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Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton

BACKGROUND: Photosynthetic light-harvesting proteins are the mechanism by which energy enters the marine ecosystem. The dominant prokaryotic photoautotrophs are the cyanobacterial genera Prochlorococcus and Synechococcus that are defined by two distinct light-harvesting systems, chlorophyll-bound pr...

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Detalles Bibliográficos
Autores principales: Bibby, Thomas S., Zhang, Yinan, Chen, Min
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2644788/
https://www.ncbi.nlm.nih.gov/pubmed/19240807
http://dx.doi.org/10.1371/journal.pone.0004601
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author Bibby, Thomas S.
Zhang, Yinan
Chen, Min
author_facet Bibby, Thomas S.
Zhang, Yinan
Chen, Min
author_sort Bibby, Thomas S.
collection PubMed
description BACKGROUND: Photosynthetic light-harvesting proteins are the mechanism by which energy enters the marine ecosystem. The dominant prokaryotic photoautotrophs are the cyanobacterial genera Prochlorococcus and Synechococcus that are defined by two distinct light-harvesting systems, chlorophyll-bound protein complexes or phycobilin-bound protein complexes, respectively. Here, we use the Global Ocean Sampling (GOS) Project as a unique and powerful tool to analyze the environmental diversity of photosynthetic light-harvesting genes in relation to available metadata including geographical location and physical and chemical environmental parameters. METHODS: All light-harvesting gene fragments and their metadata were obtained from the GOS database, aligned using ClustalX and classified phylogenetically. Each sequence has a name indicative of its geographic location; subsequent biogeographical analysis was performed by correlating light-harvesting gene budgets for each GOS station with surface chlorophyll concentration. CONCLUSION/SIGNIFICANCE: Using the GOS data, we have mapped the biogeography of light-harvesting genes in marine cyanobacteria on ocean-basin scales and show that an environmental gradient exists in which chlorophyll concentration is correlated to diversity of light-harvesting systems. Three functionally distinct types of light-harvesting genes are defined: (1) the phycobilisome (PBS) genes of Synechococcus; (2) the pcb genes of Prochlorococcus; and (3) the iron-stress-induced (isiA) genes present in some marine Synechococcus. At low chlorophyll concentrations, where nutrients are limited, the Pcb-type light-harvesting system shows greater genetic diversity; whereas at high chlorophyll concentrations, where nutrients are abundant, the PBS-type light-harvesting system shows higher genetic diversity. We interpret this as an environmental selection of specific photosynthetic strategy. Importantly, the unique light-harvesting system isiA is found in the iron-limited, high-nutrient low-chlorophyll region of the equatorial Pacific. This observation demonstrates the ecological importance of isiA genes in enabling marine Synechococcus to acclimate to iron limitation and suggests that the presence of this gene can be a natural biomarker for iron limitation in oceanic environments.
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spelling pubmed-26447882009-02-25 Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton Bibby, Thomas S. Zhang, Yinan Chen, Min PLoS One Research Article BACKGROUND: Photosynthetic light-harvesting proteins are the mechanism by which energy enters the marine ecosystem. The dominant prokaryotic photoautotrophs are the cyanobacterial genera Prochlorococcus and Synechococcus that are defined by two distinct light-harvesting systems, chlorophyll-bound protein complexes or phycobilin-bound protein complexes, respectively. Here, we use the Global Ocean Sampling (GOS) Project as a unique and powerful tool to analyze the environmental diversity of photosynthetic light-harvesting genes in relation to available metadata including geographical location and physical and chemical environmental parameters. METHODS: All light-harvesting gene fragments and their metadata were obtained from the GOS database, aligned using ClustalX and classified phylogenetically. Each sequence has a name indicative of its geographic location; subsequent biogeographical analysis was performed by correlating light-harvesting gene budgets for each GOS station with surface chlorophyll concentration. CONCLUSION/SIGNIFICANCE: Using the GOS data, we have mapped the biogeography of light-harvesting genes in marine cyanobacteria on ocean-basin scales and show that an environmental gradient exists in which chlorophyll concentration is correlated to diversity of light-harvesting systems. Three functionally distinct types of light-harvesting genes are defined: (1) the phycobilisome (PBS) genes of Synechococcus; (2) the pcb genes of Prochlorococcus; and (3) the iron-stress-induced (isiA) genes present in some marine Synechococcus. At low chlorophyll concentrations, where nutrients are limited, the Pcb-type light-harvesting system shows greater genetic diversity; whereas at high chlorophyll concentrations, where nutrients are abundant, the PBS-type light-harvesting system shows higher genetic diversity. We interpret this as an environmental selection of specific photosynthetic strategy. Importantly, the unique light-harvesting system isiA is found in the iron-limited, high-nutrient low-chlorophyll region of the equatorial Pacific. This observation demonstrates the ecological importance of isiA genes in enabling marine Synechococcus to acclimate to iron limitation and suggests that the presence of this gene can be a natural biomarker for iron limitation in oceanic environments. Public Library of Science 2009-02-25 /pmc/articles/PMC2644788/ /pubmed/19240807 http://dx.doi.org/10.1371/journal.pone.0004601 Text en Bibby et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Bibby, Thomas S.
Zhang, Yinan
Chen, Min
Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton
title Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton
title_full Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton
title_fullStr Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton
title_full_unstemmed Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton
title_short Biogeography of Photosynthetic Light-Harvesting Genes in Marine Phytoplankton
title_sort biogeography of photosynthetic light-harvesting genes in marine phytoplankton
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2644788/
https://www.ncbi.nlm.nih.gov/pubmed/19240807
http://dx.doi.org/10.1371/journal.pone.0004601
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