Nakamurella flava sp. nov., a novel endophytic actinobacterium isolated from Mentha haplocalyx Briq.

A Gram-stain-positive, aerobic, coccus-shaped, non-spore-forming actinobacterium, designated strain N5BH11(T), was isolated from a surface-sterilized sample of Mentha haplocalyx Briq. collected from Guizhou, PR China and tested by a polyphasic approach to determine its taxonomic position. Strain N5BH11(T) grew optimally at 30 degrees C, pH 6.0-7.0. Substrate mycelia and aerial mycelia were not formed, and no diffusible pigments were observed on the media tested. Phylogenetic analysis based on 16S rRNA gene sequence suggested that strain N5BH11(T) belonged to the genus Nakamurella and had the highest 16S rRNA gene sequence similarity to Nakamurella flavida DS-52T (98.1 %). The DNA G+C content of strain N5BH11(T) was 71.6 mol%. The average nucleotide identity values between strain N5BH11(T) and the type strains of Nakamurella panacisegetis, Nakamurella multipartite and Nakamurella lactea were 74.0, 76.5 and 73.6%, respectively. The estimated DDH values between strain N5BH11(T) and the type strains of N. panacisegetis, N. multipartita and N. lactea were 20.3%, 21.4 and 20.2%, respectively. The cell-wall peptidoglycan contained meso-diaminopimelic acid, and MK-8(H-4) was the predominant menaquinone. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine. phosphatidylmonomethylethanolamine and unidentified phospholipids. The major fatty acids were iso-C-15:0, anteiso-C-15:0, C-16:0 and C-16:1 omega 7c. On the basis of the results of phylogenetic analysis and phenotypic and chemotaxonomic characteristics, strain N5BH11(T) represents a novel species of the genus Nakamurella. for which the name Nakamurella flava sp. nov. is proposed. The type strain is N5BH11(T) (=KCTC 49196(T)=CGMCC 4.7524(T)).