Particle-attached bacteria act as gatekeepers in the decomposition of complex phytoplankton polysaccharides.

Autor: Wang FQ; Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany., Bartosik D; Institute of Pharmacy, University of Greifswald, Felix-Hausdorff-Straße 3, 17489, Greifswald, Germany.; Institute of Marine Biotechnology, Walther-Rathenau-Straße 49a, 17489, Greifswald, Germany., Sidhu C; Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany., Siebers R; Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Straße 8, 17489, Greifswald, Germany., Lu DC; Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany.; Marine College, Shandong University, Weihai, 264209, China., Trautwein-Schult A; Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Straße 8, 17489, Greifswald, Germany., Becher D; Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Straße 8, 17489, Greifswald, Germany., Huettel B; Max Planck Genome Centre Cologne, Carl von Linné-Weg 10, 50829, Cologne, Germany., Rick J; Alfred Wegener Institute for Polar and Marine Research, Biologische Anstalt Helgoland, Helgoland, 27483, Germany., Kirstein IV; Alfred Wegener Institute for Polar and Marine Research, Biologische Anstalt Helgoland, Helgoland, 27483, Germany., Wiltshire KH; Alfred Wegener Institute for Polar and Marine Research, Biologische Anstalt Helgoland, Helgoland, 27483, Germany., Schweder T; Institute of Pharmacy, University of Greifswald, Felix-Hausdorff-Straße 3, 17489, Greifswald, Germany.; Institute of Marine Biotechnology, Walther-Rathenau-Straße 49a, 17489, Greifswald, Germany., Fuchs BM; Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany., Bengtsson MM; Institute of Microbiology, University of Greifswald, Felix-Hausdorff-Straße 8, 17489, Greifswald, Germany. mia.bengtsson@uni-greifswald.de., Teeling H; Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany. hteeling@mpi-bremen.de., Amann RI; Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359, Bremen, Germany. ramann@mpi-bremen.de.
Jazyk: angličtina
Zdroj: Microbiome [Microbiome] 2024 Feb 20; Vol. 12 (1), pp. 32. Date of Electronic Publication: 2024 Feb 20.
DOI: 10.1186/s40168-024-01757-5
Abstrakt: Background: Marine microalgae (phytoplankton) mediate almost half of the worldwide photosynthetic carbon dioxide fixation and therefore play a pivotal role in global carbon cycling, most prominently during massive phytoplankton blooms. Phytoplankton biomass consists of considerable proportions of polysaccharides, substantial parts of which are rapidly remineralized by heterotrophic bacteria. We analyzed the diversity, activity, and functional potential of such polysaccharide-degrading bacteria in different size fractions during a diverse spring phytoplankton bloom at Helgoland Roads (southern North Sea) at high temporal resolution using microscopic, physicochemical, biodiversity, metagenome, and metaproteome analyses.
Results: Prominent active 0.2-3 µm free-living clades comprised Aurantivirga, "Formosa", Cd. Prosiliicoccus, NS4, NS5, Amylibacter, Planktomarina, SAR11 Ia, SAR92, and SAR86, whereas BD1-7, Stappiaceae, Nitrincolaceae, Methylophagaceae, Sulfitobacter, NS9, Polaribacter, Lentimonas, CL500-3, Algibacter, and Glaciecola dominated 3-10 µm and > 10 µm particles. Particle-attached bacteria were more diverse and exhibited more dynamic adaptive shifts over time in terms of taxonomic composition and repertoires of encoded polysaccharide-targeting enzymes. In total, 305 species-level metagenome-assembled genomes were obtained, including 152 particle-attached bacteria, 100 of which were novel for the sampling site with 76 representing new species. Compared to free-living bacteria, they featured on average larger metagenome-assembled genomes with higher proportions of polysaccharide utilization loci. The latter were predicted to target a broader spectrum of polysaccharide substrates, ranging from readily soluble, simple structured storage polysaccharides (e.g., laminarin, α-glucans) to less soluble, complex structural, or secreted polysaccharides (e.g., xylans, cellulose, pectins). In particular, the potential to target poorly soluble or complex polysaccharides was more widespread among abundant and active particle-attached bacteria.
Conclusions: Particle-attached bacteria represented only 1% of all bloom-associated bacteria, yet our data suggest that many abundant active clades played a pivotal gatekeeping role in the solubilization and subsequent degradation of numerous important classes of algal glycans. The high diversity of polysaccharide niches among the most active particle-attached clades therefore is a determining factor for the proportion of algal polysaccharides that can be rapidly remineralized during generally short-lived phytoplankton bloom events. Video Abstract.
(© 2024. The Author(s).)
Databáze: MEDLINE
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