Paenibacillus radicis sp. nov., an endophytic bacterium isolated from maize root.

Abstract

A novel Gram-stain-positive, aerobic, endospore-forming, and rod-shaped strain designated 694T was isolated from surface-sterilized root tissue of a maize planted in the Fangshan District of Beijing, People's Republic of China. A polyphasic taxonomic study was performed on the new isolate. On the basis of 16S rRNA gene sequence similarity studies, this isolate belongs to the genus Paenibacillus. High levels of 16S rRNA gene sequence similarity were found between strain 694T and Paenibacillus xinjiangensis DSM 30034T (98.5 %) and Paenibacillus glycanilyticus (98.1 %), respectively. However, the DNA-DNA hybridization values between strain 694T and its close relatives P. xinjiangensis 16970T and Paenibacillus algorifonticola CGMCC 1.10223T were 30.0 % and 36.7 % respectively. The DNA G+C content of strain 694T was determined to be 46.9 mol%. The predominant respiratory quinone was identified as menaquinone-7 and the polar lipid profile was found to be composed of the major lipids diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major fatty acids were found to be anteiso-C15 : 0 (42.1 %), iso-C15 : 0 (18.4 %), iso-C16 : 0 (11.2 %) and C16 : 0 (12.1 %). The results of physiological and biochemical tests and minor differences in the fatty acid profiles allowed a clear phenotypic differentiation of strain 694T from the closely related species in the genus Paenibacillus. Strain 694T is concluded to represent a novel species within the genus Paenibacillus, for which the name Paenibacillus radicis sp. nov. is proposed, with the type strain 694T ( = CGMCC 1.15286T = DSM 100762T).