Measurement of a possible signal for nitrogen starvation

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 NH 3 www. Isuagcenter. com

Chemical Fertilizer Production N 2 $100's of $billions / year Chemical production of NH 3 Fixan PE, West FB (2002) Ambio 31: 169 -176. NH 3 8 fold

Downstream effects of fertilizer runnoff N 2 $100's of $billions / year NH 3 Low oxygen What to do? NASA Visible Earth http: //visibleearth. nasa. gov/ High oxygen

Biological Fertilizer Production N 2 $100's of $billions / year Free and Clean Plant Symbiont NH 3 Cyanobacterial Symbiont + N 2 NH 3 Nostoc punctiforme Anthoceros (bryophyte)

Biological Fertilizer Production N 2 $100's of $billions / year Free and Clean Plant Symbiont NH 3 Cyanobacterial Symbiont + N 2 NH 3 Nostoc punctiforme Cycads (gymnosperm)

Biological Fertilizer Production N 2 $100's of $billions / year Free and Clean Plant Symbiont NH 3 Cyanobacterial Symbiont + N 2 NH 3 Nostoc punctiforme Gunnera (angiosperm)

Biological Fertilizer Production N 2 $100's of $billions / year Free and Clean But not NH 3 Cyanobacterial Symbiont + N 2 NH 3 Nostoc punctiforme Why not crop plants?

How do symbiotic plants differ from others? A clue from free-living Nostoc? Plenty of Nitrogen N 2 NH 3 Starving for Nitrogen N 2 NH 3

How does NH 3 shut off N-fixation?

How does NH 3 shut off N-fixation? α-ketoglutarate AMINO ACIDS Glutamate + Glutamate N 2 NH 3 Glutamine

How does NH 3 shut off N-fixation? α-ketoglutarate AMINO ACIDS Glutamate + Glutamate N 2 Glutamine NH 3

How does NH 3 shut off N-fixation? Could plants use this to fool Nostoc? α-ketoglutarate AMINO ACIDS Glutamate + Glutamate N 2 Glutamine NH 3

How does NH 3 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 (CFP) (YFP)

How to measure α-ketoglutarate inside cells? The hydromedusa Aequoria victoria Source of Green Fluorescent Protein (GFP) Cyano Yellow 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 NH 3 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 NH 3 shut off N-fixation? Could crop plants do the same? α-ketoglutarate Does Nostoc within plants have a high level of α-ketoglutarate?
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