Comparative genomics reveals insight into the phylogeny and habitat adaptation of novel Amycolatopsis species, an endophytic actinomycete associated with scab lesions on potato tubers.

A novel endophytic actinomycete, strain MEP2-6T, was isolated from scab tissues of potato tubers collected from Mae Fag Mai Sub-district, San Sai District, Chiang Mai Province, Thailand. Strain MEP2-6T is a gram-positive filamentous bacteria characterized by meso-diaminopimelic acid in cell wall peptidoglycan and arabinose, galactose, glucose, and ribose in whole-cell hydrolysates. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and hydroxy-phosphatidylethanolamine were the major phospholipids, of which MK-9(H6) was the predominant menaquinone, whereas iso-C16:0 and iso-C15:0 were the major cellular fatty acids. The genome of the strain was 10,277,369 bp in size with a G + C content of 71.7%. The 16S rRNA gene phylogenetic and core phylogenomic analyses revealed that strain MEP2-6T was closely related to Amycolatopsis lexingtonensis NRRL B-24131T (99.4%), A. pretoriensis DSM 44654T (99.3%), and A. eburnea GLM-1T (98.9%). Notably, strain MEP2-6T displayed 91.7%, 91.8%, and 87% ANIb and 49%, 48.8%, and 35.4% dDDH to A. lexingtonensis DSM 44653T (=NRRL B-24131T), A. eburnea GLM-1T, and A. pretoriensis DSM 44654T, respectively. Based on phenotypic, chemotaxonomic, and genomic data, strain MEP2-6T could be officially assigned to a novel species within the genus Amycolatopsis, for which the name Amycolatopsis solani sp. nov. has been proposed. The type of strain is MEP2-6T (=JCM 36309T = TBRC 17632T = NBRC 116395T). Amycolatopsis solani MEP2-6T was strongly proven to be a non-phytopathogen of potato scab disease because stunting of seedlings and necrotic lesions on potato tuber slices were not observed, and there were no core biosynthetic genes associated with the BGCs of phytotoxin-inducing scab lesions. Furthermore, comparative genomics can provide a better understanding of the genetic mechanisms that enable A. solani MEP2-6T to adapt to the plant endosphere. Importantly, the strain smBGCs accommodated 33 smBGCs encoded for several bioactive compounds, which could be beneficially applied in the fields of agriculture and medicine. Consequently, strain MEP2-6T is a promising candidate as a novel biocontrol agent and antibiotic producer.

Actinomycetospora termitidis sp. nov., an insect-derived actinomycete isolated from termite (Odontotermes formosanus).

Strain Odt1-22T, an insect-derived actinomycete was isolated from a termite (Odontotermes formosanus) that was collected from Chanthaburi province, Thailand. Strain Odt1-22T was aerobic, Gram-stain-positive, and produced bud-like spore chain on the substrate hypha. According to chemotaxonomic analysis, strain Odt1-22T contained meso-diaminopimelic acid in peptidoglycan and the whole-cell hydrolysates contained arabinose, galactose, glucose, and ribose. The major menaquinone was MK-8(H4). The diagnostic phospholipids were diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on 16 S rRNA gene sequence revealed that strain Odt1-22T was identified to the genus Actinomycetospora and showed high similarity values with A. chiangmaiensis DSM 45062 T (99.24%), A. soli SF1T (99.24%) and A. corticicola 014-5 T (98.17%). The genomic size of strain Odt1-22T was 6.6 Mbp with 73.8% G + C content and 6355 coding sequences (CDSs). The genomic analysis, strain Odt1-22T and closely related species A. chiangmaiensis DSM 45062 T, A. soli SF1T and A. corticicola DSM 45772 T displayed the values of average nucleotide identity-blast (ANIb) at 83.7-84.1% and MUMmer (ANIm) at 86.6-87.0%. Moreover, the results of digital DNA-DNA hybridization values between strain Odt1-22T and related Actinomycetospora species were 45.8-50.5% that lower than the threshold value of commonly used to delineate separated species level. On the basis of phenotypic, chemotaxonomic, and genotypic data, strain Odt1-22T represented a novel species within the genus Actinomycetospora, for which the name Actinomycetospora termitidis sp. nov. is proposed. The type strain of the species is Odt1-22T (= TBRC 16192 T = NBRC 115965 T).

Glycomyces amatae sp. nov., isolated from a yellow-ringed grass moth (Amata sperbius).

A novel mycelium-forming actinomycete strain, designated A-F 0318T, was isolated from a yellow-ringed grass moth (Amata sperbius) collected from Phitsanulok Province, Thailand. Long chains of non-motile cylindrical spores with a smooth surface developed on aerial mycelia. The polyphasic taxonomic study suggested that strain A-F 0318T belonged to the genus Glycomyces. The 16S rRNA gene sequence analysis indicated that strain A-F 0318T was closely related to Glycomyces harbinensis LL-DO5139T with 97.94 % sequence similarity. The average nucleotide identity (ANI) based on blast, ANI based on the MUMmer algorithm and average amino acid identity values of strain A-F 0318T with G. harbinensis LL-DO5139T were 86.9, 89.1 and 84.24 %, respectively. The digital DNA-DNA hybridization value between A-F 0318T and its closest relative, G. harbinensis LL-DO5139T was 33.8 %. The digital G+C content of the genomic DNA was 71.7 mol%. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, xylose, glucose and galactose. The predominant menaquinone was MK-10(H4). The predominant fatty acids were iso-C16 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 1 G. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, two unknown phosphoglycolipids and one unknown phospholipid. Based on comparative analysis of genotypic, phenotypic and chemotaxonomic data, the novel actinomycete strain A-F 0318T (=TBRC 13612T=NBRC 115417T) represents the type strain of a novel species, for which the name Glycomyces amatae sp. nov. is proposed.

Chitinophaga oryzae sp. nov., an epiphytic bacterium isolated from rice root surfaces.

Two Gram-stain-negative, non-motile, rod-shaped bacterial strains were isolated from the surfaces of rice roots. They were designated as strains 1303T and 1310. Their colonies were circular, entire, opaque, convex and yellow. They were chitinase- and catalase-positive, reduced nitrate and grew at 16-37 °C (optimum, 30 °C), pH 5.0-10.0 (optimum, pH 7.0) and 0-2.0% NaCl (optimum, 1.0 %). Based on the 16S rRNA gene sequence analysis, they were classified as members of the genus Chitinophaga. Results of phylogenetic and phylogenomic analyses indicated that they formed a cluster with Chitinophaga eiseniae YC6729T, Chitinophaga qingshengii JN246T, Chitinophaga varians 10-7 W-9003T and Chitinophaga fulva G-6-1-13T. When the genomic sequences of strains 1303T and 1310 were compared with their close relatives, the average nucleotide identity and digital DNA-DNA hybridization values were below the cut-off levels. Phosphatidylethanolamine was the major polar lipid. MK-7 was the major respiratory quinone. iso-C15 : 0, C16 : 1 ω5c, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c) were the predominant fatty acids. Differential characteristics between both strains and their close relatives were also observed. Based on the distinctions in genotypic, phenotypic and chemotypic features, strains 1303T and 1310 represent members of a novel species of the genus Chitinophaga, for which the name Chitinophaga oryzae sp. nov. is proposed. The type strain is 1303T (=KACC 22075T=TBRC 12926T).

Abyssomicin derivatives from the rhizosphere soil actinomycete Microbispora rhizosphaerae sp. nov. TBRC6028.

Three undescribed abyssomicin derivatives, including microbimisin, abyssomicins Z1, and Z2, were isolated from the soil actinomycete Microbispora rhizosphaerae sp. nov. TBRC6028. Chemical structures were determined by NMR spectroscopic data (1H, 13C, COSY, HSQC, HMBC, and NOESY spectra) and the absolute configurations were verified by single-crystal X-ray diffraction analyses together with the ECD spectral data. Microbimisin and abyssomicin Z1 exhibited weak antibacterial activity against Bacillus cereus with MIC values of 25.0 and 50.0 µg/mL without cytotoxicity against MCF-7 and Vero cells at the concentration of 50 µg/mL.

Neuroprotective potential of new chromones isolated from the soil actinomycete Microbispora sp. TBRC6027.

Nine new chromone analogs (1-9) were isolated from the soil actinomycete Microbispora sp. TBRC6027. The chemical structures were determined based upon NMR spectroscopic methods. These compounds were evaluated in vitro by using P19-derived neurons for neuroprotective activity against oxidative stress induced by serum deprivation and showed % viability of neurons at the concentration of 1 ng/mL varied from 43.51% to 52.99% without significant neurotoxicity for P19-derived neurons at the same concentration. Moreover, all tested compounds were inactive for antibacterial activity against both Gram-positive and Gram-negative bacteria and for cytotoxicity against MCF-7 (human breast cancer) and Vero cells at maximum tested concentration 50 µg/mL. However, compounds 4, 6, and 7 displayed weak cytotoxicity against NCI-H187 (human small-cell lung cancer) cells with IC50 in a range of 87.99-91.57 µM.

Jiangella endophytica sp. nov., an endophytic actinomycete isolated from the rhizome of Kaempferia elegans.

An endophytic actinobacterium, designated strain KE2-3T, was isolated from surface-sterilised rhizome of Kaempferia elegans. The polyphasic approach was used for evaluating the taxonomic position of this strain. The taxonomic affiliation of this strain at genus level could be confirmed by its chemotaxonomic characteristic, i.e. the presence of ll-diaminopimelic acid in the cell peptidoglycan, MK-9(H4) as the major menaquinone, iso-C16 : 0, anteiso-C15 : 0, iso-C14 : 0 and iso-C15 : 0 as the predominant fatty acids in cells, and the presence of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside in its membranes. Based on 16S rRNA gene sequence analysis, strain KE2-3T was identified as a member of the genus Jiangella and showed the highest similarities to Jiangella muralis DSM 45357T (99.3 %) followed by Jiangella albaDSM 45237T (99.2 %), Jiangella alkaliphilia DSM 45079T (99.0 %), Jiangella gansuensisDSM 44835T (98.8 %) and Jiangella mangrovi3SM4-07T (98.6 %). However, the draft genome sequence of strain KE2-3T exhibited low average nucleotide identity values to the reference strains (85.5-90.2 %), which were well below the 95-96 % species circumscription threshold. The DNA G+C content of genomic DNA was 72.3 mol%. With the differences of physiological, biochemical and genotypic data, strain KE2-3T could be discriminated from its closest neighbour. Thus, strain KE2-3T should be recognised as a novel species of genus Jiangella, for which the name Jiangellaendophytica sp. nov. is proposed. The type strain is KE2-3T (=BCC 66359T=NBRC 110004T).

Herbidospora soli sp. nov., isolated from soil.

A novel actinomycete strain PS42-9T, which formed short chains of spores borne on the tip of long sporophores arising from the substrate mycelium, was isolated from soil in Phu-Sang National Park, Phayao province, Thailand. The isolate contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars of strain PS42-9T were glucose, madurose, mannose, rhamnose and ribose. The characteristic phospholipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxyphosphatidylethanolamine and ninhydrin-positive glycophospholipids. The major menaquinone was MK-10(H4). The main cellular fatty acids were C17 : 1ω8c and C17 : 0. The G+C content of the genomic DNA was 71.5 mol%. Phylogenetic analysis using 16S rRNA gene sequences revealed that strain PS42-9T should be classified in the genus Herbidospora and was closely related to Herbidospora sakaeratensis DMKUA 205T (99.10 %) and Herbidospora yilanensis NBRC 106371T (98.61 %). The result of DNA-DNA hybridization and some physiological and biochemical properties indicated that strain PS42-9T could be readily distinguished from its closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, this strain represents a novel species, for which the name Herbidospora soli sp. nov. is proposed. The type strain is PS42-9T (=BCC 46909T=NBRC 108780T).

Nonomuraea stahlianthi sp. nov., an endophytic actinomycete isolated from the stem of Stahlianthus campanulatus.

A novel endophytic actinomycete, designated strain SC1-1T, was isolated from sterilized stem tissue from Stahlianthus campanulatus collected in Udon Thani province, Thailand. The isolate formed short chains of spores on aerial mycelium and presented meso-diaminopimelic acid in the cell wall peptidoglycan. Glucose, madurose, mannose, rhamnose and ribose were observed as sugars in the cells. The cell membrane phospholipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxy-phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and ninhydrin-positive phosphoglycolipids. The major menaquinones were MK-9(H4) and MK-9(H2). The main cellular fatty acids were iso-C16:0, 10-methyl C17 : 0 and C17 : 1ω6c. A high G+C content (70.7 mol%) was present in the genomic DNA. The taxonomic position based on the 16S rRNA gene sequence analysis revealed that strain SC1-1T belonged to the genus Nonomuraea and shared the highest 16S rRNA gene sequence similarity value with Nonomuraea dietziae DSM 44320T (98.82 %), followed by Nonomuraea africana IFO 14745T (98.58 %), Nonomuraea jabiensis A4036T (98.43 %), Nonomuraea endophytica YIM 65601T (98.36 %), Nonomuraea purpurea 1SM4-01T (98.34 %), Nonomuraea angiospora IFO 13155T (98.29 %), Nonomuraea roseola IFO 14685T (98.23 %) and Nonomuraea recticatena IFO 14525T (98.23 %). On the basis of the DNA-DNA hybridization relatedness and including the physiological and biochemical characteristics, strain SC1-1T should be judged as a novel species of the genus Nonomuraea, for which the name Nonomuraea stahlianthi sp. nov. is proposed. The type strain is strain SC1-1T (=BCC 66361T=NBRC 110006T).

Phytohabitans kaempferiae sp. nov., an endophytic actinomycete isolated from the leaf of Kaempferia larsenii.

A novel endophytic actinomycete, designated strain KK1-3T, which formed single spores and long chains of spores (more than 10 spores) was isolated from surface-sterilized Kaempferia larsenii leaf collected from Ubon Ratchathani province, Thailand. The isolate contained l-lysine, meso-diaminopimelic acid and hydroxyl diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars included glucose, mannose, rhamnose, ribose, galactose and xylose. The characteristic phospholipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and phosphoglycolipids. The predominant menaquinones were MK-10(H8), MK-10(H6) and MK-10(H4). The predominant cellular fatty acids were anteiso-C17 : 0 and iso-C16 : 0. The G+C content of the genomic DNA was 71 mol%. Phylogenetic analysis using 16S rRNA gene sequences revealed that strain KK1-3T should be classified as representing a member of the genus Phytohabitans. The similarity values of sequences between this strain and those of the closely related species, Phytohabitans houttuyneae K11-0057T (99.0 %), Phytohabitans suffuscus K07-0523T (98.9 %), Phytohabitans flavus K09-0627T (98.6 %) and Phytohabitans rumicisK11-0047T (98.1 %) were observed. The DNA-DNA hybridization result and some physiological and biochemical properties indicated that KK1-3T could be readily distinguished from its closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, this strain represents a novel species, for which the name Phytohabitans kaempferiae sp. nov. is proposed. The type strain is strain KK1-3T (=BCC 66360T =NBRC 110005T).

Asanoa endophytica sp. nov., an endophytic actinomycete isolated from the rhizome of Boesenbergia rotunda.

A novel Gram-stain-positive, non-motile, endophytic actinomycete, designated strain BR3-1T, which produced spore chains borne on the tips of short sporophores, was isolated from the rhizome of Boesenbergia rotunda collected from Udon Thani province, Thailand. This strain was investigated for its taxonomic position using a polyphasic approach. The strain contained 3-hydroxydiaminopimelic acid and meso-diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars comprised glucose, mannose, rhamnose, ribose and xylose. Phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides were found as the characteristic phospholipids. The predominant menaquinones were MK-10(H8) and MK-10(H6). The major cellular fatty acids were iso-C16 : 0, iso-C15 : 0 and anteiso-C15 : 0. The G+C content of the genomic DNA was 71.4 mol%. 16S rRNA gene sequence analysis revealed that strain BR3-1T belonged to the genus Asanoa and was most closely related to Asanoa ishikariensis (99.39 %), Asanoa iriomotensis (99.31 %), Asanoa siamensis (99.17 %), Asanoa ferruginea (98.84 %) and Asanoa hainanensis (98.71 %). The DNA-DNA relatedness value between strain BR3-1T and its phylogenetically closest relatives was in the range of 15.4 % ± 1.2 to 45.8 % ± 2.6. In addition, some physiological and biochemical properties indicated that strain BR3-1T could be readily distinguished from all type strains in the genus Asanoa. Thus, strain BR3-1T should be classified as a representative of a novel species, for which the name Asanoa endophytica sp. nov. is proposed. The type strain is BR3-1T ( = BCC 66355T = NBRC 110002T).

Planobispora takensis sp. nov., isolated from soil.

A novel Gram-stain-positive, filamentous bacterial strain (A-T 7458(T)) was isolated from soil collected from hill evergreen forest in Thailand. The strain developed cylindrical sporangia containing a longitudinal pair of motile spores, on short ramifications of aerial mycelia. From a taxonomic study using a polyphasic approach, strain A-T 7458(T) had typical characteristics of members of the genus Planobispora. 16S rRNA gene sequence analysis indicated that the isolate was closely related to Planobispora siamensis A-T 4600(T) (98.5 %), Planobispora rosea JCM 3166(T) (97.6 %) and Planobispora longispora NBRC 13918(T) (97.6 %). The DNA-DNA relatedness values, which differentiated the novel strain from the closest species, were significantly below 70 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, madurose, mannose and glucose. The predominant menaquinone was MK-9(H2). The diagnostic phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylinositol, phosphatidylinositol-mannoside and aminophosphoglycolipid. The predominant cellular fatty acids were unsaturated C17 : 1 and C18 : 1, and saturated C16 : 0 and C17 : 0. Following an evaluation of phenotypic, chemotaxonomic and genotypic characteristics, the novel isolate is proposed to represent a novel species of the genus Planobispora, to be named Planobispora takensis sp. nov. The type strain is A-T 7458(T) ( = BCC 48396(T) = NBRC 109077(T)).

Asanoa siamensis sp. nov., isolated from soil from a temperate peat swamp forest.

A novel actinomycete strain, PS7-2(T), which produced spore chains borne on the tips of short sporophores, was isolated from soil collected from a temperate peat swamp forest in Phu-Sang National Park, Phayao province, Thailand. The isolate contained glutamic acid, glycine, alanine, 3-hydroxy-diaminopimelic acid and meso-diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars were glucose, mannose, rhamnose and xylose, and the major phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylethanolamine. The predominant menaquinones were MK-10(H(8)) and MK-9(H(8)) and the predominant cellular fatty acids were iso-C(15 : 0), anteiso-C(15 : 0) and anteiso-C(17 : 0). The G+C content of the genomic DNA was 72.3 mol%. On the basis of 16S rRNA gene sequence analysis, strain PS7-2(T) clustered with members of the genus Asanoa and appeared most closely related to the type strains of Asanoa hainanensis (99.5 % sequence similarity), Asanoa iriomotensis (99.0 %), Asanoa ishikariensis (98.9 %) and Asanoa ferruginea (98.5 %). DNA-DNA hybridizations and some physiological and biochemical properties indicated that strain PS7-2(T) could be readily distinguished from its closest phylogenetic relatives. Based on the phenotypic and genotypic evidence and DNA-DNA relatedness values, strain PS7-2(T) represents a novel species in the genus Asanoa, for which the name Asanoa siamensis sp. nov. is proposed; the type strain is PS7-2(T) (=BCC 41921(T) =NBRC 107932(T)).

Acrocarpospora phusangensis sp. nov., isolated from a temperate peat swamp forest soil.

A novel actinomycete, strain PS33-18(T), that formed club-shaped and spherical structures borne on the tip of the aerial mycelia was isolated from a temperate peat swamp forest soil in Phu-Sang National Park, Phayao Province, Thailand. The isolate contained glutamic acid, alanine and meso-diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars of strain PS33-18(T) were glucose, madurose, mannose, rhamnose and ribose. The characteristic phospholipids were phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxy-phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides and ninhydrin-positive phosphoglycolipids. The predominant menaquinone was MK-9(H4). The major cellular fatty acids were C17:1ω8c, iso-C16:0 and C16:0. The G+C content of the genomic DNA of strain PS33-18(T) was 71.0 mol%. Phylogenetic analysis using 16S rRNA gene sequences revealed that strain PS33-18(T) should be classified in the genus Acrocarpospora. The level of similarity between this strain and the closely related species Acrocarpospora macrocephala NBRC 16266(T) was 98.3%, Acrocarpospora pleiomorpha NBRC 16267(T) was 97.9%, Acrocarpospora corrugata NBRC 13972(T) was 97.6%, Herbidospora sakaeratensis NBRC 102641(T) was 97.6% and Planotetraspora kaengkrachanensis NBRC 104272(T) was 97.3%. DNA-DNA hybridization results and physiological and biochemical properties indicated that strain PS33-18(T) could be distinguished readily from its closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, this strain represents a novel species, for which the name Acrocarpospora phusangensis sp. nov. is proposed. The type strain is PS33-18(T) (=BCC 46906(T)=NBRC 108782(T)).