Oyster hemolymph is a complex and dynamic ecosystem hosting bacteria, protists and viruses

Area of Science:

• Marine biology
• Microbial ecology
• Host-microbiome interactions

Background:

• Bacterial microbiome impact on host fitness is well-known.
• Host-associated protist and viral communities are less understood.
• Microorganisms interact with each other, host, and environment, affecting host health.

Purpose of the Study:

• Investigate environmental and host factors shaping bacterial, protist, and viral communities in Pacific oyster hemolymph.
• Analyze microbial communities during health and disease (Pacific oyster mortality syndrome).

Main Methods:

• Utilized metabarcoding and shotgun metagenomics.
• Studied five oyster families with varying susceptibility to disease.
• Transplanted oysters to natural environments before and during disease outbreaks.

Main Results:

• Oyster hemolymph hosts distinct bacterial, protist, and viral communities, shaped by environment more than host genetics.
• Microbial networks disrupted after transplantation, especially during disease outbreaks.
• OsHV-1 μVar virus dominated during disease, with minimal impact on other microbial components.

Conclusions:

• Oyster hemolymph is a complex ecosystem influenced primarily by environmental conditions.
• Host genetic background also shapes microbial communities, indicating host interaction.
• Further research on hemolymph viruses is needed to understand their independent responses.