Streptomyces iconiensis sp. nov. and Streptomyces smyrnaeus sp. nov., Two Halotolerant Actinomycetes Isolated from a Salt Lake and Saltern

Abstract

The taxonomic positions of two novel actinomycetes, designated strains BNT558T and SM3501T, were established by using a polyphasic approach. The organisms had chemical and morphological features that were consistent with their classification in the genus Streptomyces. The whole-cell hydrolysates of the two strains contained LL-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were MK-9(H<inf>6</inf>) and MK-9(H<inf>8</inf>) for strain BNT558T and MK-9(H<inf>8</inf>) and MK-9(H<inf>6</inf>) for strain SM3501T. Major fatty acids of the strains were anteiso-C<inf>15: 0</inf>, anteiso-C<inf>17: 0</inf> and iso-C<inf>16: 0</inf>. The polar lipid profile of strain BNT558T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, one unidentified glycolipid and one unidentified aminophospholipid, while that of strain SM3501T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylethanolamine, three unidentified atypical aminolipids, one unidentified aminolipid and two unidentified glycolipids. The G+C contents of the genomic DNA were 70.2 and 69.6 mol% for strains BNT558T and SM3501T, respectively. 16S rRNA gene sequence data supported the classification of the isolates in the genus Streptomyces and showed that they formed two distinct branches within the genus. Based on almost-complete 16S rRNA gene sequences, strain BNT558T was related most closely to Streptomyces albiaxialis NRRL B-24327T and strain SM3501T was related most closely to Streptomyces cacaoi subsp. cacaoi NBRC 12748T. DNA–DNA relatedness between each of the isolates and its closest phylogenetic neighbours showed that they belonged to distinct species. The two isolates were readily distinguished from one another and from the type strains of the other species classified in the genus Streptomyces based on a combination of phenotypic and genotypic properties. Based on the genotypic and phenotypic evidence, strains BNT558T and SM3501T belong to two novel species in the genus Streptomyces, for which the names Streptomyces iconiensis sp. nov. (type strain BNT558T=KCTC 29198T=DSM 42109T) and Streptomyces smyrnaeus sp. nov. (type strain SM3501T=KCTC 29214T=DSM 42105T) are proposed, respectively. © 2014 IUMS.