What shapes a microbiome? Differences in bacterial communities associated with helminth-amphipod interactions

Area of Science:

• Parasitology
• Microbiome Research
• Ecology

Background:

• Molecular tools reveal host-parasite-microbiome interactions.
• Parasitic infections can alter host microbiomes, influencing host-parasite dynamics.
• Understanding parasite-induced microbiome changes is crucial, considering host and parasite specificity.

Purpose of the Study:

• To characterize the hemolymph bacterial communities of amphipods infected with two different parasites.
• To compare the impact of parasitic infections on host microbiome diversity against other factors like host size and parasite load.
• To identify unique and shared microbial taxa associated with different parasitic infections.

Main Methods:

• Used 16S rRNA gene sequencing (v4 hypervariable region) to analyze bacterial communities.
• Examined hemolymph from uninfected, acanthocephalan-infected, and cestode-infected amphipods.
• Analyzed bacteria in the amphipod environment and within the parasites themselves.

Main Results:

• Parasitic infections strongly influenced host bacterial community richness, surpassing host size and parasite load effects.
• Amphipods infected with acanthocephalans showed the most distinct bacterial communities, with reduced alpha diversity.
• Unique microbial taxa were associated with each parasite species, alongside shared taxa in all parasitized amphipods.

Conclusions:

• Parasitic infections are significant modulators of host microbiomes, with species-specific effects.
• Shared bacteria in parasitized hosts may play roles in host defense or parasite success.
• These findings highlight potential co-evolutionary interactions between hosts, parasites, and their associated microbiomes.