Aeoliella straminimaris sp. nov., a novel member of the phylum Planctomycetota with an unusual filamentous structure.

Abstract

Organisms with distinctive biological features and cellular organization constitute the bacterial phylum Planctomycetota. In this study, we formally describe a novel isolate, strain ICT_H6.2T, isolated from sediment samples collected in the brackish environment of the Tagus River estuary (Portugal) using an iChip-based culturing technique. The 16S rRNA gene analysis placed this strain into the phylum Planctomycetota and family Lacipirellulaceae, with a similarity value of 98.0 % to its closest relative Aeoliella mucimassa Pan181T, the currently only known member of the genus. Strain ICT_H6.2T has a genome size of 7.8 Mbp and a DNA G+C content of 59.6 mol %. Strain ICT_H6.2T is heterotrophic, aerobic and capable of microaerobic growth. This strain grows from 10 to 37 °C and from pH 6.5 to 10.0, requires salt to grow, and can tolerate up to 4 % (w/v) NaCl. Diverse nitrogen and carbon sources are utilized for growth. Morphologically, strain ICT_H6.2T is white to beige pigmented, spherical to ovoid in shape and around 1.4×1.1 µm in size. The strain clusters mainly in aggregates and younger cells show motility. Ultrastructural studies showed a cell plan with cytoplasmatic membrane invaginations and unusual filamentous structures with hexagonal organization in transversal section. Morphological, physiological and genomic comparison between strain ICT_H6.2T and its closest relatives strongly suggests it represents a novel species within the genus Aeoliella, for which we propose the name Aeoliella straminimaris sp. nov., represented by strain ICT_H6.2T as the type strain (=CECT 30574T=DSM 114064T).