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The hydrological context determines the beta-diversity of aerobic anoxygenic phototrophic bacteria in European Arctic seas but does not favor endemism.

Lehours AC, Jeanthon C - Front Microbiol (2015)

Bottom Line: A majority (>60%) of pufM sequences were affiliated to the Gammaproteobacteria reasserting that this class often represents the major component of the AAP bacterial community in oceanic regions.Two alphaproteobacterial groups dominate locally suggesting that they can constitute key players in this marine system transiently.Whereas we expected specific AAP bacterial populations in this peculiar and newly explored ecosystem, most pufM sequences were highly related to sequences retrieved elsewhere.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Microorganismes: Génome et Environnement, Clermont Université, Université Blaise Pascal Clermont-Ferrand, France ; Laboratoire Microorganismes: Génome et Environnement, Centre National de la Recherche Scientifique, UMR 6023 Aubière, France.

ABSTRACT
Despite an increasing number of studies over the last 15 years, aerobic anoxygenic photoheterotrophic (AAP) bacteria remain a puzzling functional group in terms of physiology, metabolism, and ecology. To contribute to a better knowledge of their environmental distribution, the present study aims at analyzing their diversity and structure at the boundary between the Norwegian, Greenland, and Barents Seas. The polymorphism of a marker gene encoding a sub-unit of the photosynthetic apparatus (pufM gene) was analyzed and attempted to be related to environmental parameters. The Atlantic or Arctic origin of water masses had a strong impact on the AAP bacterial community structure whose populations mostly belonged to the Alpha- and Gammaproteobacteria. A majority (>60%) of pufM sequences were affiliated to the Gammaproteobacteria reasserting that this class often represents the major component of the AAP bacterial community in oceanic regions. Two alphaproteobacterial groups dominate locally suggesting that they can constitute key players in this marine system transiently. We found that temperature is a major determinant of alpha diversity of AAP bacteria in this marine biome with specific clades emerging locally according to the partitioning of water masses. Whereas we expected specific AAP bacterial populations in this peculiar and newly explored ecosystem, most pufM sequences were highly related to sequences retrieved elsewhere. This observation highlights that the studied area does not favor AAP bacteria endemism but also opens new questions about the truthfulness of biogeographical patterns and on the extent of AAP bacterial diversity.

No MeSH data available.


Diversity and distribution of AAP bacteria along the sampled transects. (A)pufM phylogenetic tree showing the inferred phylogenetic relationships of pufM gene sequences. Color ranges highlight the different phylogroups defined by Yutin et al. (2007). Tree is based on a neighbor-joining (NJ) tree to which short sequences were added by ARB_PARISMONY. Circles on nodes represent confidence values >50% for branches found in the initial NJ tree. Sequences retrieved in this study are indicated as SPIT1 to SPIT35. The multivalue bar charts represent the relative frequencies of the corresponding OTU in the clone libraries. Samples are labeled as follows: Station-Depth. Colors used to represent the clone libraries are indicated at the left of the tree. (B) Relative proportions of the phylogroups defined by Yutin et al. (2007) in individual libraries, in both transects, and in all stations.
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Figure 3: Diversity and distribution of AAP bacteria along the sampled transects. (A)pufM phylogenetic tree showing the inferred phylogenetic relationships of pufM gene sequences. Color ranges highlight the different phylogroups defined by Yutin et al. (2007). Tree is based on a neighbor-joining (NJ) tree to which short sequences were added by ARB_PARISMONY. Circles on nodes represent confidence values >50% for branches found in the initial NJ tree. Sequences retrieved in this study are indicated as SPIT1 to SPIT35. The multivalue bar charts represent the relative frequencies of the corresponding OTU in the clone libraries. Samples are labeled as follows: Station-Depth. Colors used to represent the clone libraries are indicated at the left of the tree. (B) Relative proportions of the phylogroups defined by Yutin et al. (2007) in individual libraries, in both transects, and in all stations.

Mentions: To further examine the complexity of the AAP bacterial community, 10 of the 44 samples, including 2–3 representatives of each group identified by the PCA (Figure 2A), were selected for phylogenetic analyses. With the exception of the Z59-35 m library, coverage values (>79%) indicated that most of the diversity was detected in the libraries (Table S1). All the 341 sequences were aligned, subjected to phylogenetic analyses and 35 distinct OTUs were identified after grouping the sequences at 94% nucleic acid sequence similarity (Table S2). Similarity-based OTUs did not contain sequences with mixed phylogenetic signal and all were monophyletic (data not shown). Similarly to previous observations in other oceanic regions (e.g., Yutin et al., 2007; Lehours et al., 2010; Jeanthon et al., 2011; Ritchie and Johnson, 2012; Boeuf et al., 2013), most AAP bacteria belonged to the Alpha- and Gammaproteobacteria classes (Figures 3A,B, Table S2).


The hydrological context determines the beta-diversity of aerobic anoxygenic phototrophic bacteria in European Arctic seas but does not favor endemism.

Lehours AC, Jeanthon C - Front Microbiol (2015)

Diversity and distribution of AAP bacteria along the sampled transects. (A)pufM phylogenetic tree showing the inferred phylogenetic relationships of pufM gene sequences. Color ranges highlight the different phylogroups defined by Yutin et al. (2007). Tree is based on a neighbor-joining (NJ) tree to which short sequences were added by ARB_PARISMONY. Circles on nodes represent confidence values >50% for branches found in the initial NJ tree. Sequences retrieved in this study are indicated as SPIT1 to SPIT35. The multivalue bar charts represent the relative frequencies of the corresponding OTU in the clone libraries. Samples are labeled as follows: Station-Depth. Colors used to represent the clone libraries are indicated at the left of the tree. (B) Relative proportions of the phylogroups defined by Yutin et al. (2007) in individual libraries, in both transects, and in all stations.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490794&req=5

Figure 3: Diversity and distribution of AAP bacteria along the sampled transects. (A)pufM phylogenetic tree showing the inferred phylogenetic relationships of pufM gene sequences. Color ranges highlight the different phylogroups defined by Yutin et al. (2007). Tree is based on a neighbor-joining (NJ) tree to which short sequences were added by ARB_PARISMONY. Circles on nodes represent confidence values >50% for branches found in the initial NJ tree. Sequences retrieved in this study are indicated as SPIT1 to SPIT35. The multivalue bar charts represent the relative frequencies of the corresponding OTU in the clone libraries. Samples are labeled as follows: Station-Depth. Colors used to represent the clone libraries are indicated at the left of the tree. (B) Relative proportions of the phylogroups defined by Yutin et al. (2007) in individual libraries, in both transects, and in all stations.
Mentions: To further examine the complexity of the AAP bacterial community, 10 of the 44 samples, including 2–3 representatives of each group identified by the PCA (Figure 2A), were selected for phylogenetic analyses. With the exception of the Z59-35 m library, coverage values (>79%) indicated that most of the diversity was detected in the libraries (Table S1). All the 341 sequences were aligned, subjected to phylogenetic analyses and 35 distinct OTUs were identified after grouping the sequences at 94% nucleic acid sequence similarity (Table S2). Similarity-based OTUs did not contain sequences with mixed phylogenetic signal and all were monophyletic (data not shown). Similarly to previous observations in other oceanic regions (e.g., Yutin et al., 2007; Lehours et al., 2010; Jeanthon et al., 2011; Ritchie and Johnson, 2012; Boeuf et al., 2013), most AAP bacteria belonged to the Alpha- and Gammaproteobacteria classes (Figures 3A,B, Table S2).

Bottom Line: A majority (>60%) of pufM sequences were affiliated to the Gammaproteobacteria reasserting that this class often represents the major component of the AAP bacterial community in oceanic regions.Two alphaproteobacterial groups dominate locally suggesting that they can constitute key players in this marine system transiently.Whereas we expected specific AAP bacterial populations in this peculiar and newly explored ecosystem, most pufM sequences were highly related to sequences retrieved elsewhere.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Microorganismes: Génome et Environnement, Clermont Université, Université Blaise Pascal Clermont-Ferrand, France ; Laboratoire Microorganismes: Génome et Environnement, Centre National de la Recherche Scientifique, UMR 6023 Aubière, France.

ABSTRACT
Despite an increasing number of studies over the last 15 years, aerobic anoxygenic photoheterotrophic (AAP) bacteria remain a puzzling functional group in terms of physiology, metabolism, and ecology. To contribute to a better knowledge of their environmental distribution, the present study aims at analyzing their diversity and structure at the boundary between the Norwegian, Greenland, and Barents Seas. The polymorphism of a marker gene encoding a sub-unit of the photosynthetic apparatus (pufM gene) was analyzed and attempted to be related to environmental parameters. The Atlantic or Arctic origin of water masses had a strong impact on the AAP bacterial community structure whose populations mostly belonged to the Alpha- and Gammaproteobacteria. A majority (>60%) of pufM sequences were affiliated to the Gammaproteobacteria reasserting that this class often represents the major component of the AAP bacterial community in oceanic regions. Two alphaproteobacterial groups dominate locally suggesting that they can constitute key players in this marine system transiently. We found that temperature is a major determinant of alpha diversity of AAP bacteria in this marine biome with specific clades emerging locally according to the partitioning of water masses. Whereas we expected specific AAP bacterial populations in this peculiar and newly explored ecosystem, most pufM sequences were highly related to sequences retrieved elsewhere. This observation highlights that the studied area does not favor AAP bacteria endemism but also opens new questions about the truthfulness of biogeographical patterns and on the extent of AAP bacterial diversity.

No MeSH data available.