Inherent differential microbial assemblages and functions associated with corals exhibiting different thermal...

Area of Science:

• Marine Biology
• Microbiology
• Coral Reef Ecology

Background:

• Coral bleaching is a major threat to marine ecosystems, driven by rising sea temperatures.
• Some coral individuals display natural resistance to thermal stress, but the underlying mechanisms are not fully understood.
• The coral microbiome, including bacteria and eukaryotes, is increasingly recognized for its role in host health and resilience.

Purpose of the Study:

• To investigate the distinct microbial communities associated with thermal bleaching-resistant (TBR) and thermal bleaching-sensitive (TBS) coral phenotypes.
• To identify specific microbial taxa and functional genes that differentiate between thermal resistance strategies in corals.
• To understand how pre-existing microbiome differences contribute to coral holobiont resilience against climate-induced thermal stress.

Main Methods:

• Comparative analysis of microbial communities in TBR and TBS coral samples.
• Utilized metabarcoding and metagenomics for comprehensive microbial profiling.
• Multidomain approach to analyze both eukaryotic and bacterial components of the coral microbiome.

Main Results:

• Stable and distinct microbial compositions were identified between TBR and TBS coral phenotypes.
• TBR corals showed enrichment in microbial eukaryotes, including Symbiodiniaceae, associated with photosynthesis and biosynthesis of beneficial compounds.
• TBS corals were characterized by bacterial metabolic genes involved in nitrogen, amino acid, and lipid metabolism.

Conclusions:

• Inherent microbiome differences exist between TBR and TBS corals, predating thermal stress.
• These microbial disparities suggest distinct holobiont phenotypes are linked to thermal bleaching resistance.
• The findings offer crucial insights into the mechanisms of coral response to climate change-induced thermal stress and inform conservation strategies.