. vitamin A. Vitamin A is needed for proper eyesight.

3.3.Biotechnology company Syngenta, who owns the Biotechnology company Syngenta, who owns the rights to Golden Rice, is exploring commercial rights to Golden Rice, is exploring commercial opportunities in the United States and Japan. opportunities in the United States and Japan. Monsanto will provide licenses to Golden Rice Monsanto will provide licenses to Golden Rice technology royalty-free. technology royalty-free.

4.4.Other enhanced crops include iron-enriched rice and Other enhanced crops include iron-enriched rice and tomatoes with three times the normal amount of tomatoes with three times the normal amount of beta-carotene beta-carotene

Plant Biotechnology RevolutionPlant Biotechnology RevolutionNutritionally Enhanced Plants Nutritionally Enhanced Plants

6.6. Cause for Concern? The Case of StarLink Corn. Cause for Concern? The Case of StarLink Corn. a)a) StarLink corn had been approved for animal consumption, StarLink corn had been approved for animal consumption,

but in 2000 ended up in Taco Bell taco shells. The shells but in 2000 ended up in Taco Bell taco shells. The shells were immediately recalled. were immediately recalled.

b)b) Aventis CropScience believed that precautions regarding Aventis CropScience believed that precautions regarding the corn were in place, but some farmers did not know the the corn were in place, but some farmers did not know the corn was not for humans.corn was not for humans.

c)c) Engineered and non-engineered corn was mixed in mills, Engineered and non-engineered corn was mixed in mills, contaminating food. contaminating food.

d)d) StarLink contained two new genes: StarLink contained two new genes: i.i. Resistance to butterfly and moth caterpillars by a Resistance to butterfly and moth caterpillars by a

modified Bt toxin gene called Cry9c. modified Bt toxin gene called Cry9c. ii.ii. Resistance to herbicides such as Basta and Liberty. Resistance to herbicides such as Basta and Liberty.

e)e) StarLink was approved for animals because the Cry9c StarLink was approved for animals because the Cry9c protein could be an allergen in humans because it was protein could be an allergen in humans because it was more stable to heat and in the stomachmore stable to heat and in the stomach. .

Plant Biotechnology RevolutionPlant Biotechnology RevolutionNutritionally Enhanced PlantsNutritionally Enhanced Plants

f)f) Currently, no cases of allergic reactions have been Currently, no cases of allergic reactions have been reported, and the EPA ruled in 2001 that StarLink was reported, and the EPA ruled in 2001 that StarLink was not safe for humans.not safe for humans.

7.7. Cause for Concern? Genetically Engineered Foods and Cause for Concern? Genetically Engineered Foods and Public Concerns. Public Concerns.

a)a) The release of the Flavr Savr tomato generated much The release of the Flavr Savr tomato generated much discussion over the potential risks of genetically discussion over the potential risks of genetically engineered food:engineered food:i.i. The primary public fear was that genetically The primary public fear was that genetically

engineering a plant may produce unexpected engineering a plant may produce unexpected results, such as allergic reactions or even shock. results, such as allergic reactions or even shock.

ii.ii. Genetically engineered food may also raise Genetically engineered food may also raise concerns about the selection of food if, for concerns about the selection of food if, for example, an apple has a gene from an animal. example, an apple has a gene from an animal.

iii.iii. The use of antibiotic resistance markers may The use of antibiotic resistance markers may possibly inactivate antibiotics, leading to scientists possibly inactivate antibiotics, leading to scientists trying to find ways to remove markers from plants.trying to find ways to remove markers from plants.


iv.iv. Another concern is that deleting genes may bring Another concern is that deleting genes may bring about side effects when ingested, such as secondary about side effects when ingested, such as secondary metabolites that may protect people from compounds metabolites that may protect people from compounds that would normally be broken down by the plant. that would normally be broken down by the plant.

v.v. Uncharacterized DNA included along with the gene of Uncharacterized DNA included along with the gene of interest may produce unexpected, harmful side effects interest may produce unexpected, harmful side effects in the plant. in the plant.

vi.vi. Crops may spread the trait to other plants through Crops may spread the trait to other plants through pollination, which may damage ecosystems. pollination, which may damage ecosystems. Male-Male-sterile plants may deal with this problem. sterile plants may deal with this problem.


Normal rice

“Golden” rice

Golden 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

1.1. A new field where plants and animals are A new field where plants and animals are genetically engineered to produce important genetically engineered to produce important pharmaceuticals, vaccines, and other pharmaceuticals, vaccines, and other valuable compounds.valuable compounds.

2.2. Plants may possibly be used as bioreactors to Plants may possibly be used as bioreactors to mass-produce chemicals that can accumulate mass-produce chemicals that can accumulate within the cells until they are harvested. within the cells until they are harvested.

3.3. Soybeans have been used to produce Soybeans have been used to produce monoclonal antibodies with therapeutic value monoclonal antibodies with therapeutic value for the treatment of colon cancer. Drugs can for the treatment of colon cancer. Drugs can also be produced in rice, corn, and tobacco also be produced in rice, corn, and tobacco plants. plants.

Plant Biotechnology RevolutionPlant Biotechnology RevolutionMolecular FarmingMolecular Farming

4.4. Plants have been engineered to produce Plants have been engineered to produce human antibodies against HIV and Epicyte human antibodies against HIV and Epicyte Pharmaceuticals has begun clinical trials with Pharmaceuticals has begun clinical trials with herpes antibodies produced in plants. herpes antibodies produced in plants.

5.5. The reasons that using plants may be more The reasons that using plants may be more cost-effective than bacteria: cost-effective than bacteria:

a)a) Scale-up involves just planting seeds. Scale-up involves just planting seeds.

b)b) Proteins are produced in high quantity. Proteins are produced in high quantity.

c)c) Foreign proteins will be biologically active.Foreign proteins will be biologically active.

d)d) Foreign proteins stored in seeds are very Foreign proteins stored in seeds are very stable. stable.

e)e) Contaminating pathogens are not likely to Contaminating pathogens are not likely to be present (no animal contaminations)be present (no animal contaminations). .


6.6. Edible VaccinesEdible Vaccines a)a) People in developing countries have limited People in developing countries have limited

access to many vaccines. access to many vaccines. b)b) Making plants that produce vaccines may be Making plants that produce vaccines may be

useful for places where refrigeration is limited. useful for places where refrigeration is limited. c)c) Potatoes have been studied using a portion of Potatoes have been studied using a portion of

the the E. coliE. coli enterotoxin in mice and humans. enterotoxin in mice and humans. d)d) Other candidates for edible vaccines include Other candidates for edible vaccines include

banana and tomato, and alfalfa, corn, and banana and tomato, and alfalfa, corn, and wheat are possible candidates for use in wheat are possible candidates for use in livestock. livestock.

e)e) Edible vaccines may lead to the eradication of Edible vaccines may lead to the eradication of diseases such as hepatitis B and polio.diseases such as hepatitis B and polio.


Pharmaceutical Production in PlantsGenetically 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.

Vol. 19, No. 3 Feb. 1, 1999

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.

Edible Vaccines

There is hope to produce edible vaccines in bananas, which are grown extensively throughout the developing world.

Examples of BiopharmaceuticalsExamples of Biopharmaceuticals

Hepatitis B and other subunit vaccinesHepatitis B and other subunit vaccines Urokinase (clot dissolving drug)Urokinase (clot dissolving drug) Human serum albumin (liver cirrhosis Human serum albumin (liver cirrhosis

treatment)treatment) HemoglobinHemoglobin Human erythropoietinHuman erythropoietin Glucocerebrosidase (Gaucher’s disease)Glucocerebrosidase (Gaucher’s disease)

Blood coagulantsBlood coagulants Proteases (e.g. trypsin)Proteases (e.g. trypsin) Protease inhibitors (e.g. aprotinin - Protease inhibitors (e.g. aprotinin -

used by surgeons)used by surgeons) Growth promotersGrowth promoters HIV viral coat protein (HIV therapy)HIV viral coat protein (HIV therapy) Nutraceuticals (Vitamin A and E, Nutraceuticals (Vitamin A and E,

amino acids)amino acids)

Examples of Examples of BiopharmaceuticalsBiopharmaceuticals

Neurologically active agents (human Neurologically active agents (human enkephalins)enkephalins)

Protein based sweetener (Brazzein)Protein based sweetener (Brazzein) Avidin Avidin Beta-glucoronidaseBeta-glucoronidase Indirect thrombin inhibitor (Hirudin – Indirect thrombin inhibitor (Hirudin –

anticoagulant originally isolated from the leech anticoagulant originally isolated from the leech Hirudo medicinalisHirudo medicinalis))

Human epidermal growth factorHuman epidermal growth factor Human interferon-alpha (Hepatitis B and C Human interferon-alpha (Hepatitis B and C

treatment)treatment)


Bacterial enterotoxinsBacterial enterotoxins Human insulinHuman insulin Norwalk virus capsid proteinNorwalk virus capsid protein ““Natural” plastic (plastic-like Natural” plastic (plastic-like

polymers) (Biopol)polymers) (Biopol) Human alpha-1 antitrypsin (cystic Human alpha-1 antitrypsin (cystic

fibrosis/liver treatment)fibrosis/liver treatment) Angiotensin-1-converting enzyme Angiotensin-1-converting enzyme

(hypertension)(hypertension)


Edible VaccinesEdible Vaccines Ongoing Research AreasOngoing Research Areas

Hepatitis BHepatitis B Dental caries - Anti-tooth decay Ab (CaroRxTM) Dental caries - Anti-tooth decay Ab (CaroRxTM)

(anti(anti-Streptococcus mutans-Streptococcus mutans)) Autoimmune diabetesAutoimmune diabetes CholeraCholera RabiesRabies HIVHIV RhinovirusRhinovirus Foot and MouthFoot and Mouth Enteritis virusEnteritis virus MalariaMalaria InfluenzaInfluenza CancerCancer

Edible VaccineEdible Vaccine

Foodborne PathogenFoodborne Pathogen Vaccine exists, cost prohibitive deliveryVaccine exists, cost prohibitive delivery Plant-based vaccination can be cost Plant-based vaccination can be cost

effectiveeffective Improved safety of the food supply Improved safety of the food supply Safety evaluation of the vaccine proteinSafety evaluation of the vaccine protein

a)a) Plant seeds may be a potential source for Plant seeds may be a potential source for plastics that could be produced and easily plastics that could be produced and easily extracted. extracted.

b)b) A type of PHA (polyhydroxylalkanoate) A type of PHA (polyhydroxylalkanoate) polymer called “poly-beta-hydroxybutyrate”, polymer called “poly-beta-hydroxybutyrate”, or PHB, is produced in Arabidopsis, or mustard or PHB, is produced in Arabidopsis, or mustard plant. plant.

c)c) PHB can be made in canola seeds by the PHB can be made in canola seeds by the transfer of three genes from the bacterium transfer of three genes from the bacterium Alicaligenes eutrophus, which codes for Alicaligenes eutrophus, which codes for enzymes in the PHB synthesis pathway.enzymes in the PHB synthesis pathway.

d)d) Monsanto produces a polymer called PHBV Monsanto produces a polymer called PHBV through Alicaligenes fermentation, which is through Alicaligenes fermentation, which is sold under the name Biopol. sold under the name Biopol.

Plant Biotechnology RevolutionPlant Biotechnology RevolutionBiopolymers and PlantsBiopolymers and Plants

Areas of ongoing debateAreas of ongoing debate

EnvironmentEnvironment Human HealthHuman Health Food securityFood security Socio-economic concernsSocio-economic concerns

EnvironmentEnvironment

Loss of biodiversityLoss of biodiversity Cross-pollinationCross-pollination Emergence of Emergence of

superweeds and superweeds and superbugssuperbugs

Potential increase Potential increase in use of herbicidesin use of herbicides

Need to increase Need to increase yields to feed yields to feed growing populationgrowing population

Possibility of Possibility of reducing need for reducing need for pesticides, pesticides, fertilizersfertilizers

Grow more food on Grow more food on same amount of same amount of landland

Anti-GM Pro-GM

*Opinions are generalized, and not all opponents or proponents may hold all of these views.

Human HealthHuman Health

Fear of unknown Fear of unknown allergensallergens

Spread of anti-Spread of anti-biotic resistancebiotic resistance

Inadequate Inadequate regulation of new regulation of new productsproducts

Greater regulations Greater regulations than other foodsthan other foods

Potential benefits Potential benefits to nutritionto nutrition• golden ricegolden rice• enhanced protein enhanced protein

content in corncontent in corn• soybean oil with soybean oil with

less saturated fatless saturated fat

Anti-GM Pro-GM

Food SecurityFood Security

Need redistribution, Need redistribution, not just morenot just more

Farmers will not be Farmers will not be able to afford able to afford expensive seedexpensive seed

Developing Developing countries should countries should not have to eat the not have to eat the food others rejectfood others reject

Modified seeds will Modified seeds will allow farmers to allow farmers to grow more to feed grow more to feed their family and to their family and to sell, reducing the sell, reducing the need for food aidneed for food aid

Public-private Public-private cooperation can cooperation can transfer technologytransfer technology

Pro-GMAnti-GM

Socio-economic concernsSocio-economic concerns

Corporations benefit, Corporations benefit, not those in neednot those in need

Products needed in Products needed in developing countries developing countries are not being are not being developed because developed because the market is not the market is not profitableprofitable

It is wrong to patent It is wrong to patent lifelife

Patents needed Patents needed because new because new strains are strains are intellectual intellectual propertyproperty

Publicly funded Publicly funded research can research can benefit the public benefit the public goodgood

Documents

Applications of Transgenic technology. Transgenic technology Breeding method Breeding method Crop Improvement Crop Improvement The Potential traits: The