Characterization ofProchlorococcusclades from iron-depleted oceanic regions
Open Access
- 23 August 2010
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 107 (37), 16184-16189
- https://doi.org/10.1073/pnas.1009513107
Abstract
Prochlorococcus describes a diverse and abundant genus of marine photosynthetic microbes. It is primarily found in oligotrophic waters across the globe and plays a crucial role in energy and nutrient cycling in the ocean ecosystem. The abundance, global distribution, and availability of isolates make Prochlorococcus a model system for understanding marine microbial diversity and biogeochemical cycling. Analysis of 73 metagenomic samples from the Global Ocean Sampling expedition acquired in the Atlantic, Pacific, and Indian Oceans revealed the presence of two uncharacterized Prochlorococcus clades. A phylogenetic analysis using six different genetic markers places the clades close to known lineages adapted to high-light environments. The two uncharacterized clades consistently cooccur and dominate the surface waters of high-temperature, macronutrient-replete, and low-iron regions of the Eastern Equatorial Pacific upwelling and the tropical Indian Ocean. They are genetically distinct from each other and other high-light Prochlorococcus isolates and likely define a previously unrecognized ecotype. Our detailed genomic analysis indicates that these clades comprise organisms that are adapted to iron-depleted environments by reducing their iron quota through the loss of several iron-containing proteins that likely function as electron sinks in the photosynthetic pathway in other Prochlorococcus clades from high-light environments. The presence and inferred physiology of these clades may explain why Prochlorococcus populations from iron-depleted regions do not respond to iron fertilization experiments and further expand our understanding of how phytoplankton adapt to variations in nutrient availability in the ocean.Keywords
This publication has 59 references indexed in Scilit:
- History of biological metal utilization inferred through phylogenomic analysis of protein structuresProceedings of the National Academy of Sciences, 2010
- Widespread metabolic potential for nitrite and nitrate assimilation among Prochlorococcus ecotypesProceedings of the National Academy of Sciences, 2009
- Aggressive assembly of pyrosequencing reads with matesBioinformatics, 2008
- An original adaptation of photosynthesis in the marine green alga OstreococcusProceedings of the National Academy of Sciences of the United States of America, 2008
- The tiny eukaryote Ostreococcus provides genomic insights into the paradox of plankton speciationProceedings of the National Academy of Sciences of the United States of America, 2007
- Modern proteomes contain putative imprints of ancient shifts in trace metal geochemistryProceedings of the National Academy of Sciences, 2006
- Genome sequence of Synechococcus CC9311: Insights into adaptation to a coastal environmentProceedings of the National Academy of Sciences of the United States of America, 2006
- Phosphate acquisition genes in Prochlorococcus ecotypes: Evidence for genome-wide adaptationProceedings of the National Academy of Sciences, 2006
- Genomic scale sub-family assignment of protein domainsNucleic Acids Research, 2006
- CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choiceNucleic Acids Research, 1994