Microscale tracking of coral-vibrio interactions.

Area of Science:

• Marine Biology
• Coral Pathology
• Microbial Ecology

Background:

• Coral diseases threaten reef ecosystems globally.
• Understanding host-pathogen dynamics is crucial for coral health.
• Vibrio coralliilyticus is a significant coral pathogen.

Purpose of the Study:

• To dynamically visualize early-stage coral infection by Vibrio coralliilyticus in Pocillopora damicornis.
• To elucidate the spatio-temporal mechanisms of coral disease progression.
• To identify key host-pathogen interaction events during infection.

Main Methods:

• Utilized a microfluidics-based system for controlled environmental conditions (flow, light, temperature).
• Integrated time-resolved biochemical and microbial analyses of system exudates.
• Employed dynamic microscopic observation of coral-pathogen interactions.

Main Results:

• Infection initiated via pathogen ingestion or colonization of tissue lesions.
• Pathogen ingestion triggered mucus release from the gastrovascular cavity.
• Symptomatic infections led to coenosarc severing, polyp necrosis, and increased matrix metalloprotease activity.
• Some coral polyps exhibited survival and polyp bail-out despite severe colony damage.

Conclusions:

• The study provides unprecedented spatio-temporal resolution of early coral infection phases.
• Identified distinct pathways of infection and disease progression in Pocillopora damicornis.
• Highlights the role of matrix metalloproteases in disease severity.
• Offers insights into coral resilience mechanisms and disease management strategies.