Targeted metagenomics and ecology of globally important uncultured eukaryotic phytoplankton

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Cuvelier, Marie L., Latasa, Mikel
• Format: Article in Journal/Newspaper
• Language: English
• Published: National Academy of Sciences (U.S.) 2010
• Subjects: Comparative genomics; Primary production; Prymnesiophytes; Marine photosynthesis; Haptophytes; North Atlantic
• Online Access: http://hdl.handle.net/10261/80830; https://doi.org/10.1073/pnas.1001665107

Cuvelier, Marie L. . et al.-- 6 pages, 4 figures, 1 table, this article contains supporting information online at https://www.pnas.org/content/pnas/suppl/2010/07/27/1001665107.DCSupplemental/pnas.201001665SI.pdf.-- Data deposition: The sequences reported in this paper have been deposited in the Gen-Bank database (accession nos. HM581528–HM581638 and HM565909–HM565914). Other scaffolds with predicted genes from this Whole Genome Shotgun/454 project have been deposited at DNA Data Bank of Japan/European Molecular Biology Laboratory/GenBank under the accession no. AEAR00000000. The version described in this paper is the first version, AEAR01000000 Among eukaryotes, four major phytoplankton lineages are responsible for marine photosynthesis; prymnesiophytes, alveolates, stramenopiles, and prasinophytes. Contributions by individual taxa, however, are not well known, and genomes have been analyzed fromonly the latter two lineages. Tiny >picoplanktonic> members of the prymnesiophyte lineage have long been inferred to be ecologically important but remain poorly characterized. Here, we examine pico-prymnesiophyte evolutionary history and ecology using cultivation-independent methods. 18S rRNA gene analysis showed picoprymnesiophytes belonged to broadly distributed uncultivated taxa. Therefore, we used targeted metagenomics to analyze uncultured pico-prymnesiophytes sorted by flow cytometry from subtropical North Atlantic waters. The data reveal a composite nuclear-encoded gene repertoire with strong green-lineage affiliations, which contrasts with the evolutionary history indicated by the plastid genome. Measured pico-prymnesiophyte growth rates were rapid in this region, resulting in primary production contributions similar to the cyanobacterium Prochlorococcus. On average, pico-prymnesiophytes formed 25% of global picophytoplankton biomass, with differing contributions in five biogeographical provinces spanning tropical to subpolar systems. Elements likely contributing to success include high gene density and ...