Wheat Variety Update

jamaicanabsorbingΒιοτεχνολογία

5 Δεκ 2012 (πριν από 4 χρόνια και 7 μήνες)

233 εμφανίσεις

 
 
    
Biotechnology and Crops
E. Souza
Professor, 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
TATAGTCCAUG
Gene sequence
Arabidopsis
TATAGTCCAUG
Gene sequence
Potato
Protein structure
and function
Model
proteins
Design DNA
probes
New understanding of plant
function 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.
Wheat
Rye
Barley
Rice
Maize
Source: Graingenes
Autoradiogram of
DNA marker from oat
CDO64
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 DNA
rather 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 non­sexual means

Comparable human research: ‘Gene therapy’ 
treatments


Genetic Engineering of Crops
Isolation 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 – APHIS
Safety and use – EPA, FDA, or both
Marketing – 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
ons
1992­1997
1999­2003
Transgenic Plants
Crop 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 Round­up Herbicide by a modified enzyme from bacteria.
Potatoes with 
Cry
 proteins from 
B. thuringensis
 protected from
Colorado 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
17
8
0.5
0
10
20
30
40
50
60
70
80
90
100
% o
f
GE crops
Herbicide
Tolerance
I nsect
Resistance
Herb &
I nsect
Resist.
Quality or
Virus
Source: C. James, 2002, ISAAA


United States
63%
Argentina
21%
Canada
6%
Brazil
4%
Other
1%
South Africa
1%
China
4%
Percent of land area planted to transgenic crops by country
 
2003 – total global land area planted: 167 million acres
http://www.
colostate
.
edu
/programs/
lifesciences
/
TransgenicCrops
/current.html#crops
 


Soybean
62%
Maize
21%
Cotton
12%
Canola
5%
Squash
0%
Papaya
0%
Relative percent of transgenic cultivars by crop, 2002
http://www.isaaa.org/kc/Publications/pdfs/isaaabriefs/Briefs%2027.pdf


Traits Used for GE Crops: 
Crop Quality
Ripening gene modifications
Pharmaceuticals and Vaccines


Traits Used for GE Crops: Crop Quality
Ripening gene modifications
Pharmaceuticals and Vaccines
 
Vitamin A enhancement of rice
Additional gluten genes
Oil composition
Essential oils/flavors


GE Crops: Risks and Problems
Consumer acceptance

Safety/allergenicity (Perceived and actual) 

Naturalness


GE Crops: Risks and Problems
Consumer acceptance
Poor Utilization

Traits are expensive – the cost of technology as 
described in essay

Tendency to overuse


GE Crops: Risks and Problems
Consumer acceptance
Naturalness
Poor Utilization
Weediness

Weediness of crop

Escape of genes


GE Crops: Risks and Problems
Consumer acceptance
Naturalness
Poor Utilization
Weediness
Safety/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?