Nocardioides pymetrozini sp. nov., a pymetrozine-degrading bacterium isolated from long-term continuous cropping cotton fields.

A novel bacterial strain, designated as R1-1T, was isolated from the saline-alkaline soil of a cotton field in Xinjiang, China. Strain R1-1T grew at 20-45 ℃, pH 4.0-11.0 and 0-10% NaCl. Notably, this strain degraded 50 mg l-1 pymetrozine within 18 h at pH 8.0. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain R1-1T belongs to the genus Nocardioides, showing a high sequence similarity to 'Nocardioides carbamazepini' CBZ-1T (98.5%). Other closely related species included Nocardioides albidus THG-S11.7T (98.0%), Nocardioides convexus W3-2-3T (98.0%), Nocardioides kongjuensis A2-4T (98.0%) and Nocardioides daeguensis JCM 17460T (97.4%). The genome sequence of strain R1-1T had a G+C content of 72.2 mol%. The average nucleotide identity and DNA-DNA hybridization values between strain R1-1T and its closest phylogenetic relatives were 84.5-84.9% and 28.5-28.7%, respectively. These values were below the determined thresholds for species delineation. The major fatty acids of strain R1-1T were identified as 10-methyl C18 : 0, iso-C16 : 0 and C18 : 1 ω9c. The predominant respiratory quinone was menaquinone-8 (H4), and the polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, two unidentified phospholipids and two unidentified lipids. Based on the polyphasic taxonomic data, strain R1-1T represents a novel species within the genus Nocardioides, for which the name Nocardioides pymetrozini sp. nov. is proposed. The type strain is R1-1T (=KCTC 59241T=GDMCC 4.365T).