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

Actinomadura monticuli sp. nov., isolated from Darangshi Oreum (a volcanic cone), and the reclassification of Actinomadura glauciflava Lu et al. 2003 as a later heterotypic synonym of Actinomadura luteofluorescens (Shinobu 1962) Preobrazhenskaya et al. 1975 (Approved Lists 1980)

Two mycelium-forming actinobacterial strains, designated as DLS-47 and DLS-62T, were isolated from volcanic ash collected from the surface of a rock on the peak of Darangshi Oreum (a volcanic cone) in Jeju, Republic of Korea, and their taxonomic positions were investigated by a polyphasic approach. Both of the isolates showed growth at 20-42 °C, pH 6.0-9.0 and 0-1% (w/v) NaCl. Furthermore, DLS-47 was found to grow at 45 °C, while strain DLS-62T grew at pH 10.0 and 3% (w/v) NaCl. The 16S rRNA gene-based phylogeny showed that both of the isolates belonged to the genus Actinomadura; strain DLS-47 was most closely related to Actinomadura chokoriensis DSM 45346T (100% sequence identity), while strain DLS-62T formed a tight cluster with Actinomadura bangladeshensis DSM 45347T (99.5% sequence similarity). Morphological and chemotaxonomic characteristics supported the affiliation of the two isolates to the genus Actinomadura. Phylogenomic analysis based on 92 core gene sequences showed that both of the isolates were most closely related to A. chokoriensis DSM 45346T. Strain DLS-47 shared 100% of orthologous average nucleotide identity and digital DNA-DNA hybridization values with A. chokoriensis DSM 45346T, while strain DLS-62T showed orthologous average nucleotide identity ≤89.8% and digital DNA-DNA hybridization values ≤39.4% with strain DLS-47 and members of the genus Actinomadura. The results of phenotypic assays and comparison of overall genomic relatedness indices support the conclusion that strain DLS-47 (= KACC 23347=DSM 116423) is a strain of A. chokoriensis, while strain DLS-62T (= KACC 23345T = DSM 116424T) represents a new species of the genus Actinomadura, for which the name Actinomadura monticuli sp. nov. is proposed. Also, Actinomadura glauciflava Lu et al. 2003 is reclassified as a later heterotypic synonym of Actinomadura luteofluorescens (Shinobu 1962) Preobrazhenskaya et al. 1975 (Approved Lists 1980) based on analysis of overall genomic relatedness indices and phenotypic similarity.

Amycolatopsis heterodermiae sp. nov. and Actinacidiphila polyblastidii sp. nov., two new actinobacteria isolated from foliose lichens

Two novel actinomycete strains, designated as V23-08T and V4-01T, were isolated from a foliose lichen collected in Doi Inthanon National Park, Chiang Mai Province, Thailand. Strain V23-08T showed the highest similarity (98.40%) to Amycolatopsis tolypomycina DSM 44544T. Similarly, strain V4-01T showed the highest 16S rRNA gene similarity relatedness (98.89%) to Actinacidiphila acidipaludis PLK6-54T. Chemotaxonomic analysis revealed distinct characteristics for each strain. The isomers of diaminopimelic acid were identified as meso-DAP in strain V23-08T and ll -DAP in strain V4-01T. The predominant menaquinones were MK-9(H2) for strain V23-08T and MK-9(H6) and MK-9(H8) for strain V4-01T. Strain V23-08T contained mannose, glucose, galactose and arabinose as whole-cell sugars, with iso-C16:0 as the major fatty acid. The polar lipid profile included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipids, unidentified phospholipids and unidentified lipids. In contrast, strain V4-01T exhibited glucose and galactose as whole-cell sugars, with iso-C16:0, anteiso-C16:0 and C16:0 as major fatty acids, and a polar lipid composition of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The taxonomic data, supported by digital DNA–DNA hybridization and average nucleotide identity analyses, confirm that strains V23-08T and V4-01T represent novel species within the genera Amycolatopsis and Actinacidiphila, respectively. Based on these findings, the names Amycolatopsis heterodermiae sp. nov. (strain V23-08T: TBRC 16208T and NBRC 115837T) and Actinacidiphila polyblastidii sp. nov. (strain V4-01T: TBRC 16209T and NBRC 115865T) are proposed.

Actinomadura terrae sp. nov. and Actinomadura litoris OS3-89, isolated from rhizosphere soil of cactus

Two mycelium-forming actinobacterial strains, designated OS3-83 ^T and OS3-89, were isolated from rhizosphere soil of a cactus (Opuntia ficus-indica) sampled on Mara Island, Jeju, Republic of Korea. Both of the isolates were found to grow at 20-37 °C, pH 6.0-10.0 and with 0-2 % (w/v) NaCl. Their taxonomic positions were investigated by a polyphasic approach. Strains OS3-83^T and OS3-89 were most closely related to the type strain of Actinomadura litoris (99.5 % and 98.9 % 16S rRNA gene sequence similarity, respectively). Both of the isolates shared 99.2 % sequence similarity to each other. Morphological and chemotaxonomic characteristics supported the affiliation of the two isolates to the genus Actinomadura. 16S rRNA gene phylogeny exhibited that strain OS3-83^T formed a tight cluster with A. litoris, while strain OS3-89 occupied a position located remotely from A. litoris. Nevertheless, phylogenomic analysis based on 92 core gene sequences showed that both of the isolates formed a tight clade with A. litoris. The values of average nucleotide identity and digital DNA-DNA hybridization between strain OS3-83^T and the closest relative, A. litoris, were 92.2 and 46.2 %, respectively, whereas strain OS3-89 shared an average nucleotide identity value of 97.5 % and a digital DNA-DNA hybridization value of 76.9 % with A. litoris. These results strongly suggested that strain OS3-83^T (=KACC 19752^T=NBRC 114688^T) represents a novel species and strain OS3-89 (=KACC 19753=NBRC 114400) is a strain of A. litoris. On the basis of the data obtained here, strain OS3-83^T is considered to represent a new species of the genus Actinomadura, for which the name Actinomadura terrae sp. nov. is proposed.

Actinomadura parmotrematis sp. nov., isolated from the foliose lichen, Parmotrema praesorediosum (Nyl.) Hale

A novel actinomycete strain PM05-2T was isolated from the lichen Parmotrema praesorediosum (Nyl.) Hale collected from Chaiyaphum Province, Thailand. The taxonomic position of the strain was studied using the polyphasic approach. Based on the morphology and chemotaxonomic properties, strain PM05-2T was identified as a member of the genus Actinomadura . The whole-cell hydrolysate contained meso-diaminopimelic acid, rhamnose, ribose, xylose, madurose, glucose and galactose. The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, one unidentified phosphoglycolipid, four unidentified phospholipids and one unidentified lipid. The menaquinones were MK-9(H6), MK-9(H4), MK-9(H2), MK-9(H8) and MK-9(H0). The major cellular fatty acids were C16:0 and C18:1 ω9c. Strain PM05-2T showed the highest 16S rRNA gene similarity to Actinomadura hibisca NBRC 15177T (98.58%), Actinomadura kijaniata NBRC 14229T (98.29 %) and Actinomadura namibiensis DSM 44197T (98.14 %). The phylogenetic tree analysis revealed that strain PM05-2T was related to A. hibisca NBRC 15177T, A. kijaniata NBRC 14229T, A. namibiensis DSM 44197T and Actinomadura macrotermitis RB68T. The genomic analysis revealed that average nucleotide identity values based on both blast and MUMmer between strain PM05-2T and the relative type strains ranged from 77.6 to 86.4%. The digital DNA–DNA hybridization values among the strains were lower than the threshold for assigning to the same species. The taxonomic results suggested that strain PM05-2T represented a novel species of the genus Actinomadura for which the name Actinomadura parmotrematis is proposed. The type strain is PM05-2T (=TBRC 15492T=NBRC 115416T).