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Nocardia zhihengii sp. nov., an actinobacterium isolated from rhizosphere soil of Psammosilene tunicoides

Huang, Mei-Juan, Xiao, Min, Rao, Manik Prabhu Narsing, Cheng, Tao, Yang, Yan-Yu, Alkhalifah, Dalal Hussien M., Hozzein, Wael N., Huang, Hai-Quan, Li, Wen-Jun
Antonie van Leeuwenhoek 2018 v.111 no.11 pp. 2149-2156
DNA, Nocardia nova, arabinose, cell walls, chemotaxonomy, fatty acids, fucose, galactose, genomics, glucose, mannose, menaquinones, mycelium, new species, pH, phenotype, phosphatidylethanolamines, phylogeny, quinones, rhizosphere, ribose, ribosomal RNA, sequence analysis, sodium chloride, soil, China
A Nocardia-like actinobacterial strain, designated YIM TG2190ᵀ, was isolated from rhizosphere soil of Psammosilene tunicoides collected from Gejiu, Yunnan province, China. The cells of strain YIM TG2190ᵀ were observed to be Gram-stain positive and non-motile. The strain forms extensively branched substrate mycelia that fragments into rod-shaped elements. The 16S rRNA gene sequence analysis showed that strain YIM TG2190ᵀ is closely related to Nocardia nova (97.5%), Nocardia jiangxiensis (97.1%) and Nocardia miyunensis (96.8%). Growth occurs at 4–30 °C (optimum 28 °C), pH 6.0–8.0 (optimum pH 7.0) and the strain can tolerate NaCl (w/v) up to 3% (optimum 0–1%). The cell walls were found to contain meso-diaminopimelic acid. The whole-cell sugars were identified as glucose, mannose, ribose, galactose, arabinose and fucose. The polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylglycerol and an unidentified phospholipid. The menaquinones detected were MK-9 (H₂) and MK-8 (H₄). The major fatty acids (> 5%) were found to be C₁₆:₀ (33.9%), summed feature 3 (21.7%), C₁₈:₀ 10-methyl TBSA (13.7%) and C₁₈:₁ω9c (7.0%). The DNA G+C content was determined to be 61.1 mol%. DNA-DNA relatedness between the strain YIM TG2190ᵀ and N. nova CGMCC 4.1705ᵀ, N. jiangxiensis CGMCC 4.1905ᵀ and N. miyunensis CGMCC 4.1904ᵀ were 46.9 ± 2.6, 36.8 ± 1.3, and 35.7 ± 2.6%, respectively, values which are less than the threshold value (70%) for the delineation of prokaryotic genomic species. The phenotypic, chemotaxonomic and phylogenetic data indicates that strain YIM TG2190ᵀ represents a novel species of the genus Nocardia, for which the name Nocardia zhihengii sp. nov. is proposed. The type strain is YIM TG2190ᵀ (=KCTC 39596ᵀ = DSM 100515ᵀ).