Assessing the core microbial symbionts of jellyfish in Indonesian and Vietnamese marine lakes

Abstract

AbstractJellyfish are a well-known component of marine ecosystems. Here, we aimed to assess whether populations of the jellyfish species Mastigias cf. papua and Cassiopea ornata inhabiting different marine lakes and jellyfish species from open water habitat host ‘core’ symbionts and if there is evidence of species-specific host-microbial associations. Compositionally, jellyfishes hosted prokaryotic communities distinct from those found in water samples. All jellyfish samples across habitats and species exhibited a core OTU, assigned to the genus Endozoicomonas. This OTU was particularly abundant (>90% of all sequences) in C. ornata from one Papuan marine lake. Additionally, an OTU assigned to the Entomoplasmatales order was found in all but two jellyfish specimens, and was particularly abundant in marine lake specimens from Berau and Papua, Indonesia. Given the well-known relationship between Endozoicomonas and Symbiodinium spp., we tested for Symbiodinium presence in pooled specimens of M. papua from Berau. Our results showed that OTUs assigned to the genus Symbiodinium accounted for >99% of all sequences in jellyfish-associated microeukaryotic communities; these were closely related to organisms from Symbiodinium clade C. These results suggest the existence of a widespread and abundant jellyfish core symbiont, which may interact with symbiotic Symbiodinium populations to influence host fitness.