Diel Protein Regulation of Marine Picoplanktonic Communities Assessed by Metaproteomics

ABSTRACT: Diel cycle is of enormous biological importance in that it imposes temporal structure on ecosystem productivity. In the world oceans, microorganisms form complex communities that carry out about half of photosynthesis and the bulk of life-sustaining nutrient cycling. Within these natural microbial assemblages, photoautotrophs, such as Cyanobacteria, display diel rhythmicity in gene expression. To what extent autotrophs and heterotrophs are impacted by light and dark oscillations and how this collectively influences community structure and functionality remains poorly documented. In this study, we compared eight day/night metaproteome profiles of Cyanobacteria and both free-living and attached bacterial fractions from picoplanktonic communities sampled over two consecutive days from the surface north-west Mediterranean Sea. Our results showed similar taxonomic structure in both free-living and particle-attached bacteria, dominated by Alphaproteobacteria and Gammaproteobacteria. Temporal rhythmicity in protein expression was observed in both Synechococcales and Rhodobacterales in light-dependent processes such as photosynthesis or UV-stress response. Other biological processes, such as phosphorus or amino acid metabolisms, were also found to cycle in phototrophs. In contrast, proteins from the ubiquitous Pelagibacterales remained stable independently of the day/night oscillations. This work integrated for the first time diel comparative metaproteomics on both free-living and particle attached bacterial fractions in coastal oligotrophic environment. Our findings demonstrated a taxa-specific response to diel cycle with a more controlled protein regulation for phototrophs. This study provided additional evidences that timekeeping mechanisms might be widespread among Bacteria, broadening our knowledge on diel microbial assemblage dynamics.

ORGANISM(S): Marine Metagenome

SUBMITTER: S. Matallana-Surget  

PROVIDER: PXD017373 | iProX | Fri Mar 06 00:00:00 GMT 2020

REPOSITORIES: iProX