Transcript α-ketoglutarate - People.vcu.edu

Measurement of a possible
signal for nitrogen starvation in a
cyanobacterium-plant symbiosis
Jeff Elhai
World Population
Green Revolution
Conventional wheat
High yield
dwarf wheat
NH3
NH3
www.Isuagcenter.com
Chemical Fertilizer Production
$100's of $billions / year
N2
NH3
Chemical
production
of NH3
Fixan PE, West FB (2002) Ambio 31:169-176.
8 fold
Downstream effects of fertilizer runnoff
$100's of $billions / year
N2
NH3
Low oxygen
What to do?
High oxygen
NASA Visible Earth http://visibleearth.nasa.gov/
Biological Fertilizer Production
N2
$100's
of $billions
/ year
Free
and Clean
Plant Symbiont
NH3
Cyanobacterial Symbiont
+
N2
NH3
Nostoc punctiforme
Anthoceros (bryophyte)
Biological Fertilizer Production
N2
$100's
of $billions
/ year
Free
and Clean
Plant Symbiont
NH3
Cyanobacterial Symbiont
+
N2
NH3
Nostoc punctiforme
Cycads (gymnosperm)
Biological Fertilizer Production
N2
$100's
of $billions
/ year
Free
and Clean
Plant Symbiont
NH3
Cyanobacterial Symbiont
+
N2
NH3
Nostoc punctiforme
Gunnera (angiosperm)
Biological Fertilizer Production
N2
$100's
of $billions
/ year
Free
and Clean
But not
NH3
Cyanobacterial Symbiont
+
N2
NH3
Nostoc punctiforme
Why not crop plants?
How do symbiotic plants differ from others?
A clue from free-living Nostoc?
Plenty of Nitrogen
Starving for Nitrogen
N2
N2
NH3
NH3
NH3
NH3
How does NH3 shut off N-fixation?
How does NH3 shut off N-fixation?
α-ketoglutarate
AMINO ACIDS
Glutamate
+
Glutamate
N2
NH3
Glutamine
How does NH3 shut off N-fixation?
α-ketoglutarate
α-ketoglutarate
AMINO ACIDS
Glutamate
+
Glutamate
N2
Glutamine
Glutamine
NH3
How does NH3 shut off N-fixation?
Could plants use this to fool Nostoc?
α-ketoglutarate
AMINO ACIDS
Glutamate
+
Glutamate
N2
Glutamine
Glutamine
NH3
How does NH3 shut off N-fixation?
Could plants use this to fool Nostoc?
α-ketoglutarate
Does Nostoc within plants have
a high level of α-ketoglutarate?
How to measure α-ketoglutarate inside cells?
The hydromedusa
Aequoria victoria
Source of Green
Fluorescent Protein
(GFP)
Cyano
Yellow
Fluorescent Protein Fluorescent Protein
(CFP)
(YFP)
How to measure α-ketoglutarate inside cells?
The hydromedusa
Aequoria victoria
Source of Green
Fluorescent Protein
(GFP)
Cyano
Yellow
Fluorescent Protein Fluorescent Protein
(CFP)
(YFP)
How to measure α-ketoglutarate inside cells?
α-ketoglutarate
CFP
YFP
How to measure α-ketoglutarate inside cells?
α-ketoglutarate
CFP
α-ketoglutarate
YFP
Yellow fluorescence
Blue fluorescence
How to measure α-ketoglutarate inside cells?
α-ketoglutarate
CFP
α-ketoglutarate
YFP
Yellow fluorescence
Blue fluorescence
How does NH3 shut off N-fixation?
Could plants use this to fool Nostoc?
α-ketoglutarate
Does Nostoc within plants have
a high level of α-ketoglutarate?
How does NH3 shut off N-fixation?
Could crop plants do the same?
α-ketoglutarate
Does Nostoc within plants have
a high level of α-ketoglutarate?