adaptation of sat crops to water limitation and climate change
TRANSCRIPT
Adaptation of SAT crops
To water limitation
And climate change
Vincent Vadez – Jana Kholova
ICRISAT
CSSA – ASA – SSSA meeting – Long Beach 2-5 Nov 2014
Today’s presentation
Basic considerations on CC / Drought
Transpiration response to VPD
Possible mechanisms
Aquaporin gene expression
Modelling effects on yield
Maximum temperature in the SAT
HypotheticTemperature
threshold
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
5
10
15
20
25
30
35
40
45
1983-HQ 1992-HQ
2001-HQ 2012-HQ
1983-ISC 1990-ISC
1998-ISC
Max
imum
T°C
Headquarter
Sahelian Center
T°C rarely crosses critical limits for SAT crops
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
1
2
3
4
5
6
7
8
Max
imum
VPD
Sahelian Center
Headquarter
Vapor pressure deficit (VPD) in the SAT
Prevalent high VPD Effect on plant water balance
VPDthreshold
21 28 35 42 49 56 63 70 77 84 91 980
1
2
3
4
5
6
7
8
9
Days after sowing
Wat
er u
sed
(kg
pl-1
)Water extraction at key times
Less water extraction at vegetative stage, more for grain filling
Zaman-Allah et al 2011See Borrell et al 2014See Vadez et al 2013
SensitiveTolerant
Trait dissectionVegetative Reprod/ Grain fill
ConductanceCanopy area
Terminal drought sensitive
Terminal drought tolerant
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.50 1.00 1.50 2.00 2.50 3.00 3.50
VPD (kPa)
H77/2 833-2PRLT-2/89-33
Tran
spir
atio
n (g
cm
-2 h
-1)
From Kholova et al 2010b
2 mechanisms of water saving: • Low Tr at low VPD• Further restriction of Tr at high VPD
Transpiration response to high VPD – Pearl millet
Transpiration response to high VPD - Peanut
Mouride
If VPD < 2.09, TR = 0.0083 (VPD) – 0.002 If VPD ≥ 2.09, TR = 0.0013 (VPD) + 0.015 R² = 0.97
B UC-CB46
TR = 0.0119 (VPD) - 0.0016 R² = 0.97
D
Transpiration response to VPD - cowpea
Tolerant lines have a breakpoint (water saving)
Tolerant Sensitive
Belko et al – 2012 (Plant Biology)
Staygreen ILs (Stg3 – Stg B) are VPD-sensitive
9 11 13 15 170.0000
0.0020
0.0040
0.0060
0.0080
0.0100
0.0120
stg1stg3stg4stgB
Time of the day (h)
Tran
spira
tion
(g
cm-2
h-1
)Recurrent R16
Stg3StgB
Transpiration response to VPD in Sorghum1 - Introgression lines
0.62 1.05 1.58 2.01 2.43 3.05 3.450.000
0.002
0.004
0.006
0.008
0.010
0.012
VPD (kPa)
Tran
spira
tion
(g p
l-1 cm
-2)
VPD-insensitive
VPD-sensitive
Transpiration response to VPD in Sorghum2 - Germplasm
2.0
3.0
4.0
5.0
6.0
7.0
152 Germplasm tested
TE
10 lowest TE are all VPD-Insensitive
10 highest TE are all VPD-sensitive
High TE lines limit transpiration at high VPD
Why are VPD-sensitive sorghum so interesting?
Vapor Pressure Deficit (VPD, in kPa)
Tran
spira
tion
rate
(g c
m-2 h
-1)
0.0 2.0 4.0
0.0
1.0
A – Insensitive to VPD – High rate at low VPD
B – Sensitive to VPD – High rate at low VPD
C – Sensitive to VPD – Low rate at low VPD
D – Insensitive to VPD – Low rate at low/high VPD
Main types of Tr response to VPD
Water use difference
Leaf conductance differences = waterVadez et al 2013 – FPB in press
4 replications
RH & T hourly recording
Weighing:7-11am = low VPD11am-15pm = high VPD
8” pots re-saturated every daysoil evaporation minimized with plastic beads
How to phenotype at large scale?
Capacity: 4,800 plotsThroughput: 2,400 plots/hour
Traits: LA, Height, Leaf angle, …
LeasyScan at ICRISAT
Leaf canopy area and conductance
Canopy Scanning
+ plant transpiration
= live water budget
Leaf canopy conductanceLoad Cells
Possible mechanisms??
???Hydraulic
Possibly located in the roots
Apoplastic Pathway
(Structural)
Symplastic Pathway
(AQP)
Water pathways in the root cylinder
Two pathways have different hydraulic conductance
Hypothesis: Aquaporin control plant water loss ?
????
Apoplastic path inhibition: H-Ferrocyanide +CuSO4Symplast path inhibition: AgNO3,
Follow-up of transpiration before/after inhibition
0
0.2
0.4
0.6
0.8
1
1.2Apoplast & symplast inhibition at low
VPD
Time
Nor
mal
ized
tra
nspi
rati
on
Apoplastic & Symplastic inhibi-
tion
Symplasticinhibition
Apoplasticinhibition
Apoplastic transport predominant
Low VPD small differences/effects
VPD-sensitive
VPD - insensitive
VPD - insensitive
0
0.2
0.4
0.6
0.8
1
1.2
Time(mins)
Nor
mal
ized
tran
spir
atio
nApoplast & symplast inhibition at high VPD
Symplasticinhibition
Apoplasticinhibition
Apoplastic transport less predominant
High VPD larger differences/effects
VPD-sensitive
VPD-insensitive
VPD-sensitive
Any difference in aquaporin expressionIn sorghum contrasting for VPD response??
0.62 1.05 1.58 2.01 2.43 3.05 3.450.000
0.002
0.004
0.006
0.008
0.010
0.012
0.014
0.016
0.018
VPD (kPa)
Tran
spir
atio
n (g
pl-1
cm
-2)
Low TE High TE Low TE High TE0
2
4
6
8
10
12
14
16
18 PIP1;1PIP1;2PIP1;3PIP1;4PIP2;1PIP2;2PIP2;4PIP2;5PIP2;6PIP2;7PIP2;8PIP2;9PIP2;10
Hig
h VP
D/L
ow V
PD
PIP relative expression (High VPD/Low VPD)
VPD – insensitive line increases expression of PIP2
PIP2;6
PIP2;9
PIP2;7
VPD-Insensitive VPD-Sensitive
grain yield gain (low TR)
-300
-200
-100
0
100
200
300
400
0 500 1000 1500 2000 2500 3000 3500
original yield (kg/ha)
yiel
d ga
in (k
g/ha
)
1 postflowering
2 flowering
3 postflowering-relieved
4 no stress
5 prefloweringOriginal yield (kg ha-1)
0
Yield increase (kg/ha) with transpiration sensitivity to high VPD: Rabi sorghum
Yiel
d in
crea
se
-1 0 +33
Crop modelling used to predict trait effects
15-30% yield increase at high latitudes
% yield increase with transpiration sensitivity to high VPD: Peanut
Lysimetric evaluation
Transpiration in pots
0.62 1.05 1.58 2.01 2.43 3.05 3.450.000
0.004
0.008
0.012
0.016
0.020
Low TEHigh TE
VPD
Tran
spira
tion
(g c
m-2
h-1
)
Low TE High TE01234567
TE
grain yield gain (low TR)
-300
-200
-100
0
100
200
300
400
0 500 1000 1500 2000 2500 3000 3500
original yield (kg/ha)
yiel
d ga
in (k
g/ha
)
1 postflowering
2 flowering
3 postflowering-relieved
4 no stress
5 preflowering
Original yield (kg ha-1)
0
AQP gene expression
Modeling of Tr restriction effect on yield
The VPD response lead to higher TE
It is itself related to differences in AQP gene expression
Major yield increase possible across crops
Breeding (donors identified)
Harness genetics – Phenotyping (new platform)
In Summary…
Thank you
Collaborators:F. Chaumont (Univ. Louvain)G. Hammer / A. Borrell / G McLean /
E van Oosterom (Univ. Queensland)B Sine / N Belko / Ndiaga Cisse (CERAAS)C Messina (Pioneer)
Donors:B&MG FoundationGCPACIARDFIDICRISAT
Technicians / Data analyst:Srikanth MalayeeRekha BadhamM AnjaiahN Pentaiah
Students:M TharanyaS SakthiT Rajini
Colleagues:KK Sharma / T Shah / F HamidouHD Upadhyaya / R Srivastava / Bhasker RajSP Deshpande / PM Gaur