Thalassoglobus polymorphus sp. nov., a novel Planctomycete isolated close to a public beach of Mallorca Island.

Access to axenic cultures is crucial to extend the knowledge of the biology, lifestyle or metabolic capabilities of bacteria from different phyla. The phylum Planctomycetes is an excellent example since its members display an unusual cell biology and complex lifestyles. As a contribution to the current collection of axenic planctomycete cultures, here we describe strain Mal48 isolated from phytoplankton material sampled at the coast of S'Arenal close to Palma de Mallorca (Spain). The isolated strain shows optimal growth at pH 7.0-7.5 and 30 °C and exhibits typical features of Planctomycetes. Cells of the strain are spherical to pear-shaped, divide by polar budding with daughter cells showing the same shape as the mother cell, tend to aggregate, display a stalk and produce matrix or fimbriae. Strain Mal48 showed 95.8% 16S rRNA gene sequence similarity with the recently described Thalassoglobus neptunius KOR42. The genome sequence of the novel isolate has a size of 6,357,355 bp with a G+C content of 50.3%. A total of 4874 protein-coding genes, 41 tRNA genes and 2 copies of the 16S rRNA gene are encoded in the genome. Based on phylogenetic, morphological and physiological analyses, we conclude that strain Mal48 (= DSM 100737 = LMG 29019) should be classified as the type strain of a new species in the genus Thalassoglobus, for which the name Thalassoglobus polymorphus sp. nov. is proposed.