Rubinisphaera margarita sp. nov., a novel planctomycete isolated from marine sediments collected in the Portuguese north coast.

The phylum is constituted by bacteria with unique features that are well adapted to a vast range of habitats. Here, we describe a novel planctomycete isolated from marine sediments collected on a beach in Matosinhos (Portugal) using an iChip-based culturing technique. Strain ICM_H10 forms beige-coloured colonies in modified M14 medium and its cells are spherical to ovoid in shape, stalked, rosette-forming and showing motility in a phase of the life cycle. Transmission electron microscopy observations showed a typical planctomycetal cell plan and cell division by budding. This strain requires salt for growth and grows in the range of 2.0-5.0 % (w/v) NaCl, from 20 to 37 °C, within a pH of 6.0-9.0 and is able to use diverse nitrogen and carbon sources. It is heterotrophic, aerobic and capable of microaerobic growth. This strain has a genome size of approximately 6.0 Mb and a G+C content of 58.1 mol%. A 16S rRNA gene-based phylogenetic analysis supports the association of strain ICM_H10 to the phylum and the family , as it shares only 96.8 and 96.4% similarity to its closest relatives Pan54 and IFAM 1448, respectively. Other phylogenetic markers also support the separation of this strain into a novel species. Morphological, physiological and genomic comparisons between strain ICM_H10 and its closest relatives strongly suggest that ICM_H10 represents a new species of the genus , for which we propose the name sp. nov., with ICM_H10 (=CECT 30326=LMG 32234) as type strain.