Microbacterium yannicii sp. nov., isolated from Arabidopsis thaliana roots

Bacterial strain G72T was isolated from surface-sterilized roots of Arabidopsis thaliana growing in its natural habitat. This Gram-positive, rod-shaped, non-motile, microaerophilic and aerobically growing isolate was characterized by using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity, strain G72T belongs to the genus Microbacterium. However, reassociation values in a DNA-DNA hybridization analysis with closely related strains were between 45.1  and 15.9 %. The DNA G+C content was 70.1 mol%. Strain G72T possessed a peptidoglycan type based on B2β with partial substitution of glutamic acid by 3-hydroxy glutamic acid (Glu/Hyg-Gly-D-Orn). The isolate contained MK-13, MK-12 and MK-11 as major respiratory quinones and anteiso-C15:0, anteiso-C17:0 and iso-C16:0 as predominant fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and three unidentified glycolipids. Based on its physiological and biochemical traits, as well as genotypic results, strain G72T is considered to represent a novel species, for which the name Microbacterium yannicii sp. nov. is proposed. The type strain is G72T (=DSM 23203T=LMG 25521T).