Nocardioides euryhalodurans sp. Nov., nocardioides seonyuensis sp. nov. and nocardioides eburneiflavus sp. nov., isolated from soil

Abstract

Three aerobic, rod-shaped actinobacterial strains, designated MMS17-SY117T, MMS17-SY207-3T and MMS17-SY213T, were isolated from soil and their taxonomic positions were analysed using a polyphasic approach. The isolates showed best growth at 30 °C, pH 7 and 0–1% (w/v) NaCl. On the basis of 16S rRNA gene sequence similarity, the isolates were affiliated to the genus Nocardioides, and the closest species to MMS17-SY117T, MMS17-SY207-3T and MMS17-SY213T were Nocardioides aestuarii JC2056T (97.76%), Nocardioides currus IB-3T (97.41%) and Nocardioides exalbidus RC825T (98.71%), respectively. Each isolate formed a distinct cluster within the Nocardioides clade in the phylogenetic tree. The orthologous average nucleotide identity and digital DNA–DNA hybridization values were in the range of 74.4–85.7% and 16.6–39.2%, respectively, with the type strains of related species. The major polar lipids in all three strains were phosphatidylinositol, phosphatidylglycerol and diphosphatidyl-glycerol. The predominant fatty acids were iso-C16:0 and C17:1 ω8c. MK-8(H4) was the major isoprenoid quinone and ll-DAP was the major diamino acid. Galactose, glucose and rhamnose were present in the whole-cell hydrolysate, and MMS17-SY213T also contained mannose and ribose. The DNA G+C contents of MMS17-SY117T, MMS17-SY207-3T and MMS17-SY213T were 72.2, 70.4 and 71.5 mol%, respectively. The phylogenetic, phenotypic and chemotaxonomic data supported the classification of each strain as representing a new species of Nocardioides, for which the names Nocardioides euryhalodurans sp. nov. (MMS17-SY117T=KCTC 49175T=JCM 32831T), Nocardioides seonyuensis sp. nov. (MMS17-SY207-3T=KCTC 49176T=JCM 32832T) and Nocardioides ebur-neiflavus sp. nov. (MMS17-SY213T=KCTC 49177T=JCM 32833T) are proposed accordingly.