A Genetic-Mitigation Strategy GV Subbarao
Transcript of A Genetic-Mitigation Strategy GV Subbarao
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Biological Nitrification Inhibition (BNI)-Technology Tackling Agricultural Greenhouse Gas Emissions
GV SubbaraoJIRCAS, Japan
Collaborators & PartnersCIAT
CIMMYTICRISAT
CCAF
A Genetic-Mitigation Strategy
BNIBiological Nitr i fication Inhibi t ion
Global GHG emissions Monetization of climate effects using “the best available science and economics”
*49 Gt of CO2 eq.yr-12004 data; Nature 2011
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
1 Gt = 1 billion tonsIWG = Interagency Working Group on Social cost of GHGCost of global damage from GHG is
$50 t-1 CO2**based on IWG recent estimate (Science 2017, 357:655)
Cost of Global damage from GHG emissions estimated at
$US 2450 billion y-1 ($US 2.45 trillion y-1)
BNIBiological Nitr i fication Inhibi t ion
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
A major portion (80%) of agricultural GHG emissions are associated with
Production and Use of N-fertilizers(based on life-cycle analysis, which is energy and carbon intensive)
Agriculture alone is responsible for 14 Gt CO2.eq.y-1About 24% of total GHG emissions
The social cost of 14 Gt of GHG emissions from agriculture is
$US 700 billion y-1
BNIBiological Nitr i fication Inhibi t ion
Why NUE is <30% in most agricultural systems?Uncontrolled rapid nitrification in
agricultural soils
Global food production has doubled from 1960 – 2000Nitrogen fertilizer consumption increased 10-fold
Nearly 70% of the N fertilizer applied is lost to the environment
Amounts to a direct annual economic loss of
US$ 90 billion*[*based on - a) world annual N fertilizer production is 150 million Mg; b) 0.45 US$ kg-1 urea]
Nitrogen fertilizer consumption worldwide in 2010
>120 Tg (million metric tons)
Energy cost of nitrogen fertilizer – 1.8 to 2 L diesel oil per kg N fertilizer
1.70 billion barrels of diesel oil (energy equivalent) is needed to produce this nitrogen
fertilizer
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, JapanBNIBiological Nitr i fication Inhibi t ion
Tillman et al. 2011PNAS 108:20260-20264
Based on Khalil and Rasmussen 1988Annals of Glaceology 10:73-79
N-fertilizer usage to
reach 250 Tg yr-1
N2O emissions
double from 2011 levels
Soil
OMOrganic N
NH4+
Microbial
N NO3-
>95% of the total soil inorganic N pool
Plant N uptake & Assimilation
Mineralization
Nitrification
Inorganic
N
Crop Residues
NFertilizer
Intensification of agricultural practices led to acceleration of nitrification in modern production
systems BNIBiological Nitr i fication Inhibi t ion
Nitrification(NH4….NO3
-)Nitrosomonas
ArchaeaNitrobacter
Aerobic process
Denitrification(NO3
-….N2)>15 groups of bacteria and fungi use NO3- as
source of energy Anaerobic process
N2ONO
Nitrification and denitrificationare the primary drivers for generation of
N2O>80% of global N2O
emissions is generated from Farming
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
How to achieve low-nitrifying agricultural soils?
Switch to low-nitrifying agricultural systems
BNIBiological Nitr i fication Inhibi t ion
BNI Concept
Ammonium(NH4
+)Nitrite(NO2
-)
Nitrate(NO3
-)Ammonia-oxidizing Bacteria Nitrite-oxidizing BacteriaBL
BL
BL BL
Microbial-N
Imm
obili
zatio
n
Min
eral
izat
ion
Nitrate leaching
Denitrification
N2O, NO and N2
N lost from agricultural system
N lost from agricultural system
Concept of Biological Nitrification Inhibition (BNI)
BNI-Mitigation Technology?
BNIBiological Nitr i fication Inhibi t ion
A Genetic-Mitigation Strategy
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Characterization of BNI function
Strength of BNIs production in crops/pasturesGenetic variability in BNI-traitChemical-identity of BNIsHow stable are BNIs?Soil conditions influence on BNIs functioningBNI concentration required in soil to be effectiveEffectiveness in tropics vs temperature environsRegulatory mechanisms for BNI release Mode of inhibitory actionNegative effects on soil microbial community
How to engineer a plant function into
Technology & Research Strategy
BNIBiological Nitr i fication Inhibi t ion
BNI activity added to the soil (AT g-1 soil)
0 5 10 15 20 25
NO
3 co
ncen
trat
ion
in so
il (p
pm)
0
50
100
150
200
250
Threshold
Releases about 200 to 400 ATU hydrophilic BNI d-1
55 d soil incubation
50% inhibition
90% inhibition
BNIBiological Nitr i fication Inhibi t ion
Release ratesStability
ED50Determines
Effectiveness of BNI function in the fieldBNIs can provide stable inhibitory effect on soil nitrification
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Methyl p-coumarate Methyl ferulate
Methyl 3-(4-hydroxyphenyl)propionate
Root exudate
Root exudate
Root exudate
Root exudate
Root tissue Root tissue
Root tissue Root tissue
Sorgoleone
Sakuranetin
Brachialactone
Linoleic acidα-linoleic acid
BNIs isolated from sorghum BNIs isolated from B. humidicola
Plants produce a cocktail of BNIs to suppress nitrifying bacteriaNitrosomonas
BNIBiological Nitr i fication Inhibi t ion
AMO blocker
AMO & HAO blockerET disruptor
AMO & HAO blocker
AMO blocker
AMO & HAO blocker
How much BNI-activity is released from root systems of B. humidicola?An assessment
• Active root biomass in a long-term BH pasture being 1.5 Mg ha-1 •(Root mass up to 9.0 Mg ha-1 has been reported in BH pastures)
• BNI release rates can be 17 to 50 ATU g-1 root dry wt. d-1
• Estimated BNI activity release d-1 could be 2.6 x 106 to 7.5 x 106 ATU(CIAT 679) (CIAT 26159)
•1 ATU being equal to 0.6 µg of nitrapyrin
• This amounts to an inhibitory potential equivalent to the application of 6.2 to 18 kg of nitrapyrin application ha-1 yr-1
Does it work in the field?
BNIMitigation Technology
B. humidicola roots can release 2.6 to 7.5 million BNI activity d-1 ha-1
BNIBiological Nitr i fication Inhibi t ion
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Can we breed for high-BNI capacity in food- and -feed crops?Developing low-nitrifying and low-N2O emitting systems
Cumulative N2O emissions (mg of N2O N per m2 per year) from field plots of tropical pasture grasses (monitored monthly over a 3-year period, from September 2004 to November 2007)
Subbarao G V et al. PNAS 2009;106:17302-17307©2009 by National Academy of Sciences
Brachiaria pastures suppressed N2O emissions from the fieldCan BNI function in plants be exploited to develop low-N2O emitting systems then?
BNI capacity in root systems – Field plots
No BNIcapacity
Highest BNIcapacity
BNI-Mitigation Technology
BNIBiological Nitr i fication Inhibi t ion
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Nitrogen excreted (from urine) from grazing animals from managed grasslands (9 million km2) is estimated at
>120 Tg N y-1
1800 million livestock units; 182 to 392 g N excreted per animal d-1
Equal to synthetic Nitrogen fertilizer to global agricultural systemsSource: Saggar et al. 2005
Can BNI-enabled pastures help reducing N2O emissions from these grazing systems?
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Sorghum-BNI characterization at a field site in ICRISAT, India
JIRCAS-ICRISAT Collaboration
Hydrophilic BNIs released from sorghum roots
Developing BNI-enabled crop/pasture varieties?
Mini-core Sorghum germplasm lines
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Sorg
oleo
ne re
leas
ed (µ
g pl
ant-1
)
0
20
40
60
80
100
120
Sorgoleone phenotyping of mini-core sorghum germplasm (231 lines) - 2015
Highest sorgoleone producing germplasm
Germplasm lineCollected from Niger, WA
PVK 801
296-B
BNIBiological Nitr i fication Inhibi t ion
Breeding for high-sorgoleone producting sorghum cultivars - Feasible?
Sorgoleone-capacity in elite-breeding lines
00.20.40.60.8
11.21.41.61.8
2
200N 200N+Sorgoleone 200N+DCD
N2O
em
issi
on (u
g N
2O-N
)
Treatments
Integrated N2O emissiona
b
c
-8
-3
2
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17
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27
32
37
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44
N2O
em
issi
on (n
g N
2O-N
(g d
ry so
il)-1
hr
-1 m
-2)
Days of incubation
N2O emission
200N
200N+Sorgoleone
200N+DCD
Sorgoleone additions to the soil suppressed N2O emissions
BNI-Mitigation Technology
High-sorgoleone producing genetic stocks suppress N2O emissions better than low-sorgoleone producing genetic stocks?
BNIBiological Nitr i fication Inhibi t ion
High sorgoleone producing sorghum genetic stocks have low N2O emissions?
Sorghum germplasm linesIS 32087 IS 20762
Sorg
oleo
ne p
rodu
ctio
n (
g pl
ant-1
)
0
20
40
60
80
100
120
140
IS 32087 IS 20762
Germplasm line collected from
Yemen
Germplasm line collected from
USA
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
Control DCD IS 32087 IS 20762
N2O
em
issi
on (µ
g N2O
-N m
-2 h-1
)
Treatment
Effect of sorghum genetic stocks on total N2O emission from incubated soil
IS 32087 IS 20762
High-sorgoleone germplasm line has 50% lower N2O emissions compared to
low-sorgoleone producing germplasm
O
O
OH
O
Breeding for high-sorgoleone production could a proxy to develop low-N2O emitting sorghum cultivars?
Nobeoka Chinese Spring
L. racemosus
Wild-wheat has high-BNI capacity
Leymus racemosus
Leymus does not release BNI when grown with NO3
--N where pH of RE-collection solution will be of >6.0
RE collection
pH 4.0
RE collection
pH 7.5
JIRCAS-CIMMYT partnership
BNIBiological Nitr i fication Inhibi t ion
BNI-Mitigation Technology
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Benefits from Genetic-Mitigation using BNI-Technology
Cost effective and Scalable Delivery of BNIs - precise and effective Cocktail of inhibitors from BNIs – more stable effect No negative environmental consequencesNo health issues on food or feed qualityImprove soil-N-retention and fertility
BNIBiological Nitr i fication Inhibi t ion
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Portfolio of current technologies to reduce nitrification and N2O emissions
Synthetic nitrification inhibitorsUrease inhibitorsSlow-release nitrogen fertilizersPolythene-coated nitrogen fertilizersSplit-Nitrogen applicationsPrecision farming – ‘Green-seeker’ technologyAWD (alternate wetting and drying) for paddy rice systems
BNI-technology could become part of portfolio of technologies to address GHG emissions from agriculture
BNIBiological Nitr i fication Inhibi t ion
JIRCAS-NARO International Symposium on Agricultural Greenhouse Gas Mitigation,
31st August 2017, Tsukuba, Japan
Developing novel Mitigation-technologies critical to reduce GHG emissions from agriculture
With substantial mitigation
Withoutadditionalmitigation
Change in average surface temperature (1986–2005 to 2081–2100)
Source: IPCC AR5 synthesis report BNIBiological Nitr i fication Inhibi t ion
Paris Climate Agreement signed in 2015 calls to hold the global average temperature to <2C above preindustrial levels by for 80% reduction in GHG
emissions from current levels by 2050
“ . . . holding the increase in the global average temperature to well below 2 °C above preindustrial levels and pursuing efforts to limit the temperature increase to 1.5 °C”
Paris-Climate Agreement Signed in 2015
Funding support for BNI ResearchMAFF
MOFA – CGIAR CollaboratorsCRP-WHEAT
JIRCAS-President’s special grantsJSPS Research Grants
The smart way to address climate change is through
Innovation
Reducing GHG emissions from Agriculture reduces N-pollution, N-fertilizer consumption, improve soil fertility and sustainability of production systems
Low N2O emission systems are a ‘WIN WIN’ situation for both environment and for Agriculture
Energy Production and Transport SectorsSolar-electricity, Hybrid Cars, Electric cars are some of the GHG reducing technologies
emerged recently
BNIBiological Nitr i fication Inhibi t ion
Arctic is melting fastTime for action
from Agricultural Scientific Community
JIRCAS
BNIBiological Nitr i fication Inhibi t ion
Thank You for the attention
Huge waterfall spouting from the ice edge of Brasvell Glacier – Getty image