Planctopirus ephydatiae, a novel Planctomycete isolated from a freshwater sponge

The microbiome of freshwater sponges is rarely studied, and not a single novel bacterial species has been isolated and subsequently characterized from a freshwater sponge to date. A previous study showed that 14.4% of the microbiome from Ephydatia fluviatilis belong to the phylum Planctomycetes. Therefore, we sampled an Ephydatia sponge from a freshwater lake and employed enrichment techniques targeting bacteria from the phylum Planctomycetes. The obtained strain spb1(T) was subject to genomic and phenomic characterization and found to represent a novel planctomycetal species proposed as Planctopirus ephydatiae sp. nov. (DSM 106606=CECT 9866). In the process of differentiating spb1(T) from its next relative Planctopirus limnophiia DSM 3776(T), we identified and characterized the first phage - Planctopirus phage vB_PlimS_J1 - infecting planctomycetes that was only mentioned anecdotally before. Interestingly, classical chemotaxonomic methods would have failed to distinguish Planctopirus ephydatiae strain spb1(T) from Planctopirus limnophiia DSM 3776(T). Our findings demonstrate and underpin the need for whole genome-based taxonomy to detect and differentiate planctomycetal species. (C) 2019 Elsevier GmbH. All rights reserved.