Coral larvae have unique transcriptomic responses to pathogenic and probiotic bacteria

Area of Science:

• Marine Biology
• Immunology
• Coral Reef Ecology

Background:

• Coral reefs face threats from disease and environmental stressors impacting all life stages.
• Limited understanding of coral larval physiology and immune function hinders conservation.
• The temperate coral *Astrangia poculata* serves as a model for studying coral responses.

Purpose of the Study:

• Characterize the immune response of *A. poculata* larvae to bacterial stimuli.
• Identify defense mechanisms involved in coral larval resistance to pathogens.
• Investigate the effects of probiotic exposure on larval gene expression.

Main Methods:

• Transcript-level analysis of *A. poculata* larvae exposed to *Vibrio coralliilyticus* (pathogen) and *Phaeobacter inhibens* (probiont).
• Differential gene expression analysis to identify immune-related pathways.
• Clustering analyses to explore shared and divergent responses.

Main Results:

• Larval immune responses to probiotic and pathogenic bacteria showed both shared and distinct patterns.
• Enrichment of immunological peptidases, including endopeptidases and metallopeptidases, was observed.
• Pathogen exposure elicited diverse immune components, while probiont exposure was linked to developmental and metabolic terms.

Conclusions:

• Identified key immune components involved in coral larval responses to bacterial encounters.
• Findings provide insights into early-life stage resilience relevant to coral health.
• Data supports the development of novel restoration and conservation strategies for coral reefs.