Luedemannella gen. nov., a new member of the family Micromonosporaceae and description of Luedemannella helvata sp. nov. and Luedemannella flava sp. nov.

Abstract

Three actinomycete strains were isolated from soil samples collected in Bangladesh. The cultures formed spherical sporangia on short sporangiophores directly above the surface of the substrate mycelium. The sporangia developed singly or in clusters and each sporangium contained several nonmotile spherical to oval spores with a smooth surface. The strains 3-9(24)^T, 3-21(27) and 7-40(26)^T contained meso-diaminopimelic acid in the cell walls, predominant menaquinone MK-9(H₆) and MK-9(H₄) and glucose, xylose, galactose, mannose, rhamnose, ribose and arabinose in the whole-cell hydrolysates. Diagnostic phospholipid is phosphatidylethanolamine and branched anteiso-C_{17 : 0} (30.0–38.0%), anteiso-C_{15 : 0} (12.5–14.0%), iso-C_{16 : 0} (10.0–15.0%) and iso-C_{15 : 0} (10.0–12.0%) were detected as the major cellular fatty acids. The acyl type of the peptidoglycan was glycolyl and mycolic acids were not detected. The G+C content of the DNA was 71 mol%. The chemotaxonomic data indicate that these strains belong to the family Micromonosporaceae. Phylogenetic analysis based on 16S rRNA gene sequence data suggested that the strains 3-9(24)^T, 3-21(27) and 7-40(26)^T fall within the family Micromonosporaceae. On the basis of phylogenetic analysis and characteristic patterns of signature nucleotides as well as morphological and chemotaxonomic data, Luedemannella gen. nov. is proposed for our 3 isolates. DNA-DNA hybridization experiment and phenotypic characterization indicated that the new genus was constituted of 2 species, as Luedemannella helvata sp. nov. for the strain 3-9(24)^T (=JCM 13249^T=MTCC 8091^T) and Luedemannella flava for the strain 7-40(26)^T (=JCM 13250^T=MTCC 8095^T) in the family Micromonosporaceae.