Microbacterium shaanxiense sp. nov., isolated from the nodule surface of soybean.

A Gram-stain-positive, non-motile, catalase- and oxidase-positive rod, designated CCNWSP60(T), was isolated from the nodule surface of soybean [Glycine max (L.) Merrill] cultivar Zhonghuang 13. 16S rRNA gene sequence analysis clearly showed that the isolate belonged to the genus Microbacterium . On the basis of pairwise comparisons of 16S rRNA gene sequences, strain CCNWSP60(T) was most closely related to Microbacterium murale DSM 22178(T) (98.8% similarity), Microbacterium aerolatum DSM 14217(T) (98.3%), Microbacterium ginsengiterrae DSM 24823(T) (98.0%) and Microbacterium profundi DSM 22239(T) (97.8%). However, the DNA-DNA relatedness values of strain CCNWSP60(T) to M. murale DSM 22178(T), M. aerolatum DSM 14217(T), M. ginsengiterrae DSM 24823(T) and M. profundi DSM 22239(T) were 48%, 43%, 28% and 41%, respectively. Growth of strain CCNWSP60(T) occurred at 4-40 °C and at pH 5.0-9.0. The NaCl range for growth was 0-4% (w/v). The predominant menaquinone of strain CCNWSP60(T) was MK-13; MK-12 was also detected. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unidentified glycolipid and one unidentified phospholipid. The diagnostic diamino acid of the peptidoglycan was ornithine. The acyl type of the peptidoglycan was glycolyl. The major fatty acids were anteiso-C15 : 0, iso-C16 : 0 and C16 : 0. The DNA G+C content of the type strain was 67.4 mol%. As the physiological and biochemical characteristics as well as the DNA-DNA relatedness between strain CCNWSP60(T) and the type strains of its closest phylogenetic neighbours showed clear differences, a novel species Microbacterium shaanxiense is proposed to accommodate it. The type strain is CCNWSP60(T) ( =DSM 28301(T) = ACCC 19329(T) =JCM 30164(T)).