Metagenomic sequencing of marine periphyton: taxonomic and functional insights
into biofilm communities
#MMPMID26579098
Sanli K
; Bengtsson-Palme J
; Nilsson RH
; Kristiansson E
; Alm Rosenblad M
; Blanck H
; Eriksson KM
Front Microbiol
2015[]; 6
(?): 1192
PMID26579098
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Periphyton communities are complex phototrophic, multispecies biofilms that
develop on surfaces in aquatic environments. These communities harbor a large
diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans,
and metazoans. However, thus far the total biodiversity of periphyton has not
been described. In this study, we use metagenomics to characterize periphyton
communities from the marine environment of the Swedish west coast. Although we
found approximately ten times more eukaryotic rRNA marker gene sequences compared
to prokaryotic, the whole metagenome-based similarity searches showed that
bacteria constitute the most abundant phyla in these biofilms. We show that
marine periphyton encompass a range of heterotrophic and phototrophic organisms.
Heterotrophic bacteria, including the majority of proteobacterial clades and
Bacteroidetes, and eukaryotic macro-invertebrates were found to dominate
periphyton. The phototrophic groups comprise Cyanobacteria and the
alpha-proteobacterial genus Roseobacter, followed by different micro- and
macro-algae. We also assess the metabolic pathways that predispose these
communities to an attached lifestyle. Functional indicators of the biofilm form
of life in periphyton involve genes coding for enzymes that catalyze the
production and degradation of extracellular polymeric substances, mainly in the
form of complex sugars such as starch and glycogen-like meshes together with
chitin. Genes for 278 different transporter proteins were detected in the
metagenome, constituting the most abundant protein complexes. Finally, genes
encoding enzymes that participate in anaerobic pathways, such as denitrification
and methanogenesis, were detected suggesting the presence of anaerobic or
low-oxygen micro-zones within the biofilms.
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