Nocardioides astragali sp. nov., isolated\xa0from\xa0a nodule of wild Astragalus chrysopterus in northwestern China

Abstract

A Gram-positive, non-motile, rod-shaped bacterial strain, designated HH06T, was isolated from a nodule of Astragalus chrysopterus in northwestern China. Phylogenetic analysis of the 16S rRNA gene sequence showed that the strain is closely related to Nocardioides alpinus Cr7-14T and Nocardioides furvisabuli DSM 18445T with 98.5 and 98.1% similiarity, respectively. Growth was observed at 4–28 °C in R2A medium (optimum at 25 °C), at 10–30 °C in YMA and LB medium (optimum in both at 28 °C) and at pH 5.0–10.0 in R2A medium (optimum at pH 7.0–8.0). The cell wall peptidoglycan was found to contain LL-diaminopimelic acid as the principal diamino acid and MK-8(H4) was identified as the predominant menaquinone. The major polar lipids were identified as phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, two unidentified glycolipids and two unidentified polar lipids. The major fatty acids were identified as iso-C16:0 (32.8%) and C18:1ω9c (15.1%). The DNA G+C content of strain HH06T was determined to be 71.4 mol%. Based on phenotypic, chemotaxonomic, phylogenetic properties and DNA–DNA relatedness, it is concluded that strain HH06T represents a novel species of the genus Nocardioides, for which the name Nocardioides astragali sp. nov. is proposed. The type strain is HH06T (= CGMCC 4.7327T = NBRC 112322T).