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Abundances of Iron-Binding Photosynthetic and Nitrogen-Fixing Proteins of Trichodesmium Both in Culture and In Situ from the North Atlantic

Abundances of Iron-Binding Photosynthetic and Nitrogen-Fixing Proteins of Trichodesmium Both in Culture and In Situ from the North Atlantic
Abundances of Iron-Binding Photosynthetic and Nitrogen-Fixing Proteins of Trichodesmium Both in Culture and In Situ from the North Atlantic
Marine cyanobacteria of the genus Trichodesmium occur throughout the oligotrophic tropical and subtropical oceans, where they can dominate the diazotrophic community in regions with high inputs of the trace metal iron (Fe). Iron is necessary for the functionality of enzymes involved in the processes of both photosynthesis and nitrogen fixation. We combined laboratory and field-based quantifications of the absolute concentrations of key enzymes involved in both photosynthesis and nitrogen fixation to determine how Trichodesmium allocates resources to these processes. We determined that protein level responses of Trichodesmium to iron-starvation involve down-regulation of the nitrogen fixation apparatus. In contrast, the photosynthetic apparatus is largely maintained, although re-arrangements do occur, including accumulation of the iron-stress-induced chlorophyll-binding protein IsiA. Data from natural populations of Trichodesmium spp. collected in the North Atlantic demonstrated a protein profile similar to iron-starved Trichodesmium in culture, suggestive of acclimation towards a minimal iron requirement even within an oceanic region receiving a high iron-flux. Estimates of cellular metabolic iron requirements are consistent with the availability of this trace metal playing a major role in restricting the biomass and activity of Trichodesmium throughout much of the subtropical ocean.
1932-6203
e35571
Richier, Sophie
0fc0b375-6918-4c06-9d6f-229f6c4046ca
Macey, Anna I.
04c3fff6-93ca-437c-8280-a94cc10f7fed
Pratt, Nicola J.
c94f98bd-897c-4853-bebd-be93b8aecc8a
Honey, David J.
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Moore, C. Mark
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Bibby, Thomas S.
e04ea079-dd90-4ead-9840-00882de27ebd
Richier, Sophie
0fc0b375-6918-4c06-9d6f-229f6c4046ca
Macey, Anna I.
04c3fff6-93ca-437c-8280-a94cc10f7fed
Pratt, Nicola J.
c94f98bd-897c-4853-bebd-be93b8aecc8a
Honey, David J.
7aec4239-185a-416e-b32b-6ac057dc7cd8
Moore, C. Mark
7ec80b7b-bedc-4dd5-8924-0f5d01927b12
Bibby, Thomas S.
e04ea079-dd90-4ead-9840-00882de27ebd

Richier, Sophie, Macey, Anna I., Pratt, Nicola J., Honey, David J., Moore, C. Mark and Bibby, Thomas S. (2012) Abundances of Iron-Binding Photosynthetic and Nitrogen-Fixing Proteins of Trichodesmium Both in Culture and In Situ from the North Atlantic. PLoS ONE, 7 (5), e35571. (doi:10.1371/journal.pone.0035571).

Record type: Article

Abstract

Marine cyanobacteria of the genus Trichodesmium occur throughout the oligotrophic tropical and subtropical oceans, where they can dominate the diazotrophic community in regions with high inputs of the trace metal iron (Fe). Iron is necessary for the functionality of enzymes involved in the processes of both photosynthesis and nitrogen fixation. We combined laboratory and field-based quantifications of the absolute concentrations of key enzymes involved in both photosynthesis and nitrogen fixation to determine how Trichodesmium allocates resources to these processes. We determined that protein level responses of Trichodesmium to iron-starvation involve down-regulation of the nitrogen fixation apparatus. In contrast, the photosynthetic apparatus is largely maintained, although re-arrangements do occur, including accumulation of the iron-stress-induced chlorophyll-binding protein IsiA. Data from natural populations of Trichodesmium spp. collected in the North Atlantic demonstrated a protein profile similar to iron-starved Trichodesmium in culture, suggestive of acclimation towards a minimal iron requirement even within an oceanic region receiving a high iron-flux. Estimates of cellular metabolic iron requirements are consistent with the availability of this trace metal playing a major role in restricting the biomass and activity of Trichodesmium throughout much of the subtropical ocean.

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Published date: 2012
Organisations: Ocean Biochemistry & Ecosystems

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Local EPrints ID: 338005
URI: http://eprints.soton.ac.uk/id/eprint/338005
ISSN: 1932-6203
PURE UUID: ddb77c5f-1917-4e51-a2b7-8e72e8bf6e3a
ORCID for Nicola J. Pratt: ORCID iD orcid.org/0000-0002-0664-3467
ORCID for C. Mark Moore: ORCID iD orcid.org/0000-0002-9541-6046

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Date deposited: 08 May 2012 09:27
Last modified: 15 Mar 2024 03:37

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Contributors

Author: Sophie Richier
Author: Anna I. Macey
Author: Nicola J. Pratt ORCID iD
Author: David J. Honey
Author: C. Mark Moore ORCID iD
Author: Thomas S. Bibby

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