Leifsonia araucanica sp. nov., isolated from nodules of Lupinus luteus and reclassification of Leifsonia naganoensis as a later heterotypic synonym of Leifsonia aquatica

A Gram-positive, non-spore-forming, rod-shaped actinobacterium, designated strain Le1 ^T , was isolated from root nodules of Lupinus luteus cultivated in volcanic soils of southern Chile. Phylogenetic analysis based on the 16S rRNA gene placed strain Le1ᵀ within the genus Leifsonia , showing the highest sequence similarity to Leifsonia lichenia and related species. However, genome-based analyses supported clear taxonomic separation. The draft genome of strain Le1ᵀ is 4.03 Mb, with a DNA G+C content of 69.26 mol%. Average nucleotide identity and digital DNA–DNA hybridization values between strain Le1ᵀ and its closest relatives ranged from 88.5 to 80.8% and 32.8 to 21.3%, respectively, below the accepted species delineation thresholds. Phylogenomic reconstruction based on 92 conserved core genes confirmed that strain Le1ᵀ forms a distinct and well-supported lineage within the genus. The predominant cellular fatty acids of strain Le1ᵀ are anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and C16 : 0. Phenotypic characteristics differentiate strain Le1ᵀ from its closest phylogenetic relatives. On the basis of polyphasic taxonomic evidence, strain Le1ᵀ represents a novel species of the genus Leifsonia , for which the name Leifsonia araucanica sp. nov. is proposed. The type strain is Le1ᵀ (=RGM 3741ᵀ=LMG 34089ᵀ). In addition, genome-based comparisons indicate that Leifsonia naganoensis Suzuki et al . 2000 should be regarded as a later heterotypic synonym of Leifsonia aquatica (ex Leifson 1962) Evtushenko et al . 2000.