Transcript Plant Biotechnology

Chapter 6
Plant Biotechnology
Agriculture: The Next Revolution
 Biggest industry in the world ($1.3 trillion of products
per year)
 Plant transgenesis allows innovations that are
impossible to achieve with conventional hybridization
methods
• Resistant to herbicides
• Pest resistant
• Vaccines
Methods Used in Plant
Transgenesis
Unique advantages of plants:
• The long history of plant breeding provides plant
geneticists with a wealth of strains that can be
exploited at the molecular level
• Plants produce large numbers of progeny; so rare
mutations and recombinations can be found more
easily
• Plants have been regenerative capabilities, even from
one cell
• Species boundaries and sexual compatibility are no
longer an issue
Methods Used in Plant
Transgenesis
Selective Breeding
• Farmers cross plants with desirable traits to increase
the likelihood of producing offspring with that trait.
selective breeding animation
Methods Used in Plant
Transgenesis
 Protoplast Fusion to create plant
hybrids
• Degrade cell wall with cellulase
• A cell lacking a cell wall is called a
protoplast
• The protoplasts from different species of
plants can be fused together to create a
hybrid
• The fused protoplasts grow in nutrient
agar for a few weeks
• The colonies are then transferred to
media to induce root and shoot growth
Methods Used in Plant
Transgenesis
Selective Breeding vs. Biotechnology
Traditional selective breeding vs. biotechnology
Methods Used in Plant
Transgenesis
 Transgene – gene for a desirable trait introduced into a
novel organism
• Transgene construct contains a promoter, terminator, and
selectable marker gene
Methods Used in Plant
Transgenesis
 Transformation by Agrobacterium Method
• Ti plasmid integrates into the DNA of the host cell, making it an
ideal vehicle for transferring recombinant DNA to plant cells
Animation: Gene Transfer in Plants Using Ti Plasmid
Methods Used in Plant
Transgenesis
 Leaf Fragment Technique
• Small discs of leaf incubated with
genetically modified Agrobacterium
Ti plasmid
• Treat with hormones to stimulate
shoot and root development
Animation: Engineer a Crop
Methods Used in Plant
Transgenesis
 Transformation by Gene
Gun Method
• Blast tiny metal
beads coated with
DNA into an
embryonic plant cell
Gene Gun animation
Methods Used in Plant
Transgenesis
 Chloroplast Engineering
• More genes can be inserted at one time
• Genes are more likely to be expressed
• DNA is separate from the nucleus
Methods Used in Plant
Transgenesis
Plant Breeding and Testing
Overview of crop genetic engineering
Methods Used in Plant
Transgenesis
 Antisense Technology
• Flavr SavrTM tomato introduced in 1994
• Ripe tomatoes normally produce the
enzyme, polyglacturonase (PG) which
digests pectin
• Scientists isolated the PG gene,
produced a complementary gene
which produces a complementary
mRNA that binds to the normal mRNA
inactivating the normal mRNA for this
enzyme
Antisense technology
Methods Used in Plant
Transgenesis
 RNA Interference (RNAi)
• Inhibits gene expression by interfering with transcription or
translation of RNA molecules
Active protein expression
Protein expression silenced
by RNAi
RNAi video and animations
Practical Applications in the Field
Disease Resistance
• Vaccines for plants contain
dead or weakened strains of
plant viruses to turn on the
plant’s immune system
• Transgenic plants express viral
proteins to confer immunity
Practical Applications in the Field
Insect Control
• Bacillus thuringiensis (Bt) produces a protein that is
toxic to plant pests
• Transgenic plants contain the gene for the Bt toxin
and have a built-in defense against these plant pests
Animation: How Bt Affects Insects
Practical Applications in the Field
Weed Management
• Herbicide resistance
Weed-infested
soybean plot
Transgenic soybean
plot after Roundup
treatment
Practical Applications in the Field
Safe Storage
• avidin-blocks the availability of biotin for insects
Stronger fibers
• Increase strength of cotton fiber by 60%
Practical Applications in the Field
Enhanced Nutrition
• Golden rice that is genetically modified to
produce large amounts of beta carotene
• QPM: Maize with increased nutritive value
QPM program in Haiti
Practical Applications in the Field
 Future Transgenic Products
• RNAi to generate caffeine free coffee beans.
• Biotech Crop Database
Animation: Future GMOs
Practical Applications in the Field
The Future: From Pharmaceuticals to Fuel
• Plant-based petroleum for fuels
• Biofuel – fuel derived from biomass
Types of Biofuels
 Bioethanol – alcohol made by fermenting plant based
sugar compounds
Video tour of an Ethanol Plant
Types of Biofuels
 Biodiesel-vegetable oil or animal fat derived diesel fuel
Comparison of biodiesel output for different feed stocks
Biofuel Production
Generation 1 Biofuels: Food Sources
Biofuel Production
Corn Used for Ethanol production 1985-2008
4,000
3,600
3,500
3,026
2,500
2,120
2,000
1,603
1,500
1,323
1,168
996
1,000
398 426 458
500 271 279 287 321 349
533
566 628
481 526
429
396
706
2008a
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
0
1985
Million Bushels
3,000
Biofuel Production
Biotechnology Solutions for Generation 1
• The soybean
Biofuel Production
Generation 2 Biofuels: Non-Food Sources
Biofuel Production
Biotechnology Solutions for Generation 2
• GM Jatropha doubles oil yield
Practical Applications in the Field
Metabolic Engineering
• Manipulation of plant biochemistry to produce
nonprotein products or to alter cellular
properties
Health and Environmental
Concerns
Human Health
• Allergens
• Antibiotic resistance
Health and Environmental
Concerns
Environmental Impact
• Effect on non-target species
• Super weeds
Health and Environmental
Concerns
Regulations
• US Department of Agriculture (USDA)
• Safe to grow
• Food and Drug Administration (FDA)
• Safe to consume
• Environmental Protection Agency (EPA)
• Poses little or no environmental risk
Plant Biotechnology