Viral communities from long-term anaerobic alkane-oxidizing enrichment cultures encode predicted cell surface...

Area of Science:

• Marine microbiology
• Virology
• Geochemistry

Background:

• Anaerobic oxidation of methane and alkanes is a key process in deep-sea sediments, driven by archaea and bacteria.
• The viral communities in these hydrocarbon-rich environments have been largely unstudied.
• Understanding viral roles is crucial for comprehending deep-sea carbon cycling.

Purpose of the Study:

• To characterize viral assemblages in long-term enrichments of alkane-degrading microorganisms.
• To investigate the potential impact of viruses on hydrocarbon metabolism.
• To identify novel viral functions and host-virus interactions in sediment ecosystems.

Main Methods:

• Analysis of viral communities from multi-year sediment-free enrichments.
• Bioinformatic analysis of viral genomes for auxiliary metabolic genes (AMGs).
• CRISPR- and tRNA-based methods to identify potential host-virus interactions.
• Genomic analysis of nosD-like proteins in viral sequences.

Main Results:

• Viral community composition was primarily correlated with abiotic factors (e.g., temperature) rather than host phylogeny.
• No direct AMGs for hydrocarbon oxidation or sulfate reduction were found; however, candidate AMGs in heme synthesis pathways were identified.
• Novel nosD-like proteins, potentially involved in adhesion, were found in sediment viruses but not in water column viruses.
• Potential host-virus interactions were explored.

Conclusions:

• Abiotic factors significantly shape viral communities in alkane-degrading enrichments.
• Viruses may indirectly influence alkane degradation through mechanisms like heme synthesis.
• Sediment-specific viral proteins like nosD-like proteins suggest unique adaptations to benthic environments.
• Further research into viral roles in deep-sea sediments is warranted.