A Gram-positive-staining, filamentous bacterial strain that developed cylindrical sporangia containing four oval- to rod-shaped spores at the ends of short sporangiophores on branched aerial mycelium was isolated from tropical rainforest soil near a hot spring. The cell-wall peptidoglycan contained meso-diaminopimelic acid, glutamic acid and alanine as cell-wall amino acids; the whole-cell hydrolysate contained rhamnose, madurose, glucose, galactose and 3-O-methylmannose as whole-cell sugars. The predominant menaquinone was MK-9(H4). Mycolic acids were not detected. The diagnostic phospholipid was phosphatidylethanolamine. The predominant cellular fatty acids were iso-C16 : 0 and 10-methylated C17 : 0. The G+C content of the DNA was 71.1 mol%. The phenotypic and chemotaxonomic analyses showed that the isolate had characteristics typical of members of the genus Planotetraspora. Furthermore, 16S rRNA gene sequence analysis also indicated that this strain belongs to the genus Planotetraspora, but as a putative novel species. Following phenotypic, chemotaxonomic and genotypic studies, the isolate is proposed to be a representative of a novel species, to be named Planotetraspora thailandica sp. nov. The type strain is BCC 21825T (=NBRC 104271T). An emended description of the genus Planotetraspora is also presented.

A Gram-staining-positive, filamentous bacterium, which developed large globose sporangia at the ends of long sporangiophores on aerial mycelium, was isolated from dry soil collected in a deciduous forest in Thailand. The cell-wall peptidoglycan of the novel bacterium, which was designated strain A-T 1846^T, contained meso-diaminopimelic acid and the whole-cell sugars comprised rhamnose, ribose, mannose, glucose and galactose. The predominant menaquinone was MK-9(H₄). Mycolic acids were not detected. The identified phospholipids were phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol, phosphatidylglycerol and diphosphatidylglycerol. The predominant cellular fatty acids were iso-C_16 : 0, iso-C_16 : 0 2-OH and C_16 : 0 10-methyl. The G+C content of the genomic DNA was 72 mol%. The phenotypic and chemotaxonomic characteristics of the novel strain resembled those of established members of the genus Kutzneria . Phylogenetic analyses based on 16S rRNA gene sequences also indicated that this strain belonged to the genus Kutzneria but as a representative of a putative novel species. In hybridization experiments, the DNA–DNA relatedness values recorded between the novel strain and established members of the genus Kutzneria all fell well below 70 %. Based on the phenotypic, chemotaxonomic and genotypic evidence and the results of the DNA–DNA hybridizations, strain A-T 1846^T represents a novel species in the genus Kutzneria , for which the name Kutzneria buriramensis sp. nov. is proposed. The type strain is A-T 1846^T ( = BCC 29373^T = NBRC 107931^T). An emended description of the genus Kutzneria is provided.

Morphological and chemotaxonomic characterization of actinomycete strain MW2-25^T, isolated from tropical forest soil in Nakhon Sawan Province, Thailand, clearly demonstrated that this strain belongs to the genus Dactylosporangium. Phylogenetic analysis using 16S rRNA gene sequences also indicated that this strain should be classified in the genus Dactylosporangium and showed that the closest relative was Dactylosporangium aurantiacum IFO 12592^T (99.3 % sequence similarity). DNA–DNA hybridization values and some physiological and biochemical properties indicated that this strain could be readily distinguished from its closest phylogenetic relatives. On the basis of these phenotypic and genotypic data, this strain represents a novel species, for which the name Dactylosporangium maewongense sp. nov. is proposed. The type strain is MW2-25^T (=BCC 34832^T=JCM 15933^T).

Culture-independent and culture-dependent approaches were employed to investigate the taxonomic diversity and biosynthetic gene cluster potential of Actinomycetota in the Mekong River. Through 16S rRNA gene metabarcoding, 21,103 OTUs were revealed to represent 190 genera and at least 595 species of Actinomycetota, including putatively novel taxa. Conventional and in situ cultivation (IC) methods provided 75 Actinomycetota isolates representing 72 species from 21 genera. Of these, 45 species in 4 genera were new to the Thailand Bioresource Research Center (TBRC), a collection of 20,079 Actinomycetota strains from 660 species. Applying both culture-independent and culture-dependent approaches to the same sample revealed greater diversity among the Actinomycetota in the Mekong River than one approach alone.