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 G32T, 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 43926T, Nonomuraea aridisoli KC333T, Nonomuraea candida NRRL B-24552T, Nonomuraea polychroma DSM 43925T and Nonomuraea endophytica DSM 45385T, 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 43926T, N. polychrom DSM 43925T, N. aridisoli KC333T and N. endophytica DSM 45385T, revealed an open pangenome of 24,056 orthologous families, of which G32T 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 fhuDBC siderophore transporter, highlights adaptations to periodic salinity, iron limitation and rhizosphere contact in island soil. Chemotaxonomic markers (meso-diaminopimelic, madurose, MK-9(H4), iso-C16 : 0, iso-C16 : 0 2OH and C17 : 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 G32T 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 G32T (=KCTC 49887T=CGMCC 4.7873T).