First insights into the microbiome of a carnivorous sponge.

Using 454 pyrosequencing, we characterized for the first time the associated microbial community of the deep-sea carnivorous Demosponge Asbestopluma hypogea (Cladorhizidae). Targeting the 16S rRNA gene V3 and V6 hypervariable regions, we compared the diversity and composition of associated microbes of two individual sponges of A. hypogea freshly collected in the cave with surrounding seawater and with one sponge sample maintained 1 year in an aquarium after collection. With more than 22 961 high quality sequences from sponge samples, representing c. 800 operational taxonomic units per sponge sample at 97% sequence similarities, the phylogenetic affiliation of A. hypogea-associated microbes was assigned to 20 bacterial and two archaeal phyla, distributed into 45 classes and 95 orders. Several differences between the sponge and seawater microbes were observed, highlighting a specific and stable A. hypogea microbial community dominated by Proteobacteria and Bacteroidetes and Thaumarchaeota phyla. A high relative abundance of ammonia-oxidizing archaea and a dominance of sulfate oxidizing/reducing bacteria were observed. Our findings shed lights on the potential roles of associated microbial community in the lifestyle of A. hypogea.