Isoptericola luteus sp. nov., a novel yellow bacterium isolated from soil

Abstract

An aerobic, non-motile, Gram-stain-positive bacterium, designated strain NEAU-Y5^T, was isolated from a soil sample collected from Northeast Agricultural University, Heilongjiang province. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-Y5^T belonged to the genus and showed high 16S rRNA sequence similarity to Isoptericola variabilis (98.9 %), Isoptericola nanjingensis (98.9 %), Isoptericola cucumis (98.5 %), Isoptericola hypogeus (98.5 %), Isoptericola dokdonensis (98.5 %), Isoptericola jiangsuensis (98.3 %), and Isoptericola halalbus (98.1 %), followed by other members of the genus Isoptericola (<98 %), and phylogenetically clustered with I. dokdonensis and I. jiangsuensis. Strain NEAU-Y5^T was found to grow at 4-40 °C (optimum, 28 °C), pH 6.0-12.0 (optimum, pH 7.0), and tolerated 0-6 % NaCl (w/v). The cell-wall peptidoglycan type was l-Lys-d-Asp. The whole-cell hydrolysates contained glucose, galactose, and ribose. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, and glucosamine unknown phospholipid. Major fatty acids were anteiso-C_{15 : 0} and anteiso-C_{17 : 0}. The predominant menaquinone was MK-9(H₄). The DNA G+C content was 73.4 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between strain NEAU-Y5^T and the type strains of the genus Isoptericola ranged from 18.6 to 23.5 % and from 77.3 to 81.6 %, respectively. Based on morphological, physiological, chemotaxonomic, and phylogenetic data, as well as digital DNA-DNA hybridization and average nucleotide identity values, the novel strain NEAU-Y5^T could be differentiated from its closest relatives. Therefore, the strain represents a novel species of the genus Isoptericola, for which the name Isoptericola luteus sp. nov. is proposed. The type strain is NEAU-Y5^T (=CCTCC AA 2019087^T=DSM 110637^T).

Keywords: 16S rRNA gene sequence; Isoptericola luteus sp. nov.; polyphasic taxonomy; soil; whole genome.