Microbial Community Dynamics in Cnidarian Holobionts

Cnidarian holobionts encompass the host organism and its diverse assemblage of associated microorganisms, including bacteria, archaea and microalgae. Microbial communities within corals and sea anemones undergo dynamic processes of colonisation, succession and stabilisation from early developmental stages through adulthood. Initial symbiont acquisition may occur via vertical transmission within gametes or by horizontal uptake from the environment, with host factors such as immune modulation and mucus chemistry shaping early assembly. Subsequent bacterial succession is largely governed by inter-microbial metabolic interactions, nutrient exchange and competitive dynamics. Environmental variables—including temperature, salinity and water chemistry—drive shifts in community composition, while host genotype imposes a secondary layer of selection, together generating microbiota plasticity. These dynamic interactions underpin the holobiont’s capacity for acclimation to stressors such as thermal anomalies and ocean acidification. Understanding the drivers of microbiome assembly and resilience is critical for coral reef conservation, as manipulations of microbial partners may offer novel routes to bolster stress tolerance and support ecosystem recovery.

Research from Nature Portfolio

Recent studies have shown that the microbiota of the starlet sea anemone can mediate rapid thermal acclimation. Clonal lines acclimated to elevated temperatures exhibited enhanced thermal tolerance, which could be transferred to naïve hosts by transplantation of the acclimated microbiome. Furthermore, specific bacterial taxa were found to be vertically transmitted to offspring, underpinning a heritable component of microbiota-mediated plasticity and suggesting a mechanism for rapid adaptation to warming.

Microbial Community Dynamics in Cnidarian Holobionts publication trend

The graph below shows the total number of articles in microbial community dynamics in cnidarian holobionts across all publications each year (not limited to Nature Index journals).

Technical terms

Holobiont: The ecological unit combining a host and its associated microbial community.

Microbiota plasticity: The capacity of microbial communities to change composition in response to environmental or host factors.

Bacterial succession: Sequential changes in bacterial community composition over time or developmental stages.

Vertical transmission: Transfer of microbial symbionts from parent to offspring.

Symbiont establishment: The process by which microbes colonise and form stable associations with the host.

References

1. Sequential host-bacteria and bacteria-bacteria interactions determine the microbiome establishment of Nematostella vectensis. Microbiome (2023).
2. Genotype–environment interactions determine microbiota plasticity in the sea anemone Nematostella vectensis. PLOS Biology (2023).
3. Microbiota mediated plasticity promotes thermal adaptation in the sea anemone Nematostella vectensis. Nature Communications (2022).
4. Broadcast Spawning Coral Mussismilia hispida Can Vertically Transfer its Associated Bacterial Core. Frontiers in Microbiology (2017).
5. Establishment of Coral-Bacteria Symbioses Reveal Changes in the Core Bacterial Community With Host Ontogeny. Frontiers in Microbiology (2019).