Nocardioides acrostichi sp. nov., a novel endophytic actinobacterium isolated from leaf of Acrostichum aureum

A short-rod-shaped, non-spore-forming endophytic actinobacterium, was isolated from a surface-sterilized leaf of Acrostichum aureum in Fangchenggang, Guangxi Zhuang Autonomous Region, China, designated strain CBS4Y-1(T) and examined by a polyphasic approach to determine its taxonomic position. This actinobacterium was Gram-staining-positive and aerobic. Substrate mycelia and aerial mycelia were not observed, and no diffusible pigments were observed on the media tested. Strain CBS4Y-1(T) grew optimally with 0-1.0% (w/v) NaCl at 30 degrees C, pH 7.0-8.0. Comparative analysis of 16S rRNA genes showed that strain CBS4Y-1(T) shared the highest 16S rRNA gene sequence similarities with Nocardioides marinus CL-DD14(T) (96.7%) and Nocardioides terrae BX5-10(T) (96.7%). Phylogenetic analyses based on 16S rRNA gene sequence and phylogenomic analysis based on core proteomes alignment revealed that strain CBS4Y-1(T) belonged to the genus Nocardioides and formed a distinct cluster within the genus Nocardioides. The DNA G + C content of strain CBS4Y-1(T) was 71.1 mol%. The cell-wall peptidoglycan contained LL-diaminopimelic acid and MK-8(H-4) was the predominant menaquinone. Phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylinositol (PI) were detected in the polar lipid extracts. The major fatty acids were iso-C-16:0, C-18:1 omega 9c and iso-C-17:0. On the basis of phylogenetic analysis, phenotypic and chemotaxonomic characteristics, strain CBS4Y-1(T) represents a novel species of the genus Nocardioides, for which the name Nocardioides acrostichi sp. nov. is proposed. The type strain is CBS4Y-1(T) (= KCTC 49238(T) = CGMCC 4.7548(T)).

Automated summary

A novel species Nocardioides acrostichi sp. nov. was isolated from the leaf surface of Acrostichum aureum in Fangchenggang, Guangxi Zhuang Autonomous Region, China. Through comparative analysis of 16S rRNA gene sequences, phylogenetic analysis and chemotaxonomic characteristics, it was determined that strain CBS4Y-1(T) belongs to the genus Nocardioides.