Actinophytocola gossypii sp. nov. and Streptomyces gossypii sp. nov., two novel actinomycetes isolated from rhizosphere soil of cotton

Two Gram-positive, aerobic and non-motile actinomycetes, designated S1-96^T and N2-109^T, were isolated from soils collected from a cotton field. They are described as representing two novel species of genera Actinophytocola and Streptomyces through a polyphasic approach. Analysis of 16S rRNA gene sequences revealed that strains S1-96^T and N2-109^T showed highest similarity to Actinophytocola xinjiangensis CGMCC 4.4663^T (99.10 %) and Streptomyces iconiensis BNT558^T (98.21 %), respectively. Phylogenetic analyses based on 16S rRNA and core genes confirmed the close relationships of these strains. Genomic analyses further supported the novel taxonomic delimitation of these two species based on digital DNA-DNA hybridization and average nucleotide identity. Strains S1-96^T and N2-109^T contained MK-9(H₄) and MK-9(H₆) as the most abundant menaquinone, respectively. High abundances of iso-fatty acids were detected in both strains, which was similar to their close relatives. Physiological and polar lipid analyses also revealed differences between these strains and their phylogenetic neighbours, supporting their taxonomic delimitation as novel species. The names Actinophytocola gossypii sp. nov. (type strain S1-96^T=JCM 34412^T=CGMCC 4.7707^T) and Streptomyces gossypii sp. nov. (type strain N2-109^T=JCM 34628^T=CGMCC 4.7717^T) are proposed.

Actinophytocola glycyrrhizae sp. nov. isolated from the rhizosphere of Glycyrrhiza inflata

A Gram-stain-positive, aerobic actinomycete, designated strain BMP B8152^T, was isolated from the rhizosphere of Glycyrrhiza inflata collected ashore, in Kashi, Xinjiang province, northwest PR China. A polyphasic approach was used to establish the taxonomic position of this strain. BMP B8152^T was observed to form non-fragmented substrate mycelium, and relatively scanty aerial mycelium with rod-shaped spores. Cell-wall hydrolysates contained meso-diaminopimelic acid, galactose, arabinose, glucose and rhamnose (trace). Mycolic acids were not detected. The diagnostic phospholipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, ninhydrin-positive phosphoglycolipid and phosphatidylinositol. The predominant menaquinone and fatty acid were MK-9(H4) and iso-branched hexadecanoate (iso-C16 : 0), respectively. The phylogenetic analyses based on the 16S rRNA gene sequences indicated that BMP B8152^T formed a distinct monophyletic clade clustered with Actinophytocola timorensisID05-A0653^T (98.8 % 16S rRNA gene sequence similarity), Actinophytocola oryzaeGMKU 367^T (98.6 %), Actinophytocola corallinaID06-A0464^T (98.2 %) and Actinophytocola burenkhanensisMN08-A0203^T (97.5 %). In addition, DNA-DNA hybridization values between BMP B8152^T and A. timorensisID05-A0653^T(44.2±3.6 %) and A. oryzaeGMKU 367^T(36.7±2.3 %) were well below the 70 % limit for species identification. The combined phenotypic and genotypic data indicate that the isolate represents a novel species of the genus Actinophytocola, for which the name Actinophytocola glycyrrhizae sp. nov., is proposed, with the type strain BMP B8152^T (=KCTC 49002^T=CGMCC 4.7433^T).

Actinophytocola xanthii sp. nov., an actinomycete isolated from rhizosphere soil of the plant Xanthium sibiricum

A novel actinomycete strain, 11-183T, was isolated from the rhizosphere soil of Xanthium sibiricum, which was collected in Tangshan, Hebei, China. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain 11-183T formed a clade within the genus Actinophytocola, with a maximum similarity of 98.44 % to Actinophytocola xinjiangensis QAIII60T, followed by 97.76 % similarity to Actinophytocola sediminis YIM M13705T. The average nucleotide identity and digital DNA-DNA hybridization values differed by 79.24 and 23.4 %, respectively, between strain 11-183T and Actinophytocolaxinjiangensis QAIII60T. Strain 11-183T grew well on N-Z-amine agar, and it produced a scant, white aerial mycelium. The isolate formed pale yellow to brown-black colonies and a dense, non-fragmented, branched substrate mycelium, and produced aerial hyphae on which nodular spore chains formed. Growth was observed at salinities ranging from 0 to 2 %, at pH values ranging from pH 6.5 to 8.0 and at temperatures ranging from 15 to 37 °C. The cell-wall amino acids included meso-diaminopimelic acid. Whole cell hydrolysates contained galactose and glucose. The principal fatty acids were iso-C16 : 0, iso-C16 : 1 H and C17 : 1ω6c. Diphosphatidylglycerol, phosphatidylmonomethylethanolamine and phosphatidylethanolamine were the diagnostic phospholipids. The isoprenoid quinones included MK-9(H4) and MK-10(H4). The G+C content of the genomic DNA was 71.7 mol%. Based on the genotypic and phenotypic data, we conclude that strain 11-183T belongs to a novel species of the genus Actinophytocola. The name proposed for the novel species is Actinophytocola xanthii sp. nov., with the type strain 11-183T (=KCTC 39690T= MCCC 1K02062T).

Herbihabitans rhizosphaerae gen. nov., sp. nov., a member of the family Pseudonocardiaceae isolated from rhizosphere soil of the herb Limonium sinense (Girard)

The taxonomic position of an actinobacterium, designated CPCC 204279T, which was isolated from a rhizosphere soil sample of the herb Limonium sinense collected from Xinjiang Province, China, was established using a polyphasic approach. Whole-cell hydrolysates of strain CPCC 204279T contained galactose and arabinose as diagnostic sugars and meso-diaminopimelic acid as the diamino acid. The muramic acid residues in the peptidoglycan were N-acetylated. The predominant menaquinone was MK-9(H4). The phospholipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The major fatty acids were iso-C16 : 0, iso-C16 : 0 2-OH, C16 : 1ω9c, iso-C16 : 1 and C16 : 0. The genomic DNA G+C content was 73.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204279T should be placed in the family Pseudonocardiaceae, in which the strain formed a distinct lineage next to the genus Actinophytocola. Signature nucleotides in the 16S rRNA gene sequence showed that the strain contained the Pseudonocardiaceae family-specific 16S rRNA signature nucleotides and a genus-specific diagnostic nucleotide signature pattern. The combination of phylogenetic analysis and phenotypic characteristics supported the conclusion that strain CPCC 204279T represents a novel species of a new genus in the family Pseudonocardiaceae, for which the name Herbihabitans rhizosphaerae gen. nov., sp. nov. is proposed. Strain CPCC 204279T (=NBRC 111774T=DSM 101727T) is the type strain of the type species.

Actinophytocola algeriensis sp. nov., an actinobacterium isolated from Saharan soil

During our investigations of new actinobacterial taxa, a novel actinobacterial strain, designated MB20^T, was isolated from a Saharan soil sample, collected in the Mzab region (Ghardaïa province, southern Algeria). In order to reveal its taxonomic position, the novel strain was characterized following a polyphasic taxonomic approach. It was noticed that strain MB20^T produced white, branched and fragmented substrate mycelium with no aerial mycelium on most of the media tested. Chemotaxonomic and phylogenetic studies clearly demonstrated that strain MB20^T belonged to the family Pseudonocardiaceae and was closely related to the genus Actinophytocola. Cell-wall hydrolysates contained meso-diaminopimelic acid but not glycine, and whole-cell hydrolysates contained galactose, glucose and ribose. The diagnostic phospholipid was phosphatidylethanolamine. Mycolic acids were not detected while the predominant fatty acid was found to be iso-branched hexadecanoate (iso-C16 : 0). The major menaquinone was MK-9(H4). Results of the 16S rRNA gene sequence comparison revealed that strain MB20^T shared the highest degree of similarity with Actinophytocola gilvus DSM 45828^T (98.5 %), Actinophytocola corallina DSM 45659^T (98.0 %) and Actinophytocola timorensis DSM 45660^T (97.5 %). However, DNA-DNA hybridization studies showed only 32.9 % similarity with A. timorensis, 23.7 % similarity with A. gilvus and 17.9 % similarity with A. corallina. On the basis of phenotypic characteristics, 16S rRNA gene sequence comparisons and DNA-DNA hybridization, strain MB20^T was revealed to be a representative of a novel species of the genus Actinophytocola, for which the name Actinophytocola algeriensis sp. nov. (type strain MB20^T =DSM 46746^T =CECT 8960^T) is proposed.

Actinophytocola gilvus sp. nov., isolated from desert soil crusts, and emended description of the genus Actinophytocola Indananda et al. 2010

An actinomycete strain, designated I12A-02593(T), was isolated from a desert soil crust sample collected in the Shapotou region of Tengger Desert, north-west China. The isolate grew well on International Streptomyces Project (ISP) media 2, 3, 5 and 7, YS and Bennett's agar; it produced spherical bodies and formed clumps on the aerial mycelia on ISP 5 agar plates. Chemotaxonomically, the strain contained meso-diaminopimelic acid as the diagnostic diamino acid, arabinose and galactose as the diagnostic sugars in whole-cell hydrolysates, MK-9(H4) as the sole isoprenoid quinone, and iso-C16 : 0, iso-C16 : 0 2-OH and iso-C16 : 1 H as the major cellular fatty acids, without mycolic acids. The profile of the phospholipids mainly comprised diphosphatidylglycerol, phosphatidylethanolamine and hydroxyphosphatidylethanolamine. The genomic DNA G+C content was 70.1 mol%. The 16S rRNA gene sequence of strain I12A-02593(T) exhibited 96.4-97.4 % similarities with members of the genus Actinophytocola. In the phylogenetic tree based on 16S rRNA gene sequences, the isolate formed a robust cluster with Actinophytocola oryzae NBRC 105245(T), Aactinophytocola timorensis NBRC 105524(T), Actinophytocola corallina NBRC 105525(T), Actinophytocola burenkhanensis NBRC 105883(T)and Actinophytocola xinjiangensis NBRC 106673(T). DNA-DNA hybridization values between strain I12A-02593(T) and the five species of the genus Actinophytocola were all less than 70 %. On the basis of the polyphasic taxonomy evidence, a novel species of the genus Actinophytocola is proposed, with the name Actinophytocola gilvus sp. nov. The type strain is I12A-02593(T) ( = CPCC 203543(T) = DSM 45828(T) = NBRC 109453(T) = KCTC 29165(T)). An emended description of the genus Actinophytocola is also provided.

Actinophytocola sediminis sp. nov., an actinomycete isolated from a marine sediment

A novel actinomycete strain, designated YIM M13705(T), was isolated from a marine sediment sample of the South China Sea and its characteristics were determined by a polyphasic approach. The slowly growing, Gram-stain-positive, aerobic strain produced branched substrate mycelium and aerial hyphae, and no diffusible pigment was produced on the media tested. At maturity, spore chains were formed on aerial hyphae and substrate mycelium was not fragmented. Whole-cell hydrolysates of the strain contained meso-diaminopimelic acid and galactose, glucose, ribose and rhamnose. The predominant menaquinones were MK-9(H4) and MK-10(H2). The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol and ninhydrin-positive phosphoglycolipids. The major fatty acid was iso-C(16 : 0). The G+C content of the genomic DNA was 68.2 mol%. On the basis of 16S rRNA gene sequence, the strain was shown to be most closely related to species of the genus Actinophytocola. DNA-DNA hybridization relatedness values (<70%) of the isolate with its closest neighbour Actinophytocola xinjiangensis QAIII60(T) supported classification of the isolate as a representative of a novel species. On the basis of phylogenetic analysis, and phenotypic and genotypic data, it is concluded that the new isolate belongs to a novel species of the genus Actinophytocola, for which the name Actinophytocola sediminis sp. nov. (type strain YIM M13705(T) = DSM 45939(T) = BCRC 16956(T)) is proposed.

Labedaea rhizosphaerae gen. nov., sp. nov., isolated from rhizosphere soil

A novel actinomycete, designated strain RS-49T, was isolated from the rhizosphere soil of a cliff-associated plant (Peucedanum japonicum Thunb.) in the Republic of Korea and subjected to a polyphasic taxonomic study. The results of comparative 16S rRNA gene sequence analyses showed that the organism belonged to the family Pseudonocardiaceae , suborder Pseudonocardineae and that it was most closely related to members of the genera Kibdelosporangium (96.6–97.0 % sequence similarity), Actinokineospora (96.3–96.7 %), Streptoalloteichus (96.2 %) and Actinophytocola (96.2 %). Substrate mycelia were well-developed and whitish or pale yellow to strong yellow. Aerial mycelia were branched and fragmented into rod-shaped elements. Single spherical spores were produced directly on the substrate mycelium. Sporangium-like structures and fragmentation of the substrate mycelium were absent. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The acyl type of the muramic acid residues in the peptidoglycan was N-acetylated. Whole-cell sugars were glucose, rhamnose, galactose, ribose, mannose, arabinose and xylose. The major menaquinone was MK-9(H4). Small amounts of MK-8 and MK-9(H2) were also detected. The polar lipids contained diphosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylglycerol, phosphatidylinositol, an unknown phospholipid and an unknown lipid. The predominant fatty acids were iso-C15 : 0 and iso-C16 : 0. The DNA G+C content was 64.2 mol%. The phenotypic and phylogenetic characteristics show that strain RS-49T can be differentiated from members of all genera in the suborder Pseudonocardineae and thus represents a novel species in a new genus for which the name Labedaea rhizosphaerae gen. nov., sp. nov. is proposed; the type strain of the type species is RS-49T ( = KCTC 19662T = DSM 45361T).