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

ABSTRACT

A Gram-staining-positive actinomycete named YZH12T 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 YZH12T showed 98.7% 16S rRNA gene sequence similarity Nocardioides zeae JM-1068T 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 YZH12T was phylogenetically affiliated to the genus Nocardioides and formed a subclade with N. zeae JM-1068T and N. alkalitolerans DSM 16699T. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between YZH12T and closely related type strain N. zeae JM-1068T 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 YZH12T represents a novel species of the genus Nocardioides, for which the name Nocardioides imazamoxiresistens YZH12T is proposed, with strain YZH12T (= KCTC 49964T = MCCC 1K0892T) as the type strain.