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Identification of Associations between Bacterioplankton and Photosynthetic Picoeukaryotes in Coastal Waters.

Farnelid HM, Turk-Kubo KA, Zehr JP - Front Microbiol (2016)

Bottom Line: Photosynthetic picoeukaryotes are significant contributors to marine primary productivity.The results show that diverse bacterial phylotypes are found in association with photosynthetic picoeukaryotes.Taxonomic identification of these associations is a prerequisite for further characterizing and to elucidate their metabolic pathways and ecological functions.

View Article: PubMed Central - PubMed

Affiliation: Ocean Sciences Department, University of California at Santa CruzSanta Cruz, CA, USA; Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus UniversityKalmar, Sweden.

ABSTRACT
Photosynthetic picoeukaryotes are significant contributors to marine primary productivity. Associations between marine bacterioplankton and picoeukaryotes frequently occur and can have large biogeochemical impacts. We used flow cytometry to sort cells from seawater to identify non-eukaryotic phylotypes that are associated with photosynthetic picoeukaryotes. Samples were collected at the Santa Cruz wharf on Monterey Bay, CA, USA during summer and fall, 2014. The phylogeny of associated microbes was assessed through 16S rRNA gene amplicon clone and Illumina MiSeq libraries. The most frequently detected bacterioplankton phyla within the photosynthetic picoeukaryote sorts were Proteobacteria (Alphaproteobacteria and Gammaproteobacteria) and Bacteroidetes. Intriguingly, the presence of free-living bacterial genera in the photosynthetic picoeukaryote sorts could suggest that some of the photosynthetic picoeukaryotes were mixotrophs. However, the occurrence of bacterial sequences, which were not prevalent in the corresponding bulk seawater samples, indicates that there was also a selection for specific OTUs in association with photosynthetic picoeukaryotes suggesting specific functional associations. The results show that diverse bacterial phylotypes are found in association with photosynthetic picoeukaryotes. Taxonomic identification of these associations is a prerequisite for further characterizing and to elucidate their metabolic pathways and ecological functions.

No MeSH data available.


Pie graphs showing the phylogenetic affiliations of non-Eukaryota 16S rRNA gene sequences in photosynthetic picoeukaryote sorts (P1, 1,000 cells), and bulk seawater (0.2–10 μm) from Illumina MiSeq libraries for each sampling date. The absolute numbers of sequences for the triplicate sort samples from each sampling date have been pooled. The colors for each phyla are indicated below the graphs.
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Figure 5: Pie graphs showing the phylogenetic affiliations of non-Eukaryota 16S rRNA gene sequences in photosynthetic picoeukaryote sorts (P1, 1,000 cells), and bulk seawater (0.2–10 μm) from Illumina MiSeq libraries for each sampling date. The absolute numbers of sequences for the triplicate sort samples from each sampling date have been pooled. The colors for each phyla are indicated below the graphs.

Mentions: The Illumina MiSeq sequencing confirmed the presence of non-Eukaryota cells among the sorted photosynthetic picoeukaryote cells. In total, 1,372 OTUs of non-Eukaryota origin were present in the dataset ranging from between 36 and 103 OTUs present in each sorted sample (Table 3). The most frequently detected phyla in the photosynthetic picoeukaryote sorts were Proteobacteria (Alphaproteobacteria and Gammaproteobacteria), Bacteroidetes, and Cyanobacteria, corresponding to the main phyla in the bulk seawater samples (Figure 5) but the OTU composition was different in the sorted samples compared to the bulk seawater samples (Figure 3B). In general, there was patchiness in the presence/abundance of non-Eukaryota OTUs between replicates even among the OTUs with highest relative abundances (Figures 3B and 6). The patchiness between the biological replicates indicate that there is a large variation in the associated microbes and that larger population sorts will be required in order to reliably quantify the occurrences of specific taxa.


Identification of Associations between Bacterioplankton and Photosynthetic Picoeukaryotes in Coastal Waters.

Farnelid HM, Turk-Kubo KA, Zehr JP - Front Microbiol (2016)

Pie graphs showing the phylogenetic affiliations of non-Eukaryota 16S rRNA gene sequences in photosynthetic picoeukaryote sorts (P1, 1,000 cells), and bulk seawater (0.2–10 μm) from Illumina MiSeq libraries for each sampling date. The absolute numbers of sequences for the triplicate sort samples from each sampling date have been pooled. The colors for each phyla are indicated below the graphs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834442&req=5

Figure 5: Pie graphs showing the phylogenetic affiliations of non-Eukaryota 16S rRNA gene sequences in photosynthetic picoeukaryote sorts (P1, 1,000 cells), and bulk seawater (0.2–10 μm) from Illumina MiSeq libraries for each sampling date. The absolute numbers of sequences for the triplicate sort samples from each sampling date have been pooled. The colors for each phyla are indicated below the graphs.
Mentions: The Illumina MiSeq sequencing confirmed the presence of non-Eukaryota cells among the sorted photosynthetic picoeukaryote cells. In total, 1,372 OTUs of non-Eukaryota origin were present in the dataset ranging from between 36 and 103 OTUs present in each sorted sample (Table 3). The most frequently detected phyla in the photosynthetic picoeukaryote sorts were Proteobacteria (Alphaproteobacteria and Gammaproteobacteria), Bacteroidetes, and Cyanobacteria, corresponding to the main phyla in the bulk seawater samples (Figure 5) but the OTU composition was different in the sorted samples compared to the bulk seawater samples (Figure 3B). In general, there was patchiness in the presence/abundance of non-Eukaryota OTUs between replicates even among the OTUs with highest relative abundances (Figures 3B and 6). The patchiness between the biological replicates indicate that there is a large variation in the associated microbes and that larger population sorts will be required in order to reliably quantify the occurrences of specific taxa.

Bottom Line: Photosynthetic picoeukaryotes are significant contributors to marine primary productivity.The results show that diverse bacterial phylotypes are found in association with photosynthetic picoeukaryotes.Taxonomic identification of these associations is a prerequisite for further characterizing and to elucidate their metabolic pathways and ecological functions.

View Article: PubMed Central - PubMed

Affiliation: Ocean Sciences Department, University of California at Santa CruzSanta Cruz, CA, USA; Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus UniversityKalmar, Sweden.

ABSTRACT
Photosynthetic picoeukaryotes are significant contributors to marine primary productivity. Associations between marine bacterioplankton and picoeukaryotes frequently occur and can have large biogeochemical impacts. We used flow cytometry to sort cells from seawater to identify non-eukaryotic phylotypes that are associated with photosynthetic picoeukaryotes. Samples were collected at the Santa Cruz wharf on Monterey Bay, CA, USA during summer and fall, 2014. The phylogeny of associated microbes was assessed through 16S rRNA gene amplicon clone and Illumina MiSeq libraries. The most frequently detected bacterioplankton phyla within the photosynthetic picoeukaryote sorts were Proteobacteria (Alphaproteobacteria and Gammaproteobacteria) and Bacteroidetes. Intriguingly, the presence of free-living bacterial genera in the photosynthetic picoeukaryote sorts could suggest that some of the photosynthetic picoeukaryotes were mixotrophs. However, the occurrence of bacterial sequences, which were not prevalent in the corresponding bulk seawater samples, indicates that there was also a selection for specific OTUs in association with photosynthetic picoeukaryotes suggesting specific functional associations. The results show that diverse bacterial phylotypes are found in association with photosynthetic picoeukaryotes. Taxonomic identification of these associations is a prerequisite for further characterizing and to elucidate their metabolic pathways and ecological functions.

No MeSH data available.