applications of transgenic technology

Applications of Applications of Transgenic technologyTransgenic technology

Transgenic technologyTransgenic technology

Breeding methodBreeding method Crop Improvement Crop Improvement

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

Critics claim that genetically engineered plants will lead to more Critics claim that genetically engineered plants will lead to more

chemical use, and possible development of weeds resistant to the chemical use, and possible development of weeds resistant to the chemicals. chemicals.

Herbicide ResistanceHerbicide Resistance

a)a) Glyphosate ResistanceGlyphosate Resistance i.i. Glyphosate = “Roundup”, “Tumbleweed” = Systemic herbicideGlyphosate = “Roundup”, “Tumbleweed” = Systemic herbicideii.ii. Marketed under the name Roundup, glyphosate inhibits the enzyme EPSPS Marketed under the name Roundup, glyphosate inhibits the enzyme EPSPS (S-(S-

enolenolppyruvlyruvlsshikimate-3 hikimate-3 pphosphate – involved in chloroplast amino acid hosphate – involved in chloroplast amino acid synthesis)synthesis), makes aromatic amino acids., makes aromatic amino acids.

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

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

of the amino acid glutamine, which blocks the enzyme glutamate synthase.of the amino acid glutamine, which blocks the enzyme glutamate synthase.ii.ii. Plants receive a gene from the bacterium Streptomyces that produce a protein Plants receive a gene from the bacterium Streptomyces that produce a protein

that inactivates the herbicidethat inactivates the herbicide. .


c) c) Bromoxynil ResistanceBromoxynil 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 the Kills plants by blocking an enzyme needed for synthesis of the

amino acids valine, leucine, and isoleucine. 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

a) Toxic crystal protein from a) Toxic crystal protein from Bacillus thuringensisBacillus thuringensis Toxic crystals found during sporulationToxic crystals found during sporulation Alkaline protein degrades gut wall of lepidopteran larvae Alkaline protein degrades gut wall of 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

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

b) Plant protease inhibitors have been explored since the b) 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 ingest They inhibit insect digestive enzymes after insects ingest them, causing starvation. 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 of viruses, but Chemicals are used to control the insect vectors of viruses, but controlling the disease itself is difficult because the disease spreads controlling the disease itself is difficult because the disease spreads quickly. quickly.

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

c)c) Virus-resistant plants have a viral protein coat gene that is Virus-resistant plants have a viral protein coat gene that is overproduced, preventing the virus from reproducing in the host overproduced, preventing the virus from reproducing in the host cell, because the plant shuts off the virus’ protein coat gene in cell, because the 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 diseases such as Coat protein genes are involved in resistance to diseases such as cucumber mosaic virus, tobacco rattle virus, and potato virus X. cucumber mosaic virus, 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 be tobacco mosaic virus have been isolated from plants and may be transferred to crop plants.transferred to crop plants.

f)f) Yellow Squash and ZucchiniYellow Squash and Zucchini Seeds are available that are resistant to watermelon mottle virus, 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.

g) Potatog) Potato.. a)a) Monsanto developed potatoes resistant to potato leaf roll virus and potato virus X, which Monsanto developed potatoes resistant to potato leaf roll virus and potato virus X, which

also contained a Bt toxin gene as a pesticide. also contained a Bt toxin gene as a pesticide. b)b) hain restaurants do not use genetically engineered potatoes due to public pressures. hain restaurants do not use genetically engineered potatoes due to public pressures.

h) Papayah) Papaya Varieties resistant to papaya ring spot virus have been developed. Varieties resistant to papaya ring spot virus have been 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 synthesis Done in plants by modifying an enzyme in the fatty acid synthesis pathway (oils are lipids, which fatty acids are a part of). pathway (oils are lipids, which fatty acids are a part of).

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

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

Altered Oil ContentAltered Oil Content

Laurate canola oilLaurate canola oil

Canola plant modified with thioesterase gene obtained Canola plant modified with thioesterase gene obtained from California bay laurel treefrom California bay laurel tree

Enzyme produces lauric acid (up to 40% in oil from Enzyme produces lauric acid (up to 40% in oil from genetically modified (GM) canola seeds)genetically modified (GM) 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 higher shelf life. Allow for crops, such as tomatoes, to have a higher shelf life. b)b) Tomatoes generally ripen and become soft during shipment to a Tomatoes generally ripen and become soft during shipment to a

store. store. c)c) Tomatoes are usually picked and sprayed with the plant hormone Tomatoes are usually picked and sprayed with the plant hormone

ethylene to induce ripening, although this does not improve tasteethylene to induce ripening, although this does not improve tasted)d) Tomatoes have been engineered to produce less Tomatoes have been engineered to produce less

ethylene so they can develop more taste before ethylene so they can develop more taste before ripening, and shipment to markets. ripening, and shipment to markets.

Delayed Fruit RipeningDelayed Fruit Ripening

d)d) What happened to the Flavr Savr tomato? What happened to the Flavr Savr tomato? i.i. Produced by Calgene by blocking the polygalacturonase (PG) gene, which is Produced by Calgene by blocking the polygalacturonase (PG) gene, which is

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

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

iii.iii. First genetically modified organism to be approved by the FDA, in 1994. First genetically modified organism to be approved by the FDA, in 1994. iv.iv. Tomatoes were delicate, did not grow well in Florida, and cost much more than Tomatoes were delicate, did not grow well in Florida, and cost much more than

regular tomatoes.regular tomatoes.v.v. Calgene was sold to Monsanto after Monsanto filed a patent-infringement lawsuit Calgene was sold to Monsanto after Monsanto filed a patent-infringement lawsuit

against Calgene, and the Flavr Savr tomato left the market. against Calgene, and the Flavr Savr tomato left the market.

Delayed Fruit RipeningDelayed Fruit Ripening

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

How enzyme is How enzyme is made?made?

DNA

PRODUCED

Summary of Antisense Summary of Antisense mechanism:mechanism:

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

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

““Rot-Resistant Tomato”Rot-Resistant Tomato” Anti-sense gene Anti-sense gene complementary to polygalacturonase (PG) complementary to polygalacturonase (PG)

PG = pectinase PG = pectinase accelerates plant decay/rotting accelerates plant decay/rotting

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

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

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

d)d) Genetic laser approachGenetic laser approach

Pollen ControlPollen Control

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

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

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

RNAse RNAse production leads to precocious degeneration of tapetum cells, production leads to precocious degeneration of tapetum cells, the arrest of microspore development and male sterility. It is a dominant the arrest of microspore development and male sterility. It is a dominant nuclear encoded or genetic male sterile (GMS), although the majority of nuclear encoded or genetic male sterile (GMS), although the majority of endogenous GMS is recessiveendogenous 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 dissolution Reproducing a specific phenotype-premature callose wall dissolution

around the microsporogenous cellsaround the microsporogenous cells Reproducing mitocondrial dysfunction, a general phenotype observed Reproducing mitocondrial dysfunction, a general phenotype observed

in many CMSin many CMS

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

action of the male sterility gene (Barstar)action of the male sterility gene (Barstar)1. a specific inhibitor of barnase1. a specific inhibitor of barnase2. derived from B. amyloliquefaciens2. derived from B. amyloliquefaciens3. Served to protect the bacterium from its own RNAse activity by 3. Served to protect the bacterium from its own RNAse activity by forming a diffusion-dependent, extremely one to one complex which is forming a diffusion-dependent, extremely one to one complex which is devoid of residual RNase activitydevoid of residual RNase activity

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

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

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

When using a dominant GMS gene, a means to produce 100% When using a dominant GMS gene, a means to produce 100% male sterile population is required in order to produce a practical male sterile population is 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 confers Use of a dominant selectable marker gene (bar) that confers tolerance to glufosinate herbicidetolerance to glufosinate herbicideTreatment at an early stage with glufosinate during female parent Treatment at an early stage with glufosinate during female parent increase and hybrid seed production phases eliminates 50% increase and hybrid seed production phases eliminates 50% sensitive plantssensitive plants

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

Plant Biotechnology Revolution:Plant 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 contain More than 60% of processed foods in the United States contain ingredients from genetically engineered organisms. ingredients from genetically engineered organisms.

2.2. 12 different genetically engineered plants have been approved in the 12 different genetically engineered plants have been approved in the United States, with many variations of each plant, some approved and United States, with many variations of each plant, some approved and some not. some not.

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

herbicides. herbicides. b)b) Scientists in 2003 removed an antigen from soybean called P34 that Scientists in 2003 removed an antigen from soybean called P34 that

can cause a severe allergic response. can cause a severe allergic response. 4.4. Corn Corn

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

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

4. 4. Corn Corn a)a) Bt insect resistance is the most common use of engineered corn, but herbicide resistance Bt insect resistance is the most common use of engineered corn, but herbicide resistance

is also a desired trait. is also a desired trait. b)b) Products include corn oil, corn syrup, corn flour, baking powder, and alcohol.Products include corn oil, corn syrup, corn flour, baking powder, and alcohol. c)c) By 2002 about 32% of field corn in the United States was engineered. By 2002 about 32% of field corn in the United States was engineered.

5.5. Canola. Canola. a)a) More than 60% of the crop in 2002 was genetically engineered; it is found in many 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.processed foods, and is also a common cooking 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 foods, and peanut Engineered cottonseed oil is found in pastries, snack foods, fried foods, and peanut

butter. butter. 7.7. Other CropsOther Crops

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

Plant Biotechnology Revolution:Plant Biotechnology Revolution: Genetically Engineered FoodsGenetically Engineered Foods

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

staple, so rice is an attractive target for enhancement. staple, so rice is an attractive target for enhancement. 2.2. Golden Rice was genetically engineered to produce high levels of beta-Golden Rice was genetically engineered to produce high levels of beta-

carotene, which is a precursor to vitamin A. Vitamin A is needed for carotene, which is a precursor to vitamin A. Vitamin A is needed for proper eyesight. proper eyesight.

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

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

Plant Biotechnology Revolution:Plant Biotechnology Revolution:Nutritionally Enhanced PlantsNutritionally 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, but in 2000 ended up StarLink corn had been approved for animal consumption, but in 2000 ended up

in Taco Bell taco shells. The shells were immediately recalled. in Taco Bell taco shells. The shells were immediately recalled. b)b) Aventis CropScience believed that precautions regarding the corn were in place, Aventis CropScience believed that precautions regarding the corn were in place,

but some farmers did not know the corn was not for humans.but some farmers did not know the corn was not for humans.c)c) Engineered and non-engineered corn was mixed in mills, contaminating food. Engineered and non-engineered corn was mixed in mills, contaminating food. d)d) StarLink contained two new genes: StarLink contained two new genes:

i.i. Resistance to butterfly and moth caterpillars by a modified Bt toxin gene Resistance to butterfly and moth caterpillars by a modified Bt toxin gene called Cry9c. 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 protein could be an StarLink was approved for animals because the Cry9c protein could be an

allergen in humans because it was more stable to heat and in the stomachallergen in humans because it was more stable to heat and in the stomachf) Currently, no cases of allergic reactions have been reported, and the EPA ruled in

2001 that StarLink was not safe for humans.. .


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

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

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

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

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


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

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

vi.vi. Crops may spread the trait to other plants through pollination, Crops may spread the trait to other plants through pollination, which may damage ecosystems. which may damage ecosystems. Male-sterile plants may deal Male-sterile plants may deal with this problemwith 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 genetically A new field where plants and animals are genetically engineered to produce important pharmaceuticals, engineered to produce important pharmaceuticals, vaccines, and other valuable compounds.vaccines, and other valuable compounds.

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

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

Plant Biotechnology Revolution:Plant Biotechnology Revolution:Molecular FarmingMolecular Farming

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

5.5. The reasons that using plants may be more cost-effective than The reasons that using plants may be more cost-effective than bacteria: 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 stable. Foreign proteins stored in seeds are very stable. e)e) Contaminating pathogens are not likely to be present (no Contaminating pathogens are not likely to be present (no

animal contaminations). animal contaminations).


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

vaccines. vaccines. b)b) Making plants that produce vaccines may be useful for Making plants that produce vaccines may be useful for

places where refrigeration is limited. places where refrigeration is limited. c)c) Potatoes have been studied using a portion of the Potatoes have been studied using a portion of the E. coliE. coli

enterotoxin in mice and humans. enterotoxin in mice and humans. d)d) Other candidates for edible vaccines include banana and Other candidates for edible vaccines include banana and

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

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

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.

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

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

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

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

Plant Biotechnology Revolution:Plant Biotechnology Revolution:Biopolymers 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 superweeds Emergence of superweeds

and superbugsand superbugs Potential increase in use of Potential increase in use of

herbicidesherbicides

Need to increase yields to Need to increase yields to feed growing populationfeed growing population

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

Grow more food on same Grow more food on same amount of landamount of land

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 allergensFear of unknown allergens Spread of anti-biotic Spread of anti-biotic

resistanceresistance Inadequate regulation of Inadequate regulation of

new productsnew products

Greater regulations than Greater regulations than other foodsother foods

Potential benefits to Potential benefits to nutritionnutrition• golden ricegolden rice• enhanced protein content in enhanced protein content in

corncorn• soybean oil with less soybean oil with less

saturated fatsaturated fat

Anti-GM Pro-GM

Food SecurityFood Security

Need redistribution, not Need redistribution, not just morejust more

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

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

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

Public-private cooperation Public-private cooperation can transfer technologycan transfer technology

Pro-GMAnti-GM

Socio-economic concernsSocio-economic concerns

Corporations benefit, not Corporations benefit, not those in needthose in need

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

It is wrong to patent lifeIt is wrong to patent life

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

Publicly funded research Publicly funded research can benefit the public goodcan benefit the public good