Success Story ofSuccess Story of Transgenic cropsTransgenic crops

Important Traits for Crop Important Traits for Crop ImprovementImprovement High crop yieldHigh crop yield

High nutritional qualityHigh nutritional quality Abiotic stress toleranceAbiotic stress tolerance

Pest resistancePest resistance Adaptation to inter-croppingAdaptation to inter-cropping

Nitrogen FixationNitrogen Fixation Insensitivity to photo-periodInsensitivity to photo-period

Elimination of toxic compoundsElimination of toxic compounds

TRANSGENIC PLANTS

NUTRITIONALQUALITY

BIOTIC STRESSTOLERANCE

ABIOTIC STRESSTOLERANCE

PHARMACEUTICALS & EDIBLE VACCINE

HYBRID DEVELOPMENTFOR HIGHER YIELD

ENHANCED SHELF LIFE

INDUSTRIAL PRODUCTS

1985

19921988

1994

1998

1996

1999

2000

1st transgenic plants producedParticle 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 developedMcDonald’s rejects GM potatoes

Tearless Onion

Colorful Cauliflowers

Purple tomatoes

Blue Roses

Insect ResistanceInsect Resistance Delayed Fruit Ripening Delayed Fruit Ripening Nutritional Enhancing Nutritional Enhancing Herbicide ResistanceHerbicide Resistance

Virus ResistanceVirus Resistance

The big five successful traitsThe big five successful traits

Glyphosate ResistanceGlyphosate Resistancei.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-enol(S-enolppyruvlyruvlsshikimate-3 hikimate-3 pphosphate – hosphate – involved in chloroplast amino acid synthesis)involved in chloroplast amino acid synthesis), makes aromatic , makes aromatic amino acids.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 be glyphosate-resistant E. coli into plants, allowing plants to be resistant.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 (bar Plants receive a gene from the bacterium Streptomyces (bar gene) that produce a protein that inactivates the herbicide. gene) that produce a protein that inactivates the herbicide.

Herbicide ResistanceHerbicide Resistance

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 ResistanceHerbicide Resistance

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.

EPSP SYNTHASE

Phosphoenol pyruvate

Tryptophan

Tyrosine

Phenylalaline

ROUNDUP(Glyphosate )

Glucose

3 phosphoglycerate

GlycolysisEPSP SYNTHASE

ROUNDUP(Glyphosate )

In transgenic plant, herbicide cannot bind the mutant of EPSPS (Roundup resistant cotton and soybean)

ROUNDUP (Glyphosate) RESISTANCEROUNDUP (Glyphosate) RESISTANCE(( HERBICIDE TOLERANCE IN CROPS) HERBICIDE TOLERANCE IN CROPS)

Insect resistanceInsect resistance

Anti-Insect Strategy - InsecticidesAnti-Insect Strategy - Insecticidesa) Toxic crystal protein from a) Toxic crystal protein from Bacillus Bacillus

thuringensisthuringensis 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

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.

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.

δ -endotoxin gene (Cry gene) of Bacillus thuriengenesis

GENE FOR Bt TOXIN WAS TRANSFERREDTO OBTAIN BT TRANSGENIC PLANTS

PLANT SYNTHESIZES INACTIVE PROTOXIN

PROTEINASEDIGESTION ININSECT GUT MAKES THEACTIVE 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 ONTRANSGENIC PLANT

a)a) 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.

b)b) 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.

c)c) 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

a)a) Allow for crops, such as tomatoes, to have Allow for crops, such as tomatoes, to have a higher shelf life. a 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 Tomatoes are usually picked and sprayed with the plant hormone ethylene to induce with the plant hormone ethylene to induce ripening, although this does not improve ripening, although this does not improve tastetaste

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

Delayed Fruit RipeningDelayed Fruit Ripening

What happened to the Flavr Savr tomato? What happened to the Flavr Savr tomato?

i.i. Produced by blocking the polygalacturonase (PG) gene, Produced by blocking the polygalacturonase (PG) gene, which is involved in spoilage. PG is an enzyme that which is involved in spoilage. PG is an enzyme that breaks down pectin, which is found in plant cell walls. 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 First genetically modified organism to be approved by the FDA, in 1994. the FDA, in 1994.

iv.iv.Tomatoes were delicate, did not grow well in Florida, Tomatoes were delicate, did not grow well in Florida, and cost much more than regular tomatoes.and 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 patent-infringement lawsuit against Calgene, and the Flavr Savr tomato left the market. Flavr Savr tomato left the market.

Delayed Fruit RipeningDelayed Fruit Ripening

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

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

““Rot-Resistant Tomato”Rot-Resistant Tomato”

Anti-sense gene Anti-sense gene complementary to complementary to polygalacturonase (PG)polygalacturonase (PG)

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

1.1.More than one third of the world’s More than one third of the world’s population relies on rice as a food staple, population relies on rice as a food staple, so rice is an attractive target for so rice is an attractive target for enhancement. enhancement.

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

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

Nutritionally Enhanced Nutritionally Enhanced PlantsPlants

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

Phytoene

Phytoene synthase

Gernayl Gernayl diphosphate (GGPP)

Phytoene desaturase

Lycopene

Lycopene cyclase

Beta carotene

Complete biochemical pathway in the rice for production of beta-carotene, a precursor for

vitamin A

The prototype of golden rice was developed in 2000 and is a light yellow color (b). It contains

1.6 mg/g of carotenoid. In 2005, new transgenic lines were developed

that dramatically increased the amount of carotenoid synthesized, making the rice a deep

golden color (c). This latest form contains 37 mg/g of

carotenoid, of which 84% is b-carotene – trial

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

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

Molecular FarmingMolecular Farming

Ease of Scale-up

Low Cost

Reduced Capital Expenditures

No Animal Contaminants (virus)

Plants offer unique benefits for the production of pharmaceutical proteins:

Why Plants?

a)a) Making plants that produce vaccines Making plants that produce vaccines

b)b) 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.

c)c) Other candidates for edible vaccines include Other candidates for edible vaccines include banana and tomato, and alfalfa, corn, and wheat banana and tomato, and alfalfa, corn, and wheat are possible candidates for use in livestock. are possible candidates for use in livestock.

d)d) 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.

Molecular FarmingMolecular Farming (Vaccines) (Vaccines)

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

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

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

d)d) A polymer called PHBV produced through A polymer called PHBV produced through Alicaligenes fermentation, which is sold under Alicaligenes fermentation, which is sold under the name Biopthe name Biopol. ol.

Molecular FarmingMolecular Farming (Biopolymers and Plants) (Biopolymers and Plants)