Global biogeography of SAR11 marine bacteria.
The ubiquitous SAR11 bacterial clade is the most abundant type of organism in the world's oceans, but the reasons for its success are not fully elucidated. We analysed 128 surface marine metagenomes, including 37 new Antarctic metagenomes. The large size of the data set enabled internal transcribed spacer (ITS) regions to be obtained from the Southern polar region, enabling the first global characterization of the distribution of SAR11, from waters spanning temperatures -2 to 30°C. Our data show a stable co-occurrence of phylotypes within both 'tropical' (>20°C) and 'polar' (<10°C) biomes, highlighting ecological niche differentiation between major SAR11 subgroups. All phylotypes display transitions in abundance that are strongly correlated with temperature and latitude. By assembling SAR11 genomes from Antarctic metagenome data, we identified specific genes, biases in gene functions and signatures of positive selection in the genomes of the polar SAR11-genomic signatures of adaptive radiation. Our data demonstrate the importance of adaptive radiation in the organism's ability to proliferate throughout the world's oceans, and describe genomic traits characteristic of different phylotypes in specific marine biomes.
School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
Mark V
MV
Brown
Federico M
FM
Lauro
Matthew Z
MZ
DeMaere
Les
L
Muir
David
D
Wilkins
Torsten
T
Thomas
Martin J
MJ
Riddle
Jed A
JA
Fuhrman
Cynthia
C
Andrews-Pfannkoch
Jeffrey M
JM
Hoffman
Jeffrey B
JB
McQuaid
Andrew
A
Allen
Stephen R
SR
Rintoul
Ricardo
R
Cavicchioli
D020561:Alphaproteobacteria / Q000235:genetics*; D000864:Antarctic Regions; D002980:Climate; D016680:Genome, Bacterial / Q000235:genetics / Q000528:radiation effects*; D008386:Marine Biology; D054892:Metagenome / Q000235:genetics / Q000528:radiation effects*; D008954:Models, Biological; D010802:Phylogeny; D058974:Phylogeography; D012623:Seawater / Q000382:microbiology*; D016415:Sequence Alignment; D013696:Temperature