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Diversity of bacterial dimethylsulfoniopropionate degradation genes in surface seawater of Arctic Kongsfjorden

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ABSTRACT

Dimethylsulfoniopropionate (DMSP), which is the major source of organic sulfur in the world’s oceans, plays a significant role in the global sulfur cycle. This compound is rapidly degraded by marine bacteria either by cleavage to dimethylsulfide (DMS) or demethylation to 3-methylmercaptopropionate (MMPA). The diversity of genes encoding bacterial demethylation (dmdA) and DMS production (dddL and dddP) were measured in Arctic Kongsfjorden. Both dmdA and dddL genes were detected in all stations along a transect from the outer to the inner fjord, while dddP gene was only found in the outer and middle parts of the fjord. The dmdA gene was completely confined to the Roseobacter clade, while the dddL gene was confined to the genus Sulfitobacter. Although the dddP gene pool was also dominated by homologs from the Roseobacter clade, there were a few dddP genes showing close relationships to both Alphaproteobacter and Gammaproteobacter. The results of this study suggest that the Roseobacter clade may play an important role in DMSP catabolism via both demethylation and cleavage pathways in surface waters of Kongsfjorden during summer.

No MeSH data available.


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Phylogenetic tree of deduced DmdA sequences from three clone libraries of seawater in Kongsfjorden as well as those from known bacterial species available in NCBI.Cluster A indicates genotypes only observed in station K1, Cluster B indicates genotypes shared by stations K1 and K3 (or K5), and Cluster C genotypes shared among all stations. Bootstrap values of <50 have been removed for clarity. Numbers in parentheses following clone names or cluster names indicate the number of sequences found in stations K1, K3, and K5, respectively. The scale bar indicates evolutionary distance.
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f2: Phylogenetic tree of deduced DmdA sequences from three clone libraries of seawater in Kongsfjorden as well as those from known bacterial species available in NCBI.Cluster A indicates genotypes only observed in station K1, Cluster B indicates genotypes shared by stations K1 and K3 (or K5), and Cluster C genotypes shared among all stations. Bootstrap values of <50 have been removed for clarity. Numbers in parentheses following clone names or cluster names indicate the number of sequences found in stations K1, K3, and K5, respectively. The scale bar indicates evolutionary distance.

Mentions: Based on 90% amino acid identity, a phylogenetic tree of these DmdA clone sequences (Fig. 2) yielded 19 major clusters (termed A1 to A8, B1 to B8, and C1 to C3), accounting for 95% of the total clone sequences. All sequences were distributed within the putative dmdA genes of strains belonging to the Roseobacter clade within the Rhodobacteraceae family. Clones affiliated with the genera Sulfitobacter (including Clusters A1, A2, A3, A4, B1, B2, B3 and C1) and Roseovarius (i.e., Cluster C2), and a member of the Roseobacter clade (i.e., Cluster C3) accounted for 28%, 25%, and 18% of the total clones, respectively. In addition, dmdA genotypes within Clusters C1, C2 and C3 found in all samples accounted for more than 44% of the total clones. Sequences affiliated with the genera Rhodobacter and Thalassobius were only observed in sample K1. However, sequences within Cluster B5 were more frequently observed at the inner station K5 than at the outer station K1.


Diversity of bacterial dimethylsulfoniopropionate degradation genes in surface seawater of Arctic Kongsfjorden
Phylogenetic tree of deduced DmdA sequences from three clone libraries of seawater in Kongsfjorden as well as those from known bacterial species available in NCBI.Cluster A indicates genotypes only observed in station K1, Cluster B indicates genotypes shared by stations K1 and K3 (or K5), and Cluster C genotypes shared among all stations. Bootstrap values of <50 have been removed for clarity. Numbers in parentheses following clone names or cluster names indicate the number of sequences found in stations K1, K3, and K5, respectively. The scale bar indicates evolutionary distance.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015088&req=5

f2: Phylogenetic tree of deduced DmdA sequences from three clone libraries of seawater in Kongsfjorden as well as those from known bacterial species available in NCBI.Cluster A indicates genotypes only observed in station K1, Cluster B indicates genotypes shared by stations K1 and K3 (or K5), and Cluster C genotypes shared among all stations. Bootstrap values of <50 have been removed for clarity. Numbers in parentheses following clone names or cluster names indicate the number of sequences found in stations K1, K3, and K5, respectively. The scale bar indicates evolutionary distance.
Mentions: Based on 90% amino acid identity, a phylogenetic tree of these DmdA clone sequences (Fig. 2) yielded 19 major clusters (termed A1 to A8, B1 to B8, and C1 to C3), accounting for 95% of the total clone sequences. All sequences were distributed within the putative dmdA genes of strains belonging to the Roseobacter clade within the Rhodobacteraceae family. Clones affiliated with the genera Sulfitobacter (including Clusters A1, A2, A3, A4, B1, B2, B3 and C1) and Roseovarius (i.e., Cluster C2), and a member of the Roseobacter clade (i.e., Cluster C3) accounted for 28%, 25%, and 18% of the total clones, respectively. In addition, dmdA genotypes within Clusters C1, C2 and C3 found in all samples accounted for more than 44% of the total clones. Sequences affiliated with the genera Rhodobacter and Thalassobius were only observed in sample K1. However, sequences within Cluster B5 were more frequently observed at the inner station K5 than at the outer station K1.

View Article: PubMed Central - PubMed

ABSTRACT

Dimethylsulfoniopropionate (DMSP), which is the major source of organic sulfur in the world&rsquo;s oceans, plays a significant role in the global sulfur cycle. This compound is rapidly degraded by marine bacteria either by cleavage to dimethylsulfide (DMS) or demethylation to 3-methylmercaptopropionate (MMPA). The diversity of genes encoding bacterial demethylation (dmdA) and DMS production (dddL and dddP) were measured in Arctic Kongsfjorden. Both dmdA and dddL genes were detected in all stations along a transect from the outer to the inner fjord, while dddP gene was only found in the outer and middle parts of the fjord. The dmdA gene was completely confined to the Roseobacter clade, while the dddL gene was confined to the genus Sulfitobacter. Although the dddP gene pool was also dominated by homologs from the Roseobacter clade, there were a few dddP genes showing close relationships to both Alphaproteobacter and Gammaproteobacter. The results of this study suggest that the Roseobacter clade may play an important role in DMSP catabolism via both demethylation and cleavage pathways in surface waters of Kongsfjorden during summer.

No MeSH data available.


Related in: MedlinePlus