Microbacterium altimontanum sp. nov., Microbacterium longlingense sp. nov., and Microbacterium cucumeris sp. nov.: Three New Species of Microbacterium Isolated from Soil in Yunnan Province, China

Abstract

Three actinobacterial strains, AW10-10T, M8-1T and HGHZ1-2T, were isolated from soil in Yunnan Province, China. Analyses of 16S rRNA gene sequences and shotgun-sequenced draft genomes placed them within the genus Microbacterium. OrthoANI, FastANI and dDDH values between the three strains and their closest relatives were 75.7–79.6%, 79.9–81.9% and 19.7–22.5%, respectively, all well below the accepted species-level thresholds. Cells of all three strains were Gram-stain-positive, aerobic and rod-shaped. The major fatty acids were anteiso-C17:0, anteiso-C15:0 and iso-C16:0 in AW10-10T and HGHZ1-2T, and anteiso-C15:0, anteiso-C17:0 and iso-C16:0 in M8-1T. AW10-10T and M8-1T contained ribose, galactose, mannose, glucose and minor rhamnose, whereas HGHZ1-2T lacked rhamnose. The predominant menaquinones were MK-12 and MK-13 in AW10-10T, MK-13 and MK-12 in HGHZ1-2T, and MK-10, MK-11 and MK-9 in M8-1T. Polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid in AW10-10T and HGHZ1-2T, but two unidentified glycolipids in M8-1T. DNA G + C contents were 70.0, 69.7 and 69.5 mol%, respectively. The strains represent three novel species, Microbacterium altimontanum sp. nov., Microbacterium longlingense sp. nov. and Microbacterium cucumeris sp. nov., with type strains AW10-10T (=GDMCC 16749T = KCTC 59693T), M8-1T (=GDMCC 16752T = KCTC 59696T) and HGHZ1-2T (=GDMCC 16751T = KCTC 59694T), respectively.