transgenic technology traits that plant breeders would like in plants high primary productivity high...

TRANSGENIC TECHNOLOGY

Traits that plant breeders Traits that plant breeders would like in plantswould like in plants

High primary High primary productivityproductivity

High crop yieldHigh crop yield High nutritional High nutritional

qualityquality Adaptation to inter-Adaptation to inter-

croppingcropping Nitrogen Fixation Nitrogen Fixation

Drought resistanceDrought resistance Pest resistancePest resistance Adaptation to Adaptation to

mechanised mechanised farmingfarming

Insensitivity to Insensitivity to photo-periodphoto-period

Elimination of toxic Elimination of toxic compoundscompounds

getting DNA into a cell

getting it stably integrated

getting a plant back from the cell

Plant transformation

1. a suitable transformation method

2.2. a means of screening for transformantsa means of screening for transformants

3. an efficient regeneration system

4. genes/constructs Vectors

Promoter/terminator

reporter genes

selectable marker genes

‘genes of interest’

Requirement

Transformation methods

DNA must be introduced into plant cells

Indirect - Agrobacterium tumefaciens

Direct - microprojectile bombardment - electroporation - Polyethylene glycol (PEG)-

mediated - glass-beads - silicon carbide whiskers

Method depends on plant type, cost, application

AgrobacteriumAgrobacterium-mediated -mediated transformationtransformation

A natural genetic A natural genetic engineerengineer

2 species2 species• A.tumefaciensA.tumefaciens

(produces a gall)(produces a gall)• A. rhizogenesA. rhizogenes

(produces roots)(produces roots) OncOncoogenesgenes (for (for

auxin and cytokinin auxin and cytokinin synthesis) + Opinessynthesis) + Opines

In the presence of In the presence of exudates (e.g. exudates (e.g. acetosyringone) from acetosyringone) from wounded plants, wounded plants, VirVirulence (Vir) genes ulence (Vir) genes are activated and are activated and cause the t-DNA to be cause the t-DNA to be transferred to plants. transferred to plants. Everything between Everything between the left and right the left and right border is transferred.border is transferred.

BACTERIAL GALL DISEASESBACTERIAL GALL DISEASES

Galls:Galls: overgrowth or proliferation of tissue, primarily overgrowth or proliferation of tissue, primarily due to increased cell division (hyperplasia) and due to increased cell division (hyperplasia) and increased cell size (hypertrophy).increased cell size (hypertrophy).

Bacterial Galls:Bacterial Galls:

induced by bacteria in 3 different genera. induced by bacteria in 3 different genera. • AgrobacteriumAgrobacterium• PseudomonasPseudomonas• ClavibacterClavibacter

Genes for plant hormone production found Genes for plant hormone production found on bacterial plasmids!on bacterial plasmids!

Crown Gall Disease: Crown Gall Disease: Agrobacterium tumefaciensAgrobacterium tumefaciens

Gram -Gram - DicotsDicots WorldwideWorldwide

Disease Cycle

Agrobacterium tumefaciensAgrobacterium tumefaciens

CharacteristicsCharacteristics• Plant parasite that causes Crown Gall Plant parasite that causes Crown Gall

DiseaseDisease• Encodes a large (~250kbp) plasmid called Encodes a large (~250kbp) plasmid called

Tumor-inducing (Ti) plasmidTumor-inducing (Ti) plasmid Portion of the Ti plasmid is transferred between Portion of the Ti plasmid is transferred between

bacterial cells and plant cells bacterial cells and plant cells T-DNA (Tumor T-DNA (Tumor DNADNA))


T-DNA integrates stably into plant genomeT-DNA integrates stably into plant genomeSingle stranded T-DNA fragment is Single stranded T-DNA fragment is converted to dsDNA fragment by plant cellconverted to dsDNA fragment by plant cell Then integrated into plant genomeThen integrated into plant genome 2 x 23bp direct repeats play an important role in 2 x 23bp direct repeats play an important role in

the excision and integration processthe excision and integration process


Tumor formation = hyperplasiaTumor formation = hyperplasia Hormone imbalanceHormone imbalance Caused by Caused by A. tumefaciensA. tumefaciens

• Lives in intercellular spaces of the plantLives in intercellular spaces of the plant• Plasmid contains genes responsible for the Plasmid contains genes responsible for the

diseasedisease Part of plasmid is inserted into plant DNAPart of plasmid is inserted into plant DNA Wound = entry point Wound = entry point 10-14 days later, 10-14 days later,

tumor formstumor forms


What is naturally encoded in T-DNA?What is naturally encoded in T-DNA?• Enzymes for auxin and cytokinin synthesisEnzymes for auxin and cytokinin synthesis

Causing hormone imbalance Causing hormone imbalance tumor tumor formation/undifferentiated callusformation/undifferentiated callus

Mutants in enzymes have been characterizedMutants in enzymes have been characterized

• Opine synthesis genes (e.g. octopine or Opine synthesis genes (e.g. octopine or nopaline)nopaline)

Carbon and nitrogen source for Carbon and nitrogen source for A. tumefaciensA. tumefaciens growth growth Insertion genes Insertion genes

• Virulence (vir) genesVirulence (vir) genes• Allow excision and integration into plant genomeAllow excision and integration into plant genome

Ti plasmid of Ti plasmid of A. tumefaciensA. tumefaciens

1. Auxin, cytokinin, opine synthetic genes transferred to plant

2. Plant makes all 3 compounds

3. Auxins and cytokines cause gall formation

4. Opines provide unique carbon/nitrogen source only A. tumefaciens can use!

Agrobacterium tumefaciensAgrobacterium tumefaciens How is T-DNA modified to allow genes of How is T-DNA modified to allow genes of

interest to be inserted?interest to be inserted?• In vitroIn vitro modification of Ti plasmid modification of Ti plasmid

T-DNA tumor causing genes are deleted and replaced T-DNA tumor causing genes are deleted and replaced with desirable genes (under proper regulatory control)with desirable genes (under proper regulatory control)

Insertion genes are retained (vir genes)Insertion genes are retained (vir genes) Selectable marker gene added to track plant cells Selectable marker gene added to track plant cells

successfully rendered transgenic [antibiotic resistance successfully rendered transgenic [antibiotic resistance gene gene geneticin (G418) or hygromycin] geneticin (G418) or hygromycin]

Ti plasmid is reintroduced into Ti plasmid is reintroduced into A. tumefaciensA. tumefaciens A. tumefaciensA. tumefaciens is co-cultured with plant leaf disks is co-cultured with plant leaf disks

under hormone conditions favoring callus under hormone conditions favoring callus development (undifferentiated)development (undifferentiated)

Antibacterial agents (e.g. chloramphenicol) added to Antibacterial agents (e.g. chloramphenicol) added to kill kill A. tumefaciensA. tumefaciens

G418 or hygromycin added to kill non-transgenic plant G418 or hygromycin added to kill non-transgenic plant cellscells

Surviving cells = transgenic plant cellsSurviving cells = transgenic plant cells

Agrobacterium and genetic engineering:Engineering the Ti plasmid

Co-integrative and binary vectorsCo-integrative and binary vectors

Binary vector

LB RB

Co-integrative

cause ‘Crown gall’ disease

Agrobacterium tumefaciens

Agrobacterium-mediated transformation

Agrobacterium is a ‘natural genetic engineer’

i.e. it transfers some of its DNA to plants

Electroporate T-DNA vector into Agrobacterium and select for tetr

Expose wounded plant cells to transformed agro strain

Induce plant regeneration and select for Kanr cell growth

Microprojectile bombardment

• uses a ‘gene gun’

• DNA is coated onto gold (or tungsten) particles

(inert)

• gold is propelled by helium into plant cells

• if DNA goes into the nucleus it can be integrated into the plant chromosomes

• cells can be regenerated to

whole plants

In the "biolistic" (a cross between biology and ballistics In the "biolistic" (a cross between biology and ballistics )or "gene gun" method, microscopic gold beads are )or "gene gun" method, microscopic gold beads are coated with the gene of interest and shot into the coated with the gene of interest and shot into the plant cell with a pulse of helium.plant cell with a pulse of helium.

Once inside the cell, the gene comes off the bead and Once inside the cell, the gene comes off the bead and

integrates into the cell's genome.integrates into the cell's genome.

Model from BioRad: Model from BioRad: Biorad's Helios Gene Biorad's Helios Gene GunGun

How do we get plants back from cells?

We use tissue culture techniques to regenerate whole plants from single cells

getting a plant back from a single cell is important so that every cell has the new DNA

Regeneration

Regeneration of shoots from leaf protoplasts in Arabidopsis thaliana

Plant tissue culture uses growth regulators and nutrients to regenerate plants in vitro

Somatic embryogenesis in peanut

Screening TechniqueScreening Technique

Not all cells take up DNA & not all cells can regenerate so

Need an efficient regeneration system and transformation system i.e. lots of cells take up DNA and lots of cells regenerate into a plant

to maximize chance of both happening

Transformed cellsregenerable cells

Cells containing new DNA that are able to regenerate into a new plant

There are many thousands of cells in a leaf disc or callus clump - only a proportion of these will have taken up the DNA

therefore can get hundreds of plants back - maybe only 1% will be transformed

How do we know which plants have taken up the DNA?

Could test each plant - slow, costly

Or use reporter genes & selectable marker genes

SelectionSelection Transformation frequency is low (Max 3% of all Transformation frequency is low (Max 3% of all

cells) and unless there is a selective advantage for cells) and unless there is a selective advantage for transformed cells, these will be overgrown by non-transformed cells, these will be overgrown by non-transformed.transformed.

Usual to use a positive selective agent like Usual to use a positive selective agent like antibiotic resistance. The NptII gene encoding antibiotic resistance. The NptII gene encoding Neomycin phospho-transferase II phosphorylates Neomycin phospho-transferase II phosphorylates kanamycin group antibiotics and is commonly kanamycin group antibiotics and is commonly

usedused. .

Reporter genes - easy to visualise or assay

most common - ß-glucuronidase (GUS) (E.coli)

- green fluorescent protein (GFP) (jellyfish)

- luciferase (firefly, bacterial, jellyfish etc)

GUS

Cells that are transformed with GUS will form a blue precipitate when tissue is soaked in the GUS substrate and incubated at 37oC

this is a destructive assay (cells die)

The UidA gene encoding activity is commonly The UidA gene encoding activity is commonly used. Gives a blue colour from a colourless used. Gives a blue colour from a colourless substrate (substrate (X-gluX-glu) for a qualitative assay. Also ) for a qualitative assay. Also causes fluorescence from causes fluorescence from MMethyl ethyl UUmbelliferyl mbelliferyl GGlucuronide (lucuronide (MUGMUG) for a quantitative assay.) for a quantitative assay.

GUS

Bombardment of GUS gene

- transient expression

Stable expression of GUS in moss Phloem-limited expression of

GUS

HAESA gene encodes a receptor protein kinase that controls floral organ abscission. (A) transgenic plant expressing a HAESA::GUS fusion. It is expressed in the floral abscission zone at the base of an Arabidopsis flower.

Transgenic plants that harbor the AGL12::GUS fusions show root-specific expression.

GFP (Green Fluorescent Protein)

GFP glows bright green when irradiated by blue or UV light

This is a nondestructive assay so the same cells can be monitored all the way through

Fluoresces green under UV illuminationFluoresces green under UV illumination Problems with a cryptic intron now resolved.Problems with a cryptic intron now resolved. Has been used for selection on its own.Has been used for selection on its own.

GFP

protoplast colony derived from protoplast

mass of callus

regenerated plant

Selectable marker genes - let you kill cells that haven’t taken up DNA- usually genes that confer resistance to a phytotoxic substance

Most common:

antibiotic resistance - e.g. kanamycin, hygromycin [ only phytotoxic antibiotics can be used]

herbicide resistance - e.g. phosphinothricin (PPT); glyphosate

Only those cells that have taken up the DNA can grow on media containing the selection agent

APPLICATIONS

transfer of exogenous genes

manipulation of endogenous genes

Gene silencing/ downregulation

Pathogen resistanceHerbicide resistance

Bioreactors/molecular farming

Delivery systems

Plant improvement

Gene silencing/ downregulation of endogenous genes

Antisense RNA – delayed ripening; FlavR SavR tomatoes

- modified flower colour (paler flowers)

Post-transcriptional gene silencing

induces cytoplasmic RNA degradation system

induced by dsRNA

highly sequence specific

Applications of Plant BiotechnologyApplications of Plant Biotechnology

A.A. Crop ImprovementCrop Improvement

1.1. The following traits are potentially useful to plant The following traits are potentially useful to plant genetic engineering: controlling insects, manipulating genetic engineering: controlling insects, manipulating petal color, production of industrially important petal color, production of industrially important compounds, and plant growth in harsh conditions. compounds, and plant growth in harsh conditions.

B.B. Genetically Engineered Traits: The Big SixGenetically Engineered Traits: The Big Six..

1.1. Herbicide Resistance Herbicide Resistance

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

b)b) Critics claim that genetically engineered plants will Critics claim that genetically engineered plants will lead to more chemical use, and possible development lead to more chemical use, and possible development of weeds resistant to the chemicalsof weeds resistant to the chemicals. .

c)c) Glyphosate ResistanceGlyphosate Resistance

i.i. Marketed under the name Roundup, glyphosate inhibits Marketed under the name Roundup, glyphosate inhibits the enzyme EPSPS, makes aromatic amino acids.the enzyme EPSPS, makes aromatic amino acids.

ii.ii.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.

d)d) 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. .


e)e) 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.

f)f) SulfonylureaSulfonylurea.. 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.


2.2. Insect ResistanceInsect Resistance a)a) The Bt toxin isolated from Bacillus thuringiensis has The Bt toxin isolated from Bacillus thuringiensis 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)b) Plant protease inhibitors have been explored since Plant protease inhibitors have been explored since the 1990s: the 1990s: i.i. Naturally produced by plants, are produced in Naturally produced by plants, are produced in

response to wounding. response 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 Tobacco, potato, and peas have been engineered

to resist insects such as weevils that damage to resist insects such as weevils that damage crops while they are in storage crops while they are in storage

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


3.3. Virus ResistanceVirus Resistance

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

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

c)c) Virus-resistant plants have a viral protein coat gene Virus-resistant plants have a viral protein coat gene that is overproduced, preventing the virus from that is overproduced, preventing the virus from reproducing in the host cell, because the plant shuts reproducing in the host cell, because the plant shuts off the virus’ protein coat gene in response to the off the virus’ protein coat gene in response to the overproduction. 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, tobacco diseases such as cucumber mosaic virus, tobacco rattle virus, and potato virus X.rattle virus, and potato virus X.


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

f)f) Yellow Squash and ZucchiniYellow Squash and Zucchini i.i. Seeds are available that are resistant to watermelon Seeds are available that are resistant to watermelon

mottle virus, zucchini yellow mosaic virus, and cucumber mottle virus, zucchini yellow mosaic virus, and cucumber mosaic virus. mosaic virus.

g)g) PotatoPotato.. 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)h) Papaya.Papaya.a)a)Varieties resistant to papaya ring spot virus have been Varieties resistant to papaya ring spot virus have been

developed. developed.


4.4.Altered Oil ContentAltered Oil Content 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 part synthesis pathway (oils are lipids, which fatty acids are a part of). 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 engineered to produce oils with better cooking and nutritional properties. 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, lubricants, oils that are used in detergents, soaps, cosmetics, lubricants, and paints. and paints.

5.5.Delayed Fruit Ripening Delayed Fruit Ripening 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 Tomatoes generally ripen and become soft during shipment

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

hormone ethylene to induce ripening, although this does not hormone ethylene to induce ripening, although this does not improve taste.improve taste.


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.


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:

What Happens When A Cloned What Happens When A Cloned Antisense DNA Is Added To The Antisense DNA Is Added To The

Original DNA?Original DNA?

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

6.6. Pollen ControlPollen Control

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.amyloliqueifaciens.


C.C. Biotech Revolution: Cold and Drought Tolerance and Biotech Revolution: Cold and Drought Tolerance and WeatherGard Genes. WeatherGard Genes.

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 A transcription factor for a group of COR genes called “CBF” was patented as WeatherGard in 1997 by a group at “CBF” 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.


D.D. Genetically Engineered FoodsGenetically Engineered Foods..

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 engineered corn, but herbicide resistance is also a desired traitdesired trait. .


b)b) Products include corn oil, corn syrup, corn flour, Products include corn oil, corn syrup, corn flour, baking powder, and alcohol.baking powder, and alcohol.

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

5.5. Canola. Canola. a)a) More than 60% of the crop in 2002 was genetically More than 60% of the crop in 2002 was genetically

engineered; it is found in many processed foods, and engineered; it is found in many processed foods, and is also a common cooking oil.is also a common cooking oil.

6.6. Cotton. Cotton. a)a) More than 71% of the cotton crop in 2002 was More than 71% of the cotton crop in 2002 was

engineered. engineered. b)b) Engineered cottonseed oil is found in pastries, snack Engineered cottonseed oil is found in pastries, snack

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

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


E.E. Nutritionally Enhanced Plants—Golden Rice: An International Nutritionally Enhanced Plants—Golden Rice: An International EffortEffort..

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

3.3. Golden Rice was developed by Ingo Potrykus and Peter Golden Rice was developed by Ingo Potrykus and Peter Beyer, and several agencies are attempting to distribute Beyer, and several agencies are attempting to distribute the rice worldwide. the rice worldwide.

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

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


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. .


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.


F.F. Molecular FarmingMolecular Farming 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. for the treatment of colon cancer. Clot-Clot-busting drugs can also be produced in rice, busting drugs can also be produced in rice, corn, and tobacco plants. corn, and tobacco plants.


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 presentbe present. .


6.6. Edible VaccinesEdible Vaccines

a)a) People in developing countries have limited access People in developing countries have limited access to many vaccines. to many vaccines.

b)b) Making plants that produce vaccines may be useful Making plants that produce vaccines may be useful for places where refrigeration is limited. for 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 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.

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.


7.7. Biopolymers and PlantsBiopolymers and Plants 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) Monsanto produces a polymer called PHBV through Monsanto produces a polymer called PHBV through Alicaligenes fermentation, which is sold under the Alicaligenes fermentation, which is sold under the name Biopol. name Biopol.


transgenic technology traits that plant breeders would like in plants high primary productivity high...

Documents

plant genome tdna

plant type

requirement slide

application slide

bacterial cells

bacterial galls

plant hormone production

transformation methods