Nocardioides luti sp. nov., belonging to the family Nocardioidaceae isolated from kaolinite, exhibiting the biosynthesis potential of alkylresorcinol.

A novel Gram-staining-positive, short rod-shaped, non-motile, and non-pigmented actinobacterial strain (KIGAM211) was isolated from kaolinite, a soft white clay mineral, collected from Sancheong in the Republic of Korea. On the basis of 16S rRNA gene sequence analysis, strain KIGAM211 was determined to belong to the genus Nocardioides and was most closely related to N. ungokensis UKS-03 (97.5% similarity). Cells could grow between 4 and 35 °C (optimum 30 °C), 0-3% (w/v) NaCl concentration (optimum 0%) and pH 5.5-8.5 (optimum 7.0) on R2A agar. Morphological appearance of colonies was cream-white, arranged singly or in groups. Biochemical characterization of strain KAGAM211 indicated that it could hydrolyze casein, gelatin, Tweens 40 and tyrosine. Furthermore, the strain was positive for both oxidase and catalase activity. Strain KIGAM211 was characterized chemotaxonomically by MK-8 (H) as the predominant menaquinone and phosphatidylglycerol (PG) and phosphatidylinositol (PI) as the major polar lipids. Major fatty acids were iso-C and C ω9c. The Ortholog average nucleotide identity (OrthoANI) and in silico DNA-DNA hybridization (isDDH) values between strain KIGAM211T and its most closely related strains of the Nocardioides genus were < 82% and < 24%, respectively, suggesting that strain KIGAM211 represent a novel species. The whole genome size of KIGAM211 was 4.52 Mb, comprising a total of 4,294 genes with DNA G + C content of 72.3 mol%. The genome of strain KIGAM211 also comprises the biosynthetic gene cluster for alkylresorcinol as secondary metabolite. The results of physiological, taxonomical, phylogenetic, and whole genome analyses allowed for differentiation of strain KIGAM211 from the recognized Nocardioides species. Therefore, strain KIGAM211 is considered to represent a novel species, for which the name Nocardioides luti sp. nov. (type strain KIGAM211 = KCTC 49364 = JCM 33859) is proposed.