Saccharopolyspora ipomoeae sp. nov., an Actinomycete Isolated from Sweet Potato Field Soils.

During the course of the isolation of actinobacteria from sweet potato field soils collected from Phra Nakhon Si Ayutthaya province of Thailand, strain TS4A08T was isolated and subjected to a polyphasic taxonomic approach. The 16S rRNA gene sequence analysis of strain TS4A08T revealed that it is closely related to the type strains of Saccharopolyspora aridisoli, and Saccharopolyspora endophytica with 98.7%, and 98.6% similarity, respectively. However, phylogenetic analyses using 16S rRNA gene and genome sequences indicated that strain TS4A08T clustered with Saccharopolyspora flava AS4.1520T (98.2% similarity), well-supported by bootstrap values, and formed distinct line from the two closest strains. The average nucleotide identity (ANI) values and digital DNA-DNA hybridization (dDDH) values between the genome sequences of strain TS4A08T and the closest type strains of S. aridisoli, S. endophytica, and S. flava, were 86.1-93.2% and 33.1-49.6%, respectively, which were less than the threshold for the species delineation. The genome size and the DNA G + C content of strain TS4A08T were 6.6 Mbp and 70.5%, respectively. The strain grew well at 25-37 °C, pH range of 7-9, and NaCl concentration of 0-5% (w/v). Whole-cell hydrolysates contained meso-diaminopimelic acid. The major fatty acids were iso-C16:0, anteiso-C17:0, and iso-C15:0. Strain TS4A08T exhibited phosphatidylcholine in its polar lipid profile, with MK-9(H4) being the predominant isoprenologue. The strain exhibits typical chemotaxonomic properties of the genus Saccharopolyspora, including arabinose, galactose, and ribose as whole-cell sugars. Strain TS4A08T represents a novel species within the genus Saccharopolyspora, for which the name Saccharopolyspora ipomoeae sp. nov. is proposed. The type strain is TS4A08T (= TBRC 17271T = NBRC 115967T).

Actinomycetospora lemnae sp. nov., A Novel Actinobacterium Isolated from Lemna aequinoctialis Able to Enhance Duckweed Growth.

Duckweed-associated actinobacteria are co-existing microbes that affect duckweed growth and adaptation. In this study, we aimed to report a novel actinobacterium species and explore its ability to enhance duckweed growth. Strain DW7H6T was isolated from duckweed, Lemna aequinoctialis. Phylogenetic analysis based on its 16S rRNA gene sequence revealed that the strain was most closely related to Actinomycetospora straminea IY07-55T (99.0%), Actinomycetospora chibensis TT04-21T (98.9%), Actinomycetospora lutea TT00-04T (98.8%) and Actinomycetospora callitridis CAP 335T (98.4%). Chemotaxonomic and morphological characteristics of strain DW7H6T were consistent with members of the genus Actinomycetospora, while average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) between the draft genomes of this strain and its closely related type strains were below the proposed threshold values used for species discrimination. Based on chemotaxonomic, phylogenetic, phenotypic, and genomic evidence obtained, we describe a novel Actinomycetospora species, for which the name Actinomycetospora lemnae sp. nov. is proposed. The type strain is DW7H6T (TBRC 15165T, NBRC 115294T). Additionally, the duckweed-associated actinobacterium strain DW7H6T was able to enhance duckweed growth when compared to the control, in which the number of fronds and biomass dry weight were increased by up to 1.4 and 1.3 fold, respectively. Moreover, several plant-associated gene features in the genome of strain DW7H6T potentially involved in plant-microbe interactions were identified.

Duckweed-associated bacteria as plant growth-promotor to enhance growth of Spirodela polyrhiza in wastewater effluent from a poultry farm.

Duckweed has been highlighted as an invaluable resource because of its abilities to remove nitrogen and phosphorus from wastewater coupling with the production of high starch/protein-containing plant biomass. Duckweed recruits microbes and particularly forms a stable "core" bacterial microbiota, which greatly reduces the colonization efficiency of plant growth-promoting bacteria (PGPB). In this study, natural duckweeds were enriched in a sterilized-partially treated wastewater effluent from a poultry farm. After 24 days of cultivation, the duckweed-associated bacteria (DAB) were isolated and evaluated for their plant growth-promoting (PGP) potentials by co-cultivation with axenic Spirodela polyrhiza. Ten species were found in more than one location and could be considered candidates for the stable "core" DAB. Among them, all isolates of Acinetobacter soli, Acidovorax kalamii, Brevundimonas vesicularis, Pseudomonas toyotomiensis, and Shinella curvata increased duckweed growth in Hoagland medium. The highest PGP ability was observed in Sh. curvata W12-8 (with EPG value of 208.72%), followed by Paracoccus marcusii W7-16 (171.31%), Novosphingobium subterraneum W5-13 (156.96%), and Ac. kalamii W7-18 (156.96%). However, the highest growth promotion in the wastewater was observed when co-cultured with W7-16, which was able to increase biomass dry weight and root length of duckweed by 3.17 and 2.26 folds, respectively.

Actinoallomurus soli sp. nov. and Actinoallomurus rhizosphaericola sp. nov., two novel actinobacteria isolated from rhizosphere soil of Oryza rufipogon Griff.

The taxonomic position of two novel Actinoallomurus strains isolated from rhizosphere soil of wild rice (Oryza rufipogon Griff.) was established using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains WRP6H-15T and WRP9H-5T were closely related to Actinoallomurus spadix JCM 3146T and Actinoallomurus purpureus TTN02-30T. Chemotaxonomic and morphological characteristics of both strains were consistent with members of the genus Actinoallomurus, while phenotypic properties, genome-based comparisons and phylogenomic analyses distinguished strains WRP6H-15T and WRP9H-5T from their closest phylogenetic relatives. The two strains showed nearly identical 16S rRNA gene sequences (99.9 %). Strain WRP6H-15T showed 68.7 % digital DNA-DNA hybridization, 95.9 % average nucleotide identity (ANI) based on blast and 96.4 % ANI based on MUMmer to strain WRP9H-5T. A phylogenomic tree based on draft genome sequences of the strains and representative of the genus Actinoallomurus confirmed the phylogenetic relationships. The genomes sizes of strains WRP6H-15T and WRP9H-5T were 9.42 Mb and 9.68 Mb, with DNA G+C contents of 71.5 and 71.3 mol%, respectively. In silico analysis predicted that the strains contain biosynthetic gene clusters encoding for specialized metabolites. Characterization based on chemotaxonomic, phylogenetic, phenotypic and genomic evidence demonstrated that strains WRP6H-15T and WRP9H-5T represent two novel species of the genus Actinoallomurus, for which the names Actinoallomurus soli sp. nov. (type strain WRP6H-15T=TBRC 15726T=NBRC 115556T) and Actinoallomurus rhizosphaericola sp. nov. (type strain WRP9H-5T=TBRC 15727T=NBRC 115557T) are proposed.

Streptomyces silvisoli sp. nov., a polyene producer, and Streptomyces tropicalis sp. nov., two novel actinobacterial species from peat swamp forests in Thailand.

Two novel actinobacterial strains, designated RB6PN23T and K1PA1T, were isolated from peat swamp soil samples in Thailand and characterized using a polyphasic taxonomic approach. The strains were filamentous Gram-stain-positive bacteria containing ll-diaminopimelic acid in their whole-cell hydrolysates. Phylogenetic analysis of their 16S rRNA gene sequences revealed that strain RB6PN23T was most closely related to Streptomyces rubrisoli (99.1 % sequence similarity) and Streptomyces ferralitis (98.5%), while strain K1PA1T showed 98.8 and 98.7% sequence similarities to Streptomyces coacervatus and Streptomyces griseoruber, respectively. However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were below the species-level thresholds (95-96 % ANI and 70 % dDDH). The genomes of strains RB6PN23T and K1PA1T were estimated to be 7.88 Mbp and 7.39 Mbp in size, respectively, with DNA G+C contents of 70.2 and 73.2 mol%. Moreover, strains RB6PN23T and K1PA1T encode 37 and 24 putative biosynthetic gene clusters, respectively, and in silico analysis revealed that these new species have a high potential to produce unique natural products. Genotypic and phenotypic characteristics confirmed that strains RB6PN23T and K1PA1T represented two novel species in the genus Streptomyces. The names proposed for these strains are Streptomyces silvisoli sp. nov. (type strain RB6PN23T=TBRC 17040T=NBRC 116113T) and Streptomyces tropicalis sp. nov. (type strain K1PA1T=TBRC 17041T=NBRC 116114T). Additionally, a giant linear polyene compound, neotetrafibricin A, exhibiting antifungal activity in strain RB6PN23T, was identified through HPLC and quadrupole time-of-flight MS analysis. The crude extract from the culture broth of strain RB6PN23T exhibited strong antifungal activity against Fusarium verticillioides, Fusarium fujikuroi and Bipolaris zeicola. This finding suggests that strain RB6PN23T could be a promising candidate for biological control of fungal diseases.

Saccharopolyspora oryzae sp. nov., isolated from rhizosphere soil of the wild rice species Oryza rufipogon.

A novel actinobacterium, designated as strain WRP15-2T, was isolated from rhizosphere soil of rice plant (Oryza rufipogon). The strain was Gram-stain-positive, aerobic, and non-motile. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain WRP15-2T fell into the genus Saccharopolyspora. The strain shared the highest 16S rRNA gene sequence similarity with the type strains Saccharopolyspora kobensis JCM 9109T (99.1%), Saccharopolyspora indica VRC122T (98.9%), and Saccharopolyspora antimicrobica DSM 45119T (98.7%). However, the digital DNA-DNA hybridization and average nucleotide identity values among these strains confirmed that the microorganism represented a novel member of the genus Saccharopolyspora. Chemotaxonomic data revealed that strain WRP15-2T possessed MK-9(H4) as the predominant menaquinone. It contained meso-diaminopimelic acid as the diagnostic diaminopimelic acid and arabinose, galactose, and ribose as predominant whole-cell sugars. The detected phospholipids were dominated by phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxy-phosphatidylmethylethanolamine, and phosphatidylcholine. The predominant cellular fatty acids were iso-C16:0, C16:0, and iso-C15:0. The G + C content of the genomic DNA was 69.5%. Based on these genotypic and phenotypic data, it is supported that strain WRP15-2T represents a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora oryzae sp. nov. is proposed. The type strain is WRP15-2T ( = TBRC 15728T = NBRC 115560T).

Nocardiopsis suaedae sp. nov. and Nocardiopsis endophytica sp. nov., two novel halophilic actinobacteria isolated from halophytes.

A polyphasic approach was used to describe two halophilic actinobacterial strains, designated LSu2-4T and RSe5-2T, which were isolated from halophytes [Suaeda maritima (L.) Dum. and Sesuvium portulacastrum (L.) L.] collected from Prachuap Khiri Khan province, Thailand. Comparative analysis of 16S rRNA gene sequences showed that strains LSu2-4T and RSe5-2T were assigned to the genus Nocardiopsis, with Nocardiopsis chromatogenes YIM 90109T(99.2 and 99.2 % similarities, respectively) and Nocardiopsis halophila DSM 44494T(99.0 and 98.8 % similarities, respectively) being their closely related strains. Whereas the 16S rRNA gene sequence similarity between LSu2-4T and RSe5-2T was 99.4 %. Phylogenetic and phylogenomic analyses based on 16S rRNA gene and whole-genome sequences revealed that both strains clustered with N. chromatogenes YIM 90109T and N. halophila DSM 44494T. The average nucleotide identity (ANI) based on blast, ANI based on MUMmer and digital DNA-DNA hybridization (dDDH) relatedness values between the two strains and their closest type strains were below the threshold values for identifying a novel species. Morphological characteristics and chemotaxonomic features of both strains were typical for the genus Nocardiopsis by formed well-developed substrate mycelia and aerial mycelia which fragmented into rod-shaped spores. Whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were variously hydrogenated with 10 isoprene units and contained phosphatidylcholine in their polar lipid profiles. Major fatty acids were iso-C16:0 and 10-methyl C18:0. In silico analysis predicted that the genomes of LSu2-4T and RSe5-2T contained genes associated with stress responses and biosynthetic gene clusters encoding diverse bioactive metabolites. Characterization based on chemotaxonomic, phenotypic, genotypic and phylogenetic evidence demonstrated that strains LSu2-4T and RSe5-2T represents two novel species of the genus Nocardiopsis, for which the names Nocardiopsis suaedae sp. nov. (type strain LSu2-4T=TBRC 16415T=NBRC 115855T) and Nocardiopsis endophytica sp. nov. (type strain RSe5-2T=TBRC 16416T=NBRC 115856T) are proposed.

Streptomyces rhizoryzae sp. nov., isolated from paddy rhizosphere soil and formal proposal to reclassify Streptomyces albulus as a later heterotypic synonym of Streptomyces noursei.

The taxonomic position of a novel actinomycete, designated strain RS10V-4T, was determined using a polyphasic approach. Strain RS10V-4T was isolated from paddy rhizosphere soil of rice plant (Oryzae sativa L.). The morphological, physiological and chemotaxonomic properties were consistent with its classification in the genus Streptomyces. On the basis of 16S rRNA gene sequence analysis, strain RS10V-4T belongs to the genus Streptomyces and had the highest sequence similarity to Streptomyces noursei NBRC 15452T (98.3 %). The G+C content of the genomic DNA was 73.8 %. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequences of strain RS10V-4T and S.noursei ATCC 11455T were lower than the recommendation threshold values for the recognition of species within the same genus. The whole-cell hydrolysates of strain RS10V-4 T contained ll -diaminopimelic acid as the diagnostic diamino acid and the whole-cell sugars were glucose and ribose. The predominant menaquinones were MK-9(H6) and MK-9(H8). The predominant cellular fatty acids (>10 %) were iso-C16 : 0, anteiso-C15 : 0, iso-C14 : 0 and iso-C15 : 0. The polar lipids of strain RS10V-4T contained diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, an unidentified aminolipid, two unidentified lipids and an unidentified phospholipid. On the basis of these phenotypic and genotypic characteristics, it is supported that strain RS10V-4T represents a novel species of the genus Streptomyces, for which the name Streptomyces rhizoryzae sp. nov. is proposed. The type strain is RS10V-4T (=TBRC 15167T=NBRC 115345T). In addition, the comparison of the whole genome sequences and phenotypic features suggested that S. noursei and S. albulus belong to the same species. Therefore, it is proposed that S. albulus is reclassified as a later heterotypic synonym of S. noursei.

Cadmium-resistant Streptomyces stimulates phytoextraction potential of Crotalaria juncea L. in cadmium-polluted soil.

This work evaluated the competence of two strains of cadmium (Cd)-resistant Streptomyces, namely Streptomyces rapamycinicus K5PN1, an indole-3-acetic acid (IAA) producer, and Streptomyces cyaneus 11-10SHTh, a siderophore producer on promoting Cd phytoextraction by sunn hemp. The results showed that S. rapamycinicus improved root elongation of sunn hemp seedlings under Cd stress conditions. S. rapamycinicus and S. cyaneus were colonized on the root surface of sunn hemp at concentrations of 2.3 × 104 and 6.4 × 103 CFU g-1 root fresh weight, respectively. The results of pot-culture experiments showed that S. rapamycinicus increased the root and shoot lengths, and dry biomass of sunn hemp planted in high Cd-contaminated soil. The Cd concentration in the leaves of sunn hemp inoculated with S. cyaneus (73.82 ± 2.20 mg kg-1 plant dry wt) was higher than that of plants with S. rapamycinicus inoculation and the uninoculated control. The phytoextraction of Cd by sunn hemp was significantly increased with Cd-resistant Streptomyces inoculation. In conclusion, both strains of Cd-resistant Streptomyces had potential on enhancing Cd phytoextraction efficiency of sunn hemp. Our study suggests the application of Cd-resistant Streptomyces can improve Cd phytoextraction by sunn hemp for restoration of Cd-polluted sites.

Our study demonstrated the potential of two strains of Cd-resistant Streptomyces to stimulate Cd phytoextraction from soil by sunn hemp. Cadmium-resistant Streptomyces strongly stimulated Cd uptake and accumulation in sunn hemp planted in high level of Cd-polluted soil, supporting sunn hemp to be a superior Cd accumulator.

Actinomycetospora soli sp. nov., isolated from the rhizosphere soil of Averrhoa carambola L.

A novel actinobacterium, designated strain SF1T, was isolated from the rhizosphere soil of a star fruit plant (Averrhoa carambola L.) collected from Bangkok, Thailand, and its taxonomic position was evaluated. The strain showed morphological, chemotaxonomic and phylogenetic characteristics consistent with its classification in the genus Actinomycetospora. Strain SF1T was an aerobic, Gram-stain-positive and non-motile actinobacterium. Growth occurred at 15-35 °C, at pH 4.0-12.0 and in the presence of 0-10 % (w/v) NaCl. The 16S rRNA gene sequence of strain SF1T showed the highest similarity to Actinomycetospora chiangmaiensis YIM 0006T (99.5 %), Actinomycetospora corticicola 014-5T (98.8 %) and Actinomycetospora endophytica A-T 8314T (98.8 %). The genome sequencing revealed a genome size of 6.52 Mbp and a DNA G+C content of 74.0 %. In addition, the average nucleotide identity values between strain SF1T and reference strains, A. chiangmaiensis DSM 45062T, A. corticicola DSM 45772T and A. endophytica TBRC 5722T, were found to be 86.1, 86.5 and 79.7 %, respectively, and the level of digital DNA-DNA hybridization between them were 32.4, 32.4 and 23.3 %, respectively. The whole-cell hydrolysates of strain SF1T contained meso-diaminopimelic acid as the diagnostic diamino acid, with arabinose, galactose, glucose and ribose as whole-cell sugars. The predominant menaquinone was MK-8(H4). Major cellular fatty acids were iso-C16 : 0 and a summed feature consisting of C16 : 1 ω6c/C16 : 1 ω7c. Characterization based on chemotaxonomic, phylogenetic, phenotypic and genomic evidence demonstrated that strain SF1T represents a novel species of the genus Actinomycetospora, for which the name Actinomycetospora soli sp. nov. is proposed. The type strain is strain SF1T (=TBRC 15166T= NBRC 115295T).

Pseudonocardia terrae sp. nov., an actinobacterium isolated from rice rhizosphere soil in Thailand.

A novel actinomycete, designated strain RS11V-5T, was isolated from rhizosphere soil of Oryza sativa L. collected from Roi Et Province, Thailand, and its taxonomic position was evaluated. Cells of strain RS11V-5T were Gram-stain-positive, aerobic, and non-motile. Whole-cell hydrolysates contained meso-diaminopimelic acid, arabinose, galactose, glucose and ribose. MK-8(H4) was detected as the predominant menaquinone of this strain. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxy-phosphatidylmethylethanolamine, hydroxy-phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminolipid and an unidentified glycolipid. The major fatty acids were iso-C16 : 0, C16 : 0 and C16 : 1 ω7c/C16 : 1 ω6c. Phylogenetic analyses based on the 16S rRNA gene sequences showed that strain RS11V-5T belonged to the genus Pseudonocardia and had high 16S rRNA sequence similarity of 99.3 % to Pseudonocardia kujensis KCTC 29062T and less than 98.4 % to other members of the genus Pseudonocardia. The DNA G+C content of the strain RS11V-5T was 73.3 mol%. Strain RS11V-5T showed 46.5 % digital DNA-DNA hybridization, 92.2 % orthologous average nucleotide identity (OrthoANI), 90.2 % ANI based on blast and 92.7 % ANI based on MUMmer to P. kujensis KCTC 29062T. Based its phenotypic, genotypic, phylogenetic and chemotaxonomic characteristics, strain RS11V-5T represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia terrae sp. nov. is proposed. The type strain is RS11V-5T (=TBRC 15286T=NBRC 115296T).

Kitasatospora humi sp. nov., isolated from a tropical peat swamp forest soil, and proposal for the reclassification of Kitasatospora psammotica as a later heterotypic synonym of Kitasatospora aureofaciens.

A polyphasic approach was used to describe strain RB6PN24T, a novel actinobacterium isolated from peat swamp forest soil collected from Rayong province, Thailand. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain belonged to the genus Kitasatospora and showed the highest sequence similarities to Kitasatospora kifunensis IFO 15206T (98.7 %) and Kitasatospora acidiphila MMS16-CNU292T (98.5 %). Strain RB6PN24T contained major amounts of meso-diaminopimelic acid, galactose, mannose and ribose in the whole-cell hydrolysates. MK-9(H6) and MK-9(H8) were the predominant menaquinones of the micro-organism. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, an unidentified lipid, four unidentified aminolipids and six unidentified phospholipids. Mycolic acids were not present. The major fatty acids were iso-C15 : 0, iso-C16 : 0, anteiso-C15 : 0, iso-C17:0, anteiso-C17 : 0 and C16 : 0. The draft genome size of strain RB6PN24T was 8.09 Mbp, with 72.1 mol% G+C content and predicted to contain at least 44 biosynthetic gene clusters encoding diverse secondary metabolites. Furthermore, the strain exhibited low average nucleotide identity and digital DNA-DNA hybridization values with K. acidiphila MMS16-CNU292T (89.1 %, 42.4 %) and K. kifunensis DSM 41654T (79.5 %, 25.5 %). The results of phenotypic, chemotaxonomic, genotypic and phylogenetic analyses revealed that strain RB6PN24T represents a novel species of the genus Kitasatospora, for which the name Kitasatospora humi sp. nov. is proposed. The type strain is RB6PN24T (=TBRC 14818T=NBRC 115116T). In addition, the comparison of the whole genome sequences and phenotypic features suggested that Kitasatospora aureofaciens and Kitasatospora psammotica belong to the same species. Therefore, it is proposed that K. psammotica is reclassified as a later heterotypic synonym of K. aureofaciens.

Streptomyces humicola sp. nov., a novel actinobacterium isolated from peat swamp forest soil in Thailand.

A polyphasic approach was used to describe strain RB6PN25T, an actinobacterium isolated from peat swamp forest soil in Rayong Province, Thailand. The strain was a Gram-stain-positive and filamentous bacterium that contained ll-diaminopimelic acid, mannose and ribose in whole-cell hydrolysates. MK-9(H8) was the major menaquinone. The major fatty acids were iso-C16 : 0, anteiso-C15 : 0 and iso-C15 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, two unidentified glycophospholipids, two unidentified aminolipids and an unidentified phospholipid. The 16S rRNA gene sequences analysis indicated that it was most closely related to Streptomyces rubrisoli DSM 42083T (97.6 %) and Streptomyces palmae TBRC 1999T (97.4 %). Strain RB6PN25T exhibited low average nucleotide identity and digital DNA-DNA hybridization values with S. rubrisoli DSM 42083T (78.6 %, 23.2 %) and S. palmae TBRC 1999T (76.0 %, 22.6 %). The DNA G+C content of strain RB6PN25T was 69.9%. The results of phenotypic, chemotaxonomic, genotypic and phylogenetic analyses reveal that strain RB6PN25T represents a novel species of the genus Streptomyces, for which the name Streptomyces humicola sp. nov. is proposed. The type strain is RB6PN25T (=TBRC 14819T=NBRC 115204T).

Streptomyces spirodelae sp. nov., isolated from duckweed.

A novel actinobacterium, designated strain DW4-2T, was isolated from duckweed (Spirodela sp.) collected from an agricultural pond in Kasetsart University, Bangkok, Thailand. The morphological, chemotaxonomic and phylogenetic characteristics were consistent with its classification in the genus Streptomyces. Strain DW4-2T showed the highest 16S rRNA gene sequence similarity values to Streptomyces qinglanensis DSM 42035T (98.5 %), Streptomyces smyrnaeus DSM 42105T (98.4 %) and Streptomyces oryzae S16-07T (98.4 %). Digital DNA-DNA hydridization and average nucleotide identity values between the genome sequences of strain DW4-2T with S. qinglanensis DSM 42035T (29.8 and 87.8 %), S. smyrnaeus DSM 42105T (33.1 and 89.0 %) and S. oryzae S16-07T (33.0 and 88.9 %) were below the thresholds of 70 and 95-96 % for prokaryotic conspecific assignation. Chemotaxonomic data revealed that strain DW4-2T possessed MK-9(H6) and MK-9(H8) as the predominant menaquinones. It contained ll -diaminopimelic acid as the diagnostic diamino acid and glucose, ribose and trace amount of madurose in whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, an unidentified aminolipid, an unidentified lipid and an unidentified phospholipid. The predominant cellular fatty acids were anteiso-C17 : 0, anteiso-C15 : 0 and iso-C16 : 0. The genomic DNA size of the strain DW4-2T was 7 310 765 bp with DNA G+C content 71.0 mol%. Genomic analysis of the genome indicated that the strain DW4-2T had the potential to produce bioactive compounds. On the basis of these genotypic and phenotypic data, it is supported that strain DW4-2T represents a novel species of the genus Streptomyces, for which the name Streptomyces spirodelae sp. nov. is proposed. The type strain is strain DW4-2T (=TBRC 13095T=NBRC 114803T).

Microbispora oryzae sp. nov., isolated from leaves of rice plant (Oryza sativa L.).

An endophytic actinomycete, designated strain RL4-1ST, was isolated from surface-sterilized leaves of rice plant (Oryza sativa L.) collected from Buri Rum province, Thailand. Its taxonomic status was determined using a polyphasic approach. Phylogenetic analysis based on the 16S rRNA gene sequences showed that the strain RL4-1ST belongs to the genus Microbispora and is most closely related to Microbispora rosea subsp. rosea ATCC 12950T (98.5%). The strain forms pairs of spores on short sporophores borne on the aerial mycelium. Polar lipid profile of strain RL4-1ST is diphosphatidylglycerol, hydroxy-phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, ninhydrin-positive glycophospholipid, two unidentified phospholipids, an unidentified aminolipid, and an unidentified glycolipid. MK-9(H4), MK-9(H2), and MK-9 are major menaquinones of this organism. The predominant cellular fatty acids are iso-C16:0, C17:0 and C16:0. Strain RL4-1ST contains meso-diaminopimelic acid, glucose, madurose and ribose in whole-cell hydrolysates. The draft genome of strain RL4-1ST consists of 7.46 Mbp and has a G + C content 71.2 mol%. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain RL4-1ST with Microbispora rosea subsp. rosea ATCC 12950T are 26.0% and 80.7%, respectively. Based on data of genotypic, phenotypic, phylogenetic and chemotaxonomic analysis, strain RL4-1ST represents a novel species of the genus Microbispora, for which the name Microbispora oryzae sp. nov. is proposed. The type strain is RL4-1ST (= TBRC 14817T = NBRC 115115T).

Streptomyces acididurans sp. nov., isolated from peat swamp forest soil.

A novel actinomycete, designated strain KK5PA1T, was isolated from a soil sample collected from Kuan Kreng peat swamp forest, Nakhon Si Thammarat Province, Thailand. The morphological, chemotaxonomic and phylogenetic characteristics were consistent with its classification in the genus Streptomyces. Strain KK5PA1T was most closely related to Streptomyces bryophytorum NEAU-HZ10T (98.0 %) and Streptomyces guanduensis 701T (97.6 %). The G+C content of the genomic DNA was 72.3 mol%. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain KK5PA1T and those of S. bryophytorum DSM 42138T(25.1 and 79.1 %) and S. guanduensis DSM 41944T(25.1 and 79.7%) were below the thresholds of 70 and 96 % for prokaryotic conspecific assignation. Chemotaxonomic data revealed that strain KK5PA1T possessed MK-9(H6) and MK-9(H8) as the predominant menaquinones. It contained ll-diaminopimelic acid as the diagnostic diamino acid and galactose, glucose, mannose and ribose as whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, two unidentified aminolipids, five unidentified phospholipids and an unidentified lipid. The predominant cellular fatty acids were iso-C16 : 0, anteiso-C15 : 0 and C16 : 0. On the basis of these genotypic and phenotypic data, it is proposed that strain KK5PA1T represents a novel species of the genus Streptomyces, for which the name Streptomyces acididurans sp. nov. is proposed. The type strain is strain KK5PA1T (=TBRC 13094T=NBRC 114802T).

Influence of cadmium-resistant Streptomycetes on plant growth and cadmium uptake by Chlorophytum comosum (Thunb.) Jacques.

This work aims to explore the role of cadmium-resistant actinomycetes on promoting plant growth and cadmium uptake in Chlorophytum comosum (Thunb.) Jacques, a spider plant. Actinomycetes isolated from the plant roots in peat swamp forests were screened for their cadmium resistance and the production of indole-3-acetic acid (IAA) and siderophores. The results found that K5PN1 and 11-10SHTh produced high levels of IAA and siderophores, respectively. K5PN1 and 11-10SHTh were identified to be Streptomyces rapamycinicus and Streptomyces cyaneus, respectively. Both strains were able to remove cadmium from aqueous solution and survive under cadmium stress in contaminated soil. The results of pot experiments found that the selected Streptomyces inoculation increased the root and shoot biomass and cadmium accumulation in the root and shoot of C. comosum planted in a cadmium-contaminated soil. The highest cadmium accumulation and translocation ability of cadmium from the root to shoot was found in C. comosum with S. rapamycinicus inoculation. In addition, plant with S. cyaneus inoculation had the highest phytoextraction coefficient and bioaccumulation factor. Our findings concluded that S. rapamycinicus and S. cyaneus stimulated the growth and cadmium uptake in C. comosum, suggesting a combined approach using the selected Streptomyces and C. comosum for phytoremediation of cadmium-polluted soil.

Amycolatopsis acididurans sp. nov., isolated from peat swamp forest soil in Thailand.

A polyphasic approach was used to describe strain K13G38T, a novel actinomycete isolated from peat swamp forest soil collected from Surat Thani Province, Thailand. The 16S rRNA gene phylogenetic analysis indicated that the strain belonged to the genus Amycolatopsis and showed the highest sequence similarities to both Amycolatopsis acidiphila JCM 30562T and Amycolatopsis bartoniae DSM 45807T (96.8% sequence similarity). Furthermore, strain K13G38T, which formed extensively branched substrate and aerial mycelia, exhibited chemotaxonomical characteristics of the genus Amycolatopsis which included phospholipid pattern type II and cell-wall chemotype IV. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylglycerol, two unidentified phospholipids, and an unidentified aminolipid. MK-9(H4) was a predominant menaquinone of the organism. The major cellular fatty acids were iso-C16:0, anteiso-C17:0, and C16:0. The genomic DNA size of strain K13G38T was 8.5 Mbp with 69.5 mol% G+C content. On the basis of phenotypic characteristics, overall genomic relatedness index and phylogenetic distinctiveness, strain K13G38T represents a novel species of the genus Amycolatopsis, for which the name A. acididurans sp. nov. is proposed. The type strain is K13G38T (=TBRC 12507T = NBRC 114553T).

Pseudonocardia acidicola sp. nov., a novel actinomycete isolated from peat swamp forest soil.

A novel actinobacterium, designated strain K10HN5T, was isolated from a peat soil sample collected from Kantulee peat swamp forest, Surat Thani Province, Thailand and its taxonomic position was determined using a polyphasic approach. Strain K10HN5T contained meso-diaminopimelic acid, arabinose, galactose, glucose and ribose in its whole-cell hydrolysates. The predominant menaquinone was MK-8(H4). The major fatty acids were iso-C16 : 0, iso-C15 : 0 and iso-C16 : 1H. Mycolic acids were not present. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylmethylethanolamine, hydroxyphosphatidylethanolamine, hydroxyphosphatidylmethylethanolamine and phosphatidylinositol. The 16S rRNA gene sequence analysis indicated that it was closely related to Pseudonocardia bannensis DSM 45300T (97.9 %) and Pseudonocardia xinjiangensis JCM 11839T (97.9 %). Strain K10HN5T exhibited low average nucleotide identity and digital DNA-DNA hybridization values with P. bannensis DSM 45300T (82.6, 28.7 %) and P. xinjiangensis JCM11839T (76.3, 22.2 %). The DNA G+C content of strain K10HN5T was 72.4 mol%. Based on polyphasic data, strain K10HN5T represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia acidicola sp. nov. is proposed. The type strain is K10HN5T (=TBRC 10048T=NBRC 113897T).

Nonomuraea antri sp. nov., an actinomycete isolated from cave soil in Thailand.

A novel actinobacterium, designated strain NN258T, was isolated from a cave soil sample collected from a karst cave at Khao No-Khao Kaeo, Nakhon Sawan province, Thailand. The morphological, chemotaxonomic and phylogenetic characteristics were consistent with its classification in the genus Nonomuraea. Strain NN258T showed the highest 16S rRNA gene sequence similarity values to Nonomuraea candida HMC10T, Nonomuraea mesophila 6K102T, Nonomuraea rubra DSM 43768T, Nonomuraea diastatica KC712T and Nonomuraea helvata IFO 14681T. The strain formed an extensively branched substrate and aerial mycelia. The whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, with glucose, madurose, mannose and ribose as the whole-cell sugars. The polar lipids were diphosphatidylglycerol, phosphotidylmethylethanolamine, phosphatidylethanolamine, hydroxy-phosphatidylmonomethylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, two unidentified phospholipids, three unidentified sugar-containing phosphoaminolipids, an unidentified glycolipid and two unidentified lipids. The predominant menaquinone was MK-9(H4), with minor amounts of MK-9(H0), MK-9(H2) and MK-9(H6). Major cellular fatty acids (>10%) were iso-C16 : 0 and 10-methyl-C17 : 0. The G+C content of the genomic DNA was 71.0 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain NN258T and the reference strains were 79.9-80.9 % and 26.1-27.0 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strain NN258T represents a novel species of the genus Nonomuraea, for which the name Nonomuraea antri sp. nov. is proposed. The type strain is NN258T (=TBRC 11478T=NBRC 114269T).