Globally distributed uncultivated oceanic N2-fixing cyanobacteria lack oxygenic photosystem II.
Biological nitrogen (N2) fixation is important in controlling biological productivity and carbon flux in the oceans. Unicellular N2-fixing cyanobacteria have only recently been discovered and are widely distributed in tropical and subtropical seas. Metagenomic analysis of flow cytometry-sorted cells shows that unicellular N2-fixing cyanobacteria in "group A" (UCYN-A) lack genes for the oxygen-evolving photosystem II and for carbon fixation, which has implications for oceanic carbon and nitrogen cycling and raises questions regarding the evolution of photosynthesis and N2 fixation on Earth.
Zehr
Jonathan P
JP
Ocean Sciences Department, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA. zehrj@ucsc.edu
Bench
Shellie R
SR
Carter
Brandon J
BJ
Hewson
Ian
I
Niazi
Faheem
F
Shi
Tuo
T
Tripp
H James
HJ
Affourtit
Jason P
JP
D000458:Cyanobacteria / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D019143:Evolution, Molecular; D005434:Flow Cytometry; D005798:Genes, Bacterial; D020459:Genes, rRNA; D016680:Genome, Bacterial; D023281:Genomics / Q000379:methods; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics*; D010088:Oxidoreductases / Q000235:genetics; D010140:Pacific Ocean; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*
D045332:Photosystem II Protein Complex; D010088:Oxidoreductases; C029130:nitrogenase reductase