Comparative genomics and ecological insights into Nonomuraea turcica sp. nov., an actinomycete from Black Sea island soil

A polyphasic study was undertaken to characterize strain G32 T , an actinomycete isolated from soil collected on Giresun Island (Black Sea, Turkey). 16S rRNA phylogeny placed the strain within the genus Nonomuraea , but ≤99.1% similarity to its nearest type strains, Nonomuraea turkmeniaca DSM 43926 T , Nonomuraea aridisoli KC333 T , Nonomuraea candida NRRL B-24552 T , Nonomuraea polychroma DSM 43925 T and Nonomuraea endophytica DSM 45385 T , suggested that it potentially represents a novel taxon. The total genome size is about 12.66 Mb, and the digital G+C content is 69.6 mol%. The high-quality draft genome shared ≤92.16% average nucleotide identity and ≤47.0% digital DNA–DNA hybridization with the closest related type strains, corroborating species-level distinctness. Comparative genomics against four type strains, N. turkmeniaca DSM 43926 T , N. polychrom DSM 43925 T , N. aridisoli KC333 T and N. endophytica DSM 45385 T , revealed an open pangenome of 24,056 orthologous families, of which G32 T contributed 2,785 singletons. Copy-number expansion of aqpZ with four paralogues and efeB with three paralogues, together with the sole genome-wide occurrence of ACC-deaminase and an additional fhu DBC siderophore transporter, highlights adaptations to periodic salinity, iron limitation and rhizosphere contact in island soil. Chemotaxonomic markers ( meso -diaminopimelic, madurose, MK-9(H 4 ), iso -C 16 : 0 , iso -C 16 : 0 2OH and C 17 : 0 10- methyl ) of the strain were consistent with the genus Nonomuraea , but phenotypic traits further differentiated the isolate from its relatives. Based on the evidence presented here, strain G32 T represents a novel species of the genus Nonomuraea , for which the name Nonomuraea turcica sp. nov. is proposed. The type strain of the species is G32 T (=KCTC 49887 T =CGMCC 4.7873 T ).