Nocardioides dongxiaopingii sp. nov., isolated from leaves of Lamiophlomis rotata on the Qinghai-Tibet Plateau.

Abstract

Two novel Gram-stain-positive, irregular rod-shaped actinomycetes, S-1144T and 4053, were isolated from leaves of Lamiophlomis rotata on the Qinghai-Tibet Plateau, PR China. Cells were aerobic, catalase-positive and oxidase-negative. Colonies on Reasoner's 2A agar were light yellow, circular, shiny, smooth and convex after 2 days of incubation. The isolates grew optimally at 25 °C, pH 7.5 and with 0 % (w/v) NaCl. The results of polyphasic analyses indicated that strain S-1144T belonged to the genus Nocardioides and its close phylogenetic neighbours (16S rRNA gene sequence similarity) were Nocardioides litoris DSM 103718T (98.4 %), Nocardioides rubriscoriae DSM 23986T (98.2%) and Nocardioides plantarum DSM 11054T (97.8 %). The genome of strain S-1144T showed less than 70 % digital DNA-DNA hybridization and < 95-96 % average nucleotide identity values to the above reference strains. The DNA G+C content of strain S-1144T was 73.5 mol%. MK-8(H4) was the predominant respiratory quinone (96.0 %) and llLL-2,6-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The polar lipid profile of strain S-1144T consisted of diphosphatidylglycerol, phosphatidylglycerol, three unidentified phospholipids, one unidentified glycolipid and one unidentified lipid. The major cellular fatty acids were iso-C16 : 0, C17 : 1 ω8c, C17 : 0 and C18 : 1 ω9c. On the basis of obtained data, strain S-1144T represented a novel species of the genus Nocardioides, for which the name Nocardioides dongxiaopingii sp. nov. is proposed. The type strain is S-1144T (=CGMCC 4.7568T=JCM 33469T).