sp. nov., an indole acetic acid-producing bacterium isolated from rape ( L.) rhizosphere soil.

A novel Gram-stain-negative, aerobic, rod-shaped and indole acetic acid-producing strain, designated 7209-2, was isolated from rhizosphere of rape ( L.) grown in the Yakeshi City, Inner Mongolia, PR China. The 16S rRNA gene sequence analysis indicated that strain 7209-2 belongs to the genus and is closely related to W3, shin9-1 and W44 with sequence similarities of 98.2, 98.1 and 97.9 %, respectively. Phylogenetic analysis based on concatenated housekeeping and gene sequences showed that strain 7209-2 formed a group together with W44 and W3, with sequences similarities of 92.6 and 91.1 %, respectively. The genome size of strain 7209-2 was 5.25 Mb, comprising 5027 predicted genes with a DNA G+C content of 61.2 mol%. The average nucleotide identity and digital DNA-DNA hybridization comparisons among 7209-2 and reference strains for the most closely related species showed values below the accepted threshold for species discrimination. The major fatty acids of strain 7209-2 were summed feature 8 (C 7 and/or C 6) and summed feature 2 (C aldehyde and/or unknown 10.953) . The major polar lipids were found to consist of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and an unidentified aminophospholipid. The predominant ubiquinone was identified as quinone 10. Based on all the above results, strain 7209-2 represents a novel species of the genus , for which the name sp. nov. is proposed with 7209-2 (=CGMCC 1.15691=DSM 103161) as the type strain.