Diversity, structure and convergent evolution of the global sponge microbiome

TLDR

Sponges are early‑diverging metazoa that form complex microbial symbioses. The study surveys sponge microbiomes worldwide to investigate ecological and evolutionary drivers of host–microbe interactions. It does this by conducting a global Porifera microbiome survey. The survey reveals that sponges harbor exceptional microbial diversity, with little commonality across the phylum, yet core microbiomes are stable and dominated by generalist symbionts; host phylogeny influences community complexity rather than composition, supporting independent assembly and convergent evolution of symbiont communities.

Abstract

Abstract Sponges (phylum Porifera) are early-diverging metazoa renowned for establishing complex microbial symbioses. Here we present a global Porifera microbiome survey, set out to establish the ecological and evolutionary drivers of these host–microbe interactions. We show that sponges are a reservoir of exceptional microbial diversity and major contributors to the total microbial diversity of the world’s oceans. Little commonality in species composition or structure is evident across the phylum, although symbiont communities are characterized by specialists and generalists rather than opportunists. Core sponge microbiomes are stable and characterized by generalist symbionts exhibiting amensal and/or commensal interactions. Symbionts that are phylogenetically unique to sponges do not disproportionally contribute to the core microbiome, and host phylogeny impacts complexity rather than composition of the symbiont community. Our findings support a model of independent assembly and evolution in symbiont communities across the entire host phylum, with convergent forces resulting in analogous community organization and interactions.