Paludisphaera rhizosphaereae sp. nov., a new member of the family Isosphaeraceae, isolated from the rhizosphere soil of Erianthus ravennae.

Two axenic cultures of Planctomycetota were isolated from distinct geographical locations of India. Strain JC665T was isolated from a rhizosphere soil of Loktak lake, Manipur, whereas strain JC747 was isolated from a soil sediment at Pallikkara village, Kerala, India. The two closely related strains shared the highest 16S rRNA gene sequence identity (94.6%) with Paludisphaera borealis PX4T, while the 16S rRNA gene sequence identity between both strains was 100%. Both strains grow aerobically, stain Gram negative, colonies are light pink-coloured, cells are non-motile, spherical to oval-shaped and tolerate NaCl up to 2% (w/v). While strain JC665T grows well up to pH 9.0, strain JC747 grows only up to pH 8.0. The respiratory quinone in both strains is MK-6. C16:0, C18:1ω9c and C18:0 are the major fatty acids. Phosphatidylcholine, two unidentified glycolipids, seven unidentified lipids and two unidentified phospholipids made up the polar lipid composition of both strains. Both strains have genome sizes of about 8.0 Mb and a DNA G + C content of 66.4 mol%. Both strains contain genes coding for enzymes putatively involved in the production of lycopene-related carotenoids. The phylogenetic position together with the results of the analysis of morphological, physiological and genomic features support the classification of strain JC665T as a new species of the genus Paludisphaera, for which we propose the name Paludisphaera rhizosphaerae sp. nov. Strain JC665T (= KCTC 72671 T = NBRC 114305 T) and JC747 are the type and non-type strain of the new species, respectively.

Phylotaxogenomics for the Reappraisal of the Genus Roseomonas With the Creation of Six New Genera.

The genus Roseomonas is a significant group of bacteria which is invariably of great clinical and ecological importance. Previous studies have shown that the genus Roseomonas is polyphyletic in nature. Our present study focused on generating a lucid understanding of the phylogenetic framework for the re-evaluation and reclassification of the genus Roseomonas. Phylogenetic studies based on the 16S rRNA gene and 92 concatenated genes suggested that the genus is heterogeneous, forming seven major groups. Existing Roseomonas species were subjected to an array of genomic, phenotypic, and chemotaxonomic analyses in order to resolve the heterogeneity. Genomic similarity indices (dDDH and ANI) indicated that the members were well-defined at the species level. The Percentage of Conserved Proteins (POCP) and the average Amino Acid Identity (AAI) values between the groups of the genus Roseomonas and other interspersing members of the family Acetobacteraceae were below 65 and 70%, respectively. The pan-genome evaluation depicted that the pan-genome was an open type and the members shared 958 core genes. This claim of reclassification was equally supported by the phenotypic and chemotaxonomic differences between the groups. Thus, in this study, we propose to re-evaluate and reclassify the genus Roseomonas and propose six novel genera as Pararoseomonas gen. nov., Falsiroseomonas gen. nov., Paeniroseomonas gen. nov., Plastoroseomonas gen. nov., Neoroseomonas gen. nov., and Pseudoroseomonas gen. nov.

Arenibacter lacus sp. nov., Isolated from Chilika Lagoon, India.

A shiny dark yellow pigmented, Gram-stain-negative, rod-shaped, non-motile bacterium, designated as strain JC631T, was isolated from the sediment ecosystem of Chilika lagoon, India. Strain JC631T tolerates up to pH 10 and NaCl up to 3% (w/v). MK6 is the only respiratory quinone. Predominant (> 10%) cellular fatty acids are anteiso-C11:0, anteiso-C13:0, and anteiso-C15:0. Major polar lipids are phosphatidylethanolamine, phosphatidylcholine, a few unidentified phospholipids, and a few unidentified aminolipids. 16S rRNA gene sequencing showed that strain JC631T shared the highest sequence identity (98.7%) with Arenibacter latericius KMM 426T followed by Arenibacter certesii CCUG 48006T (98.6%) and other members of the genus Arenibacter (< 97%). The genome size of strain JC631T is 4.16 Mb with a GC content of 40.8 mol%. Strain JC631T has ANI scores of 78.3% and 78.1%; dDDH values of 22.2% and 21.8%, respectively, with the type strains of A. latericius and A. certesii. The genomic distinction is well supported by chemotaxonomic characteristics and differential physiological properties. This supports strain JC631T to be described as a new species of the genus Arenibacter, named as Arenibacter lacus sp. nov. The type strain is JC631T (= KCTC 72002T = NBRC 114071T).