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Biotechnology and Crops
E. SouzaProfessor, Plant Breeding and Genetics
Basic Areas of Biotechnology Research
Sequence and Function
Sequencing all the DNA of corn, rice, and
Arabidopsis (a small mustard).
Comparable Human research: The Human
Genome Project
Sequence and function
TATAGTCCAUGGene sequence
Arabidopsis
TATAGTCCAUGGene sequence
Potato
Protein structureand function
Model proteins
Design DNAprobes
New understanding of plantfunction and faster approaches
to crop improvement
Basic Areas of Biotechnology Research
Structure and Function
Diagnostics
Identifying genes that cause disease
resistance or quality enhancement. Human research: Identifying ‘cancer’ genes
Consensus map:Triticeae Group 1 Chromosome.WheatRyeBarleyRiceMaize
Source: Graingenes
Autoradiogram of DNA marker from oatCDO64
One of many gene markers used to construct maps of cereals.Source: Graingenes
Difficult traits such as head scab resistance are easier to select by selecting directly for DNArather than the disease
Marker Assisted Selection
Smaller DNA
Large DNA
Basic Areas of Biotechnology Research
Structure and Function
Diagnostics
Genetic Engineering of Crops
Defined by transfer of genetic material from one
organism to another through non-sexual means
Comparable human research: ‘Gene therapy’
treatments
Genetic Engineering of CropsIsolation of gene
Development of new ‘construct’ or ‘vector’ A carrier often small circular or linear DNA Other genes for efficient transfer Regulatory genes to activate the target gene
Insertion into plant
Selection and recovery of plants with activated gene
Regulation of Genetically Engineered Plants
GE plants for lab use Regulated by internal biological safety
committees Vast majority of engineering ‘events’
Field testing and transport – APHISSafety and use – EPA, FDA, or bothMarketing – All of the above plus other nation’s regulatory agencies
Frequency of Journal Publications Listed in AGRICOLA Database
1351
540
5236
466
0
1000
2000
3000
4000
5000
6000
Pu
blicati
on
s
1992-1997 1999-2003
Transgenic PlantsCrop Cultivation
Traits Used for Enhancing Crops
Herbicide resistance Roundup ready Bialophos resistant Bromoxinyl resistant
Bt organic insecticide Different forms of Cry proteins from a
pathogen of insects
Virus resistance coat protein genes
Potatoes in foreground are normal, background protected from Round-up Herbicide by a modified enzyme from bacteria.
Potatoes with Cry proteins from B. thuringensis protected fromColorado potato beetles
Genetically Enhanced Daws Wheat Resistant to Wheat Streak Mosaic Virus from ‘96-’97 Field Test
Types of traits incorporated into genetically enhanced crops, 2002
75
178
0.50
102030405060708090
100%
of
GE
cro
ps
HerbicideTolerance
InsectResistance
Herb &InsectResist.
Quality orVirus
Source: C. James, 2002, ISAAA
United States63%
Argentina21%
Canada6%
Brazil4%
Other1%
South Africa1%
China4%
Percent of land area planted to transgenic crops by country 2003 – total global land area planted: 167 million acreshttp://www.colostate.edu/programs/lifesciences/TransgenicCrops/current.html#crops
Soybean62%
Maize21%
Cotton12%
Canola5%
Squash0%
Papaya0%
Relative percent of transgenic cultivars by crop, 2002http://www.isaaa.org/kc/Publications/pdfs/isaaabriefs/Briefs%2027.pdf
Traits Used for GE Crops: Crop Quality
Ripening gene modificationsPharmaceuticals and Vaccines
Traits Used for GE Crops: Crop Quality
Ripening gene modificationsPharmaceuticals and Vaccines Vitamin A enhancement of riceAdditional gluten genesOil compositionEssential oils/flavors
GE Crops: Risks and Problems
Consumer acceptance Safety/allergenicity (Perceived and
actual) Naturalness
GE Crops: Risks and Problems
Consumer acceptancePoor Utilization Traits are expensive – the cost of
technology as described in essay Tendency to overuse
GE Crops: Risks and Problems
Consumer acceptanceNaturalnessPoor UtilizationWeediness Weediness of crop Escape of genes
GE Crops: Risks and Problems
Consumer acceptanceNaturalnessPoor UtilizationWeedinessSafety/Labeling Segregation of products expensive Labeling is cheap – the process to match
the food to the label is very expensive
So Why Do Genetic Engineering?
In some cases we will not Roundup Ready Wheat Terminated in 2004
Reduce costs and lower agriculture’s environmental impact less pesticides lower rate and toxicity
Traits available throughout third world Competitive edge?
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