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

Three aerobic, rod-shaped actinobacterial strains, designated MMS17-SY117(T), MMS17-SY207-3(T) and MMS17-SY213(T), were isolated from soil and their taxonomic positions were analysed using a polyphasic approach. The isolates showed best growth at 30 degrees 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-SY117(T), MMS17-SY207-3(T) and MMS17-SY213(T) were Nocardioides aestuarii JC2056(T) (97.76%), Nocardioides currus 18-3(T) (97.41%) and Nocardioides exalbidus RC825(T) (98.71%), respectively. Each isolate formed a distinct cluster within the Nocardioides Glade 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 diphosphatidylglycerol. The predominant fatty acids were isoC16.0 and C-17:1 omega 8c. MK-8(H-4) 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-SY213(T) also contained mannose and ribose. The DNA G+C contents of MMS17-SY117(T), MMS17-SY207-3(T) and MMS17-SY213(T) 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-SY117(T)=KCTC 49175(T)=JCM 32831(T)), Nocardioides seonyuensis sp. nov. (MMS17-SY207-3(T)=KCTC 49176(T)=JCM 32832(T)) and Nocardioides eburneiflavus sp. nov. (MMS17-SY213(T)=KCTC 49177(T)=JCM 32833(T)) are proposed accordingly.