Global biogeography of SAR11 marine bacteria |
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| Authors: | Matthew Z DeMaere Les Muir David Wilkins Torsten Thomas Martin J Riddle Jed A Fuhrman Cynthia Andrews‐Pfannkoch Jeffrey M Hoffman Jeffrey B McQuaid Andrew Allen Stephen R Rintoul Ricardo Cavicchioli |
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| Affiliation: | 1. School of Biotechnology and Biomolecular Sciences, The University of New South Wales, , Sydney, New South Wales, Australia;2. CSIRO Marine and Atmospheric Research, Castray Esplanade, , Hobart, Tasmania, Australia;3. Centre for Marine Bio‐Innovation, The University of New South Wales, , Sydney, New South Wales, Australia;4. Australian Antarctic Division, Channel Highway, , Kingston, Tasmania, Australia;5. Department of Biological Sciences, Wrigley Institute for Environmental Studies, University of Southern California, , Los Angeles, CA, USA;6. J. Craig Venter Institute, , Rockville, MD, USA;7. CSIRO Marine and Atmospheric Research, Centre for Australian Weather and Climate Research—A partnership of the Bureau of Meteorology and CSIRO, and CSIRO Wealth from Oceans National Research Flagship, and the Antarctic Climate and Ecosystems Cooperative Research Centre, Castray Esplanade, , Hobart, Tasmania, Australia |
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| Abstract: | 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. |
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| Keywords: | adaptive radiation Antarctica metagenome Pelagibacter phylotype distribution |
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