Viral ecogenomics across the Porifera.

Area of Science:

• Marine virology
• Marine sponge ecology
• Microbial ecology

Background:

• Marine viruses regulate key ocean biological processes by controlling prokaryotic and eukaryotic populations.
• Marine sponges harbor complex microbial communities, making them ideal models for viral ecology studies.
• This study investigated viral diversity and function in sponge species from the Great Barrier Reef and Red Sea.

Purpose of the Study:

• To illuminate the diversity and function of viruses within marine sponge holobionts.
• To understand host-specific and site-specific patterns in viral assemblages.
• To explore the functional roles of viral auxiliary metabolic genes (AMGs) in sponge ecology.

Main Methods:

• Morphological analysis of viruses.
• Molecular approaches for viral identification.
• Viromic sequencing and analysis of viral communities.
• Bioinformatic analysis of viral genes, including AMGs.

Main Results:

• Viral assemblages in sponges were dominated by the bacteriophage order Caudovirales, with notable presence of nucleocytoplasmic large DNA viruses.
• Core viral functions were consistent, but functional profiles varied significantly due to differential representation of AMGs and accessory genes.
• Viral AMGs correlated with the sponge-associated microbiome composition, with specific genes linked to antimicrobial activity, nitrogen metabolism, and cellulose biosynthesis.

Conclusions:

• Viruses play diverse functional roles in marine sponges, contributing to the complex ecology of these reef holobionts.
• The differential representation of viral AMGs highlights their beneficial roles in sponge symbiosis and nutrient cycling.
• Viral functions are intricately linked to the host sponge and its associated microbial community.