Hologenomic insights into the molecular adaptation of deep-sea coral Bathypathes pseudoalternata.
Deep-sea coral ecosystems support biodiversity and nutrient cycling through interactions with symbionts. However, their molecular mechanisms remain unexplored. Here, hologenomic analyses of Bathypathes pseudoalternata are applied to uncover molecular adaptations underpinning host-symbiont interactions. Genomic evidence reveals that B. pseudoalternata exhibits adaptations in nutrient transport, immune response, and lysosomal digestion, reflecting its genomic adjustments for a stable symbiosis. Candidatus Nitrosopumilus bathypathes (78.43% ± 3.65%) is inferred to oxidize host-derived ammonia to synthesize amino acids and vitamins to provision the host. The presence of CRISPR-Cas and restriction-modification (R-M) systems suggests that Ca. Bathyplasma bathypathes and Ca. Thalassoplasma bathypathes (10.68% ± 2.99%) may protect the host from viral infections. Ca. Bathybacter bathypathes (8.39% ± 1.53%) is hypothesized to synthesize heme, lipoic acid, and glutathione, which serve dual functions as antioxidants and nutrients. These findings collectively provide insights into how the hologenome contributes to the survival of B. pseudoalternata in the extreme environment.