Planococcus circulans sp. nov., A Novel Bacterium Isolated from Kubuqi Desert Soil

TL;DR

A new species of desert bacterium, Planococcus circulans, was discovered in Inner Mongolia and characterized based on its unique genetic and physical traits.

Contribution

Identification of a novel bacterial species, Planococcus circulans, based on comprehensive phylogenetic and chemotaxonomic analyses.

Findings

Strain 4-30T has distinct cellular fatty acids and menaquinones, supporting its classification as a new species.

Low ANI and dDDH values confirm that 4-30T is genetically distinct from other Planococcus species.

The new species thrives under specific temperature, pH, and salt conditions typical of desert environments.

Abstract

A novel bacterial strain, designated as 4-30T, was isolated from a soil sample collected from the Kubuqi Desert in Inner Mongolia, northern China. The isolate was a Gram-stain-positive, aerobic, motile, and coccus-shaped bacterium, and its colonies were circular, opaque, convex, smooth, and orange-pigmented on Luria–Bertani agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 4-30T belonged to the genus Planococcus. Growth occurred at 4–38 °C (optimum, 25–28 °C), pH 6.0–11.0 (optimum, pH 9.0), and in 0–10% (w/v) NaCl (optimum, 1%). Strain 4-30T contained iso-C14:0, anteiso-C15:0, C16:1 ω7c alcohol, and iso-C16:0 as major cellular fatty acids (>10%) and MK-7 and MK-8 as predominant menaquinones. Its polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and two unidentified polar lipids. The genomic DNA G+C content was 45.9%. The average nucleotide identity (ANI) values between strain 4-30T and the closely related species were relatively low (ANIm < 85.6%, ANIb < 82.9% and OrthoANIu < 83.3%), and the digital DNA–DNA hybridization (dDDH) between strain 4-30T and type strains of the genus Planococcus were 20.0–26.7%. Based on phylogenetic, genotypic, chemotaxonomic, and phenotypic analyses, strain 4-30T is considered to represent a novel species of the genus Planococcus, for which the name Planococcus circulans sp. nov. is proposed. The type strain is 4-30T (=CDMCC 1.2409T = KCTC 43405T).

Figures