Micromonospora lupini sp. nov. and Micromonospora saelicesensis sp. nov., isolated from root nodules of Lupinus angustifolius.

A study was conducted to determine the taxonomic status of six actinomycete strains isolated from root nodules of Lupinus angustifolius. The strains were filamentous, Gram-positive and produced single spores at the tip of the hyphae. Phylogenetic, chemotaxonomic and morphological analyses demonstrated that all six strains belonged to the genus Micromonospora. According to the 16S rRNA gene sequence data, the strains were divided into two clusters that are moderately related to Micromonospora mirobrigensis, Micromonospora matsumotoense and Micromonospora purpureochromogenes. Fatty acid patterns also supported the division of the strains, and significant differences between the two groups were found in the amounts of iso-15 : 0, iso-16 : 0, iso-16 : 1 and iso-17 : 0. Furthermore, the two groups showed physiological differences which included utilization of arabinose, trehalose, alanine and sucrose and xylan hydrolysis. Finally, DNA-DNA hybridization and ribotyping studies confirmed that each group represents a novel species. Based on the genotypic and phenotypic data, the novel species Micromonospora lupini sp. nov. (type strain Lupac 14N(T) =DSM 44874(T) =LMG 24055(T)) and Micromonospora saelicesensis sp. nov. (type strain Lupac 09(T) =DSM 44871(T) =LMG 24056(T)) are proposed.