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Two endophytic actinobacteria, strains MK5 T and MK7, were isolated from the surface-sterilized root of Jasmine rice (Oryza sativa KDML 105). These strains were aerobic actinobacteria with a well-developed substrate and aerial mycelia that formed spiral spore chains. The type strains that shared the high 16S rRNA gene sequence similarity with both strains were Streptomyces naganishii NBRC 12892 T (99.4%), "Streptomyces griseicoloratus" TRM S81-3 T (99.2%), and Streptomyces spiralis NBRC 14215 T (98.9%). Strains MK5 T and MK7 are the same species sharing a digital DNA-DNA hybridization (dDDH) value of 95.3% and a 16S rRNA gene sequence similarity of 100%. Chemotaxonomic data confirmed the affiliation of strains MK5 T and MK7 to the genus Streptomyces. Strains MK5 T and MK7 contained MK-9(H 4 ) as a major menaquinone; the whole-cell sugar of both strains was galactose and glucose. The strain MK5 T shared 93.4% average nucleotide identity (ANI)-Blast, 95.5% ANI-MUMmer, 93% average amino acid identity, and 61.3% dDDH with S. spiralis NBRC 14215 T . The polyphasic approach confirmed that strain MK5 T represents a novel species, and the name Streptomyces mahasarakhamensis sp. nov. is proposed. The type strain is MK5 T (= TBRC 17754 = NRRL B-65683). Genome mining, using an in silico approach and searching biosynthesis gene clusters of strains MK5 T and MK7, revealed that the genomes contained genes encoding proteins relating to plant growth promotion, bioactive compounds, and beneficial enzymes. Strains MK5 T and MK7 could produce indole acetic acid and solubilize phosphate in vitro., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Endophytic actinobacteria are a group of bacteria living inside plant tissue without harmful effects, and benefit the host plant. Many can inhibit plant pathogens and promote plant growth. This study aimed to identify a strain of Streptomyces as a novel species and study its antibiotics production. An endophytic actinobacterium, strain TML10 T was isolated from a surface-sterilized leaf of a Thai medicinal plant ( Terminalia mucronata Craib and Hutch). As a result of a polyphasic taxonomy study, strain TML10 T was identified as a member of the genus Streptomyces . Strain TML10 T was an aerobic actinobacterium with well-developed substrate mycelia with loop spore chains and spiny surface. Chemotaxonomic data, including cell wall components, major menaquinones, and major fatty acids, confirmed the affiliation of strain TML10 T to the genus Streptomyces . The results of the phylogenetic analysis, including physiological and biochemical studies in combination with a genome comparison study, allowed the genotypic and phenotypic differentiation of strain TML10 T and the closest related type strains. The digital DNA-DNA hybridization (dDDH), Average nucleotide identity Blast (ANIb), and ANIMummer (ANIm) values between strain TML10 T and the closest type strain, Streptomyces musisoli CH5-8 T were 38.8%, 88.5%, and 90.8%, respectively. The name proposed for the new species is Streptomyces naphthomycinicus sp. nov. (TML10 T = TBRC 15050 T = NRRL B-65638 T ). Strain TML10 T was further studied for liquid and solid-state fermentation of antibiotic production. Solid-state fermentation with cooked rice provided the best conditions for antibiotic production against methicillin-resistant Staphylococcus aureus . The elucidation of the chemical structures from this strain revealed a known antimicrobial agent, naphthomycin A. Mining the genome data of strain TML10 T suggested its potential as a producer of antbiotics and other valuable compounds such as ε-Poly-L-lysine (ε-PL) and arginine deiminase. Strain TML10 T contains the arc A gene encoding arginine deiminase and could degrade arginine in vitro ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Kaewkla, Perkins, Thamchaipenet, Saijuntha, Sukpanoa, Suriyachadkun, Chamroensaksri, Chumroenphat and Franco.)

Blastocystis is a parasitic protist of a variety of hosts, including humans. Mapping the distribution of Blastocystis and its genetic variants across different host species can help us understand the epidemiology of this organism and its role in health and disease. This study aimed to identify subtypes of Blastocystis detected in different animal hosts in Thailand. A total of 825 fecal samples belonging to 18 vertebrate orders, 36 families, 68 genera, and 80 species were collected. Of these, 111 specimens were Blastocystis-positive by culture. Seventy-nine samples were subjected to small subunit (SSU) ribosomal DNA amplification by PCR, and reliable subtype data were obtained for 61 specimens. At least 14 subtypes (ST), namely ST1 to ST10, ST14/ST24/ST25 complex, ST23, ST26, and ST29 were detected. In addition, Blastocystis was found in tortoises. ST1 (3.2%) and ST5 (11.5%) were found in pigs, ST2 (1.6%) and ST3 (3.2%) in non-human primates, ST4 (14.7%) in rodents and ruminants, ST6 (4.9%), ST7 (30%), ST9 (1.6%), and ST29 (1.6%) in birds, ST8 (6.6%) in Green peafowl and East Asian Porcupine, and ST10 (4.9%), ST14/ST24/ST25 (9.8%), ST23 (1.6%) and ST26 (1.6%) in ruminants. The sequence recovered from the elongated tortoises (Indotestudo elongata) (3.2%) was phylogenetically placed within the reptilian cluster of Blastocystis, for which no subtype system is available yet. Of note, we did not obtain Blastocystis sequences from any of the many canids and felids sampled in the study, and our data are in support of host specificity of Blastocystis, according to both colonization and subtype distribution., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

An endophytic actinobacterium, strain PIP175 T , was isolated from the root sample of a native apricot tree ( Pittosporum angustifolium ) growing on the Bedford Park campus of Flinders University, Adelaide, South Australia. This strain is a Gram stain-positive, aerobic actinobacterium with well-developed substrate mycelia. Aerial mycelia rarely produce spores and the spore chain is spiral. Strain PIP175 T showed the highest 16S rRNA gene sequence similarity to Streptomyces aculeolatus DSM 41644 T (99.4 %). Other closely related phylogenetic representatives include Streptomyces synnematoformans DSM 41902 T (98.3 %), Streptomyces albospinus NBRC 13846 T (97.6 %), Streptomyces cacaoi subsp. cacaoi NRRL B-1220 T (97.5 %) and Streptomyces ruber NBRC 14600 T (97.4 %). The major cellular fatty acid of this strain was iso-C 16 : 0 and the major menaquinone was MK-9(H 6 ). The whole-cell sugar contained galactose, glucose and mannose. Chemotaxonomic data confirmed that strain PIP175 T belonged to the genus Streptomyces . Digital DNA-DNA hybridization, average nucleotide identity based on blast and OrthoANIu results between strain PIP175 T and S. aculeolatus DSM 41644 T were 60.0, 94.1 and 94.9 %, respectively. Genotypic and phenotypic data and genome analysis results allowed the differentiation of strain PIP175 T from its closest species with validly published names. Strain PIP175 T showed good activity against methicillin-resistant Staphylococcus aureus 03120385. Genome mining of strain PIP175 T revealed biosynthetic genes encoding proteins relating to antibiotic production, plant growth promotion and biodegradation enzymes. The name proposed for the new species is Streptomyces phytophilus sp. nov. The type strain is PIP175 T (=DSM 103379 T =TBRC 6026 T ).

Two endophytic actinobacteria, strains SBTS01 T and W18L9 T , were isolated from leaf sheath and leaf tissue, respectively, of Jasmine rice (Oryza sativa KDML 105) grown in a rice paddy field in Roi Et Province, Thailand. A polyphasic taxonomic study showed that both strains belong to the genus Streptomyces; they are aerobic, forming well-developed substrate mycelia and aerial mycelia with long chains of spores. Strain SBTS01 T shares high 16S rRNA gene sequence similarity with Streptomyces rochei NRRL B-2410  T (99.0%) and Streptomyces naganishii NRRL ISP-5282  T (99.0%). Strain W18L9 T shares high 16S rRNA gene sequence similarity with Streptomyces shenzhenensis DSM 42034  T (99.7%). The genotypic and phenotypic properties of strains SBTS01 T and W18L9 T distinguish these two strains from the closely related species with validly published names. The genome analysis showed the dDDH, ANIb and ANIm values of the draft genome between strain SBTS01 T and its close neighbour in the phylogenomic tree, Streptomyces corchorusii DSM 40340 T to be 54.1, 92.6, and 94.3%, respectively; similarly for strain W18L9 T and the closely related species S. shenzhenensis DSM 42034  T values were 72.5, 95.1 and 97.0%. The name proposed for the new species represented by the type strain SBTS01 T is Streptomyces spinosus (= NRRL B-65636  T  = TBRC 15052 T ). The name proposed for the novel subspecies of strain W18L9 T is Streptomyces shenzhenensis subsp. oryzicola (= NRRL B-65635  T  = TBRC 15051 T ). Recognition of this subspecies also permits the description of Streptomyces shenzhenensis subsp. shenzhenensis. Strains SBTS01 T and W18L9 T can produce antibiotic against rice and human pathogens and showed plant growth promoting properties such as production of indole acetic acid, cytokinin, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, siderophores and cellulase. Genomic data mining of these two strains confirmed their potential as antibiotic producers and plant growth promoters. Their genomes contain multiple biosynthetic gene clusters including those for terpene, type 1, 2 and 3 polyketide synthase, Non-ribosomal peptide synthetase and lanthipeptides. Genes encoding plant growth promoting traits such; nitrogen fixation, ACC deaminase, siderophore production and stress-related adaption may have ecological significance., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

An endophytic actinobacterium, strain CAP261 T was isolated from the surface sterilized root of Callitris preissii (Australian native pine tree). As a result of a polyphasic taxonomy study, this strain was identified as a member of the genus Streptomyces. This strain was an aerobic actinobacterium with well-developed substrate mycelia with loop spore chains and the spore surfaces are verrucose. The closest phylogenetic members which shared the highest 16S rRNA gene sequences similarity was Streptomyces bottropensis ATCC 25435  T at 98.1%. Chemotaxonomic data including cell wall components, major menaquinones, and major fatty acids confirmed the affiliation of strain CAP261 T to the genus Streptomyces. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with genome comparison study, allowed the genotypic and phenotypic differentiation of strain CAP261 T and the closest species with validly published names. ANIb, ANIm and dDDH values of strain CAP261 T and S. bottropensis ATCC 25435  T were 86.7%, 89.2% and 33.9%, respectively. The name proposed for the new species is Streptomyces adelaidensis sp. nov. The type strain is CAP261 T (= DSM 42026  T  = NRRL B-24814  T )., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A Gram-positive, aerobic, actinobacterial strain with rod-shaped spores, CAP47R T , which was isolated from the surface-sterilized root of a native pine tree (Callitris preissii), grown in South Australia is described. The major cellular fatty acid of this strain was iso-H-C 16:1 and major menaquinone was MK-8(H 4 ). The diagnostic diamino acid in the cell-wall peptidoglycan was identified as meso-diaminopimelic acid. These chemotaxonomic data confirmed the affiliation of strain CAP47R T to the genus Pseudonocardia. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed this strain in the family Pseudonocardiaceae, being most closely related to Pseudonocardia xishanensis JCM 17906 T (98.8%), Pseudonocardia oroxyli DSM 44984 T (98.7%), Pseudonocardia thailandensis CMU-NKS-70 T (98.7%), and Pseudonocardia ailaonensis DSM 44979 T (97.9%). The results of the polyphasic study which contain genome comparisons of ANIb, ANIm, and digital DNA-DNA hybridization revealed the differentiation of strain CAP47R T from the closest species with validated names. This strain represents a novel species and the name proposed for this microorganism is Pseudonocardia pini sp. nov., indicating the source of this actinobacterium from a pine tree. The type strain is CAP47R T (= DSM 108967 T  = NRRL B-65534 T ). Genome mining revealed that this strain contained a variety of genes encoding enzymes that can degrade hazardous chemicals., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Strain CAP181 T , an endophytic actinobacterium, was isolated from a surface sterilized root sample of a native pine tree, Flinders University, Adelaide, South Australia. Chemotaxonomic data including cell wall components, major fatty acids, and major menaquinones confirmed the affiliation of strain CAP181 T to the genus Micromonospora. This strain was Gram stain positive with well-developed substrate mycelia to form a single spore with hairy surface. The phylogenetic tree showed that M. coerulea NBRC 13504  T is the closest phylogenetic neighbour, sharing 99.2% 16S rRNA gene similarity and the next closest neighbor is M. chaiyaphumensis DSM 45246  T (98.7%). Genome mining of this strain revealed genes encoding to enzymes relating to nitrogen fixation and bioremediation. Based on genotypic and phenotypic studies including DNA-DNA hybridization data, strain CAP181 T was different from any of the closely related species with valid names. The name proposed for the new species is Micromonospora veneta sp. nov. The type strain is CAP181 T (= DSM 109713  T  = NRRL B-65535  T )., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

An endophytic actinobacterium, strain CAP215 T was isolated from the root sample of a native pine tree (Callitris preissii), Adelaide, South Australia. This strain was a Gram stain-positive, aerobic actinobacterium with well-developed substrate mycelia. It produced spiral chains of spores. The closest phylogenetic members which shared the highest 16S rRNA gene sequence similarity were Streptomyces marinus DSM 41968 T , Streptomyces haliclonae DSM 41970 T and Streptomyces karpasiensis K413 T at 98.2%, 98.0% and 97.9%, respectively. The major cellular fatty acid of this strain was anteiso-C 15:0 and major menaquinone was MK-9(H 4 ). Polar lipids of strain CAP215 T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol dimannoside and two unknown glycolipids. Chemotaxonomic data confirmed strain CAP215 T belonged to the genus Streptomyces. Genome of strain CAP215 T was 6.65 Mb with 69.8% DNA G + C content and contains 5992 coding sequences (CDS). Biosynthesis Genes Clusters (BGCs) comprised post-translationally modified peptides (RiPPs) cluster, genes encoding enzyme relating to antibiotic production; actinorhodin, surfactin and tetracenomycin. Genome mining of this strain identified genes encoding proteins relating to plant growth promotion such as pyrophosphatase, ectoine synthase, superoxide dismutase and siderophore production; penibactin and desferrioxamine E. Genes encoding beneficial enzymes; amylase, β-xylosidase, chitinase, lipase and protease were detected. The genome of this strain contained genes encoding enzymes degrading xenobiotic compounds such as 2,4-dichlorophenol 6-monooxygenase, nitroreductase and epoxide hydrolase. Also, genes encoding squalene, hopene and betacarotenoid production were observed. Digital DNA-DNA (dDDH) hybridization, Average Nucleotide Identity BLAST (ANIb), ANI-MUMmer (ANIm) between strain CAP215 T and S. marinus DSM 41968 T were 25.4 %, 82% and 86.4%, respectively. The data on the genotypic and phenotypic characteristics and genome analysis recognized the differentiation of strain CAP215 T with the closest species with valid names. The name Streptomyces albidus sp. nov. was proposed for which the type strain is CAP215 T (= DSM 42025 T  = NRRL B-24815 T ).

An endophytic actinobacterium, strain PIP199 T , was isolated from a root sample of a native apricot growing on the Bedford Park campus of Flinders University, Adelaide, South Australia. The result of a polyphasic study showed that this strain was identified as a new member of the genus Amycolatopsis. Strain PIP199 T is an aerobic actinobacterium with well-developed substrate mycelia and aerial mycelia that form short chains of spores. Amycolatopsis keratiniphila subsp. keratiniphila DSM 44409 T (99.7%), Amycolatopsis lurida DSM 43134 T (99.6%) and Amycolatopsis keratiniphila subsp. nogabecina DSM 44586 T (99.4%) shared the highest 16S rRNA gene sequence similarity. A. keratiniphila subsp. keratiniphila DSM 44409 T and A. lurida DSM 43134 T were the closest phylogenetic neighbors. Chemotaxonomic data including major fatty acids, cell wall components and major menaquinones confirmed the affiliation of strain PIP199 T to the genus Amycolatopsis. The phylogenetic analysis, physiological and biochemical studies and genomic study, allowed the genotypic and phenotypic differentiation of strain PIP199 T and the closely related species with valid names. ANIb and dDDH values when compared to Amycolatopsis keratiniphila subsp. keratiniphila DSM 44409 T were 87.3% and 36.4%, respectively. The name proposed for the new species is Amycolatopsis pittospori sp. nov. The type strain is PIP199 T (= NRRL B-65536 T  = TBRC 10618 T ).

An endophytic actinobacterium, strain CLES2 T , was discovered from the surface-sterilized stem of a Thai medicinal plant, Clausena excavala Burm. f., collected from the Phujong-Nayoa National Park, Ubon Ratchathani Province, Thailand. The results of a polyphasic taxonomic study identified this strain as a member of the genus Microbispora and a Gram-stain-positive, aerobic actinobacterium. It had well-developed substrate mycelia, which were non-motile and possessed paired spores. A phylogenetic evaluation based on 16S rRNA gene sequence analysis placed this strain in the family Streptosporangiaceae , being most closely related to Microbispora bryophytorum NEAU-TX2-2 T (99.4 %), Microbispora camponoti 2C-HV3 T (99.2 %), Microbispora catharanthi CR1-09 T (99.2 %) and Microbispora amethystogenes JCM 3021 T and Microbispora fusca NEAU-HEGS1-5 T (both at 99.1 %). The major cellular fatty acid of this strain was iso-C 16 : 0 and major menaquinone was MK-9(H 4 ). The polar lipid profile of strain CLES2 T contained diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylinositol and phosphatidylinositol dimannosides. These chemotaxonomic data confirmed the affiliation of strain CLES2 T to the genus Microbispora . The DNA G+C content of this strain was 70 mol%. Digital DNA-DNA hybridization and average nucleotide identity blast values between strain CLES2 T and M. catharanthi CR1-09 T were 62.4 and 94.0 %, respectively. The results of the polyphasic study allowed the genotypic and phenotypic differentiation of strain CLES2 T from its closest species with valid names. The name proposed for the new species is Microbispora clausenae sp. nov. The type strain is CLES2 T (=DSM 101759 T =NRRL B-65340 T ).

An endophytic actinobacterium, strain CAP 335 T , was isolated from a root sample of a native pine tree growing on the Bedford Park campus of Flinders University, Adelaide, South Australia. The result of a polyphasic study showed that this strain was identified as a new member of the genus Actinomycetospora. This strain was observed to be a Gram stain-positive, aerobic actinobacterium with well-developed substrate mycelia and to form short chains of spores. Actinomycetospora chibensis TT04-21 T and Actinomycetospora straminea IY07-55 T were found to be close phylogenetic neighbours, each sharing 99.1% 16S rRNA gene similarity. Chemotaxonomic data including major fatty acids, cell wall components and major menaquinones confirmed the affiliation of strain CAP 335 T to the genus Actinomycetospora. The phylogenetic analysis, physiological and biochemical studies and DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain CAP 335 T and the closely related species with valid names. The name proposed for the new species is Actinomycetospora callitridis sp. nov. The type strain is CAP 335 T (= DSM 101857 T = NRRL B-65350 T ).

An endophytic actinobacterium, strain WES2 T , was isolated from the stem of a jasmine rice plant collected from a paddy field in Thung Gura Rong Hai, Roi Et province, Thailand. As a result of a polyphasic study, this strain was identified as representing a novel member of the genus Streptomyces. This strain was a Gram-stain-positive, aerobic actinobacterium with well-developed substrate mycelia and forming chains of looped spores. The closest phylogenetic relations, which shared the highest 16S rRNA gene sequence similarity, were Streptomyces nogalater JCM 4799 T and Streptomyces lavenduligriseus NRRL-ISP 5487 T at 99.1 and 99.0 %, respectively. Chemotaxonomic data, including major fatty acids, cell wall components and major menaquinones, confirmed the affiliation of WES2 T to the genus Streptomyces. The data from the phylogenetic analysis, including physiological and biochemical studies and DNA-DNA hybridization, revealed the genotypic and phenotypic differentiation of WES2 T from the most closely related species with validly published names. The name proposed for the novel species is Streptomycesroietensis sp. nov. The type strain is WES2 T (=DSM 101729=NRRL B-65344).

A new strain of the genus Promicromonospora, CAP94T, was isolated from the surface sterilized root of Callitrispreissii (Australian native pine tree). This strain was a Gram-stain-positive, aerobic actinobacterium with hyphae breaking up into fragments which were non-motile, rod-like, coccoid elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed this isolate as a member of the family Promicromonospora ceae, and most closely to Promicromonospora sukumoe NBRC 14650T (99.4 %), Promicromonospora kroppenstedtii DSM 19349T (99.2 %) and Promicromonosporaaerolata V54AT (99.1 %). Chemotaxonomic data including cell-wall components, major menaquinone and major fatty acids confirmed the affiliation of strain CAP94T to the genus Promicromonospora. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain CAP94T and the closest species with validly published names. The name proposed for the new species is Promicromonospora callitridis sp. nov. The type strain is CAP94T (=DSM 103339T=TBRC 6025T).

An endophytic actinobacterium, strain TMS7T, was isolated from the stem of a Thai medicinal plant collected from the grounds of the Phujong-Nayoa National park, Ubon Ratchathani province, Thailand. As a result of a polyphasic taxonomy study, this strain was identified as a member of the genus Micromonospora. This strain was a Gram-stain-positive, aerobic actinobacterium with well-developed substrate mycelium with hyphae forming a single microspore was non-motile. Stran TMS7T was identified according to its 16S rRNA gene sequence as a new member of the genus Micromonospora. The closest phylogenetic members sharing a similarity were Micromonospora chersina DSM 44151T at 99.4 % and Micromonospora rosaria DSM 803T, Micromonospora tulbaghiae TVU1T, Micromonospora inositola DSM 43819T and Micromonospora endolithica DSM 44398T all at 99.2 %. Chemotaxonomic data including cell wall components, major menaquinones and major fatty acids confirmed the affiliation of strain TMS7T to the genus Micromonospora. The results of the phylogenetic analysis, addition to physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain TMS7T and the most closely related species with validly published names. The name proposed for the novel species is Micromonospora terminaliae sp. nov. The type strain is TMS7T (=DSM 101760T=NRRL B-65345T).

An endophytic actinobacterium, strain PIP 158T, was isolated from the stem of a native apricot tree (Pittosporum angustifolium) collected from the grounds of Flinders University, Adelaide, Australia. As a result of a polyphasic taxonomic study, this strain was identified as a member of the genus Kribbella. This strain was a Gram-stain-positive, aerobic actinobacterium with well-developed substrate mycelia which were non-motile and with hyphae fragmenting into short to elongated rod-like elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed this isolate in the family Nocardioidaceae, being most closely related to Kribbella sandramycini ATCC 39419T and Kribbella albertanoniae BC640T which share a similarity of 99. 26 and 99.18 % with Kribbella hippodromi S1.4T, respectively. Chemotaxonomic data including cell-wall components, major menaquinones and major fatty acids confirmed the affiliation of strain PIP 158T to the genus Kribbella. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain PIP 158T from the closest related species with validly published names. The name proposed for the novel species is Kribbella pittospori sp. nov. The type strain is PIP 158T (=DSM 23717T=NRRL B-24813T).

A new strain of the genus Kribbella, PIP 118(T), was isolated from the leaf of an Australian native apricot tree (Pittosporum angustifolium), or Gumbi Gumbi in the indigenous language. This strain is an aerobic actinobacterium consisting of hyphae that fragment into short to elongated rod-like elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed this isolate as a member of the family Nocardioidaceae and most closely related to Kribbella antibiotica YIM 31530(T) (98.6 %) and Kribbella koreensis LM 161(T) (98.4 %). Chemotaxonomic data including cell wall components, major menaquinone and major fatty acids confirmed the affiliation of strain PIP 118(T) to the genus Kribbella. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain PIP 118(T) and members of the most closely related species with validly published names. The name proposed for the new species is Kribbella endophytica sp. nov. The type strain is PIP 118(T) ( = DSM 23718(T) = NRRL B-24812(T)).

In recent years, new actinobacterial species have been isolated as endophytes of plants and shrubs and are sought after both for their role as potential producers of new drug candidates for the pharmaceutical industry and as biocontrol inoculants for sustainable agriculture. Molecular-based approaches to the study of microbial ecology generally reveal a broader microbial diversity than can be obtained by cultivation methods. This study aimed to improve the success of isolating individual members of the actinobacterial population as pure cultures as well as improving the ability to characterise the large numbers obtained in pure culture. To achieve this objective, our study successfully employed rational and holistic approaches including the use of isolation media with low concentrations of nutrients normally available to the microorganism in the plant, plating larger quantities of plant sample, incubating isolation plates for up to 16 weeks, excising colonies when they are visible and choosing Australian endemic trees as the source of the actinobacteria. A hierarchy of polyphasic methods based on culture morphology, amplified 16S rRNA gene restriction analysis and limited sequencing was used to classify all 576 actinobacterial isolates from leaf, stem and root samples of two eucalypts: a Grey Box and Red Gum, a native apricot tree and a native pine tree. The classification revealed that, in addition to 413 Streptomyces spp., isolates belonged to 16 other actinobacterial genera: Actinomadura (two strains), Actinomycetospora (six), Actinopolymorpha (two), Amycolatopsis (six), Gordonia (one), Kribbella (25), Micromonospora (six), Nocardia (ten), Nocardioides (11), Nocardiopsis (one), Nonomuraea (one), Polymorphospora (two), Promicromonospora (51), Pseudonocardia (36), Williamsia (two) and a novel genus Flindersiella (one). In order to prove novelty, 12 strains were characterised fully to the species level based on polyphasic taxonomy. One strain represented a novel genus in the family Nocardioides, and the other 11 strains were accepted as novel species. In summary, the holistic isolation strategies were successful in obtaining significant culturable actinobacterial diversity within Australian native trees that includes rare and novel species.

A novel aerobic actinobacterium, strain EUM 273(T), was isolated from the root of a Grey Box tree (Eucalyptus microcarpa Maiden). Cells were Gram-staining-positive with well-developed substrate mycelia which were non-motile and rod-like, with coccoid elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed the isolate as a member of the family Promicromonosporaceae that was most closely related to Promicromonospora xylanilytica YIM 61515(T) (98.2%) and Promicromonospora vindobonensis V45(T) (98%). Chemotaxonomic data including cell wall components, major menaquinone and major fatty acids confirmed the affiliation of strain EUM 273(T) to the genus Promicromonospora. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain EUM 273(T) from the closest related species with validly published names. The name proposed for the novel species is Promicromonospora endophytica sp. nov. The type strain is EUM 273(T) (=DSM 23716(T)=NRRL B-24816(T)).

A member of the genus Actinopolymorpha, designated PIP 143(T), was isolated from the leaves of an Australian native apricot tree (Pittosporum phylliraeoides). The isolate was a Gram-reaction-positive, aerobic actinobacterium, with a well-developed substrate mycelium that fragmented into small rods. Phylogenetic evaluation based on 16S rRNA gene sequences placed the isolate in the family Nocardioidaceae. Strain PIP 143(T) was most closely related to Actinopolymorpha cephalotaxi I06-2230(T) (98.7 %) and Actinopolymorpha rutila YIM 45725(T) (98.1 %). Chemotaxonomic data, including cell-wall components, menaquinones and fatty acids, confirmed the affiliation of strain PIP 143(T) to the genus Actinopolymorpha. Phylogenetic analysis and physiological and biochemical studies, in combination with DNA-DNA hybridization studies, allowed the differentiation of strain PIP 143(T) from its closest phylogenetic neighbours with validly published names. Therefore, a novel species is proposed, with the name Actinopolymorpha pittospori sp. nov. The type strain is PIP 143(T) ( = DSM 45354(T) = ACM 5288(T) = NRRL B-24810(T)).

A novel endophytic actinobacterium, designated strain EUM 378(T), was isolated from the surface-sterilized root tissue of Eucalyptus microcarpa, a eucalyptus tree known as Grey Box. Phylogenetic evaluation based on 16S rRNA gene sequence analysis, including alignment with taxon-specific 16S rRNA gene signature nucleotides, placed this isolate as a member of the family Nocardioidaceae. Strain EUM 378(T) showed >5.5 % 16S rRNA gene sequence divergence from other members of this family and was related most closely to Actinopolymorpha alba YIM 48868(T) (94.2 %) and Actinopolymorpha singaporensis IM 7744(T) (94.4 %). This Gram-positive, aerobic actinobacterium has well-developed substrate mycelia that fragment into small rods. Chemotaxonomic data revealed that the cell wall contains LL-diaminopimelic acid, ribose, glucose and rhamnose. MK-10(H₆) is the predominant menaquinone. Chemotaxonomic and phylogenetic evidence confirmed that strain EUM 378(T) represents a novel species of a new genus, for which the name Flindersiella endophytica gen. nov., sp. nov. is proposed. The type strain is EUM 378(T) ( = DSM 45355(T) = ACM 5289(T)).

A novel strain, designated EUM 374(T), was isolated from the root of a native Australian eucalyptus tree, Eucalyptus microcarpa, and subjected to a range of morphological, phylogenetic and chemotaxonomic analyses. The strain was Gram-reaction-positive with well-developed aerial mycelia, which fragmented into rod-shaped spores that had unique knobby protrusions on the spore surface. Substrate mycelia were not present in the media used. Strain EUM 374(T) grew as a film on the surface of static liquid culture medium but did not grow under shaking conditions. Phylogenetic evaluation based on 16S rRNA gene sequences identified the new isolate as belonging to the family Pseudonocardiaceae with sequence similarities of 96.1 and 96.3 % to Pseudonocardia acaciae GMKU095(T) and Pseudonocardia spinosispora LM 141(T), respectively, and 93-96 % sequence similarity to other members of the genus Pseudonocardia. The results of comprehensive phylogenetic analyses, including physiological and biochemical tests, differentiated strain EUM 374(T) from related members of the genus Pseudonocardia. Based on the phenotypic, phylogenetic and chemotaxonomic evidence, strain EUM 374(T) represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia eucalypti sp. nov. is proposed. The type strain is EUM 374(T) ( = DSM 45351(T)  = ACM 5285(T)).

An aerobic, actinobacterial strain with rod-shaped spores, EUM 221(T) [corrected], which was isolated from the surface-sterilized stem of a grey box tree (Eucalyptus microcarpa), is described. Phylogenetic evaluation based on 16S rRNA gene sequence similarity showed that this isolate belongs to the family Pseudonocardiaceae, with the closest neighbour being Pseudonocardia zijingensis 6330(T) (98.7 %). The level of 16S rRNA gene sequence similarity between the isolate and species of the genus Pseudonocardia with validly published names ranged from 95 to 98 %. Chemotaxonomic data (meso-diaminopimelic acid; major menaquinone MK-8(H(4)); major fatty acid iso-C(16 : 0)) confirmed the affiliation of strain EUM 221(T) [corrected] to the genus Pseudonocardia. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain EUM 221(T) [corrected] from the closest described species. Therefore, this strain represented a novel species and the name proposed is Pseudonocardia adelaidensis sp. nov. The type strain is EUM 221(T) [corrected] (=DSM 45352(T) =ACM 5286(T)).

A novel actinobacterium strain, CAP 290(T), was isolated from a surface-sterilized root of an Australian native pine tree, Callitris preissii. Comparative 16S rRNA gene sequence analysis showed that the strain belongs to the family Nocardiaceae. Strain CAP 290(T) was most closely related to Nocardia nova JCM 6044(T) (97.4 % 16S rRNA gene sequence similarity) and Nocardia terpenica IFM 0706(T) (96.7 %); similarity to other type strains of the genus Nocardia ranged from 95 to 97 %. Chemotaxonomic data [meso-diaminopimelic acid, major menaquinone MK-8(H(4omegacycl.)), major fatty acid C(16 : 0) and mycolate in the cell wall] confirmed the affiliation of strain CAP 290(T) to the genus Nocardia. The results of the phylogenetic analysis, together with the physiological and biochemical tests, allowed the differentiation of strain CAP 290(T) from strains of other Nocardia species. Therefore, strain CAP 290(T) represents a novel species, the first endophytic actinobacterium to be identified as belonging to the genus Nocardia, for which the name Nocardia callitridis sp. nov. is proposed. The type strain is strain CAP 290(T) (=DSM 45353(T) =ACM 5287(T)).