Streptomyces 16S rRNA Gene Tree Research Articles

Streptomyces alkaliterrae sp. nov., isolated from an alkaline soil, and emended descriptions of Streptomyces alkaliphilus, Streptomyces calidiresistens and Streptomyces durbertensis

A polyphasic study was undertaken to establish the taxonomic position of six representative streptomycetes isolated from an alkaline soil adjacent to a meteoric alkaline soda lake in India. Chemotaxonomic, cultural and morphological properties of the isolates were consistent with their classification in the genus Streptomyces. The isolates formed extensively branched substrate mycelia and aerial hyphae that differentiated in straight chains of spores with smooth surfaces. They contained LL-diaminopimelic acid in the wall peptidoglycan, produced either hexa- or octa-hydrogenated menaquinones with nine isoprene units, major amounts of saturated, iso- and anteiso- fatty acids and phosphatidylethanolamine as the characteristic polar lipid. The isolates grew well at 30 °C, pH 9 and in the presence of 3 to 5% (w/v) sodium chloride. Isolates OF1T, OF3 and OF8 formed a distinct clade within the Streptomyces 16S rRNA gene tree sharing relatively high sequence similarities with the type strains of Streptomyces durbertensis (99.3%), Streptomyces palmae (98.1%) and Streptomyces xinghaiensis (98.3%), but can be distinguished from them using combinations of phenotypic properties. A phylogenomic tree based on draft genome sequences of the isolates and S. durbertensis DSM 104538T confirmed the phylogenetic relationships. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values calculated from the whole genome sequences of isolate OF1T and S. durbertensis DSM 104538T were low at 92.0% and 45.2%, respectively, indicating that they belong to different genomic species. Consequently, on the basis of the genomic, phylogenetic and associated phenotypic data it is proposed that isolates OF1T, OF3 and OF8 be assigned to the genus Streptomyces as Streptomyces alkaliterrae sp. nov. with strain OF1T (NCIMB 15195T =PCM 3001T) as the type strain. Isolates IF11, IF17 and IF19, and S. alkaliphilus DSM 42118T were shown to belong to the same taxospecies and together with S. calidiresistens DSM 42108T comprised a well supported clade in the Streptomyces 16S rRNA gene tree. Isolate IF17 and S. alkaliphilus DSM 42118T formed a well-supported clade in the phylogenomic tree, had almost identical digital G + C similarity values, produced long straight chains of smooth-surfaced spores and shared ANI and dDDH values (98.0 and 79.6%, respectively) consistent with their assignment to the same genomic species. In light of all of the data isolates IF11, IF17 and IF19 should be seen as authentic stains of S. alkalihilus. Data acquired in the present study have also been used to emend the descriptions of S. alkaliphilus, S. calidiresistens and S. durbertensis. The genomes of isolates IF17, and OF1T, OF3 and OF8 contain relatively high numbers of biosynthetic gene clusters some of which were discontinously distributed indicating ones predicted to express for novel specialised metabolites.

Streptomyces tirandamycinicus sp. nov., a Novel Marine Sponge-Derived Actinobacterium With Antibacterial Potential Against Streptococcus agalactiae.

A novel actinobacterium, strain HNM0039T, was isolated from a marine sponge sample collected at the coast of Wenchang, Hainan, China and its polyphasic taxonomy was studied. The isolate had morphological and chemical characteristics consistent with the genus Streptomyces. Based on the 16S rRNA gene sequence analysis, strain HNM0039T was closely related to Streptomyces wuyuanensis CGMCC 4.7042T (99.38%) and Streptomyces spongiicola HNM0071T (99.05%). The organism formed a well-delineated subclade with S. wuyuanensis CGMCC 4.7042T and S. spongiicola HNM0071T in the Streptomyces 16S rRNA gene tree. Multi-locus sequence analysis (MLSA) based on five house-keeping gene alleles (atpD, gyrB, rpoB, recA, trpB) further confirmed their relationship. DNA–DNA relatedness between strain HNM0039T and its closest type strains, namely S. wuyuanensis CGMCC 4.7042T and S. spongiicola HNM0071T, were 46.5 and 45.1%, respectively. The average nucleotide identity (ANI) between strain HNM0039T and its two neighbor strains were 89.65 and 91.44%, respectively. The complete genome size of strain HNM0039T was 7.2 Mbp, comprising 6226 predicted genes with DNA G+C content of 72.46 mol%. Thirty-one putative secondary metabolite biosynthetic gene clusters were also predicted in the genome of strain HNM0039T. Among them, the tirandamycin biosynthetic gene cluster has been characterized completely. The crude extract of strain HNM0039T exhibited potent antibacterial activity against Streptococcus agalactiae in Nile tilapia. And tirandamycins A and B were further identified as the active components with MIC values of 2.52 and 2.55 μg/ml, respectively. Based on genotypic and phenotypic characteristics, it is concluded that strain HNM0039T represents a novel species of the genus Streptomyces whose name was proposed as Streptomyces tirandamycinicus sp. nov. The type strain is HNM0039T (= CCTCC AA 2018045T = KCTC 49236T).

Polyphasic classification of the gifted natural product producer Streptomyces roseifaciens sp. nov.

A polyphasic study was designed to establish the taxonomic status of a Streptomyces strain isolated from soil from the QinLing Mountains, Shaanxi Province, China, and found to be the source of known and new specialized metabolites. Strain MBT76T was found to have chemotaxonomic, cultural and morphological properties consistent with its classification in the genus Streptomyces. The strain formed a distinct branch in the Streptomyces16S rRNA gene tree and was closely related to the type strains of Streptomyces hiroshimensis and Streptomycesmobaraerensis. Multi-locus sequence analyses based on five conserved house-keeping gene alleles showed that strain MBT76T is closely related to the type strain of S. hiroshimensis, as was the case in analysis of a family of conserved proteins. The organism was also distinguished from S. hiroshimensis using cultural and phenotypic features. Average nucleotide identity and digital DNA-DNA hybridization values between the genomes of strain MBT76T and S. hiroshimensis DSM 40037T were 88.96 and 28.4±2.3%, respectively, which is in line with their assignment to different species. On the basis of this wealth of data it is proposed that strain MBT76T (=DSM 106196T=NCCB 100637T), be classified as a new species, Streptomycesroseifaciens sp. nov.

Streptomyces aridus sp. nov., isolated from a high altitude Atacama Desert soil and emended description of Streptomyces noboritoensis Isono et al. 1957

A polyphasic study was undertaken to determine the taxonomic status of a Streptomyces strain which had been isolated from a high altitude Atacama Desert soil and shown to have bioactive properties. The strain, isolate H9T, was found to have chemotaxonomic, cultural and morphological properties that place it in the genus Streptomyces. 16S rRNA gene sequence analyses showed that the isolate forms a distinct branch at the periphery of a well-delineated subclade in the Streptomyces 16S rRNA gene tree together with the type strains of Streptomyces crystallinus, Streptomyces melanogenes and Streptomyces noboritoensis. Multi-locus sequence analysis (MLSA) based on five house-keeping gene alleles showed that isolate H9T is closely related to the latter two type strains and to Streptomyces polyantibioticus NRRL B-24448T. The isolate was distinguished readily from the type strains of S. melanogenes, S. noboritoensis and S. polyantibioticus using a combination of phenotypic properties. Consequently, the isolate is considered to represent a new species of Streptomyces for which the name Streptomyces aridus sp. nov. is proposed; the type strain is H9T (=NCIMB 14965T=NRRL B65268T). In addition, the MLSA and phenotypic data show that the S. melanogenes and S. noboritoensis type strains belong to a single species, it is proposed that S. melanogenes be recognised as a heterotypic synonym of S. noboritoensis for which an emended description is given.

Streptomyces ferrugineus sp. nov., isolated from mangrove soil in Thailand.

Bacterial strain HV38(T) was isolated from mangrove soil, which was collected from Thailand. Chemotaxonomic and morphological characteristics were found to be typical of members of the genus Streptomyces. The strain was found to form a distinct phyletic line in the Streptomyces 16S rRNA gene tree and to be closely associated with the type strains of Streptomyces coeruleofuscus CGMCC 4.1667(T) (98.84% sequence similarity), Streptomyces chromofuscus CGMCC 4.1451(T) (98.63%) and Streptomyces albidoflavus CGMCC 4.1291(T) (98.56%). The major menaquinones were identified as MK-9(H8) and MK-9(H10). Its major cellular fatty acids were found to be iso-C14:0, iso-C15:0, anteiso-C15:0, iso-C16:1ω8c, C16:0, anteiso-C16:1ω8c, iso-C16:0 and anteiso-C16:0. The DNA-DNA hybridization values between strain HV38(T) with S. coeruleofuscus CGMCC 4.1667(T), S. chromofuscus CGMCC 4.1451(T) and S. albidoflavus CGMCC 4.1291(T) were 32.7±0.9, 21.8±0.3 and 19.9±0.9%, respectively, which clearly supported the conclusion that they belong to separate genomic species. Cumulatively, the data indicated that strain HV38(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces ferrugineus sp. nov. is proposed. The type strain is HV38(T) (=CCTCC AA2014009(T)=DSM 42152(T)).

Streptomyces araujoniae sp. nov.: an actinomycete isolated from a potato tubercle

The taxonomic position of a streptomycete isolated from a potato tubercle was determined by using a polyphasic approach. The organism had chemotaxonomic and morphological properties consistent with its classification in the genus Streptomyces and formed a distinct phyletic line in the Streptomyces 16S rRNA gene tree. It was found to be closely related to Streptomyces celluloflavus NRRL B-2493(T) (99.4 % 16S rRNA gene similarity) and shared a 99.0 % 16S rRNA gene similarity value with Streptomyces albolongus NRRL B-3604(T) and Streptomyces cavourensis subsp. cavourensis NBRC 13026(T); low levels of DNA-DNA relatedness with these organisms showed that the isolate belonged to a distinct genomic species. The isolate was distinguished readily from the type strains of these species using a combination of morphological and other phenotypic properties. On the basis of these results, it is proposed that isolate ASBV-1(T) (= CBMAI 1465(T) = CCMA 894(T) = NRRL B-24922(T)) be classified as the type strain of Streptomyces araujoniae sp. nov.

Streptomyces bullii sp. nov., isolated from a hyper-arid Atacama Desert soil

A Streptomyces strain isolated from a hyper-arid Atacama Desert soil was characterised using a polyphasic taxonomic approach. The strain, designated C2(T), had chemical and morphological properties typical of the genus Streptomyces. The isolate formed a branch in the Streptomyces 16S rRNA gene tree together with the type strain of Streptomyces chromofuscus and was also loosely related to Streptomyces fragilis NRRL 2424(T). DNA:DNA relatedness values between the isolate and its two phylogenetic neighbours showed that it formed a distinct genomic species. The strain was readily distinguished from these organisms using a combination of morphological and phenotypic data. Based on the genotypic and phenotypic results, isolate C2(T) represents a novel species in the genus Streptomyces, for which the name Streptomyces bullii sp. nov. is proposed. The type strain is C2(T) (=CGMCC 4.7019(T)=KACC 15426(T)).

Taxonomic characterization of Streptomyces strain CH54-4 isolated from mangrove sediment

An actinobacterium, designated as strain CH54-4, was isolated from mangrove sediment on the east coast of the Gulf of Thailand using starch casein agar. This isolate was found to contain chemical markers typical of members of the genus Streptomyces: This strain possessed a broad spectrum of antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. In addition, this strain also showed strong activity against breast cancer cells with an IC50 value of 2.91 µg ml−1. Phylogenetic analysis of a 16S rRNA gene sequence showed that strain CH54-4 forms a distinct clade within the Streptomyces 16S rRNA gene tree and closely related to Streptomyces thermocarboxydus.

Taxonomic evaluation of the Streptomyces griseus clade using multilocus sequence analysis and DNA–DNA hybridization, with proposal to combine 29 species and three subspecies as 11 genomic species

Streptomyces griseus and related species form the biggest but least well-defined clade in the whole Streptomyces 16S rRNA gene tree. Multilocus sequence analysis (MLSA) has shown promising potential for refining Streptomyces systematics. In this investigation, strains of 18 additional S. griseus clade species were analysed and data from a previous pilot study were integrated in a larger MLSA phylogeny. The results demonstrated that MLSA of five housekeeping genes (atpD, gyrB, recA, rpoB and trpB) is better than the previous six-gene scheme, as it provides equally good resolution and stability and is more cost-effective; MLSA using three or four of the genes also shows good resolution and robustness for differentiating most of the strains and is therefore of value for everyday use. MLSA is more suitable for discriminating strains that show >99 % 16S rRNA gene sequence similarity. DNA-DNA hybridization (DDH) between strains with representative MLSA distances revealed a strong correlation between the data of MLSA and DDH. The 70 % DDH value for current species definition corresponds to a five-gene MLSA distance of 0.007, which could be considered as the species cut-off for the S. griseus clade. It is concluded that the MLSA procedure can be a practical, reliable and robust alternative to DDH for the identification and classification of streptomycetes at the species and intraspecies levels. Based on the data from MLSA and DDH, as well as cultural and morphological characteristics, 18 species and three subspecies of the S. griseus clade are considered to be later heterotypic synonyms of 11 genomic species: Streptomyces griseinus and Streptomyces mediolani as synonyms of Streptomyces albovinaceus; Streptomyces praecox as a synonym of Streptomyces anulatus; Streptomyces olivoviridis as a synonym of Streptomyces atroolivaceus; Streptomyces griseobrunneus as a synonym of Streptomyces bacillaris; Streptomyces cavourensis subsp. washingtonensis as a synonym of Streptomyces cyaneofuscatus; Streptomyces acrimycini, Streptomyces baarnensis, Streptomyces caviscabies and Streptomyces flavofuscus as synonyms of Streptomyces fimicarius; Streptomyces flavogriseus as a synonym of Streptomyces flavovirens; Streptomyces erumpens, 'Streptomyces ornatus' and Streptomyces setonii as synonyms of Streptomyces griseus; Streptomyces graminofaciens as a synonym of Streptomyces halstedii; Streptomyces alboviridis, Streptomyces griseus subsp. alpha, Streptomyces griseus subsp. cretosus and Streptomyces luridiscabiei as synonyms of Streptomyces microflavus; and Streptomyces californicus and Streptomyces floridae as synonyms of Streptomyces puniceus.

Reclassification of Streptomyces hygroscopicus strains as Streptomyces aldersoniae sp. nov., Streptomyces angustmyceticus sp. nov., comb. nov., Streptomyces ascomycinicus sp. nov., Streptomyces decoyicus sp. nov., comb. nov., Streptomyces milbemycinicus sp. nov. and Streptomyces wellingtoniae sp. nov.

A polyphasic study was undertaken to determine the taxonomic status of six strains received as Streptomyces hygroscopicus. The strains had chemotaxonomic and morphological properties typical of members of the genus Streptomyces and formed distinct phyletic lines in the Streptomyces 16S rRNA gene tree. These strains were distinguished from one another and from phylogenetically close neighbours using a combination of phenotypic properties. The combined genotypic and phenotypic data showed that all six strains form distinct centres of taxonomic variation within the genus Streptomyces. The following novel species are proposed to accommodate the strains: Streptomyces aldersoniae sp. nov. (type strain DSM 41909(T) =NRRL 18513(T)), Streptomyces angustmyceticus sp. nov., comb. nov. (type strain DSM 41683( T)=NRRL B-2347(T)), Streptomyces ascomycinicus sp. nov. (type strain DSM 40822(T) =NBRC 13981( T)), Streptomyces decoyicus sp. nov., comb. nov. (type strain DSM 41427(T) =NRRL 2666(T)), Streptomyces milbemycinicus sp. nov. (type strain DSM 41911(T) =NRRL 5739(T)) and Streptomyces wellingtoniae sp. nov. (type strain DSM 40632(T) =NRRL B-1503(T)).

Biosystematics of alkaliphilic streptomycetes isolated from seven locations across a beach and dune sand system

Alkaliphilic streptomycetes were isolated from composite sand samples collected from six out of seven locations across a beach and dune sand system using starch-casein-nitrate agar supplemented with cycloheximide and buffered to pH 10.5. The isolates had colonial and chemotaxonomic properties consistent with their classification in the genus Streptomyces. They were assigned to 49 multimembered and 114 single-membered colour-groups given their ability to produce pigments on oatmeal and peptone-yeast-extract-iron agars and to corresponding taxa based on whole-genome rep-PCR banding patterns. Twenty-four isolates representing the colour and rep-PCR groups grew well from pH 5 to 11, and optimally at pH 9, as did phylogenetically close members of the Streptomyces griseus 16S rRNA gene clade. One hundred and twelve representative alkaliphilic streptomycetes formed a heterogeneous but distinct clade in the Streptomyces 16S rRNA gene tree. A 3-dimensional representation of 16S rRNA sequence data showed that the alkaliphilic streptomycetes formed a distinct group in multidimensional taxospace. It is evident that alkaliphilic streptomycetes are common in the beach and dune sand system and that representatives of this community form new centers of taxonomic variation within the genus Streptomyces that can be equated with species.

Streptomyces sudanensis sp. nov., a new pathogen isolated from patients with actinomycetoma

Nine strains isolated from mycetoma patients and received as Streptomyces somaliensis were the subject of a polyphasic taxonomic study. The organisms shared chemical markers consistent with their classification in the genus Streptomyces and formed two distinct monophyletic subclades in the Streptomyces 16S rRNA gene tree. The first subclade contained four organisms, including the type strain of S. somaliensis, and the second clade the remaining five strains which had almost identical 16S rRNA sequences. Members of the two subclades were sharply separated using DNA:DNA relatedness and phenotypic data which also showed that the subclade 1 strains formed an heterogeneous group. In contrast, the subclade 2 strains were assigned to a single genomic species and had identical phenotypic profiles. It is evident from these data that the subclade 2 strains should be recognised as a new species of Streptomyces. The name proposed for this new species is Streptomyces sudanensis sp. nov. The type strain is SD 504(T) (DSM = 41923(T) = NRRL B-24575(T)).

The Streptomyces violaceusniger clade: a home for streptomycetes with rugose ornamented spores

The taxonomic status of 16 strains received as Streptomyces hygroscopicus, Streptomyces melanosporofaciens, Streptomyces sparsogenes, Streptomyces sporoclivatus and Streptomyces violaceusniger was evaluated in a polyphasic study. Eleven of the organisms formed a distinct clade in the Streptomyces 16S rRNA gene tree with the type strains of Streptomyces asiaticus, Streptomyces cangkringensis, Streptomyces indonesiensis, Streptomyces javensis, Streptomyces malaysiensis, Streptomyces rhizosphaericus, Streptomyces yatensis and Streptomyces yogyakartensis, the members of this group produced rugose ornamented spores in spiral spore chains. The eleven strains were assigned to three established and four novel species, namely Streptomyces albiflaviniger sp. nov., Streptomyces demainii sp. nov., Streptomyces geldanamycininus sp. nov., Streptomyces griseiniger sp. nov., and Streptomyces hygroscopicus, Streptomyces melanosporofaciens and Streptomyces violaceusniger. It is also proposed that S. sporoclivatus becomes a subjective synonym of S. melanosporofaciens. S. sparsogenes NRRL 2940(T), which produced ridged ornamented spores in spiral spore chains, formed a distinct phyletic line in the Streptomyces 16S rRNA gene tree and was readily distinguished from the other strains using a range of phenotypic properties. S. violaceusniger strains NRRL 8097, NRRL B-5799, NRRL 2834 and ISP 5182 fell outside the S. violaceusniger 16S rRNA gene clade and formed either smooth or ridged ornamented spores in either flexuous or spiral spore chains. These organisms were distinguished from one another and from their closest phylogenetic neighbors and were considered to merit species status as Streptomyces auratus sp. nov., Streptomyces phaeoluteichromatogenes sp. nov., Streptomyces phaeogriseichromatogenes sp. nov., and Streptomyces phaeoluteigriseus sp. nov., respectively.

Neutrotolerant acidophilic Streptomyces species isolated from acidic soils in China: Streptomyces guanduensis sp. nov., Streptomyces paucisporeus sp. nov., Streptomyces rubidus sp. nov. and Streptomyces yanglinensis sp. nov.

The taxonomic status of six neutrotolerant acidophilic streptomycetes isolated from acidic soils in Yunnan Province, China, was established using a polyphasic approach. The morphological and chemotaxonomic characteristics revealed that the isolates belong to the genus Streptomyces. Almost complete 16S rRNA gene sequences of the isolates were determined and aligned with available corresponding sequences of representatives of the family Streptomycetaceae; phylogenetic trees were inferred using four tree-making algorithms. The isolates formed a distinct, albeit heterogeneous, subclade in the Streptomyces 16S rRNA gene tree together with the type strain of Streptomyces yeochonensis, but were readily distinguishable from the latter using DNA-DNA hybridization and phenotypic data. It was evident from the genotypic and phenotypic data that the isolates belonged to four novel Streptomyces species, for which the following names are proposed: Streptomyces guanduensis sp. nov. (type strain 701T=CGMCC 4.2022T=JCM 13274T), Streptomyces paucisporeus sp. nov. (type strain 1413T=CGMCC 4.2025T=JCM 13276T), Streptomyces rubidus sp. nov. (type strain 13c15T=CGMCC 4.2026T=JCM 13277T) and Streptomyces yanglinensis sp. nov. (type strain 1307T=CGMCC 4.2023T=JCM 13275T); isolates 317 and 913 belong to this latter species.