Planctopirus ephydatiae, a novel Planctomycete isolated from a freshwater sponge

Abstract

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 limnophila 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 limnophila DSM 3776^T. Our findings demonstrate and underpin the need for whole genome-based taxonomy to detect and differentiate planctomycetal species.

Keywords: Bacteriophage; Ephydatia fluviatilis; Planctomycetes; Planctopirus limnophila; Sponge; Taxonomy.