Prochlorococcus is the numerically dominant phototroph in the tropical and subtropical oceans, accounting for half of the photosynthetic biomass in some areas. Here we report the isolation of cyanophages that infect Prochlorococcus, and show that although some are host-strain-specific, others cross-infect with closely related marine Synechococcus as well as between high-light- and low-light-adapted Prochlorococcus isolates, suggesting a mechanism for horizontal gene transfer. High-light-adapted Prochlorococcus hosts yielded Podoviridae exclusively, which were extremely host-specific, whereas low-light-adapted Prochlorococcus and all strains of Synechococcus yielded primarily Myoviridae, which has a broad host range. Finally, both Prochlorococcus and Synechococcus strain-specific cyanophage titres were low (< 10(3) ml(-1)) in stratified oligotrophic waters even where total cyanobacterial abundances were high (> 10(5) cells x ml(-1)). These low titres in areas of high total host cell abundance seem to be a feature of open ocean ecosystems. We hypothesize that gradients in cyanobacterial population diversity, growth rates, and/or the incidence of lysogeny underlie these trends.
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http://dx.doi.org/10.1038/nature01929 | DOI Listing |
mBio
November 2024
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
is a diverse picocyanobacterial genus and the most abundant phototroph on Earth. Its photosynthetic diversity divides it into high-light (HL)- or low-light (LL)-adapted groups representing broad phylogenetic grades-each composed of several monophyletic clades. Here, we physiologically characterize four new strains isolated from below the deep chlorophyll maximum in the North Pacific Ocean.
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August 2023
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
is an abundant photosynthetic bacterium in the open ocean, where nitrogen (N) often limits phytoplankton growth. In the low-light-adapted LLI clade of , nearly all cells can assimilate nitrite (NO), with a subset capable of assimilating nitrate (NO). LLI cells are maximally abundant near the primary NO maximum layer, an oceanographic feature that may, in part, be due to incomplete assimilatory NO reduction and subsequent NO release by phytoplankton.
View Article and Find Full Text PDFBMC Genom Data
February 2023
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Objectives: The marine cyanobacterium Prochlorococcus is a critical part of warm ocean ecosystems and a model for studying microbial evolution and ecology. To expand the representation of this organism's vast wild diversity in sequence collections, we performed a set of isolation efforts targeting low light-adapted Prochlorococcus. Three genomes resulting from this larger body of work are described here.
View Article and Find Full Text PDFFront Microbiol
October 2022
Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
is an obligate marine microorganism and the dominant autotroph in tropical and subtropical open ocean. However, the salinity range for growing and response to low salinity exposure of are still unknown. In this study, we found that low-light adapted stain NATL1A and high-light adapted strain MED4 could be acclimated in the lowest salinity of 25 and 28 psu, respectively.
View Article and Find Full Text PDFISME J
June 2022
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Prochlorococcus and Synechococcus are the most abundant photosynthesizing organisms in the oceans. Gene content variation among picocyanobacterial populations in separate ocean basins often mirrors the selective pressures imposed by the region's distinct biogeochemistry. By pairing genomic datasets with trace metal concentrations from across the global ocean, we show that the genomic capacity for siderophore-mediated iron uptake is widespread in Synechococcus and low-light adapted Prochlorococcus populations from deep chlorophyll maximum layers of iron-depleted regions of the oligotrophic Pacific and S.
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