Bacterial predation in a marine host-associated microbiome.

Area of Science:

• Marine microbiology
• Coral reef ecology
• Bacterial predation

Background:

• Predation significantly influences ecological communities, but bacterial predation is understudied.
• Understanding microbial interactions is crucial for ecosystem health, especially in sensitive environments like coral reefs.

Purpose of the Study:

• To investigate the prevalence and activity of predatory bacteria on reef-building corals.
• To identify potential roles of bacterial predators in coral microbiome structure and health.

Main Methods:

• 16S rRNA gene sequencing of coral samples to detect bacterial communities.
• Isolation and culturing of predatory bacteria (Halobacteriovorax).
• In vitro predation assays using cultured bacteria.
• Co-occurrence network analysis to explore ecological interactions.

Main Results:

• Predatory bacteria of the genus Halobacteriovorax were detected in 79% of 198 coral samples across three genera.
• Cultured Halobacteriovorax demonstrated predation on key coral pathogens, Vibrio corallyticus and Vibrio harveyii.
• Environmental factors like temperature and nutrients influence Halobacteriovorax interactions, with prey availability potentially driving abundance.

Conclusions:

• Animal microbiomes, including those of corals, harbor active bacterial predators.
• Halobacteriovorax may play a significant role in regulating coral microbiomes and protecting hosts from pathogens.
• This research highlights a novel aspect of coral-host-microbe interactions and disease resistance.