Temporal transcriptional rhythms govern coral-symbiont function and microbiome dynamics.

Area of Science:

• Marine Biology
• Genomics
• Symbiosis Research

Background:

• Diel rhythms regulate physiological processes via light/dark cycles.
• Transcriptional-translational feedback loops control gene expression and protein activity.
• Understanding diel regulation in coral holobionts is crucial for marine ecosystem health.

Purpose of the Study:

• To investigate the in situ transcriptomic dynamics of the stony coral Pseudodiploria strigosa and its photosymbionts.
• To elucidate the diel-specific molecular mechanisms governing the coral holobiont.
• To map the coordinated transcriptional control across coral, photosymbionts, and microbial communities.

Main Methods:

• In situ transcriptomic analysis of Pseudodiploria strigosa and Breviolum sp. at multiple daily time points.
• Analysis of gene expression patterns related to RNA metabolism, anabolism, and stress responses.
• Investigation of diel shifts in photosymbiont and microbial community gene expression and network interactions.

Main Results:

• Pseudodiploria strigosa exhibits precise diel transcriptional control, with distinct molecular events at dawn, midday, dusk, and midnight.
• Photosymbionts (Breviolum sp.) show subtler diel patterns related to photoprotection, metabolism, and cell cycle regulation.
• Microbial communities display time-dependent restructuring, impacting diel-related functional consequences like microbial metabolism.

Conclusions:

• A system-level molecular framework for diel regulation in the coral holobiont has been established.
• Time-specific transcriptional control coordinates function and homeostasis across the coral, photosymbiont, and associated microbes.
• Diel rhythms are critical for maintaining the health and stability of coral reef ecosystems.