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-1T 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-1T 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-1T shared the highest 16S rRNA gene sequence similarities with Nocardioides marinus CL-DD14T (96.7%) and Nocardioides terrae BX5-10T (96.7%). Phylogenetic analyses based on 16S rRNA gene sequence and phylogenomic analysis based on core proteomes alignment revealed that strain CBS4Y-1T belonged to the genus Nocardioides and formed a distinct cluster within the genus Nocardioides. The DNA G + C content of strain CBS4Y-1T was 71.1mol%. 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-C16:0, C18:1ω9c and iso-C17:0. On the basis of phylogenetic analysis, phenotypic and chemotaxonomic characteristics, strain CBS4Y-1T represents a novel species of the genus Nocardioides, for which the name Nocardioides acrostichi sp. nov. is proposed. The type strain is CBS4Y-1T (= KCTC 49238T = CGMCC 4.7548T).