Presentation at the November 2012 dialogue workshop of the Biosciences for Farming in Africa media fellowship programme in Arusha, Tanzania.
Please see www.b4fa.org for more information
2. Map of the world showing the major centres of origin
of crops, which are distributed mainly in tropical
regions
3. Plant Improvement using Breeding and Selection
- HISTORICAL PERSPECTIVE 8000 BC (5 million people)
Domestication of cereals and Pulses
2000 BC (50 million people)
Domestication of rice, Potato, Oats,
Soybean, Grape, Cotton, Banana.
1583 (500 million people)
Sexuality in plants Described
1742
First Company (Vilmorin) Devoted to Plant
Breeding and New varieties
1799
First Cereal Hybrid Described
1927
X-Rays Used for Mutation Breeding
1983 (5 billion people)
First Use of Gene Technology for Plants
2012 (7 billion people)
160 plus million hectares of GM Crops
grown in 29 Countries by 16 million farmers
4. The evolution of maize (corn)
Domestication
The adaptation
to Europe
Extension of corn
crop
areas
years
The wild
ancestor
Teosinte
First corns
America
Mexico
Populations
South of Europe
Introduction
Hybrids
First creation of
hybrids in France
SOURCE: GNIS (Groupement National Interprofessionnel des Semences)
5. Genetic modification arose as a consequence
of cultivation and selection of the best plants
Planting seeds from
“good” plants increased
their representation in
subsequent generations
Natural
variation
within
population
Image courtesy of University of California Museum of Paleontology, Understanding Evolution - www.evolution.berkeley.edu
6. F1 Hybrid Seed Production in
self-pollinating crop species –
a basis for crop improvement and
the development of heterosis or
hybrid vigour
F1 hybrid seed production in a range of major crops
including Maize, Rice, Sorghum, Sunflower, Sugar Beet,
Carrot, Onions, Brassica’s etc
7. F1 Hybrid Seed Production in Maize
Pollen - male parent
Female parent
Tassel removed
F1 Hybrid
X
Ear
Inbred Parental Corn
Lines
Hybrid Vigour
10. Selection and Plant Breeding was Applied to a
Range of Important Crops we Grow Today
Teosinte
Rice
Corn
Tomato
The Creation of Corn
The corn that Columbus received was
created by the Native Americans some
8,000 years ago by domestication of a
wild plant called teosinte. They used
‘genetic engineering’ in a quite remarkable
way to produce a more productive variety.
12. Sustainable food security is facing a major bottleneck
•
•
•
•
•
•
Since the beginning of agriculture, humans have cultivated 7,000 plant species
Since the beginning of agriculture, humans have cultivated 7,000 plant species
Today only 150 plant species (2%) are agriculturally relevant for food and clothing
Today only 150 plant species (2%) are agriculturally relevant for food and clothing
Only 10 plant species are cultivated today to provide 95% of food and feed
Only 10 plant species are cultivated today to provide 95% of food and feed
Cultivated today
95% of food and feed
Total cultivated since
the beginning of agriculture
14. The top four – Global yield
(UN-FAO Statistics)
Soybean
Wheat
2nd
4th
Maize
Rice
1st
3rd
15. The myth of natural food
The food we eat comes from
plants already extensively
modified from their original
form. Even heritage varieties are
extensively genetically modified.
Credit: Nicolle Rager Fuller, National Science Foundation
16. What traits/characteristics are
selected by plant breeders?
•
•
•
•
•
•
•
•
•
•
•
Improved Nutrition
Improved Yield
Improved Rate of growth
Self-pollinating
Reduced pod shatter
Able to harvest & store the fruit
Palatability
Better Taste
Reduced toxins
Reduced / negligible dormancy requirement
Disease resistance
THESE TRAITS ARE ENCODED BY GENE(S)
18. There are 25-40,000 genes found in the nucleus
of each plant cell depending on the species
DNA APPEARS BLUE
CSIRO.
Introduction to
19. A gene is a code for a protein
Ca.25000 GENES
CSIRO. A
plant Gene
20. The set of genes is the master plan which
contains all the information to make a plant
What is a gene?
Control
Switch
Code for
Protein
Downstream
control region
DNA
Start
RNA
Protein
Enzymes
Stop
21. Genes provide the foundation of new
plants/products for farmers
Genes
Protein
Yield?
Tolerance to
drought?
Flowering time?
Trait
Nutrition
Taste?
Tolerance to Pests
and Diseases
Product
23. Advanced Genomics Will Accelerate
Discovery of Genes of Use to Farmers
Gene
sequence
Genome Gene
DNA
map
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GENE
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Gene
expression
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SEQUENCE FUNCTION
Plant
traits
Yield
Drought
Disease
Stress
Stress
Oil quality
Disease
Yield
Maturity
Herbicide
tolerance
TRAIT
24. Finding the needle in a haystackplant gene discovery
If selective breeding and genetic
modification are based on genes,
how does one go about finding
the genes of interest?
25. The Challenge: Finding the genes that provide the foundation of new
traits and crop improvements for farmers
A Central Role for Omics, BioInformatics and Systems Biology
Technology
Platforms
Bioinformatics
Modelling physiology
0
Transcriptomics
Metabolomics
Proteomics
leaf 2
s te
m
leaf 3
f1
Process
Grain filling
lea
Genome Sequencing
Molecular profiling
Time post anthesis
PhenomicsTRAIT ANALYSIS
26. Building Increased Productivity and
Sustainability into the Seed by
Plant Breeding and Biotechnology
The scientific basis of all crop improvement is
identification of the genes that encode and
regulate specific phenotypic characteristics or
traits of use to the farmer:
Genetic modification by marker assisted
breeding (MAB) and GM technology where
appropriate:
27. NEW TOOLS FOR CROP
IMPROVEMENT
Elite
Germplasm
Gene
Sequencing
r
ula g
c
ole edin
M re
B
Marker Assisted
BREEDING
Seeds
Better
Varieties,
Faster
Seed
Production
GENOMICS
Functional
Genomics
Finding the
Genes
Ge
ne
s
Trait
Development
PLANT
BIOTECH
Plant
Transformation
Traits
New Traits
of
Use to the
Farmer
29. What is Genetic Modification?
Genetic modification is the addition, alteration or removal of
genetic material, usually single genes, in order to alter an
organism’s characteristics.
Living organisms contain 5,000-30,000 genes arranged in linear
order in chromosomes which are long strands of DNA.
Genes are heritable segments of DNA that contain the code
for an individual protein molecule.
Nucleus
ca.25,000
Genes
Chloroplasts
ca.80 Genes
Mitochondria
ca.60 Genes
Genetic Information in a Plant Cell
30. A quick reminder
Conventional breeding
During conventional breeding,
genes are always mixed and newly
assorted. This often results in nondesired traits of elite crop
varieties.The desired
improvement is obtained by many
years of selection in the field.
Elite variety
Breeding line
New variety
=
X
(Cross)
Favorite gene
Favorite gene
Non-desired gene
Gene technology
Using gene technology, it is
possible to transfer only a
favorite/desired gene into an
elite crop variety. All other
traits of the the elite crop
variety will be preserved.
Favorite gene
Elite variety
New variety
=
(Gene transfer)
Favorite Gene
31. Gene Transfer by Classical Plant Breeding
25,000 genes
25,000 genes
Selection
S = gene for susceptibility to pest
R = gene for resistance to pest
R=gene for resistance
The backcrossing programme
(BC) can take 8 to 10 years
Single gene
32. S = gene for susceptibility to
pest
25,000 genes
R=gene for resistance
Single gene
25,000 genes
R = gene for resistance to pest
Repeated
Backcrossing
and selection for
desired traits
33. Genetic modification is the addition, alteration or removal of genetic
material usually single genes, in order to alter an organism’s
characteristics. The genes can be from any donor organisms
Microorganisms
Plants
DNA
Animals
Man
Approximately
30% of animal,
plant and fungus
genes are similar
A large percent of our
genes are the same as
those of simple organisms
such as bacteria and
viruses
34. REASONS FOR UNDERTAKING ANY
GENETIC MODIFICATION
1 To improve the efficiency of a specific metabolic pathway so as
to improve the “efficiency” of the plant as a whole in terms
of its yield, nutritional quality or agronomic
characteristics(eg height, seed size)
2 To bypass some limiting such as intolerance to heat or
cold,drought,flooding, or to improve resistance to pests and
diseases
3 To change the nature of the harvested product – as a human
foodstuff; to provide a product of therapeutic value; to provide
industrial feed-stocks (e.g. the production of biodegradable
polymers) and biofuels.
35. Conventional Plant Breeding has been very successful but yield gains
are now slowing. The new molecular technologies allow more precise
and rapid crop improvement by marker assisted selection breeding
and GM approaches. This requires the identification of the gene(s)
that underlie the traits and then combination with native traits using
molecular markers and/or GM to improve the crop– these include:
•Avoidance of losses from pests-insects,bacteria,fungi,viruses
•More effective water use-drought tolerance
•Increased tolerance towards temperature stress
•Increased yield
•Time to maturity – shortened growing season
•Growth on marginal soils-salinity, pH, metal toxicity
•More effective fertiliser use-nutrient(NPK) use efficiency
•Increased flooding tolerance
•Competing with weeds
•Improved nutritional quality-biofortification (eg.Vitamins,Iron)
•Sustainable production with a low carbon footprint
36. Specificity of Genetic Modification
Identification and isolation of specific genes with
defined function
Insertion of specific genes into a crop species to
promote desirable characters
GM progeny can be selected for the product or
activity of specific genes with a defined function
There are no “surprises” from unknown genes
transferred along with the planned cross
37. The scientific basis of all crop improvement is identification of the
genes that encode and regulate specific phenotypic characteristics or
traits of use to the farmer.
REDUCED STRESSES
Biotic and Abiotic
• Drought or
• Pests and
Flooding
Diseases
• High or low
• Weeds
Temperature
• Saline or
. Phyto-remediation
acid soils
. Increased
greenhouse
gases- Tolerance
to climate change
IMPROVED NUTRITION
AND HEALTH
IMPROVED PLANT
PERFORMANCE
MORE
SUSTAINABLE
PRODUCTION
Environment
• Nutrient use efficiency
• Water use efficiency
• Control of flowering
• Plant architecture
• Heterosis
• Yield
Plant Gene
Technology
NEW
INDUSTRIES
Quality Traits
• Vitamins & Minerals
• Biofortification
• Post harvest quality
• Taste
• Proteins
• Oils and Fats
• Carbohydrates
• Fibre & Digestible
energy
• Bloat Safety
CHEMICAL
FEEDSTOCKS
• Biodegradable
Plastics
• Biofuels
PHARMACEUTICALS
• Vaccines
• Antibodies
• Diagnostics
39. The steps involved in genetic modification
Identify the gene
an interesting gene
from a donor organism
Isolate
the interesting gene
Insert
the gene in a
genetic construction
Multiply
the genetic
construction
(bacteria,
plant ...)
Transfer the gene
Evaluate
Plant
regeneration
gene
expression
Add to other
varieties
by crosses
Selection of transformed cells
SOURCE: GNIS (Groupement National Interprofessionnel des Semences)
40. Gene Isolation by
standard techniques
of molecular biology
The first step is to isolate DNA
like you did yesterday.Then cut
the DNA into gene size pieces
with
special enzymes and identify the
genes and what they do. The trait
or characteristic which they
contain the information for.
41. Getting genes into plants
Tissue Fragment
of target
plant
THE GENE
TRANSFERRED DNA
CELL DIVISION
CELLS REGENERATE
INTO PLANTLETS
Selection of
Transgenic Cell
Transfer
to Soil
PLANTS WITH
NEW TRAIT
44. Nature’s original genetic engineer
Gall
formation
Agrobacterium
Crown Gall
The soil bacterium Agrobacterium is able to infect plants
and make them produce the food it needs to live on. The
bacterium does this by inserting a small piece of its own
DNA into the genome (DNA) of the plant. Scientist have
modified this naturally occur process to make genetically
modified plants.
45. Agrobacterium-mediated plant transformation
Agrobacteria
containing
recombinant Ti plasmid are
multiplied in liquid culture
Cocultivation:
Agrobacterium
culture is added to callus culture
(e.g. rice) in Petri dish. Agrobacteria
infect the callus cells. T-DNA
excises from the Ti plasmid and
integrates into chromosomal DNA
in the nucleus of the callus cell.
In planta transformation: Flowering Arabidopsis is
inverted so that flowers dip into the Agrobacterium
culture in a bell-jar. Application of vacuum helps
bacterial infiltration. Plants are removed and grown.
Flowers are allowed to self and seeds are germinated in
selection agent so that only transformed seedlings
(about 10% of the total) develop.
Selection: transformed cells
(white) are resistant to
selection agent (herbicide or
antibiotic. Non-transformed
cells (color) eventually die.
46. DNA delivery to plant cells:
Agrobacterium
Agrobacterium
chromosome
Genes for
transfer
T-DNA
Regeneration
Agrobacterium
cell
Plant Cell
48. More recently techniques have been developed in whereby Agrobacterium is vacuum
infiltrated into developing floral buds of a number of different plant species
49. DNA delivery to plant cells: biolistics
DNA coating
of
microscopic
metal
particles
DNA code for RR
Metal particles
DNA
DNA insertion
Plant cell
Particles
are shot
into plant
cells
Transferred
DNA
Transformed
plant cell
Cell division
58. From laboratory to commercialisation
specific gene transfer in the lab. followed by subsequent
testing in the field
this is the only plant breeding technology which requires
regulatory approval (and, in some countries, labelling of all the
food products derived from modified plants):
• testing for food toxicity, nutritional value, composition and allergenicity – includes animal feeding
trials
• characterisation of the transferred gene as well
as its effects on the host genome
•an environmental audit as well
59. A quick reminder
Conventional breeding
During conventional breeding,
genes are always mixed and newly
assorted. This often results in nondesired traits of elite crop
varieties.The desired
improvement is obtained by many
years of selection in the field.
Elite variety
Breeding line
New variety
=
X
(Cross)
Favorite gene
Favorite gene
Non-desired gene
Gene technology
Using gene technology, it is
possible to transfer only a
favorite/desired gene into an
elite crop variety. All other
traits of the the elite crop
variety will be preserved.
Favorite gene
Elite variety
New variety
=
(Gene transfer)
Favorite Gene
60. Why are GM methods used sometimes
and molecular breeding others?
Molecular breeding
1. Desired trait must be
present in population
2. Genetic resources must
be available
3. Plant should be
propagated sexually
GM
1. Gene can come from any
source
2. Genetic resources not
required
3. Plant can be propagated
vegetatively
Photo credits: Gramene.org ETH Life International
61. How have we fared thus far?
Rice genome
Sequenced
Plant
Transformation
1983
1865
Mendel’s Discovery
of Genes
1905
Genetics
1953
Structure of DNA
1001
Arabidopsis
genomes
sequenced
2002 2011
1995 2000
Crop Circles
‘Synteny’
2010
First Plant NGS
Genome
Sequence
62. The science behind gene technology
• A gene is a code for a protein
• We can purify and reconstruct genes
• We can transfer genes to plants to introduce a
useful characteristic, eg insect protection or weed
control
• The resulting plants are thoroughly tested
64. Can Genetic Improvement of Crops
Help Feed the world?
• No single solution will solve this problem but
the new genetic technologies of plant breeding
developed during the last few years can helpthey are but one tool in the toolbox.
• They can can increase agricultural efficiencies
and save people from hunger in a sustainable
manner, particularly in African nations where
the need is greatest. Genomics, markerassisted screening, phenotype analysis,
computer modeling, and genetic modification
(GM) when required, have greatly accelerated
the breeding process.