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

Abstract

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 °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(H₄) 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_18:1ω9c 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).