Nocardioides imazamoxiresistens sp. nov. Isolated from the Activated Sludge

A Gram-staining-positive actinomycete named YZH12^T was isolated from the sediment of the Yangtze River in Nanjing, Jiangsu province, China. Cells were aerobic, non-spore forming, non-motile, short rod (0.4-0.6 × 0.5-1.0 µm) or coccus (0.4-0.6 µm in diameter). Colonies were circular, smooth, and beige to yellowish. Growth occurred at 15-42 °C (optimal 28 °C), pH 5.0-9.0 (optimal 7.0), and 0-10% (w/v) NaCl (optimal 2%). The strain could tolerate 1500 mg/L of imazamox. Strain YZH12^T showed 98.7% 16S rRNA gene sequence similarity Nocardioides zeae JM-1068^T and less than 97% similarities with other type strains in the genus Nocardioides. Phylogenetic analysis based on genome and 16S rRNA gene sequences indicated that strain YZH12^T was phylogenetically affiliated to the genus Nocardioides and formed a subclade with N. zeae JM-1068^T and N. alkalitolerans DSM 16699^T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between YZH12^T and closely related type strain N. zeae JM-1068^T were 79.9% and 35.2%, respectively. The major fatty acids (> 5%) were C18: 1ω9c, iso-C16: 0, C16: 0, C17: 1ω8cand C18: 0; the major respiratory quinone was MK-8(H4); and the polar lipids profiles were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), glycolipid (GL), two aminophospholipids (APL1, APL2), and an unknown polar lipid (L). The genomic DNA G + C content is 73.5%. Based on the phenotypic, chemotaxonomic, phylogenetic analyses, and genomic data, strain YZH12^T represents a novel species of the genus Nocardioides, for which the name Nocardioides imazamoxiresistens YZH12^T is proposed, with strain YZH12^T (= KCTC 49964^T = MCCC 1K0892^T) as the type strain.