Dissecting host-microbiome interaction effects on phytoplankton microbiome composition and diversity.

Area of Science:

• Microbial ecology
• Aquatic microbiology
• Phytoplankton-bacteria interactions

Background:

• Phytoplankton and their associated bacterial microbiomes are crucial for aquatic ecosystem functions.
• Dissolved organic matter (DOM) released by phytoplankton shapes these microbiomes.
• The dynamic interplay between phytoplankton and bacteria in shaping microbiome assembly requires further investigation.

Purpose of the Study:

• To investigate the influence of innate host selection and host-microbiome feedback on phytoplankton bacterial microbiome formation.
• To determine how varying ratios of these two interaction mechanisms affect bacterial community assembly.
• To elucidate the distinct roles of host properties and microbial influence on microbiome composition.

Main Methods:

• Extraction of the microbiome associated with the phytoplankton species Chlorella sorokiniana.
• Experimental exposure of the extracted microbiome to six different ratios of innate host selection and host-microbiome feedback.
• Analysis of bacterial community composition across the experimental gradient.

Main Results:

• Bacterial microbiome composition significantly shifted across the tested ratios of host-microbiome interaction mechanisms.
• The highest compositional divergence was observed between communities experiencing the strongest and weakest ratios of the two mechanisms.
• Combined selective forces (both mechanisms) increased bacterial community richness, whereas host-microbiome feedback alone decreased evenness.

Conclusions:

• Both innate host selection and host-microbiome feedback are significant drivers of bacterial community assembly in phytoplankton microbiomes.
• Each mechanism exerts distinct selective pressures, favoring different bacterial species.
• Understanding these dynamic interactions is key to predicting microbial community structure and function in aquatic environments.