Nocardioides nematodiphilus sp. nov., isolated from rhizosphere of Arabidopsis thaliana

An actinobacterial strain, designated R-N-C8 T , was isolated from the rhizosphere soil of Arabidopsis thaliana collected in Yunnan Province, south-west China. Based on the results of 16S rRNA gene sequence analysis, strain R-N-C8 T had highest similarity to Nocardioides terrae CGMCC 1.7056 T (96.5%), Nocardioides opuntiae KCTC 19804 T (96.3%) and Nocardioides currus IB-3 T (96.1%), and lower than 96.0 % similarity to other members of the genus Nocardioides . Phylogenetic trees based on 16S rRNA gene sequences indicated that strain R-N-C8 T formed an isolated branch with N. terrae CGMCC 1.7056 T and N. opuntiae KCTC 19804 T . The polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, one unidentified phosphoglycolipid and four unidentified phospholipids in the cellular membrane. The major fatty acids were identified as iso-C 16 : 0 , anteiso-C 17 : 0 , iso-C 17 : 0 , summed feature 9 (iso-C 17 : 1 ω9 c and/or C 16 : 0 10-methyl) and iso-C 15 : 0 . The predominant respiratory quinone was MK-8(H 4 ) and ll -diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The genomic DNA G+C content was 70.9 mol%. The orthologous average nucleotide identiy values between N. terrae CGMCC 1.7056 T , N. currus IB-3 T and strain R-N-C8 T were 77.1 and 75.1 %, respectively. DNA–DNA hybridization values between N. terrae CGMCC 1.7056 T , N. currus IB-3 T and strain R-N-C8 T were 20.7 and 19.9 % respectively. Data from phenotypic and genotypic analyses supported that strain R-N-C8 T represents a new species of Nocardioides , for which the name Nocardioides nematodiphilus sp. nov. is proposed. The type strain is R-N-C8 T (=CGMCC 1.18723 T = KCTC 49528 T ).