A Gram-stain-negative, aerobic and non-motile strain, designated 18x22-1T, was isolated from a forest soil sample collected from Limushan Nature Reserve in Hainan Province, PR China. Growth occurred at 15-37 °C and pH 6.0-8.0 without NaCl. The 16S rRNA gene sequence analyses showed that strain 18x22-1T was closely related to Ramlibacter tataouinensis DSM 14655T (98.5 %), followed by Ramlibacter henchirensis DSM 14656T (97.9 %) and other Ramlibacter species and formed a stable cluster with R. tataouinensis DSM 14655T, R. henchirensis DSM 14656T, Ramlibacter solisilvae JCM 19319T and Ramlibacter rhizophilus CCTCC AB 2015357T. Results of chemotaxonomic analyses showed that ubiquinone-8 (Q-8) was the major respiratory quinone, and the major fatty acids (>10 % of the total amounts) were C16 : 0 and C17 : 0cyclo. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminopholipids and four unidentified phospholipids. The draft genome sequence was 4.47 Mb long with a G+C content of 68.9 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain 18x22-1T and four closely related type strains were in the range of 79.3-82.3 % and 21.9-25.1 %, respectively. The results of phenotypic, phylogenetic and chemotaxonomic analyses supported that strain 18x22-1T represents a novel species of the genus Ramlibacter, for which the name Ramlibacterhumi sp. nov. is proposed. The type strain is 18x22-1T (=GDMCC 1.1584T=KCTC 52922T).
Keywords: ANI; Ramlibacter; Ramlibacter humi; dDDH; draft genome sequence; tropical forest soil.