Streptomyces pacificus sp. nov., a novel spongiicolazolicin-producing actinomycete isolated from a coastal sediment.

A polyphasic approach was used to determine the taxonomic position of a marine actinomycete, designated isolate CWH03, which we previously reported to produce new linear azole-containing peptides spongiicolazolicins A and B. Strain CWH03 is mesophilic, neutrophilic, and halotolerant streptomycete that forms spiral spore chains on aerial mycelium. Comparative 16S rRNA gene sequencing showed that CWH03 was most closely related to Streptomyces tirandamycinicus HNM0039 (99.7%), Streptomyces spongiicola HNM0071 (99.4%), 'Streptomyces marianii' ICN19 (99.1%) and Streptomyces wuyuanensis CGMCC4.7042 (99.0%). The phylogenetic tree prepared using the 16S rRNA gene, as well as the phylogenomic tree using the genome BLAST distance phylogeny method and 81 core housekeeping genes, respectively, showed that the closest relative of strain CWH03 was S. spongiicola HNM0071. The average nucleotide identity and digital DNA-DNA hybridization values between strains CWH03 and S. spongiicola HNM0071 were 91.46% and 44.2%, respectively, which were below the thresholds of 96% and 70% for prokaryotic conspecific assignation. The G+C content of the genomic DNA of strain CWH03 was 72.3%. Whole-cell hydrolysates of strain CWH03 contained LL-diaminopimelic acid. The predominant menaquinone was MK-9(H) (88.3%), and the major fatty acids were iso-C (28.4%), anteiso-C (15.0%) and iso-C (12.9%). The major phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid. Based on data obtained from phenotypic, phylogenetic, genomic, and chemotaxonomic analyses, strain CWH03 represents a novel species of the genus Streptomyces, for which the proposed name is Streptomyces pacificus sp. nov. The type strain is CWH03 ( = NBRC 114659 = TBRC 15780).