Groups without cultured representatives dominate eukaryotic picophytoplankton in the oligotrophic South East Pacific Ocean
Shi, Xiao Li, Marie, D. (Dominique), Jardillier, Ludwig, Scanlan, David J. and Vaulot, Daniel. (2009) Groups without cultured representatives dominate eukaryotic picophytoplankton in the oligotrophic South East Pacific Ocean. PLoS One, Vol.4 (No.10). Article No. e7657. ISSN 1932-6203
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Official URL: http://dx.doi.org/10.1371/journal.pone.0007657
Background: Photosynthetic picoeukaryotes (PPE) with a cell size less than 3 µm play a critical role in oceanic primary production. In recent years, the composition of marine picoeukaryote communities has been intensively investigated by molecular approaches, but their photosynthetic fraction remains poorly characterized. This is largely because the classical approach that relies on constructing 18S rRNA gene clone libraries from filtered seawater samples using universal eukaryotic primers is heavily biased toward heterotrophs, especially alveolates and stramenopiles, despite the fact that autotrophic cells in general outnumber heterotrophic ones in the euphotic zone.
Methodology/Principal Findings: In order to better assess the composition of the eukaryotic picophytoplankton in the South East Pacific Ocean, encompassing the most oligotrophic oceanic regions on earth, we used a novel approach based on flow cytometry sorting followed by construction of 18S rRNA gene clone libraries. This strategy dramatically increased the recovery of sequences from putative autotrophic groups. The composition of the PPE community appeared highly variable both vertically down the water column and horizontally across the South East Pacific Ocean. In the central gyre, uncultivated lineages dominated: a recently discovered clade of Prasinophyceae (IX), clades of marine Chrysophyceae and Haptophyta, the latter division containing a potentially new class besides Prymnesiophyceae and Pavlophyceae. In contrast, on the edge of the gyre and in the coastal Chilean upwelling, groups with cultivated representatives (Prasinophyceae clade VII and Mamiellales) dominated.
Conclusions/Significance: Our data demonstrate that a very large fraction of the eukaryotic picophytoplankton still escapes cultivation. The use of flow cytometry sorting should prove very useful to better characterize specific plankton populations by molecular approaches such as gene cloning or metagenomics, and also to obtain into culture strains representative of these novel groups.
|Item Type:||Journal Article|
|Subjects:||Q Science > QK Botany
Q Science > QH Natural history > QH426 Genetics
|Divisions:||Faculty of Science > Life Sciences (2010- ) > Biological Sciences ( -2010)|
|Library of Congress Subject Headings (LCSH):||Eukaryotic cells -- Research, Photosynthesis -- Research, Phytoplankton populations -- Pacific Ocean, Flow cytometry|
|Journal or Publication Title:||PLoS One|
|Publisher:||Public Library of Science|
|Official Date:||29 October 2009|
|Page Range:||Article No. e7657|
|Access rights to Published version:||Open Access|
|Funder:||Natural Environment Research Council (Great Britain) (NERC), Centre national de la recherche scientifique (France) (CNRS), GIS Génomique Marine (GISGM), France. Agence nationale de la recherche (ANR), China Scholarship Council (CSC), Université Pierre et Marie Curie (UPMC), Fondation Franco-Chinoise pour la Science et ses Applications (FFCSA)|
|Grant number:||06-BDIV-013 (ANR), NE/C003160/1 (NERC)|
1. Li WKW (1994) Primary production of prochlorophytes, cyanobacteria, and
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