Protists' microbiome: A fine-scale, snap-shot field study on the ciliate Euplotes

Area of Science:

• Microbiology
• Ecology
• Protistology

Background:

• Host-microbiome interactions are crucial for evolution and ecology.
• Protists, as unicellular eukaryotes, offer a model for studying prokaryotic microbiome selection at the cellular level.
• Field studies are essential for understanding natural selective drivers.

Purpose of the Study:

• To analyze bacterial microbiomes associated with natural populations of the protist ciliate genus Euplotes.
• To investigate the influence of habitat and host identity on microbiome selection at a fine scale.
• To identify key drivers shaping prokaryotic communities in protist hosts.

Main Methods:

• Analysis of previously reported field study data on bacterial microbiomes of Euplotes ciliates.
• Comparative analyses of prokaryotic community structures based on environmental and host factors.
• Examination of microbiome composition across different spatial scales (sampling area, pond/channel, site).

Main Results:

• Environment at a large sampling scale was identified as the primary factor structuring prokaryotic communities.
• Habitat did not emerge as a key factor when considering smaller spatial scales (pond/channel or site).
• Host identity's influence on microbiome selection at the species level was inconclusive due to small sample sizes.

Conclusions:

• Environmental context, especially at broader scales, is a major determinant of protist-associated bacterial communities.
• Further extensive sampling is needed to clarify the role of host identity in microbiome selection.
• This research provides insights into the ecological drivers of microbial communities in natural protist populations.