BioProject

Marine sponges are one of the few documented eukaryotes that ubiquitously harbor symbiotic members of the Thaumarchaeota, which are important chemoautotrophic ammonia-oxidizers in many environments. More...

Marine sponges are one of the few documented eukaryotes that ubiquitously harbor symbiotic members of the Thaumarchaeota, which are important chemoautotrophic ammonia-oxidizers in many environments. Here we visualize and quantify the dominant thaumarchaeal symbiont of the marine sponge Ianthella basta, and demonstrate its active role in ammonia-oxidation coupled to inorganic carbon fixation based on incubation experiments measuring net and gross nitrification rates that were inhibited by the NO-scavenger PTIO. Moreover, using a metaproteogenomic approach we assembled a near-complete thaumarchaeal genome bin and document not only its expression of proteins involved in the ammonia-oxidation and inorganic carbon fixation pathways, but also of an extracellular protease, a high-affinity branched-chain ABC transporter, numerous expanded members of a well-documented thaumarchaeal s-layer family, as well as extraceullar immunoglobulin-like domain-containing proteins. Phylogenomic analyses indicate that “Candidatus Nitrosospongia bastadiensis” clusters with members of the Nitrosopumilus clade and separately from other sequenced sponge thaumarchaeotes, while sharing a similar repertoire of mobile genetic elements, the full branched-chain amino acid ABC transporter operon, and extracellular subtilisin-like proteases. Less...