Rathayibacter rubneri sp. nov. isolated from Allium cepa var. Rijnsburger, an onion landrace

Abstract

The novel, aerobic, Gram-stain-positive, rod-shaped bacterial strain, ZW T2_19T, was isolated from an onion sample (Allium cepa var. Rijnsburger). Analyses of the 16S rRNA gene sequence revealed that ZW T2_19T represented a member of the genus Rathayibacter but may represent a novel species of this genus. Analyses of the whole draft genome sequences, i.e. digital DNA–DNA hybridisation (dDDH) and average nucleotide identity (ANI) of ZW T2_19T and all type strains of species of the genus Rathayibacter confirmed that ZW T2_19T represents a novel species of the genus Rathayibacter . The genome size of ZW T2_19T is 4.01 Mbp and the DNA G+C content is 71.8 mol%. Glucose, mannose, rhamnose and ribose were detected as whole-cell sugars of ZW T2_19T. The major respiratory quinone of ZW T2_19T is menaquinone MK-10, at 78.9 %. The detected peptidoglycan type in ZW T2_19T is a variant of type B2γ with {Gly} [l-diaminobutyric acid (l-DAB)/l-homoserine (l-Hse)] d-Glu-l-DAB. Polar lipids in ZW T2_19T consisted of one diphosphatidylglycerol, one phosphatidylglycerol, seven glycolipids, one phospholipid and one lipid. The fatty acid profile of ZW T2_19T predominantly consisted of anteiso-C15 : 0 (53 %), iso-C16 : 0 (21 %) and anteiso-C17 : 0 (18 %). In addition, API 20NE, API 50CH, API Coryne, API ZYM, antibiotic susceptibility, haemolysis and growth at different temperatures and with different supplements was investigated. On the basis of the results obtained using this polyphasic approach, including molecular, phenotypic and biochemical analyses, we propose the novel species Rathayibacter rubneri with the type and only strain ZW T2_19T (= DSM 114294T = LMG 32700T).