4th Biomass-Asia Workshop Nov. 21, 2007
Improving drought and salt stress tolerance
in plants by gene transfer
*Yasunari Fujita (JIRCAS, JAPAN)
Kazuko Yamaguchi-Shinozaki (JIRCAS/Univ. Tokyo, JAPAN)
Kazuo Shinozaki (RIKEN, JAPAN)
Environmental degradation and
climatic change around the world
Explosive increase
of population
In developing
countries
Progress in
genetic engineering
Development of crop plants
tolerant to environmental
stresses such as drought,
salt loading and freezing
Plant response to environmental stresses
Drought
Temperature
stress
environmental
stress Plant Cell
Signal Perception
Signal Transduction
Gene Expression
High salinity
Stress Response
and Tolerance
Strategies to engineer environmental stress tolerance
in plants
Promoters
control gene expression under
environmental stress conditions
Promoter
Gene
Genes
function in tolerance
to environmental stresses
Promoter
Gene
Transgenic techniques
for various crops
to introduce useful genes
Arabidopsis thaliana as a model plant
Good for genetic analysis (2n).
Small plants easily grown.
Short life cycle (6-8 weeks).
Smallest genome in plant kingdom
(1.2 X 108 bp, 5 chromosomes).
Gene number is about 26,000.
Genome sequence was determined
in 2000.
Arabidopsis resource centers
supply mutants and DNA libraries.
Efficient transformation for
functional analysis of genes.
Functions of water-stress-inducible gene products
Water channel
protein
Transcription factors
(MYB, MYC, DREB, AREB)
Detxification enzymes
Protection factors of
Macromolecules
(LEA protein)
Key enzymes for
Osmolyte biosynthesis
(proline, sugar)
Protein kinases
(CDPK, MAPK)
Water stress
Phospholipid metabolism
(PLC, PIP5K)
ABA biosynthetic
enzyme
Detoxication
enzyme
DREB1A gene regulates a lot of target genes
to enhance tolerance to environmental stresses
Environmental Stress
Drought and High salinity
Signal Perception
Signal Perception
DREB1A
Tolerance
gene
expression
Tolerance
gene
expression
Overexpression of
DREB1A
Tolerance
gene
expression
Tolerance
gene
expression
DREB1A
Tolerance
gene
expression
Tolerance
gene
expression
Expression of more than 40 genes Enhanced expression of more than 40 genes
Environmental stress tolerance
Enhanced stress tolerance
Combinations of promoters and transcription factors
①
Constitutive promoter (35S) ＋ DREB1A
Constitutive promoter
DREB1A gene
The constitutive promoter leads
to generate DREB1A products all the time
②
Stress-inducible promoter (RD29A) ＋ DREB1A
Stress-inducible promoter
DREB1A gene
The stress-inducible promoter leads
to generate DREB1A products only under stress conditions
Transgenic Arabidopsis plants overexpressing DREB1 plants
display enhanced tolerance to dorught and salt stresses
No treatment
drought
high salinity
65.0%
76.7%
42.8%
16.7%
Stress-inducible
promoter (RD29A)
＋
DREB1
Constitutive
promoter (35S)
＋
DREB1
Wild type
0.0%
13.8%
Stress-inducible promoter is useful to generate
DREB1A products without affecting plant growth
Normal growth condition
ON
Constitutive promoter
DREB1A gene
Negative effect
on plat growth
stress condition
ON
Normal growth condition
OFF
Stress-inducible promoter
DREB1A gene
stress condition
ON
Non-negative effect
on plant growth
Engineering environmental stress tolerance
Model plants
Agriculturally important crops
Arabidopsis
Legumes
Rice
Developing technologies
Maize
Wheat
Sugarcane
Engineering for stress tolerance in crops
The DREB1A transgenic rice plants display
enhanced tolerance to drought stress
Wild type
DREB1A transgenic rice plants
Drought stress test: Watering was withheld for 9 days, then
rewatering for 13days, before the photograph was taken.
The DREB1A transgenic rice plants display
enhanced tolerance to salt stress
Wild
Type
Transgenic plants
Salt stress test: Treated with 250mM NaCl for 3 days
Public Research
Institute
NIAS
Collaboration for
development of stress
tolerant crops
JIRCAS
Lotus Japonicus
(a model legume)
Company Institute
Central Res. Lab.
Oji Paper Co., Ltd.
Hitachi, Ltd.
Forestry Res. Inst.
Biotechnology
Laboratory
The University Tokyo
rice
NIVTS
eucalypt
Kaisui Chemical
Industry Co., Ltd.
Arabidopsis
rice
petunia
cruciferous cropper
and vegetables
turf
CGIAR
CIMMYT
wheat
maize
IRRI
Indica rice
ICRISAT
groundnut
pigeonpea
CIAT
cassava
Drought stress tolerance of
the transgenic petunia
wt
RD29A:DREB1A
dehydrated
for １４days
Yoshiba et al. unpublished
Drought stress tolerance of the transgenic wheat
RD29A:DREB1A
wt
RD29A:DREB1A
wt
Pellegrineschi et al. genome 2004
Improving stress tolerance by gene transfer
Exploring appropriate
promoters
promoter
Exploring appropriate
stress-tolerance gene
Select best
combination for
sugarcane
Stress-tolerance gene
Making transgenic sugarcane
Laboratory test
Improving stress tolerance by
gene transfer
Drought and salt
stress
Field test to evaluate
stress tolerance and yield
Useful transcription factors to improve
stress tolerance
Wounding
Pathogen infection
Drought, Salinity
High temperature Low temperature
Transcription
factors
ciselements
Expression of stress-responsive genes
Stress tolerance