Mycolic acid composition and thermally adaptative changes in Nocardia asteroides

Actinomycetospora aeridis sp. nov., Actinomycetospora flava sp. nov. and Actinomycetospora aurantiaca sp. nov., endophytic actinobacteria isolated from wild orchid (Aerides multiflora Roxb)

Three novel mycelium-forming actinobacteria, designated OC33-EN06T, OC33-EN07T, and OC33-EN08T, were isolated from wild orchid (Aerides multiflora Roxb), collected from a hill evergreen forest in Northern Thailand. Strains OC33-EN06T and OC33-EN07T showed the highest 16S rRNA gene similarity with Actinomycetospora lutea TT00-04T, 99.17 and 99.45%, respectively. Strain OC33-EN08T showed high similarity with four species, namely 'Actinomycetospora termitidis Odt1-22T' (99.37%), Actinomycetospora chiangmaiensis DSM 45062T (99.02%), Actinomycetospora corticicola 014-5T (99.02%), and Actinomycetospora soli SF1T (98.81%). Comparative genome analysis of OC33-EN06T, OC33-EN07T, and OC33-EN08T with the closely related type strains showed that average nucleotide identity (ANI) based on blast, ANI based on MUMmer, and average amino acid identity values were less than 95% and the digital DNA-DNA hybridization values were less than 70%, all below the thresholds for species demarcation. The digital G+C content of OC33-EN06T, OC33-EN07T, and OC33-EN08T were 74.5, 74, and 74 mol%, respectively. These three strains developed bud-like chains of non-motile cylindrical spores with a smooth surface. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, arabinose, and galactose. The predominant menaquinone was MK-8(H4). The phospholipid profile included phosphatidylcholine, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylinositol. Based on comparative analysis of genotypic, phenotypic and chemotaxonomic data, strains OC33-EN06T (=TBRC 18349T=NBRC 116543T), OC33-EN07T (=TBRC 18350T=NBRC 116544T), and OC33-EN08T (=TBRC 18318T=NBRC 116542T) represent the type strains of three novel species of the genus Actinomycetospora for which the names Actinomycetospora aeridis sp. nov., Actinomycetospora flava sp. nov., and Actinomycetospora aurantiaca sp. nov., are proposed.

Klenkia sesuvii sp. nov., isolated from leaves of halophyte Sesuvium portulacastrum

During a study on the diversity of culturable actinobacteria from coastal halophytes in Thailand, strain LSe6-5T was isolated from leaves of sea purslane (Sesuvium portulacastrum L.), and a polyphasic approach was employed to determine its taxonomic position. The 16S rRNA gene sequences analysis indicated that the strain was most closely related to Klenkia brasiliensis Tu 6233T (99.2 %), Klenkia marina YIM M13156T (99.1 %), and Klenkia terrae PB261T (98.7 %). The genome of strain LSe6-5T was estimated to be 4.33 Mbp in size, with DNA G+C contents of 74.3%. A phylogenomic tree based on whole-genome sequences revealed that strain LSe6-5T formed a clade with Klenkia marina DSM 45722T, indicating their close relationship. However, the average nucleotide identity (ANI)-blast, ANI-MUMmer, and dDDH values between strain LSe6-5T with K. marina DSM 45722T (87.1, 88.9, and 33.0 %) were below the thresholds of 95-96 % ANI and 70 % dDDH for identifying a novel species. Furthermore, strain LSe6-5T showed morphological and chemotaxonomic characteristics of the genus Klenkia. Cells were motile, rod-shaped, and Gram-stain-positive. Optimal growth of strain LSe6-5T occurred at 28 °C, pH 7.0, and 0-3 % NaCl. The whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, with galactose, glucose, mannose, and ribose as whole-cell sugars. The predominant menaquinones were MK-9(H4) and MK-9(H0). The polar lipid profile was composed of diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, an unidentified phospholipid, and an unidentified lipid. Major cellular fatty acids were iso-C15 : 0, iso-C16 : 0, and iso-C17 : 0. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, it is supported that strain LSe6-5T represents a novel species of the genus Klenkia, for which the name Klenkia sesuvii sp. nov. is proposed. The type strain is strain LSe6-5T (=TBRC 16417T= NBRC 115929T).

Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov., two novel actinobacteria isolated from mangrove sediments and leaves of halophyte Sesuvium portulacastrum in Thailand

A polyphasic approach was used to characterize two novel actinobacterial strains, designated PKS22-38T and LSe1-13T, which were isolated from mangrove soils and leaves of halophyte Sesuvium portulacastrum (L.), respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that they belonged to the genus Gordonia and were most closely related to three validly published species with similarities ranging from 98.6 to 98.1 %. The genomic DNA G+C contents of strains PKS22-38T and LSe1-13T were 67.3 and 67.2 mol%, respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 93.3 and 54.9 %, respectively, revealing that they are independent species. Meanwhile, the ANI and dDDH values between the two novel strains and closely related type strains were below 80.5 and 24.0 %, respectively. Strains PKS22-38T and LSe1-13T contained C16 : 0, C18 : 1  ω9c and C18 : 0 10-methyl (TBSA) as the major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as the main phospholipids. The predominant menaquinone was MK-9(H2). Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strains PKS22-38T and LSe1-13T are considered to represent two novel species within the genus Gordonia, for which the names Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov. are proposed, with strain PKS22-38T (=TBRC 17540T=NBRC 116256T) and strain LSe1-13T (=TBRC 17706T=NBRC 116396T) as the type strains, respectively.

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).

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 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.

Nonomuraea corallina sp. nov., isolated from coastal sediment in Samila Beach, Thailand: insights into secondary metabolite synthesis as anticancer potential

A novel marine actinomycete, designated strain MCN248T, was isolated from the coastal sediment in Songkhla Province, Thailand. Based on the 16S rRNA gene sequences, the new isolate was closely related to Nonomuraea harbinensis DSM45887T (99.2%) and Nonomuraea ferruginea DSM43553T (98.6%). Phylogenetic analyzes based on the 16S rRNA gene sequences showed that strain MCN248T was clustered with Nonomuraea harbinensis DSM45887T and Nonomuraea ferruginea DSM43553T. However, the digital DNA-DNA hybridization analyzes presented a low relatedness of 40.2% between strain MCN248T and the above closely related strains. This strain contained meso-diaminopimelic acid. The acyl type of the peptidoglycan was acetyl, and mycolic acids were absent. The major menaquinones were MK-9(H2) and MK-9(H4). The whole cell sugars consisted of madurose, ribose, mannose, and glucose. Diphosphatidylglycerol, hydroxyl-phosphatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidylglycerol were detected as the major phospholipids. The predominant cellular fatty acids were iso-C16:0 (40.4%), 10-methyl-C17:0 (22.1%), and C17:1ω 8c (10.9%). The DNA G + C content of the genomic DNA was 71.7%. With in silico analyzes, the antiSMASH platform uncovered a diverse 29 secondary metabolite biosynthesis arsenal, including non-ribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) of strain MCN248T, with a high prevalence of gene cluster encoding pathways for the production of anticancer and cytotoxic compounds. Consistently, the crude extract could inhibit colorectal HCT-116 cancer cells at a final concentration of 50 μg/mL. Based on the polyphasic approach, strain MCN248 was designated as a novel species of the genus Nonomuraea, for which the name Nonomuraea corallina sp. nov. is proposed. The type strain of the type species is MCN248T (=NBRC115966T = TBRC17110T).

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.

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).

Streptomyces rugosispiralis sp. nov., a Novel Actinobacterium Isolated from Peat Swamp Forest Soil That Produces Ansamycin Derivatives and Nocardamines

Actinomycetes, especially the genus Streptomyces, are one of the most promising sources of bioactive natural products. In this study, a novel Streptomyces strain, RCU-064T, was isolated from a soil sample collected from a peat swamp forest in Thailand. Strain RCU-064T showed the highest 16S rRNA gene sequence similarity (99.06%) with Streptomyces malaysiensis NBRC 16446T. Based on a polyphasic approach, strain RCU-064T represents a novel species of the genus Streptomyces, for which the name Streptomyces rugosispiralis sp. nov. is proposed. The chemical isolation of the crude ethyl acetate extracts of the strain led to the isolation of six compounds: (1) geldanamycin, (2) 17-O-demethylgeldanamycin, (3) reblastatin, (4) 17-demethoxyreblastatin, (5) nocardamine, and (6) dehydroxynocardamine. These compounds were evaluated for their biological activities. All compounds showed no antimicrobial activity against tested microorganisms used in this study. Compounds (1)-(4) displayed cytotoxic activity against the NCI-H187 cell line, with IC50 values ranging from 0.045-4.250 µg/mL. Cytotoxicity against the MCF-7 cell line was found in compounds (1) and (3) with IC50 values of 3.51 and 1.27 µg/mL, respectively. Compounds (5) and (6) exhibited cytotoxicity only against Vero cells (IC50 of 16.57 µg/mL) and NCI-H187 cells (IC50 of 13.96 µg/mL), respectively. These results indicate that peat swamp forest soil remains a promising reservoir of novel actinomycetes capable of producing bioactive natural products.

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 LSu2-4^T and RSe5-2^T, 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 LSu2-4^T and RSe5-2^T were assigned to the genus Nocardiopsis, with Nocardiopsis chromatogenes YIM 90109^T(99.2 and 99.2 % similarities, respectively) and Nocardiopsis halophila DSM 44494^T(99.0 and 98.8 % similarities, respectively) being their closely related strains. Whereas the 16S rRNA gene sequence similarity between LSu2-4^T and RSe5-2^T 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 90109^T and N. halophila DSM 44494^T. 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-C_16:0 and 10-methyl C_18:0. In silico analysis predicted that the genomes of LSu2-4^T and RSe5-2^T 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 LSu2-4^T and RSe5-2^T represents two novel species of the genus Nocardiopsis, for which the names Nocardiopsis suaedae sp. nov. (type strain LSu2-4^T=TBRC 16415^T=NBRC 115855^T) and Nocardiopsis endophytica sp. nov. (type strain RSe5-2^T=TBRC 16416^T=NBRC 115856^T) 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-4^T, was determined using a polyphasic approach. Strain RS10V-4^T 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-4^T belongs to the genus Streptomyces and had the highest sequence similarity to Streptomyces noursei NBRC 15452^T (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-4^T and S.noursei ATCC 11455^T 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-C_16 : 0, anteiso-C_15 : 0, iso-C_14 : 0 and iso-C_15 : 0. The polar lipids of strain RS10V-4^T 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-4^T represents a novel species of the genus Streptomyces, for which the name Streptomyces rhizoryzae sp. nov. is proposed. The type strain is RS10V-4^T (=TBRC 15167^T=NBRC 115345^T). 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.

Induction of attenuated Nocardia seriolae and their use as live vaccine trials against fish nocardiosis

Nocardia seriolae, a Gram-positive facultative intercellular pathogen, has been identified as the causative agent of fish nocardiosis, causing substantial mortality and morbidity of a wide range of fish species. Looking into that fact, the effective vaccine against this pathogen is urgently needed to control the significant losses in aquaculture practices. In order to induct attenuated strains for developing the potential live vaccines, the mutagenic N. seriolae strain S-250 and U-20 were obtained from wild-type strain ZJ0503 through continuous passaging and ultraviolet (UV) irradiation, respectively. Additionally, the biological characteristic, virulence, stability, mediating immune response and supplying protective efficacy to hybrid snakehead of the S-250 and U-20 strains were determined in the present study. The results showed that U-20 strain displayed dramatic changes in morphological characteristic and significant decreased in the virulence to hybrid snakehead, while that of S-250 strain had no obvious different in comparison to ZJ0503 strain. When hybrid snakehead were intraperitoneally injected with ZJ0503, S-250 and U-20 strains at their respective sub-clinical dosage, the non-specific immunity parameters (serum LYZ, POD, ACP, AKP and SOD activities), specific antibody (IgM) titers production and immune-related genes (CC1, CC2, IL-1β, IL-8, TNFα, IFNγ, MHCIα, MHCIIα, CD4, CD8α, TCRα and TCRβ) expression were up-regulated, indicating that they were able to trigger humoral and cell-mediated immune responses. Furthermore, the protective efficacy in hybrid snakehead after vaccination with ZJ0503, S-250 and U-20 strains, in terms of relative percentage survival (RPS), were 28.85%, 56.89% and 89.65% respectively. Taken together, two attenuated N. seriolae strains S-250 and U-20 were obtained successfully and they could elicit strong immune response and supply protective efficacy to hybrid snakehead against N. seriolae, which suggested that these two attenuated strains were the potential candidates for live vaccine development to control fish nocardiosis in aquaculture.

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.

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 .

Transcriptome analysis in the spleen of Northern Snakehead (Channa argus) challenged with Nocardia seriolae

Northern snakehead (Channa argus) is an indigenous fish species and is one of popularly cultured snakeheads in China and other Asian countries. Unfortunately, Nocardia seriolae infections have caused considerable losses in the snakehead aquaculture industry. However, the infectivity and the immune response induced by N. seriolae in snakehead are unclear. In order to better understand the immune response of Northern snakehead in a series of time points after N. seriolae challenge, we conducted the transcriptomic comparison in snakehead spleen at 48, 96, and 144 h after the challenge of N. seriola against their control counterparts. Gene annotation and pathway analysis of differentially expressed genes (DEGs) were carried out to understand the functions of the DEGs. Additionally, protein-protein interaction networks were conducted to obtain the interaction relationships of immune-related DEGs. These results revealed the expression changes of multiple DEGs and signaling pathways involved in immunity during N. seriolae infection, which will facilitate our comprehensive understanding of the mechanisms involved in the immune response to bacterial infection in the northern snakehead.

Actinomadura violacea sp. nov., a madurastatin A1-producing strain isolated from lichen in Thailand

An actinomycete strain, LCR2-06^T, isolated from a lichen sample on rock collected from Chiang Rai Province (Pong Phra Bat Waterfall), Thailand, was characterized using a polyphasic approach. The strain grew at 25-45 °C, pH 6-11 and on International Streptomyces Project 2 agar plate with 5 % (w/v) NaCl. It contained meso-diaminopimelic acid as the diamino acid in whole-cell hydrolysates. Rhamnose, ribose, xylose, madurose, glucose and galactose were detected as whole-cell sugar hydrolysates. Mycolic acids were absent. The N-acyl type of muramic acid was acetyl. The strain contained C_16 : 0, TBSA 10-methyl C_18 : 0 and 2-hydroxy C_16 : 0 as the predominant fatty acids and MK-9(H₆), MK-9(H₄) and MK-9(H₈) as the major menaquinones. The major polar lipids were diphosphatidylglycerol, phosphatidylinositol and unidentified phospholipid. The draft genome of strain LCR2-06^T was closely related to Actinomadura barringtoniae TBRC 7225^T (99.2 %), Actinomadura nitritigenes NBRC 15918^T (98.8 %), Actinomadura montaniterrae TISTR 2400^T (98.5 %) and Actinomadura physcomitrii JCM 33455^T (97.9 %). The draft genome of LCR2-06^T was 11.1 Mb with 10 588 coding sequences with an average G+C content of 72.7 mol%. Results of genomic analysis revealed that the ANIb and ANIm values between strain LCR2-06^T and A. montaniterrae TISTR 2400^T were 90.0 and 92.0 %, respectively. The digital DNA-DNA hybridization value was 43.9 % in comparison with the draft genome of A. montaniterrae TISTR 2400^T. The strain produced an antibacterial compound active against Bacillus subtilis ATCC 6633 and Kocuria rhizophila ATCC 9341. The results of taxonomic analysis suggested that strain LCR2-06^T represented a novel species of the genus Actinomadura for which the name Actinomadura violacea sp. nov. is proposed. The type strain is LCR2-06^T (=JCM 33065^T=KCTC 49547^T=NBRC 114810^T=LMG 32136^T=TISTR 2935^T).

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

An endophytic actinomycete, designated strain RL4-1S^T, 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 RL4-1S^T belongs to the genus Microbispora and is most closely related to Microbispora rosea subsp. rosea ATCC 12950^T (98.5%). The strain forms pairs of spores on short sporophores borne on the aerial mycelium. Polar lipid profile of strain RL4-1S^T 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-C_16:0, C_17:0 and C_16:0. Strain RL4-1S^T contains meso-diaminopimelic acid, glucose, madurose and ribose in whole-cell hydrolysates. The draft genome of strain RL4-1S^T 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 RL4-1S^T with Microbispora rosea subsp. rosea ATCC 12950^T are 26.0% and 80.7%, respectively. Based on data of genotypic, phenotypic, phylogenetic and chemotaxonomic analysis, strain RL4-1S^T represents a novel species of the genus Microbispora, for which the name Microbispora oryzae sp. nov. is proposed. The type strain is RL4-1S^T (= TBRC 14817^T = NBRC 115115^T).

Prauserella cavernicola sp. nov., isolated from cave rock

A novel actinomycete, designated strain ASG 168^T, was isolated from cave rock collected from Stegodon Sea Cave in Thailand. Long chains of non-motile spores that were oval or spherical in shape with a smooth surface developed on aerial mycelia. Substrate mycelia fragmented into irregular rod-shaped elements. A polyphasic taxonomic study showed that strain ASG 168^T had typical characteristics of members of the genus Prauserella. 16S rRNA gene sequence analysis indicated that strain ASG 168^T shared 97.5 % similarity with Prauserella marina MS498^T and 96.7 % with Prauserella coralliicola SCSIO 11529^T. Average nucleotide identity values with P. coralliicola SCSIO 11529^T and P. marina MS498^T were 82.98 and 76.08 %, respectively. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, arabinose and galactose. The predominant menaquinone was MK-9(H₄). The predominant fatty acids were iso-C_16 : 0, C_16 : 0 and summed feature 3 (C_16 : 1 ω7c/C_16 : 1 ω6c). The phospholipid profile consisted of phosphatidylethanolamine, phosphatidylmethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides and two unknown phospholipids. The G+C content of the genomic DNA was 70.6 mol%. Differentiation of strain ASG 168^T from closely related species was evident from digital DNA-DNA hybridization values of 29.2 and 21.3 % with P. coralliicola and P. marina, respectively. Based on comparative analysis of phenotypic, chemotaxonomic and genotypic data, the novel actinomycete strain ASG 168^T (=TBRC 13679^T=NBRC 114887^T) is proposed to be the type strain of a novel species, Prauserella cavernicola sp. nov.

Microbacterium stercoris sp. nov., an indole acetic acid-producing actinobacterium isolated from cow dung

A novel growth-promoting and indole acetic acid-producing strain, designated NEAU-LLB^T, was isolated from cow dung collected from Shangzhi, Heilongjiang Province, PR China. Cells of strain NEAU-LLB^T were Gram-stain-positive, non-motile, aerobic and non-spore-forming. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain NEAU-LLB^T belonged to the genus Microbacterium. Strain NEAU-LLB^T had high 16S rRNA sequence similarities of 98.81 and 98.41 % to Microbacterium paludicola DSM 16915^T and Microbacterium marinilacus DSM 18904^T, and less than 98 % to other members of the genus Microbacterium. Chemotaxonomic characteristics showed that MK-11 and MK-12 were detected as the predominant menaquinones. The peptidoglycan contained glutamic acid, aspartic acid, glycine, ornithine and a small amount of alanine, with ornithine as the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unidentified glycolipid. The major fatty acids were identified as anteiso-C_15 : 0, iso-C_16 : 0 and iso-C_17 : 0. The genomic DNA G+C content of strain NEAU-LLB^T was 70.2 mol%. In addition, the average nucleotide identity values between strain NEAU-LLB^T and its reference strains, M. paludicola DSM 16915^T, M. marinilacus DSM 18904^T and M. album SYSU D8007^T, were found to be 81.1, 79.4 and 78.7 %, respectively, and the level of digital DNA-DNA hybridization between them were 23.8, 22.6 and 21.8 %, respectively. Based on the phenotypic, phylogenetic and genotypic data, strain NEAU-LLB^T is considered to represent a novel species of the genus Microbacterium, for which the name Microbacterium stercoris sp. nov is proposed, with NEAU-LLB^T (=CCTCC AA 2018028^T=JCM 32660^T) as the type strain.

Comparative genomics and proposal of Streptomyces radicis sp. nov., an endophytic actinomycete from roots of plants in Thailand

Strains DS1-2^T and AZ1-7, which were isolated from roots of plants, were taxonomically characterized based on polyphasic taxonomic and taxogenomic approaches. Both strains were Gram-stain-positive and filamentous bacteria which contained LL-diaminopimelic acid in cell-wall peptidoglycan and glucose and ribose in whole-cell hydrolysates. MK-9(H₆), MK-10(H₆), MK-9(H₈), MK-10(H₈) and MK-10(H₄) were major menaquinones; iso-C_16:0 and iso-C_16:1G were predominant cellular fatty acids; diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol mannoside presented as major phospholipids; and the DNA G+C contents of 73.2 mol%. Strains DS1-2^T and AZ1-7 showed 97.6-98.0 % 16S rRNA gene sequence similarity, 81.0-82.0 % ANIb, 84.8-85.3 % ANIm and 22.0-23.1 % digital DDH to their related type strains: S. specialis GW41-1564^T and S. hoynatensis S1412^T. Comparative genomics results of these strains and their related type strains also revealed the differences and distributions of key genes associated with stress responses, environmental variables, plant interactions and bioactive metabolites. Based on the phenotypic, chemotaxonomic and genomic data, strains DS1-2^T and AZ1-7 could be assigned to the novel species within the genus Streptomyces for which the name Streptomyces radicis sp. nov. is proposed. The type strain is DS1-2^T (=JCM 32152^T =KCTC 39738^T =TISTR 2403^T).

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

A novel actinomycete, designated strain KK5PA1^T, 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 KK5PA1^T was most closely related to Streptomyces bryophytorum NEAU-HZ10^T (98.0 %) and Streptomyces guanduensis 701^T (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 KK5PA1^T and those of S. bryophytorum DSM 42138^T(25.1 and 79.1 %) and S. guanduensis DSM 41944^T(25.1 and 79.7%) were below the thresholds of 70 and 96 % for prokaryotic conspecific assignation. Chemotaxonomic data revealed that strain KK5PA1^T 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-C_16 : 0, anteiso-C_15 : 0 and C_16 : 0. On the basis of these genotypic and phenotypic data, it is proposed that strain KK5PA1^T represents a novel species of the genus Streptomyces, for which the name Streptomyces acididurans sp. nov. is proposed. The type strain is strain KK5PA1^T (=TBRC 13094^T=NBRC 114802^T).

Gordonia asplenii sp. nov., isolated from humic soil on bird's nest fern (Asplenium nidus L.)

A novel member of the actinobacteria, designated strain A-T 0013^T, was isolated from humic soil on a bird's nest fern (Asplenium nidus L.) collected from Khao Yai National Park in Thailand. According the results of a polyphasic taxonomic study, A-T 0013^T had characteristics typical of members of the genus Gordonia. The 16S rRNA gene sequence indicated that A-T 0013^T shared ≤98 % sequence similarity with all members of the genus Gordonia. The most closely related species was Gordonia effusa IFM 10200^T (97.92 % sequence similarity). The average nucleotide identity based on blast (ANIb) value with G. effusa IFM 10200^T was 76.81 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, arabinose and galactose. The predominant menaquinone was MK-9(H₂). The predominant fatty acids were C_16 : 0, C_18 : 1ω9c, summed feature 3 (C_16 : 1ω7c/C_16 : 1ω6c), and C_18 : 0 10-methyl. Mycolic acid was present. The polar lipid profile for this strain ncluded diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The G+C content of the genomic DNA was 66.1 mol%. Differentiation of A-T 0013^T from the most closely related species, Gordonia effusa IFM 10200^T, was evident from digital DNA-DNA hybridization values of 21.8 %. On the basis of the results of comparative analysis of phenotypic, chemotaxonomic and genotypic data, strain A-T 0013^T is concluded to represent a novel species of the genus Gordonia, for which the name Gordonia asplenii sp. nov. is proposed. The type strain is A-T 0013^T (=TBRC 11910^T=NBRC 114549^T).

Actinomadura decatromicini sp. nov., isolated from mountain soil in Thailand

A novel actinomycete strain CYP1-5T was isolated from the mountain soil sample collected from Chaiyaphum province, Thailand and its taxonomic position was clarified by using a polyphasic taxonomic approach. The chemotaxonomic properties of strain CYP1-5T were consistent within the genus Actinomadura. Cell-wall peptidoglycan of this strain contained meso-diaminopimelic acid. Galactose, madurose, and ribose were presented as the diagnostic sugars in whole-cell hydrolysates. The major menaquinone was MK-9(H6). Major cellular fatty acids were iso-C16:0 and C16:0. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannoside were observed as predominant phospholipids. Based on the results of phylogenetic analyses of 16S rRNA gene sequence, strain CYP1-5T was constituent with the genus Actinomadura and was closely related to Actinomadura syzygii GKU157T (99.5%) and Actinomadura chibensis IFM 10266T (= JCM 14158T) (98.2%). The draft genome size of strain CYP1-5T was 9.30 Mb with 72.2 mol% of G + C content. Strain CYP1-5T showed ANIb values of 94.9% with A. syzygii GKU157T and 93.2% with A. chibensis JCM 14158T. Phenotypic characteristics, phylogenetic analysis and genome data support that strain CYP1-5T could be discriminated from its closest relatives, representing a novel species of the genus Actinomadura, for which the name Actinomadura decatromicini sp. nov. is proposed. The type strain is CYP1-5T (= JCM 16996T = KCTC 19916T = TISTR 2901T).

Nocardia terrae sp. nov., an actinomycete isolated from soil in Thailand

A novel actinomycete strain ET3-3^T isolated from soil collected from Chachoengsao province, Thailand was taxonomic evaluated using a polyphasic approach. Chemotaxonomic analysis indicated that meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. Mycolic acids were present. Ribose, arabinose, and galactose were detected in its whole-cell hydrolysates. The strain comprised C_16:0 and TBSA 10-methyl C_18:0 as the main fatty acids and MK-8(H₄ω-cycl) as the predominant menaquinone. Major polar lipids were phosphatidylinositol, phosphatidylinositol mannoside, phosphatidylethanolamine, and diphosphatidylglycerol. The results of 16S rRNA gene sequence analysis showed that strain ET3-3^T was closely related to Nocardia seriolae JCM 30082^T (99.2%), Nocardia yunnanensis JCM 30082^T (98.4%), and Nocardia concava JCM 12351^T (98.2%). The draft genome of ET3-3^T was 9.31 Mb with 8826 coding sequences with an average G + C content of 68.0%. The comparison of the draft genome of strain ET3-3^T and N. seriolae NBRC 15557^T showed the ANIb, ANIm and the digital DNA-DNA hybridization values of 86.3%, 88.5% and 32.9%, respectively. The results of the taxonomic analysis suggested that strain ET3-3^T represented a novel species of the genus Nocardia for which the name Nocardia terrae sp. nov. is proposed. The type strain is ET3-3^T (= JCM 33776^T = TISTR 2837^T).

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

A polyphasic approach was used to describe strain K13G38^T, 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 30562^T and Amycolatopsis bartoniae DSM 45807^T (96.8% sequence similarity). Furthermore, strain K13G38^T, 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-C_16:0, anteiso-C_17:0, and C_16:0. The genomic DNA size of strain K13G38^T 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 K13G38^T represents a novel species of the genus Amycolatopsis, for which the name A. acididurans sp. nov. is proposed. The type strain is K13G38^T (=TBRC 12507^T = NBRC 114553^T).

Motilibacter deserti sp. nov. and Motilibacter aurantiacus sp. nov., two novel actinobacteria isolated from soil of Cholistan Desert and emended description of the genus Motilibacter

Two novel actinobacterial strains, designated as E257^T and K478^T, were isolated from hyper-arid soil samples collected in Cholistan Desert, Pakistan. Comparative analysis of 16S rRNA genes showed that strains E257^T and K478^T were assigned to the genus Motilibacter, being their closest relative M. rhizosphaerae RS-16^T with 97.3% and 96.7% similarities, respectively. The sequence similarity between strain E257^T and K478^T was 98.9%. Phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic analysis based on multiple genes of conserved core proteins exhibited that these two strains belonged to the genus Motilibacter and formed a robust cluster separated from the two type species of the genus Motilibacter. Average Nucleotide Identity (ANI), Average Amino acid Identity (AAI), digital DNA-DNA hybridization (dDDH) values and Percentage of Conserved Proteins (POCP) calculated from the complete genome sequences indicated strains E257^T and K478^T were assigned into genus Motilibacter but clearly separated from each other and from the other species of the genus Motilibacter with values below the thresholds for species delineation. The two isolates were found to have chemotaxonomic, cultural and morphological properties consistent with their classification in the genus Motilibacter and also confirmed the differentiation from their closest species. The obtained results demonstrated that strains E257^T and K478^T represent two novel species of the genus Motilibacter, for which the names Motilibacter desertisp. nov. (type strain E257^T = JCM 33651^T = CGMCC 1.17159^T) and Motilibacter aurantiacus sp. nov. (type strain K478^T =JCM 33652^T =CGMCC 1.17229^T) are proposed.

Nocardia aurantiaca sp. nov., isolated from soil in Thailand

A novel actinomycete strain, CT2-14T, belonging to the genus Nocardia , was isolated from a soil sample collected from Phichit Province, Thailand. The taxonomic position of the strain was characterized using a polyphasic approach. The strain grew at 15–40 °C (optimum, 28–37 °C), pH 6–11 (optimum, pH 6–8) and on an International Streptomyces Project 2 with 4 % (w/v) NaCl agar plate. Meso-diaminopimelic acid was detected in the cell-wall peptidoglycan. Ribose, arabinose and galactose were detected in its whole-cell hydrolysates. Mycolic acids were present. The strain contained C16 : 0, summed feature 3, C17 : 0 10-methyl and C18 : 1 ω9c as the major fatty acids and MK-8(H4ω-cycl) as the major menaquinone. The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylinositol mannosides. Strain CT2-14T showed the highest 16S rRNA gene similarity to Nocardia veterana JCM 11307T (98.4 %), Nocardia africana JCM 11438T (98.2 %) and Nocardia kruczakiae JCM 13032T (98.0 %). The draft genome of strain CT2-14T was 7.37 Mb with 6685 coding sequences with an average G+C content of 67.9 mol %. Based on the phylogenomic tree analysis, the strain was closely related to Nocardia niigatensis NBRC 100131T. On the basis of polyphasic and genome analyses, strain CT2-14T represented a novel species of the genus Nocardia for which the name Nocardia aurantiaca sp. nov. is proposed. The type strain is CT2-14T (=JCM 33775T=TISTR 2838T).

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).

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

A novel actinobacterium, designated strain K10HN5^T, 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 K10HN5^T 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-C_16 : 0, iso-C_15 : 0 and iso-C_16 : 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 45300^T (97.9 %) and Pseudonocardia xinjiangensis JCM 11839^T (97.9 %). Strain K10HN5^T exhibited low average nucleotide identity and digital DNA-DNA hybridization values with P. bannensis DSM 45300^T (82.6, 28.7 %) and P. xinjiangensis JCM11839^T (76.3, 22.2 %). The DNA G+C content of strain K10HN5^T was 72.4 mol%. Based on polyphasic data, strain K10HN5^T represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia acidicola sp. nov. is proposed. The type strain is K10HN5^T (=TBRC 10048^T=NBRC 113897^T).

Nonomuraea nitratireducens sp. nov., a new actinobacterium isolated from Suaeda australis Moq. rhizosphere

A novel actinomycete, designated WYY166T, was isolated from the rhizosphere of Suaeda australis Moq. collected in Dongfang, PR China. The taxonomic position of this strain was investigated using a polyphasic approach. Phylogenetic analysis based on its 16S rRNA gene referred strain WYY166T to the genus Nonomuraea , and it was most closely related to the type strains Nonomuraea candida HMC10T, Nonomuraea turkmeniaca DSM 43926T, Nonomuraea maritima NBRC 106687T and Nonomuraea polychroma DSM 43925T (98.35, 97.60, 97.36 and 97.30% sequence similarity, respectively). Genome sequencing revealed a genome size of 11.27 Mbp and a G+C content of 71.10 mol%. The genome average nucleotide identity (ANI) values and the digital DNA - DNA hybridization (dDDH) values between strain WYY166T and the other species of the genus were found to be low (ANI 81.63~85.23 %, dDDH 23.6~31.6 %), suggesting that it represented a new species. The physiological evaluation showed that it had remarkable nitrate reduction activity. The whole-cell hydrolysates contained meso-diaminopimelic acid and madurose. The N-acyl type of muramic acid was acetyl. The major menaquinones were MK-9 (H4) (86.9 %) and MK-9 (H2) (13.1 %). The predominant fatty acids were iso-C16 : 0 (53.2 %), 10-methyl C17 : 0 (10.7 %), C17 : 1  ω6c (8.3 %) and iso-C16 : 1 h (7.3 %). These physiological, biochemical and chemotaxonomic data suggested that strain WYY166T should be classified as representing a novel species of the genus Nonomuraea , for which the name Nonomuraea nitratireducens sp. nov. is proposed. The type strain is WYY166T (=MCCC 1K03779T=KCTC 49343T).

Gordonia mangrovi sp. nov., a novel actinobacterium isolated from mangrove soil in Hainan

A novel actinobacterium, designated strain HNM0687^T, was isolated from mangrove soil samples collected from Hainan Province, PR China and its polyphasic taxonomy was studied. Based on the results of 16S rRNA gene sequence analysis, strain HNM0687^T was closely related to Gordonia bronchialis NBRC 16047^T (98.7 %), Gordonia rhizosphera NBRC 16068^T (98.2 %), Gordonia oryzae RS15-1S^T (97.9 %), Gordonia polyisoprenivorans NBRC 16320^T (97.7 %) and Gordonia sediminis AMA 120^T (97.7 %). Genome-based comparisons revealed a clear distinction in average nucleotide identity values between strain HNM0687^T and its closely related strains (74.4-78.3 %). Strain HNM0687^T contained meso-diaminopimelic acid, arabinose and galactose in whole-cell hydrolysates. Mycolic acid was present. The menaquinones of strain HNM0687^T were MK-9(H₂) and MK-7(H₂). The phospholipids of the isolate were composed of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The major fatty acids were C_16 : 0, C_16 : 1  ω7c/C_16 : 1  ω6c, C_18 : 010-methyl (TBSA), C_18 : 0 and C_18 : 1  ω9c. Based on its genotypic, chemotaxonomic and phenotypic characteristics, it is concluded that strain HNM0687^T represents a novel species of the genus Gordonia for which the name Gordonia mangrovi sp. nov. is proposed. The type strain is HNM0687^T (=CCTCC AA 2019074 ^T=KCTC 49383 ^T).

Amycolatopsis anabasis sp. nov., a novel endophytic actinobacterium isolated from roots of Anabasis elatior

A novel endophytic actinobacterium, designated strain EGI 650086T, was isolated from the roots of Anabasis elatior (C.A.Mey.) Schischk. collected in Xinjiang, north-west China. The taxonomic position of the strain was investigated using a polyphasic taxonomic approach. Growth occurred at 15–40 °C, pH 6.0–8.0 and in the presence of 0–6 % NaCl (w/v). Phylogenetic analysis based on 16S rRNA gene sequence and concatenation of 22 protein marker genes revealed that strain EGI 650086T formed a monophyletic clade within the genus Amycolatopsis and shared the highest sequence similarities with Amycolatopsis nigrescens JCM 14717T (97.1 %) and Amycolatopsis sacchari DSM 44468T (97.0 %). Sequence similarities with type strains of other species of the genus Amycolatopsis were less than 97.0 %. The average nucleotide identity and DNA–DNA hybridization values between strain EGI 650086T and the reference strains were 78.1–79.8 % and 22.1–23.0 %, respectively. The genome of strain EGI 650086T was 10.9 Mb, with a DNA G+C content of 70.1 mol%. The diagnostic diamino acid in the peptidoglycan was meso-diaminopimelic acid. The major whole-cell sugars contained arabinose, galactose, glucose and ribose. The predominant menaquinones were MK-9 (H4) and MK-9 (H2). Major fatty acids were iso-C16 : 0 and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The polar lipid profile of strain EGI 650086T included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, two unknown phospholipids, an unknown glycolipid and an unknown lipid. Polyphasic taxonomic characteristics indicated that strain EGI 650086T represents a novel species of the genus Amycolatopsis , for which the name Amycolatopsis anabasis sp. nov. is proposed. The type strain is EGI 650086T (=KCTC 49044T=CGMCC 4.7188T).

Micromonospora pelagivivens sp. nov., a new species of the genus Micromonospora isolated from deep-sea sediment in Japan

A novel marine actinomycete, designated strain KJ-029^T, was isolated from a marine sediment sample (water depth of 226 m) in Kagoshima, Japan. 16S rRNA gene sequence analysis revealed that the new isolate was most closely related to Micromonospora craniellae LHW 63014^T (99.3 % similarity). Phylogenetic analyses of the genus Micromonospora based on 16S rRNA gene sequences showed that strain KJ-029^T was clustered with Micromonospora craniellae LHW 63014^T and Micromonospora endophytica 202201^T. However, digital DNA-DNA hybridization analyses presented low levels of relatedness in the range of 24.8-32.9 % between strain KJ-029^T and the above closely related strains. The novel strain contained meso-diaminopimelic acid and 3-OH-diaminopimelic acid, d-glutamic acid, glycine and d-alanine in the cell-wall peptidoglycan. The acyl type of the peptidoglycan was glycolyl and mycolic acids were absent. The major menaquinone was MK-9(H₄). The whole-cell sugars consisted of glucose, mannose, xylose and ribose. Phosphatidylethanolamine was detected as the major phospholipid and corresponded to phospholipid type II. The predominant cellular fatty acid was iso-C_16 : 0. The DNA G+C content of the genomic DNA was 71.5 mol%. Based on the present polyphasic study, strain KJ-029^T represents a novel species of the genus Micromonospora, for which the name Micromonospora pelagivivens sp. nov. is proposed. The type strain is KJ-029^T (=NBRC 113519^T=TBRC 9233^T).

Fodinicola acaciae sp. nov., an Endophytic Actinomycete Isolated from the Roots of Acacia mangium Willd. and Its Genome Analysis

A novel endophytic actinomycete strain GKU 173^T isolated from the roots of Acacia mangium Willd. showed potential plant growth promoting (PGP) activity. Phylogenetic analysis, based on 16S rRNA gene, indicated that strain GKU 173^T was the most closely related to Fodinicola feengrottensis HKI 0501^T—the only species in the genus Fodinicola. Morphology and chemotaxonomy of strain GKU 173^T indicated that it belongs to the genus Fodinicola by having meso-diaminopimelic acid in the cell wall and xylose as the characteristic cell-wall sugars. The cellular fatty acid profile mainly comprised iso-C_16:0, anteiso-C_17:0, iso-C_18:0, and iso-C_17:0. The major menaquinones were MK-9(H₄), MK-9(H₆), and MK-9(H₈). The main polar phospholipids contained diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). Genome analysis signified DNA G+C content of 67.81 mol%. The level of digital DNA-DNA relatedness between strain GKU 173^T and the type strain was 21.30%. On the basis of polyphasic characteristics, strain GKU 173^T clearly represents a novel species of the genus Fodinicola, for which the name Fodinicolaacaciae sp. nov. (= TBRC 10620^T = NBRC 114213^T) is proposed. Furthermore, genome analysis of both strains suggested that members of the genus Fodinicola are promising sources of beneficial PGP-actinomycetes and novel secondary metabolites.

Tsukamurella asaccharolytica sp. nov., Tsukamurella conjunctivitidis sp. nov. and Tsukamurella sputi sp. nov., isolated from patients with bacteraemia, conjunctivitis and respiratory infection in Hong Kong

Three bacterial strains, HKU70^T, HKU71^T and HKU72^T, were isolated from the conjunctival swab, blood and sputum samples of three patients with conjunctivitis, bacteraemia and respiratory infection, respectively, in Hong Kong. The three strains were aerobic, Gram-stain positive, catalase-positive, non-sporulating and non-motile bacilli and exhibited unique biochemical profiles distinguishable from currently recognized Tsukamurella species. 16S rRNA, secA, rpoB and groEL gene sequence analyses revealed that the three strains shared 99.6-99.9, 94.5-96.8, 95.7-97.8 and 97.7-98.9 % nucleotide identities with their corresponding closest Tsukamurella species respectively. DNA-DNA hybridization confirmed that they were distinct from other known species of the genus Tsukamurella (26.2±2.4 to 36.8±1.2 % DNA-DNA relatedness), in line with results of in silico genome-to-genome comparison (32.2-40.9 % Genome-to-Genome Distance Calculator and 86.3-88.9 % average nucleotide identity values]. Fatty acids, mycolic acids, cell-wall sugars and peptidoglycan analyses showed that they were typical of members of Tsukamurella. The G+C content determined based on the genome sequence of strains HKU70^T, HKU71^T and HKU72^T were 69.9, 70.2 and 70.5 mol%, respectively. Taken together, our results supported the proposition and description of three new species, i.e. Tsukamurella sputi HKU70^T (=JCM 33387^T=DSM 109106^T) sp. nov., Tsukamurella asaccharolytica HKU71^T (=JCM 33388^T=DSM 109107^T) sp. nov. and Tsukamurella conjunctivitidis HKU72^T (=JCM 33389^T=DSM 109108^T) sp. nov.

Streptomyces acidicola sp. nov., isolated from a peat swamp forest in Thailand

A novel actinobacterium, designated strain K1PN6^T, was isolated from soil sample collected in Kantulee peat swamp forest, Surat Thani province, Thailand. The morphological, chemotaxonomic, and phylogenetic characteristics were consistent with its classification in the genus Streptomyces. Based on 16S rRNA gene sequence analysis, strain K1PN6^T showed highest similarity to Streptomyces phyllanthi PA1-07^T (98.6 %), Streptomyces spongiae Sp080513SC-24^T (98.3%) and Streptomyces adustus WH-9^T (98.3%). The G + C content of the genomic DNA was 70.3 mol%. Digital DNA-DNA hybridization and average nucleotide identity values between the genome sequence of strain K1PN6^T with S. phyllanthi TISTR 2346^T (33.7 and 89.1%), S. spongiae NBRC 106415^T (38.6 and 90.6%) and S. adustus NBRC 109810^T (26.0 and 86.2%) were below the thresholds of 70 and 95-96% for prokaryotic conspecific assignation. Chemotaxonomic data revealed that strain K1PN6^T possessed MK-9(H₈) (45%) and MK-9(H₆) (34%) 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, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, two unidentified aminolipids, an unidentified phospholipid, and glycophospholipid. The predominant cellular fatty acids (>10%) were iso-C_16:0, C_16:0, anteiso-C_15:0, and iso-C_14:0. On the basis of these genotypic and phenotypic data, strain K1PN6^T should be designated as a representative of a novel species of the genus Streptomyces, for which the name Streptomyces acidicola sp. nov. is proposed with the type strain K1PN6^T (=TBRC 11341^T=NBRC 114304^T).

Corynebacterium suranareeae sp. nov., a glutamate producing bacterium isolated from soil and its complete genome-based analysis

Strain N24T was isolated from soil contaminated with starling’s feces collected from Roi-Et province, Thailand. Cells of N24T were Gram-stain-positive rods, aerobic and non-spore-forming. N24T was positive for catalase, urease, citrate utilization, nitrate reduction and Methyl Red (MR) test but negative for oxidase, casein, gelatin liquefaction, tyrosine, Voges–Proskauer (VP) reaction and starch hydrolysis. Meso-diaminopimelic acid, rhamnose, ribose, arabinose and galactose were detected in its whole-cell hydrolysates. The results of the 16S rRNA gene sequence analysis indicated that N24T represented a member of the genus Corynebacterium . N24T was closely related to Corynebacterium glutamicum ATCC 13032T, with 99.0 % 16S rRNA gene sequence similarity. According to results obtained using in silico DNA–DNA hybridization approaches, N24T showed highest DNA–DNA relatedness (27.6 %) and average nucleotide identity (84.1 %) to Corynebacterium glutamicum ATCC 13032T. The DNA G+C content of N24T was 51.8 mol% (genome based). The major cellular fatty acids of N24T were C16 : 0, and C18 : 1ω9c. N24T had the nine isoprenes unit, MK-9(H2) as the predominant menaquinone. The predominant polar lipids were phosphatidylglycerol, phosphatidylinositol and diphosphatidylglycerol. Mycolic acids were also present. According to the complete genome sequence data, strain N24T and C. glutamicum ATCC 13032T are close phylogenetic neighbours, but have different genome characteristics. On the basis of the results of the genotypic and genomic studies and phenotypic characteristics including chemotaxonomy, strain N24T should be classified as representing a novel species of the genus Corynebacterium , for which the name Corynebacterium suranareeae sp. nov. is proposed. The type strain is N24T (TBRC 5845T=NBRC 113465T).

Amycolatopsis pithecelloba sp. nov., a novel actinomycete isolated from roots of Pithecellobium dulce in Thailand

An actinomycete strain RM579^T isolated from roots of Pithecellobium dulce in Thailand was studied using the polyphasic taxonomic approach. The results of comparative 16S rRNA gene sequence and phylogenetic analysis showed that strain RM579^T belonged to the family Pseudonocardiaceae and it was most closely related to members of the genera Amycolatopsis (≤94.5% sequence similarity) and Haloechinothrix (≤93.4% sequence similarity). A phylogenetic tree constructed by neighbor-joining method indicated that strain RM579^T was positioned within the clade of the genus Amycolatopsis and formed a monophyletic cluster with Amycolatopsis taiwanensis 0345M-7^T, Amycolatopsis pigmentata TT00-43^T and Amycolatopsis helveola TT99-32^T. Strain RM579^T formed white aerial mycelium and yellowish-brown substrate mycelium that fragments into rod-shaped elements. Morphological features and chemotaxonomic characteristics of strain RM579^T were consistent with those of the genus Amycolatopsis. The cell wall of strain RM579^T contained meso-diaminopimelic acid. Arabinose, galactose, mannose, and ribose were detected as whole-cell sugars. Mycolic acids were absent. The acyl type of the muramic acid in the cell wall was N-acetyl. Diphosphatidylglycerol, hydroxyl-phosphatidylethanolamine, phosphatidylinositol, and an unidentified phospholipid were detected as polar lipids. The major cellular fatty acids (>10%) were iso-C_16:0, iso-C_16:0 2-OH, and C_16:1 cis9. The resultant data indicated that strain RM579^T should be classified as representative of a novel species in the genus Amycolatopsis, for which the name Amycolatopsis pithecelloba sp. nov. is proposed. The type strain is RM579^T (=TBRC 1849^T =NBRC 106096^T).

Amycolatopsis acidicola sp. nov., isolated from peat swamp forest soil

A novel actinobacterial strain, designated K81G1^T, was isolated from a soil sample collected in Kantulee peat swamp forest, Surat Thani Province, Thailand, and its taxonomic position was determined using a polyphasic approach. Optimal growth of strain K81G1^T occurred at 28-30 °C, at pH 5.0-6.0 and without NaCl. Strain K81G1^T had cell-wall chemotype IV (meso-diaminopimelic acid as the diagnostic diamino acid, and arabinose and galactose as diagnostic sugars) and phospholipid pattern type II, characteristic of the genus Amycolatopsis. It contained MK-9(H₄) as the predominant menaquinone, iso-C_16 : 0, C_17 : 0 cyclo and C_16 : 0 as the major cellular fatty acids, and phospholipids consisting of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol and two unidentified phospholipids. Based on 16S rRNA gene sequence similarity and phylogenetic analyses, strain K81G1^T was most closely related to Amycolatopsis rhizosphaerae TBRC 6029^T (97.8 % similarity), Amycolatopsis acidiphila JCM 30562^T (97.8 %) and Amycolatopsis bartoniae DSM 45807^T (97.6 %). Strain K81G1^T exhibited low average nucleotide identity and digital DNA-DNA hybridization values with A. rhizosphaerae TBRC 6029^T (76.4 %, 23.0 %), A. acidiphila JCM 30562^T (77.9 %, 24.6 %) and A. bartoniae DSM 45807^T (77.8 %, 24.3 %). The DNA G+C content of strain K81G1^T was 69.7 mol%. Based on data from this polyphasic study, strain K81G1^T represents a novel species of the genus Amycolatopsis, for which the name Amycolatopsis acidicola sp. nov. is proposed. The type strain is K81G1^T (=TBRC 10047^T=NBRC 113896^T).

Identification of common antigens of three pathogenic Nocardia species and development of DNA vaccine against fish nocardiosis

Fish nocardiosis is a chronic granulomatous bacterial disease and three pathogens have been reported so far, including Nocardia asteroids, N. seriolae and N. salmonicida. However, the absence of antigen markers is a bottleneck for developing effective vaccines against fish nocardiosis. In this study, the antigenicity of whole-cell protein of these three pathogenic Nocardia species were profiled by immunoproteomic analysis and 7 common immunogenic proteins were identified as follows: molecular chaperone DnaK (DnaK), molecular chaperone GroEL (GroEL), 30 S ribosomal protein S1 (RpsA), TerD family protein (TerD), FHA domain-containing protein (FHA), 50 S ribosomal protein L7/L12 (RplL) and PspA/IM30 family protein (PspA). Furthermore, the DNA vaccine encoding FHA gene against fish nocardiosis was developed and its efficacy was investigated in hybrid snakehead. The results suggested that it needed at least 7 d to transport pcDNA-FHA DNA vaccine from injected muscle to head kidney, spleen and liver and stimulate host's immune system for later protection. In addition, non-specific immunity paraments (serum lysozyme (LYZ), peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) activities), specific antibody (IgM) titers production and immune-related genes (MHCIα, MHCIIα, CD4, CD8α, IL-1β and TNFα) were used to evaluate the immune response induced in pcDNA-FHA vaccinated hybrid snakehead, it proved that all these mentioned immune activities were significantly enhanced after immunization. The results also showed hybrid snakehead vaccinated with pcDNA-FHA had higher survival rate (79.33%) compared with the controls after challenge with N. seriolae, indicating that the pcDNA-FHA DNA vaccine can supply immune protection against N. seriolae infection. Taken together, this study may warrant further development of these common immunogenic proteins as the antigens for vaccine or diagnosis and facilitate the prevention and treatment of fish nocardiosis.

Comparison of protective efficacy between two DNA vaccines encoding DnaK and GroEL against fish nocardiosis

Fish nocardiosis is a chronic granulomatous bacterial disease mainly caused by three pathogenic bacteria, including Nocardia seriolae, N. asteroids and N. salmonicida. Molecular chaperone DnaK and GroEL were identified to be the common antigens of the three pathogenic Nocardia species in our previous studies. To evaluate the immune protective effect of two DNA vaccines encoding DnaK or GroEL against fish nocardiosis, hybrid snakehead were vaccinated and the immune responses induced by these two vaccines were comparatively analyzed. The results suggested it needed at least 7 d to transport DnaK or GroEL gene from injected muscle to head kidney, spleen and liver and stimulate host's immune system for later protection after immunization by DNA vaccines. Additionally, non-specific immunity parameters (serum lysozyme (LYZ), peroxidase (POD), acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) activities), specific antibody (IgM) production and immune-related genes (MHCIα, MHCIIα, CD4, CD8α, IL-1β and TNFα) were used to evaluate the immune responses induced in vaccinated hybrid snakehead. It proved that all the above-mentioned immune activities were significantly enhanced after immunization with these two DNA vaccines. The protective efficacy of pcDNA-DnaK and pcDNA-GroEL DNA vaccines, in terms of relative percentage survival (RPS), were 53.01% and 80.71% respectively. It demonstrated that these two DNA vaccines could increase the survival rate of hybrid snakehead against fish nocardiosis, albeit with variations in immunoprotective effects. Taken together, these results indicated that both pcDNA-DnaK and pcDNA-GroEL DNA vaccines could boost the innate, humoral and cellular immune response in hybrid snakehead and show highly protective efficacy against fish nocardiosis, suggesting that DnaK and GroEL were promising vaccine candidates. These findings will promote the development of DNA vaccines against fish nocardiosis in aquaculture.

Cryptosporangium phraense sp. nov., isolated from plant litter

A novel zoosporic actinomycete, designated strain A-T 5661^T, was isolated from plant litter collected in Thailand. Strain A-T 5661^T developed large multilocular sporangia containing motile sporangiospores at the ends of sporangiophores on substrate mycelium. The results of our polyphasic taxonomic study demonstrated that the strain had characteristics typical of members of the genus Cryptosporangium. The 16S rRNA gene sequence and phylogenetic analyses indicated that strain A-T 5661^T shared the sequence similarity ≤98.5 % with all members of the genus Cryptosporangium. The values of DNA-DNA relatedness that distinguished this novel strain from its closest related species were below 70 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars were acofriose, arabinose, galactose, glucose, mannose, xylose and ribose. The predominant menaquinones were MK-9(H₈) and MK-9(H₆) with minor amounts of MK-9(H₄) and MK-9(H₂). The predominant fatty acids were iso-C_16 : 0, C_18 : 1ω9c and anteiso-C_17 : 0. The polar lipid profile consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides and unidentified polar lipids. The G+C content of the genomic DNA was 71.6 mol%. Based on comparative analysis of phenotypic, chemotaxonomic and genotypic data, the novel zoosporic actinomycete A-T 5661^T (=TBRC 8127^T=NBRC 113237^T) is proposed to be the type strain of a novel species, Cryptosporangium phraense sp. nov.

Amycolatopsis eburnea sp. nov., an actinomycete associated with arbuscular mycorrhizal fungal spores

A novel actinomycete, designated strain GLM-1^T, was isolated from arbuscular mycorrhizal fungal spores from Funneliformis mosseae RYA08, collected from Aquilaria crassna Pierre ex Lec. rhizosphere soil in Klaeng, Rayong Province, Thailand. Morphological characteristics of this strain included long chains of rod-like cells and squarish elements. The cell-wall composition of this novel isolate contained meso-diaminopimelic acid. The whole-cell diagnostic sugars were arabinose and galactose. The predominant menaquinone was MK-9(H₄). The major fatty acids were iso-C_16 : 0 and iso-C_15 : 0. Only phosphatidylethanolamine was detected as a polar lipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain GLM-1^T was closely related to Amycolatopsis rhabdoformis SB026^T (99.11 %) with a low DNA-DNA hybridization value of 22.6-34.7 %. Genome sequencing revealed a genome size of 10 Mbp. There were obvious distinctions in the average nucleotide identity values between stain GLM-1^T and its closely related strains at around 86-93 % (ANIb) and 89-94 % (ANIm). The digital DNA-DNA hybridization values between strain GLM-1^T and type strains of phylogenetically related species were 34-55 %. The G+C content of the genomic DNA was 71.8 mol%. Based on these data, strain GLM-1^T is considered to represent a novel species of the genus Amycolatopsis, for which the name Amycolatopsiseburnea sp. nov. is proposed. The type strain is GLM-1^T (=TBRC 9315^T=NBRC 113658^T).

Micromonospora radicis sp. nov., isolated from roots of Azadirachta indica var. siamensis Valenton, and reclassification of Jishengella zingiberis as Micromonospora zingiberis comb. nov

A novel endophytic actinomycete strain AZ1-13^T was isolated from roots of Azadirachta indica, and its taxonomic position was investigated using a polyphasic approach. Pairwise 16S rRNA gene sequence similarities of strain AZ1-13^T and its closest species, Jishegella zingiberis PLAI1-1^T and Micromonospora endophytica 202201^T, were 99.7 and 99.2 %, respectively. Phylogenetic analyses of the family Micromonosporaceae based on 16S rRNA gene sequences indicated strains AZ1-13^T and J. zingiberis PLAI1-1^Tare located within the genus Micromonospora. The approximate genome size of the strain was 5.96 Mb with 71.9 mol% of G+C content. The strain AZ1-13^T exhibited ANIb values of 87.4 % with J. zingiberis PLAI1-1^T and 85.1 % with M. endophytica 202201^T. Chemotaxonomic characteristics of strain AZ1-13^T were consistent within the genus Micromonospora: cell-wall peptidoglycan of the strain contained meso-diaminopimelic acid; glucose, mannose, ribose and xylose are presented as the whole-cell sugars; the predominant menaquinones were MK-9(H₄) and MK-9(H₆); major cellular fatty acids were iso-C_15 : 0, 10-methyl C_17 : 0, C_17 : 0, anteiso-C_17 : 0 and iso-C_17 : 1ω8c; diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol were detected as distinguished phospholipids. Based on phenotypic properties, phylogeny and genomic data, the strain AZ1-13^T could be distinguished from its closest neighbours, representing a novel species of the genus Micromonospora, for which the name Micromonospora radicis sp. nov. is proposed. The type strain is AZ1-13^T (=KCTC 39786^T=NBRC 112324^T=JCM 32147^T = TISTR 2404^T). This study also proposed that J. zingiberisis transferred to the genus Micromonospora as Micromonospora zingiberis comb. nov. (type strain PLAI1-1^T=TBRC 7644^T=NBRC 113144^T=JCM 32592^T).