Nocardioides imazamoxiresistens sp. nov. Isolated from the Activated Sludge.

A Gram-staining-positive actinomycete named YZH12 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 showed 98.7% 16S rRNA gene sequence similarity Nocardioides zeae JM-1068 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 was phylogenetically affiliated to the genus Nocardioides and formed a subclade with N. zeae JM-1068 and N. alkalitolerans DSM 16699. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between YZH12 and closely related type strain N. zeae JM-1068 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 represents a novel species of the genus Nocardioides, for which the name Nocardioides imazamoxiresistens YZH12 is proposed, with strain YZH12 (= KCTC 49964 = MCCC 1K0892) as the type strain.