Mucilaginibacter auburnensis sp. nov., isolated from a plant stem

Abstract

A yellow-pigmented, Gram-negative, rod-shaped, non-spore-forming bacterium (strain JM-1070T) was isolated as a presumptive endophyte from internal stem tissue of a healthy corn stem. Phylogenetic analyses based on the 16S rRNA gene sequence placed strain JM-1070T in the monophyletic cluster of the genus Mucilaginibacter, with closest affiliation to the type strains of Mucilaginibacter composti (98% similarity) and Mucilaginibacter calamicampi (97.2%). 16S rRNA gene sequence similarity to type strains of other species of the genus Mucilaginibacter was 93.4-96.0%. DNA-DNA hybridizations between strain JM-1070T and the type strains M. composti LMG 23497T and M. calamicampi CCUG 63418T showed low relatedness values of 13% (reciprocal 18%) and 52% (reciprocal 54.4%). Major respiratory quinones were menaquinones MK-6 and MK-7. The predominant fatty acids (>15%) were iso-C15:0, iso-C15:0 2-OH/C16:1ω7c (measured as summed feature 3) and iso-C17:0 3-OH. Several other iso-branched and hydroxylated fatty acids were detected. The polar lipid profile was composed of the major components phosphatidylethanolamine and an unidentified aminophospholipid. The polyamine pattern contained predominantly sym-homospermidine. Characterization by 16S rRNA gene sequencing, physiological parameters and polyamine, ubiquinone, polar lipid and fatty acid compositions revealed that strain JM-1070T represents a novel species of the genus Mucilaginibacter. For this reason, we propose the name Mucilaginibacter auburnensis sp. nov., with the type strain JM-1070T (=CIP 110694T=LMG 28078T).