Post on 05-Feb-2021
Feed the Future Innovation Lab for Collaborative
Research on Grain Legumes
Thermo-tolerance of photosynthesis in legumes: Mapping QTLs for photosynthetic traits in cowpea under heat stress
Presenter: Isaac Osei-BonsuPhD Student
MSU-Department of Plant BiologyPlant Research Laboratory, Kramer Lab. (USA)
CSIR-Crops Research Institute (Ghana)
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Introduction
• Global mean temperatures projected to rise by 0.3 oC – 4.8 oCby the end of 21st century (IPCC 2014).
• World population estimated to reach > 9 billion by 2050• Heat stress tolerant crops would be needed to feed the
population
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Why grain legumes and photosynthesis?
• Photosynthesis is critical for crop productivity – Sensitive to high
temperature (HT)
• Grain legumes– Protein and income– Soil fertility
improvement
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
• Study photosynthesis in different legumes with differing tolerance to heat stress and establish mechanisms of tolerance of these legumes
• Identify natural variation in photosynthesis under heat stress and map loci (QTLs) controlling such traits.
Development of plants with robust photosynthesis under heat stress
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
• Chlorophyll fluorescenceɸII ɸNPQ
ɸNO
– NPQt
qEt qIt
Photosynthetic parameters assayed
SPAD/ Relative Chlorophyll Content
MultispeQ
DEPI
(Photoprotection) (Photo-inhibition)
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Mapping of QTLs for photosynthetic traits under normal and heat stress conditions in cowpea by HTP phenotyping
Germination and seedling establishment(11 days)
Regular reach-in chamber
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
Acclimation + Phenotyping (1+5 days)
DEPI chamber
0
200
400
600
800
1000
1200
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00
Ligh
t int
ensit
y (µ
mol
phot
ons m
-2s-1
)
Time (h)
Parents: CB27 x IT82E-18RIL population size: 87
Treatments:Heat stress: 45/35 °C day/night Control: 30/20 °C
RH: 15-40%
Acclimation temperature: 33/20 °C
Photoperiod: 10 h
Light regime for experiment
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Photosynthetic efficiency (ɸII) under heat stress
Day 1
IT82E-18
CB27
Day 4
Tolerant
Sensitive
Low High
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
QTLs for Photosynthetic efficiency (ɸII) under heat stress and normal growth
conditions
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
ɸII 45/35 ° CDEPI
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
ɸII 30/20 ° CDEPI
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
ɸII 45/35 ° CMultispeQ
ɸII 30/20 ° CMultispeQ
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Possible linkage between SPAD/ Relative Chlorophyll content, photoprotection (qEt) and biomass QTL
SPAD45/35 °C
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
SPAD | 30/20 °C
qEt 45/35 °CBiomassChr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11 Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr1 2 3 4 5 6 7 8 9 10 11
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Correlation between Biomass, chlorophyll content and qEt
0 61.9 0 1.80 1.4
SPAD 45/35 °C Biomass qET (Photoprotection)
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
qEt 45/35 ° C
qIt 45/35 ° C
Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr Chr
1 2 3 4 5 6 7 8 9 10 11
Pod & Seed yield
Photoprotection(qEt) and photo-inhibition (qIt) QTLs may be
controlled by the same locus as
seed yield under heat stress
PVE=12% Source: IT82E-18 (tolerant)
PVE=21% Source: CB27 (tolerant)
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
• QTLs for photosynthetic traits under control and heat stress environments have been identified in cowpea
• QTLs for SPAD and photoprotection (qEt) map to the same loci as biomass under control and heat stress conditions
• The balance between photoprotection and photo-inhibition may be controlled by the same region as seed yield under heat stress
• Both DEPI and MultispeQ (PhotosynQ) are powerful phenotyping tools for photosynthetic traits and QTL mapping
Take home message
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
• Explore the possible connection between seed yield under heat stress and photo-protection and photo-inhibition
• Identify genes within the QTLs that have been mapped
• Determine mechanisms enabling tolerance of photosynthesis under heat stress in cowpea.
Future directions
Feed the Future Innovation Lab for Collaborative Research on Grain Legumes
AcknowledgementsKramer Lab members
Dan TerAvestDonghee HohOliver TessmerDavid HallJeff CruzLinda SavageRobert Zegarac
Collaborators (UC, Riverside)Dr. Philip A. RobertsDr. Bao-Lam HuynhDr. Timothy J. CloseDr. Maria Munoz-Amatrian
Graduate Advisory Committee membersDr. David Kramer Dr. Christoph BenningDr. Wayne LoescherDr. Thomas SharkeyDr. Ousmane Boukar
Thermo-tolerance of photosynthesis in legumes: Mapping QTLs for photosynthetic traits in cowpea under heat stressIntroductionWhy grain legumes and photosynthesis?Development of plants with robust photosynthesis under heat stressPhotosynthetic parameters assayedMapping of QTLs for photosynthetic traits under normal and heat stress conditions in cowpea by HTP phenotypingPhotosynthetic efficiency (ɸII) under heat stressQTLs for Photosynthetic efficiency (ɸII) under heat stress and normal growth conditions Possible linkage between SPAD/ Relative Chlorophyll content, photoprotection (qEt) and biomass QTLCorrelation between Biomass, chlorophyll content and qEtPhotoprotection (qEt) and photo-inhibition (qIt) QTLs may be controlled by the same locus as seed yield under heat stress Take home messageFuture directionsAcknowledgements