Community Research and Development Information Service - CORDIS

Better understanding of the ecological role of uncultured microorganisms on oceans

Although suspected of being one of the main mortality agents of marine bacteria in oceans, little is known about the abundance and ecological role of marine stramenopiles (MASTs) in global ecosystems. An EU initiative explored these uncultured microorganisms and their key functions in marine environments worldwide.
Better understanding of the ecological role of uncultured microorganisms on oceans
Constituted by 18 discrete groups, these diverse eukaryotic microbes are widespread and abundant bacterial grazers. As a result, MASTs may have a tremendous impact on marine ecosystem functioning. However, most of this diversity remains uncultured, so determining the microbial diversity and ecological and evolutionary attributes of MASTs is one of the main challenges for scientists.

With this in mind, the EU-funded DYGEMAST (Dynamics, genomics and functional significance of uncultured marine stramenopiles) project set out to assess MASTs' abundance dynamics, and investigate their ecological importance in oceans through the scope of single-cell analyses.

Using an automatic picoeukaryotic cell counting approach, project partners studied the dynamics of several MAST lineages in marine systems. The approach was further optimised to provide an accurate estimation of densities of contrasting cell-size picoeukaryotes in a wide range of samples. They applied the method to the analysis of the vertical and spatial distribution of three MAST groups with respect to environmental factors. This was done to gain access to their ecology. Findings show contrasting abundances between the three lineages, with the highest densities in surface samples taken near coasts and the equator.

The DYGEMAST team also examined the genomics and role of MAST lineages in marine ecosystems using state-of-art techniques. This helped to increase the genomic information captured in one particular MAST lineage by combining multiple single cells. Thanks to this co-assembly strategy, a significant increase of the genomic information was observed, from around 20% of gene functions in a single cell to about 70% in the final co-assemblies. This approach starts giving access to the structural and functional composition of MASTs genomes, allowing to address new ecological and evolutionary questions on these eukaryotic microbes.

Thanks to DYGEMAST, the range of developed tools and approaches employed for MASTs can be now adapted to various protists. Better insight into the role of microbial biodiversity in oceans through MAST examination can ultimately benefit efforts to address global climate change and potential biodiversity loss.

Related information

Keywords

Microorganisms, marine stramenopiles, eukaryotic microbes, picoeukaryotes, single-cell genomics, automatic cell counting, DYGEMAST
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top