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Marine invertebrates represent an underexplored reservoir for actinobacteria, which are known to synthesize novel bioactive compounds. This study isolated 37 actinobacterial strains from five distinct marine invertebrate hosts, namely Chondrilla australiensis, Palythoa sp., Favia sp., Porites lutea, and Acropora cervicornis, while no strains were obtained from Lissoclinum sp. and Lithophyllon sp. These isolates were taxonomically classified into six genera: Gordonia, Microbacterium, Micromonospora, Nocardia, Rhodococcus, and Streptomyces, with Streptomyces and Micromonospora being notably predominant. Comparative genomic analysis facilitated the identification of two novel species: Micromonospora palythoicola sp. nov. (strain S2-005 T  = TBRC 18343 T and NBRC 116545 T ) and Streptomyces poriticola sp. nov. (strain C6-003 T , =TBRC 17807 T and NBRC 116425 T ). Both species exhibited substantial genetic differences from their nearest known species as demonstrated by digital DNA-DNA hybridization and average nucleotide identity scores, which fell below the thresholds of 70% and 95%, respectively. Streptomyces poriticola C6-003 T displayed significant antimicrobial activity and selective cytotoxicity against human breast cancer MCF-7 cells, with reduced toxicity towards human dermal papilla cells. Micromonospora palythoicola S2-005 T manifested antimicrobial properties against Streptococcus mutans and Kocuria rhizophila. These findings highlight the considerable diversity of actinobacteria within marine invertebrates and underscore their potential as a source of new species with promising biological properties for therapeutic applications., (© 2024. The Author(s).)

Several strains were isolated from subsurface soil of the Atacama Desert and were previously assigned to the Micromonospora genus. A polyphasic study was designed to determine the taxonomic affiliation of isolates 4G51 T , 4G53, and 4G57. All the strains showed chemotaxonomic properties in line with their classification in the genus Micromonospora, including meso-diaminopimelic acid in the cell wall peptidoglycan, MK-9(H 4 ) as major respiratory quinone, iso-C 15:0 and iso-C 16:0 as major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as major polar lipids. The 16S rRNA gene sequences of strains 4G51 T , 4G53, and 4G57 showed the highest similarity (97.9 %) with the type strain of Micromonospora costi CS1-12 T , forming an independent branch in the phylogenetic gene tree. Their independent position was confirmed with genome phylogenies, being most closely related to the type strain of Micromonospora kangleipakensis. Digital DNA-DNA hybridization and average nucleotide identity analyses between the isolates and their closest phylogenomic neighbours confirmed that they should be assigned to a new species within the genus Micromonospora for which the name Micromonospora sicca sp. nov. (4G51 T =PCM 3031 T =LMG 30756 T ) is proposed., 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 © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.)

Pigments and other secondary metabolites originating from marine microbes have been a promising natural colorants and drugs for multifaceted applications. However, marine actinobacteria producing such natural molecules are least investigated in terms of their taxonomy, chemical diversity and applications in biomedical, textile, and food industries. In this study, sioxanthin pigment-producing Gram-positive actinobacteria, Micromonospora sp. strain SH-82 was isolated from a marine sponge, Scopalina hapalia, and its whole genome was analyzed. Strain SH-82is a prolific producer of diverse chemical molecules as it produced more compounds on A1 medium with different culture conditions. The genome size of SH-82 is 6.24 Mb (6,246,890 bp) carrying 23 identified biosynthetic gene clusters. A total of 5415 CDS, 60 tRNA, 9 rRNA, and 1 tmRNA are identified from SH-82 genome. The GC content (%) of whole genome was 71.6%. Strain SH-82 harbors genes encoding type I, type II, and type III polyketide synthases. Based on the multi-locus sequence analysis and fatty acid methyl ester (FAME) composition, strain SH-82 is confirmed as a novel species. The genetic information of Micromonospora sp. SH-82 has been deposited to NCBI under the BioProject ID PRJNA1087320, with corresponding identifiers in the Sequence Read Archive (SRA) as SAMN40439676 and the Genome accession as CP148049., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

An actinobacterial strain designated MMS20-R1-14 T was isolated from a riverside soil sample. Colonies on agar plates were orange to strong orange brown in colour, which later became black. The cells grew at 10-40 °C (optimum, 37 °C), pH 5.0-11.0 (pH 8.0) and in the presence of 0-4 % NaCl (1 %). The 16S rRNA gene sequence of strain MMS20-R1-14 T showed highest similarities to Micromonospora wenchangensis CCTCC AA 2012002 T (99.51 %) and Micromonospora rifamycinica AM105 T (99.37 %). The orthoANI values between strain MMS20-R1-14 T and the two type strains were 95.72 and 90.99 %, and the digital DNA-DNA hybridization values were 63.6 and 40.8 %, respectively, thus confirming the distinction of strain MMS20-R1-14 T from its mostly related species. The DNA G+C content of strain MMS20-R1-14 T was 72.9 mol%. The strain contained meso -diaminopimelic acid as the major cell-wall amino acid, and the characteristic whole-cell sugars were arabinose, xylose, glucose, ribose and rhamnose. The main cellular fatty acids were C 18 : 1  ω 9 c , iso-C 15 : 0 and iso-C 16 : 0 , the diagnostic polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, and the predominant menaquinones were MK-10(H 4 ) and MK-10(H 6 ), all of which were consistent with those of Micromonospora . Strain MMS20-R1-14 T showed antimicrobial activity against a range of bacterial and yeast species. The genome of the strain was found to contain 33 potential biosynthetic gene clusters for secondary metabolites, thus showing a high potential as a producer of bioactive compounds. On the basis of these phenotypic, genotypic and chemotaxonomic data, strain MMS20-R1-14 T merits recognition as representing a novel species of the genus Micromonospora , for which the name Micromonospora humida sp. nov. (type strain=MMS20 R1-14 T =KCTC 49541 T =JCM 34494 T ) is proposed.

Strain Llam7 T was isolated from microbial mat samples from the hypersaline lake Salar de Llamará, located in Taracapá region in the hyper-arid core of the Atacama Desert (Chile). Phenotypic, chemotaxonomic and genomic traits were studied. Phylogenetic analyses based on 16S rRNA gene sequences assigned the strain to the family Micromonosporaceae with affiliation to the genera Micromonospora and Salinispora . Major fatty acids were C 17 : 1 ω8 c , iso-C 15 : 0 , iso-C 16 : 0 and anteiso-C 17 : 0 . The cell walls contained meso -diaminopimelic acid and ll-2,6 diaminopimelic acid (ll-DAP), while major whole-cell sugars were glucose, mannose, xylose and ribose. The major menaquinones were MK-9(H 4 ) and MK-9(H 6 ). As polar lipids phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and several unidentified lipids, i.e. two glycolipids, one aminolipid, three phospholipids, one aminoglycolipid and one phosphoglycolipid, were detected. Genome sequencing revealed a genome size of 6.894 Mb and a DNA G+C content of 71.4 mol%. Phylogenetic analyses with complete genome sequences positioned strain Llam7 T within the family Micromonosporaceae forming a distinct cluster with Micromonospora (former Xiangella ) phaseoli DSM 45730 T . This cluster is related to Micromonospora pelagivivens KJ-029 T , Micromonospora craterilacus NA12 T , and Micromonospora craniellae LHW63014 T as well as to all members of the former genera Verrucosispora and Jishengella , which were re-classified as members of the genus Micromonospora , forming a clade distinct from the genus Salinispora . Pairwise whole genome average nucleotide identity (ANI) values, digital DNA-DNA hybridization (dDDH) values, the presence of the diamino acid ll-DAP, and the composition of whole sugars and polar lipids indicate that Llam7 T represents a novel species, for which the name Micromonospora tarapacensis sp. nov. is proposed, with Llam7 T (=DSM 109510 T ,=LMG 31023 T ) as the type strain.

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.)

During a bioprospection of bacteria with antimicrobial activity, the actinomycete strain A38 T was isolated from a sediment sample of the Carpintero river located in the Gran Piedra Mountains, Santiago de Cuba province (Cuba). This strain was identified as a member of the genus Micromonospora by means of a polyphasic taxonomy study. Strain A38 T was an aerobic Gram-positive filamentous bacterium that produced single spores in a well-developed vegetative mycelium. An aerial mycelium was absent. The cell wall contained meso -diaminopimelic acid and the whole-cell sugars were glucose, mannose, ribose and xylose. The major cellular fatty acids were isoC 15:0 , 10 methyl C 17:0 , anteiso-C 17:0 and iso-C 17:0 . The predominant menaquinones were MK-10(H 4 ) and MK-10(H6). Phylogenetic analysis of 16S rRNA gene sequences revealed that this strain was closely related to Micromonospora tulbaghiae DSM 45142 T (99.5 %), Micromonospora citrea DSM 43903 T (99.4 %), Micromonospora marina DSM 45555 T (99.4 %), Micromonospora maritima DSM 45782 T (99.3 %), Micromonospora sediminicola DSM 45794 T (99.3 %), Micromonospora aurantiaca DSM 43813 T (99.2 %) and Micromonospora chaiyaphumensis DSM 45246 T (99.2 %). The results of OrthoANIu analysis showed the highest similarity to Micromonospora chalcea DSM 43026 T (96.4 %). However, the 16S rRNA and gyrB gene sequence-based phylogeny and phenotypic characteristics provided support to distinguish strain A38 T as a novel species. On the basis of the results presented here, we propose to classify strain A38 T (=LMG 30467 T =CECT 30034 T ) as the type strain of the novel species Micromonospora fluminis sp. nov.

A novel actinobacterial strain, designated NA12 T , was isolated from coastal sediment sample of Nemrut Lake, a crater lake in eastern Anatolia, Turkey. The taxonomic position of the strain was established using a polyphasic approach. Cultural and chemotaxonomic characteristics of the strain were consistent with its classification within the family Micromonosporaceae. The 16S rRNA gene sequence analysis of strain NA12 T showed that the strain closely related to M. radicis AZ1-13 T , M. zingiberis PLAI 1-1 T , M. craniella LHW63014 T and M. endophytica 202201 T with pairwise sequence identity values ranging from 99.4 to 99.3%. Digital DNA-DNA hybridization values between strain NA12 T and the closely related type strains were ranged from 41.0 to 18.3% while the average nucleotide identity values were between 87.3 and 86.5%, which are well below the designed cut-off points of 70 and 95%, respectively. The G + C content of genomic DNA was 71.5%. Whole-cell hydrolysates of strain NA12 T contained 3-hydroxydiaminopimelic acid and meso-diaminopimelic acid. Cell-wall sugars were composed of arabinose, fucose, glucose, mannose, rhamnose and xylose. The polar lipid profile contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, phosphatidylglycerol, glycophospholipid, amino-phospholipid and two unidentified phospholipids. The predominant menaquinones were MK-9(H 6 ) and MK-9(H 4 ). Major fatty acids were iso-C 16:0 and C 17:1 ω8c. Based upon the consensus of phenotypic and phylogenetic analyses as well as whole genome comparisons, strain NA12 T (DSM 100982 T  = KCTC 39647 T ) is proposed to represent the type strain of a novel species, Micromonospora craterilacus sp. nov.

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(H 4 ). 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 ).

A novel actinobacterial strain, designated S2509 T , was isolated from marine sediment collected by a dredge at a depth of 45 m along Melet River offshore of the southern Black Sea coast, Ordu, Turkey. The cell wall peptidoglycan of strain was found to contain meso-diaminopimelic acid and 3-OH-diaminopimelic acid. The whole cell sugars detected were arabinose, glucose, rhamnose, ribose and xylose. The diagnostic phospholipids of strain S2509 T were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, a glycolipid and two unidentified phospholipids. The predominant menaquinones were identified as MK-9(H 8 ), MK-9(H 6 ), MK-10(H 8 ), MK-9(H 4 ), MK-10(H 4 ) and MK-10(H 6 ). The major cellular fatty acids were found to be iso-C 16:0 , iso-C 15:0 and 10-methyl C 17:0 . The taxonomic position of the strain was established using a polyphasic approach, showing that S2509 T strain belongs to the genus Micromonospora. Phylogenetic analysis based on the 16S rRNA gene sequence of strain S2509 T showed that it is closely related to the type strain of Micromonospora chokoriensis DSM 45160 T (99.37% sequence similarity), and phylogenetically clustered with Micromonospora inaquosa LB39 T (99.37%), Micromonospora lupini Lupac 14N T (99.16%), Micromonospora violae NEAU-zh8 T (99.23%) and Micromonospora taraxaci NEAU-P5 T (99.03%). The phylogenetic analysis based on the gyrB gene sequence of strain S2509 T confirmed its close relationship with M. chokoriensis JCM 13247 T (96.5% sequence similarity). Whole genome sequences confirmed by digital DNA-DNA hybridization analysis that the strain S2509 T represents a novel species in the genus Micromonospora, for which the name Micromonospora orduensis sp. nov. is proposed. The type strain is S2509 T (=DSM 45926 T  = KCTC 29201 T ).

An isolate, 13K206 T , with typical morphological characteristics of the genus Micromonospora was obtained during a study searching for novel actinobacteria with biosynthetic potential from the Karakum Desert. A polyphasic approach was adopted to determine taxonomic affiliation of the strain. The strain showed chemotaxonomical properties consistent with its classification in the genus Micromonospora such as meso - and 3-OH-A 2 pm in the cell-wall peptidoglycan, xylose in whole-cell hydrolysate and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as major polar lipids. The results of phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain was closely related to ' Micromonospora spongicola ' S3-1 T , Micromonospora nigra DSM 43818 T and Micromonospora yasonensis DS3186 T with sequence similarities of 98.6, 98.5 and 98.4 %, respectively. Digital DNA-DNA hybridization and average nucleotide identity analyses in addition to gyrB gene analysis confirmed the assignment of the strain to a novel species within the genus Micromonospora for which the name Micromonospora deserti sp. nov. is proposed. The type strain is 13K206 T (=JCM 32583 T =DSM 107532 T ). The DNA G+C content of the type strain is 72.4 mol%.

The genus Micromonospora has been found in nodules of several legumes and some new species of this genus were isolated from these plant organs. In this study we analysed the taxonomic diversity of Micromonospora strains isolated from alfalfa nodules in Spain and Australia on the basis of three phylogenetic markers, the rrs and gyrB genes and 16S-23S intergenic spacer (ITS). The genome analysis of selected strains representative of different clusters or lineages found after rrs, gyrB and ITS analyses confirmed the results obtained with these phylogenetic markers. They showed that the analysed strains belong to at least 18 Micromonospora species including previously described ones, such as Micromonospora noduli, Micromonospora ureilytica, Micromonospora taraxaci, Micromonospora zamorensis, Micromonospora aurantiaca and Micromonospora tulbaghiae. Most of these strains belong to undescribed species of Micromonospora showing the high taxonomic diversity of strains from this genus inhabiting alfalfa nodules. Although Micromonospora strains are not able to induce the formation of these nodules, and it seems that they do not contribute to fix atmospheric nitrogen, they could play a role related with the mechanisms of plant growth promotion and pathogen protection presented by Micromonospora strains isolated from legume nodules., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

A Micromonospora strain, designated 5R2A7 T , isolated from a high altitude Atacama Desert soil was examined by using a polyphasic approach. Strain 5R2A7 T was found to have morphological, chemotaxonomic and cultural characteristics typical of members of the genus Micromonospora. The cell wall contains meso - and hydroxy -diaminopimelic acid, the major whole-cell sugars are glucose, ribose and xylose, the predominant menaquinones MK-10(H 4 ), MK-10(H 6 ), MK-10(H 8 ) and MK-9(H 6 ), the major polar lipids diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and an unknown glycolipid, and the predominant cellular fatty acids iso -C 16 : 0 , iso -C 15 : 0 and 10-methyl C 17 : 0 . The digital genomic DNA G+C content is 72.3 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain 5R2A7 T was closely related to Micromonospora coriariae DSM 44875 T (99.8 %) and Micromonospora cremea CR30 T (99.7 %), and was separated readily from the latter, its closest phylogenetic neighbour, based on gyrB and multilocus sequence data, by low average nucleotide identity (92.59 %) and in silico DNA-DNA relatedness (51.7 %) values calculated from draft genome assemblies and by a range of chemotaxonomic and phenotypic properties. Consequently, strain 5R2A7 T is considered to represent a novel species of Micromonospora for which the name Micromonospora acroterricola sp. nov. is proposed. The type strain is 5R2A7 T (=LMG 30755 T =CECT 9656 T ).

Two novel actinobacterial strains, MS1-9 T and NGC1-4, were isolated from roots of Musa (ABB) cv. 'Kluai Namwa', collected from Chachoengsao province, and Musa (ABB) cv. 'Kluai Chang', from Suphan Buri province, Thailand, respectively. Comparative analysis of 16S rRNA gene (98.0 to 98.9% similarity), gyrase subunit B (gyrB) gene and whole-genome sequences emphasised that the strains MS1-9 T and NGC1-4 showed closely related with Micromonospora peucetia DSM 43363 T , M. krabiensis JCM 12869 T and M. avicenniae DSM 45758 T , respectively. Strains MS1-9 T and NGC1-4 contained meso-diaminopimelic acid in cell-wall peptidoglycan. Whole-cell sugars were glucose, xylose, mannose, and ribose. The acyl type of peptidoglycan was glycolyl. MK-10(H 6 ), MK-9(H 6 ), and MK-10(H 8 ) were presented as the major menaquinones. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylinositol were detected as predominant phospholipid profiles. The major cellular fatty acids consisted of iso-C 15:0 , anteiso-C 15:0 , anteiso-C 17:0 , iso-C 17:0 and C 17:0 . The DNA G+C content of strains MS1-9 T and NGC1-4 were 72.2 and 72.3mol%, respectively. Draft genome sequences indicated by ANI values and digital DNA-DNA hybridisation analysis asserted that the strains MS1-9 T and NGC1-4 should be represented as a novel species within the genus Micromonospora for which the name Micromonospora musae sp. nov. is proposed. The type strain is MS1-9 T (=JCM 32149 T =TISTR 2659 T )., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

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 T are 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(H 4 ) and MK-9(H 6 ); 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 : 1 ω8 c ; 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. zingiberis is transferred to the genus Micromonospora as Micromonospora zingiberis comb. nov. (type strain PLAI1-1 T =TBRC 7644 T =NBRC 113144 T =JCM 32592 T ).

A single spore forming actinomycete, designated strain HSS6-8 T , was isolated from a sample of hot spring soil. The strain had the chemotaxonomic properties consistent with its classification in the genus Micromonospora. The strain was found to have meso-diaminopimelic acid in the cell-wall peptidoglycan. The acyl type of the cell-wall muramic acid was glycolyl. The reducing sugars in the cell hydrolysates were glucose, arabinose, xylose, ribose, mannose, galactose and rhamnose. The phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphoglycolipid. The major menaquinones were MK-10(H6) and MK-10(H4). The major cellular fatty acids were iso-C16 : 0, anteiso-C17 : 0, C17 : 0 and anteiso-C15 : 0. The G+C content of the genomic DNA was 70.5 mol%. 16S rRNA gene sequence analysis revealed that strain HSS6-8 T was closely related to Micromonospora nigra DSM 43818 T (98.2 %), Micromonospora eburnea DSM 44814 T (98.2 %) and Micromonospora spongicola S3-1 T (98.1 %). The physiological and DNA-DNA hybridization data allowed the differentiation of strain HSS6-8 T from its related species. Thus, the strain represents a novel species of the genus Micromonospora, for which the name Micromonospora caldifontis sp. nov. is proposed. The type strain is HSS6-8 T (=TBRC 8927 T =JCM 17126 T ).

During a study looking for the isolation of new actinobacteria strains with potential for antibiotic production from deep marine sediment, three strains were collected with a morphology similar to the one described for the Micromonospora genus. A polyphasic study was designed to determine the taxonomic affiliation of the strains S2901 T , S2903, and S2904. All the strains showed chemotaxonomic properties in line with their classification in the genus Micromonospora, meso-diaminopimelic acid in the wall peptidoglycan, a tetrahydrogenated menaquinone with nine isoprene units as major respiratory quinone, iso-C 15:0 and iso-C 16:0 as major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as major polar lipids. The 16S rRNA gene sequences of strain S2901 T , S2903, and S2904 showed the highest similarity (99.2%) with the type strain of Micromonospora halophytica DSM 43171 T , forming an independent branch in the phylogenetic gene tree. Their independent position was confirmed with gyrB gene and MLSA phylogenies. Whole genome sequences confirmed by digital DNA-DNA hybridization analysis that the isolates should be assigned to a new species within the genus Micromonospora for which the name Micromonospora globispora sp. nov. (S2901 T , S2903 and S2904) is proposed., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

A novel marine actinomycete, designated LHW63014 T , isolated from a marine sponge, Craniella species, collected in the South China Sea, was examined using a polyphasic approach. The 16S rRNA gene sequence of strain LHW63014 T showed highest similarities to Jishengella endophytica 202201 T (98.9 %), Micromonospora olivasterospora DSM 43868 T (98.7 %), Micromonospora maris AB-18-032 T (98.6 %) and Micromonospora gifhornensis DSM 44337 T (98.6 %). Phylogenetic analyses of the family Micromonosporaceae based on the 16S rRNA and gyrB gene sequences indicated that strain LHW63014 T and J. endophytica 202201 T located within the genus Micromonospora. Morphological and chemotaxonomic characteristics confirmed their affiliation to the genus Micromonospora. Based on phenotypic characteristics, phylogenetic data and digital DNA-DNA hybridization results, strain LHW63014 T could be distinguished from its closest taxa, representing a novel species of the genus Micromonospora, for which the name Micromonospora craniellae sp. nov., is proposed, with the type strain LHW63014 T (=DSM 106193 T =CCTCC AA 2018012 T ). It is also proposed that J. endophytica be transferred to genus Micromonospora as Micromonospora endophytica comb. nov. (type strain 202201 T =CGMCC 4.5597 T =DSM 45430 T ).

A Gram-stain positive actinomycete, strain AZ1-19 T , isolated from roots of Azadirachta indica A. Juss. var. siamensis Valeton, collected from Chachoengsao province, Thailand, was characterised taxonomically by using a polyphasic approach. Strain AZ1-19 T was found to have characteristics consistent with those of members of the genus Micromonospora. The cell wall peptidoglycan of the strain was found to contain meso-diaminopimelic acid. The predominant phospholipids were identified as diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The characteristic whole-cell sugars were identified as glucose, xylose, galactose and mannose. The major menaquinones were found to be MK-9(H 6 ), MK-10(H 6 ) and MK-10(H 8 ), and the major cellular fatty acids were identified as iso-C 16:0 , iso-C 15:0 , anteiso-C 15:0 and anteiso-C 17:0 . Comparative analysis of 16S rRNA gene sequences revealed that strain AZ1-19 T is closely related to Micromonospora costi CS1-12 T (98.75% similarity), Micromonospora avicenniae 268506 T (98.75%), Micromonospora haikouensis 232617 T (98.68%) and Micromonospora siamensis TT2-4 T (98.61%), whilst the corresponding phylogenetic analysis based on partial gyrase subunit B (gyrB) gene sequences indicated that strain AZ1-19 T forms a clade with M. avicenniae 268506 T with a high bootstrap value. The DNA G + C content was determined to be 69.8 mol%. Moreover, a combination of DNA-DNA relatedness values and some phenotypic and chemotaxonomic properties indicated that the strain could be distinguished from closely related species. Therefore, it is considered that strain AZ1-19 T represents a novel Micromonospora species for which the name Micromonospora azadirachtae sp. nov. is proposed. The type strain is AZ1-19 T (= KCTC 39941 T  = NBRC 112784 T  = JCM 32148 T  = TISTR 2559 T ).

Innovative procedures were used to selectively isolate small numbers of Micromonospora strains from extreme hyper-arid and high altitude Atacama Desert soils. Micromonosporae were recognised on isolation plates by their ability to produce filamentous microcolonies that were strongly attached to the agar. Most of the isolates formed characteristic orange colonies that lacked aerial hyphae and turned black on spore formation, whereas those from the high altitude soil were dry, blue-green and covered by white aerial hyphae. The isolates were assigned to seven multi- and eleven single-membered groups based on BOX-PCR profiles. Representatives of the groups were assigned to either multi-membered clades that also contained marker strains or formed distinct phyletic lines in the Micromonospora 16S rRNA gene tree; many of the isolates were considered to be putatively novel species of Micromonospora. Most of the isolates from the high altitude soils showed activity against wild type strains of Bacillus subtilis and Pseudomonas fluorescens while those from the rhizosphere of Parastrephia quadrangulares and from the Lomas Bayas hyper-arid soil showed resistance to UV radiation.

For decades, researchers have lacked the ability to rapidly correlate microbial identity with bacterial metabolism. Since specialized metabolites are critical to bacterial function and survival in the environment, we designed a data acquisition and bioinformatics technique (IDBac) that utilizes in situ matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to analyze protein and specialized metabolite spectra recorded from single bacterial colonies picked from agar plates. We demonstrated the power of our approach by discriminating between two Bacillus subtilis strains in <30 min solely on the basis of their differential ability to produce cyclic peptide antibiotics surfactin and plipastatin, caused by a single frameshift mutation. Next, we used IDBac to detect subtle intraspecies differences in the production of metal scavenging acyl-desferrioxamines in a group of eight freshwater Micromonospora isolates that share >99% sequence similarity in the 16S rRNA gene. Finally, we used IDBac to simultaneously extract protein and specialized metabolite MS profiles from unidentified Lake Michigan sponge-associated bacteria isolated from an agar plate. In just 3 h, we created hierarchical protein MS groupings of 11 environmental isolates (10 MS replicates each, for a total of 110 spectra) that accurately mirrored phylogenetic groupings. We further distinguished isolates within these groupings, which share nearly identical 16S rRNA gene sequence identity, based on interspecies and intraspecies differences in specialized metabolite production. IDBac is an attempt to couple in situ MS analyses of protein content and specialized metabolite production to allow for facile discrimination of closely related bacterial colonies., Competing Interests: The authors declare no conflict of interest., (Copyright © 2018 the Author(s). Published by PNAS.)

A novel endophytic actinomycete, strain WPS1-2 T , isolated from a root of Globba winitii C. H. Wright, was characterized taxonomically by using a polyphasic approach. Strain WPS1-2 T exhibited identical characteristics to the members of the genus Micromonospora. Single spores were observed directly on substrate mycelia. The cell-wall peptidoglycan of the strain contained meso-diaminopimelic acid and 3-OH-meso-diaminopimelic acid. Whole-cell hydrolysates contained glucose, ribose, arabinose and xylose. The predominant menaquinones were MK-10(H8) and MK-10(H10). The major cellular fatty acids consisted of iso-C15 : 0, iso-C16 : 0 and anteiso-C15 : 0. According to the 16S rRNA gene sequence of the strain, WPS1-2 T showed highest similarity to Micromonospora costi CS1-12 T (99.02 %). Phylogenetic analysis of the gyrase subunit B (gyrB) gene indicated that the strain was related to M. costi CS1-12 T . The DNA G+C content was 73.7 mol%. The strain could be distinguished from closely related type strains by using a combination of morphological, chemotaxonomic, physiological and biochemical data together with DNA-DNA relatedness values. Based on these observations, strain WPS1-2 T is considered to represent a novel species of the genus Micromonospora, for which the name Micromonospora globbae sp. nov. is proposed. The type strain is WPS1-2 T (=KCTC 39787 T =NBRC 112325 T =TISTR 2405 T ).

There is a need to clarify relationships within the actinobacterial genus Micromonospora, the type genus of the family Micromonosporaceae, given its biotechnological and ecological importance. Here, draft genomes of 40 Micromonospora type strains and two non-type strains are made available through the Genomic Encyclopedia of Bacteria and Archaea project and used to generate a phylogenomic tree which showed they could be assigned to well supported phyletic lines that were not evident in corresponding trees based on single and concatenated sequences of conserved genes. DNA G+C ratios derived from genome sequences showed that corresponding data from species descriptions were imprecise. Emended descriptions include precise base composition data and approximate genome sizes of the type strains. antiSMASH analyses of the draft genomes show that micromonosporae have a previously unrealised potential to synthesize novel specialized metabolites. Close to one thousand biosynthetic gene clusters were detected, including NRPS, PKS, terpenes and siderophores clusters that were discontinuously distributed thereby opening up the prospect of prioritising gifted strains for natural product discovery. The distribution of key stress related genes provide an insight into how micromonosporae adapt to key environmental variables. Genes associated with plant interactions highlight the potential use of micromonosporae in agriculture and biotechnology.

Two actinobacterial isolates, strains SG15 T and SGB14 T , were recovered through a microbial diversity study of nitrogen fixing nodules from Pisum sativum plants collected in Salamanca (Spain). The taxonomic status of these isolates was determined using a polyphasic approach and both presented chemotaxonomic and morphological properties consistent with their classification in the genus Micromonospora. For strains SG15 T and SGB14 T , the highest 16S rRNA gene sequence similarities were observed with Micromonospora coxensis JCM 13248 T (99.2 %) and Micromonospora purpureochromogenes DSM 43821 T (99.4 %), respectively. However, strains SG15 T and SGB14 T were readily distinguished from their phylogenetic neighbours both genetically and phenotypically indicating that they represent two new Micromonospora species. The following names are proposed for these species: Micromonosporaphytophila sp. nov. type strain SG15 T (=CECT 9369 T ; =DSM 105363 T ), and Micromonosporaluteiviridis sp. nov. type strain SGB14 T (=CECT 9370 T ; =DSM 105362 T ).

The discovery that the actinobacterium Micromonospora inhabits nitrogen-fixing nodules raised questions as to its potential ecological role. The capacity of two Micromonospora strains to infect legumes other than their original host, Lupinus angustifolius, was investigated using Medicago and Trifolium as test plants. Compatible rhizobial strains were used for coinoculation of the plants because Micromonospora itself does not induce nodulation. Over 50% of nodules from each legume housed Micromonospora, and using 16S rRNA gene sequence identification, we verified that the reisolated strains corresponded to the microorganisms inoculated. Entry of the bacteria and colonization of the plant hosts were monitored using a GFP-tagged Lupac 08 mutant together with rhizobia, and by using immunogold labeling. Strain Lupac 08 was localized in plant tissues, confirming its capacity to enter and colonize all hosts. Based on studying three different plants, our results support a non-specific relationship between Micromonospora and legumes. Micromonospora Lupac 08, originally isolated from Lupinus re-enters root tissue, but only when coinoculated with the corresponding rhizobia. The ability of Micromonospora to infect and colonize different legume species and function as a potential plant-growth promoting bacterium is relevant because this microbe enhances the symbiosis without interfering with the host and its nodulating and nitrogen-fixing microbes.

A novel actinobacterium, designated strain UDF-1T, was isolated from forest soil in Chungnam, South Korea, and its taxonomic position was investigated using a polyphasic approach. Strain UDF-1T formed a branched brownish-orange substrate mycelium with spherical or oval spores. No aerial mycelium was formed. Comparative 16S rRNA gene sequence analysis indicated that strain UDF-1T belongs to the genus Micromonospora, showing the highest sequence similarity to Micromonospora palomenae NEAU-CX1T (99.2 % 16S rRNA gene sequence similarity), 'Micromonospora maoerensis' NEAU-MES19 (99.0 %), Micromonospora endolithica DSM 44398T (98.8 %) and Micromonospora matsumotoense IMSNU 22003T (98.8 %). The predominant menaquinones of strain UDF-1T were MK-10 (H4) and MK-10 (H6). The cell wall contained meso-diaminopimelic acid and the whole-cell sugars were arabinose and xylose. The major polar lipids were phosphatidylinositol, diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were iso-C16 : 0, anteiso-C15 : 0 and iso-C15 : 0. The genomic DNA G+C content was 73.1 mol%. DNA-DNA relatedness between strain UDF-1T and closely related type strains in the genus Micromonospora was below 30 %. On the basis of the polyphasic analysis conducted in this study, strain UDF-1T represents a novel species of the genus Micromonospora, for which the name Micromonospora fulva sp. nov. is proposed. The type strain is UDF-1T (=KACC 18696T=NBRC 111826T).

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).

A novel endophytic actinomycete with antifungal activity, designated strain NEAU-JXY5T, was isolated from the root of Parathelypteris beddomei (Bak.) Ching. Strain NEAU-JXY5T showed closest 16S rRNA gene sequence similarity to Micromonospora luteifusca GUI2T (99.31 %), and phylogenetically clustered with Micromonospora noduli GUI43T (99.24 %), 'Micromonospora lycii' NEAU-gq11 (99.19 %), 'Micromonospora zeae' NEAU-gq9 (99.12 %), Micromonospora saelicesensis Lupac 09T (98.97 %), Micromonospora vinacea GUI63T (98.96 %), 'Micromonospora jinlongensis' NEAU-GRX11 (98.91 %), Micromonospora profundi DS3010T (98.77 %), Micromonospora zamorensis CR38T (98.76 %), Micromonospora chokoriensis 2-19(6)T (98.71 %), Micromonospora lupini Lupac 14NT (98.69 %), Micromonospora ureilytica GUI23T (98.69 %), Micromonospora violae NEAU-zh8T (98.57 %) and Micromonospora taraxaci NEAU-P5T (98.37 %). Phylogenetic analysis based on gyrB gene sequences also indicated that the isolate clustered with the above strains except M. violae NEAU-zh8T. A combination of DNA-DNA hybridization results and some phenotypic characteristics indicated that the strain could be readily distinguished from these closest phylogenetic relatives. Therefore, it is concluded that strain NEAU-JXY5T represents a novel species of the genus Micromonospora, for which the name Micromonospora parathelypteridis sp. nov. is proposed. The type strain is NEAU-JXY5T (=CGMCC 4.7347T=DSM 103125T).

A novel actinobacterial strain, designated DS3010T, was isolated from a Black Sea marine sediment and characterized using a polyphasic approach. The strain was shown to have chemotaxonomic, morphological and phylogenetic properties consistent with classification as representing a member of the genus Micromonospora. Comparative 16S rRNA gene sequence studies showed that the strain was most closely related to the type strains of Micromonospora saelicesensis (99.5 %), Micromonospora chokoriensis (99.4 %) and Micromonospora violae (99.3 %). Similarly, a corresponding analysis based on partial gyrB gene sequences showed that it formed a distinct phyletic branch in a subclade that included the type strains of Micromonosporazamorensis, 'Micromonospora zeae', 'Micromonospora jinlongensis', M. saelicesensis and Micromonospora lupini. DS3010T was distinguished from its closest phylogenetic neighbours by low levels of DNA-DNA relatedness and by a combination of chemotaxonomic and phenotypic properties. On the basis of these data, it is proposed that the isolate should be assigned to the genus Micromonospora as Micromonospora profundi sp. nov. with isolate DS3010T (=DSM 45981T=KCTC 29243T) as the type strain.

Aims: The aim of this study was to isolate and characterize the bioactive compound of Micromonospora auratinigra, HK-10 and its antibacterial inhibitory mechanism., Methods and Results: An oily bioactive compound was extracted from HK-10 (GenBank accession no. JN381554) and found to have promising antibacterial activity. The compound was characterized as 2-methylheptylisonicotinate (1) by (1) H, (13) C NMR and mass spectroscopy. Minimum inhibitory concentration (MIC) of this molecule was tested by micro broth dilution method and was found to be 70, 40, 80, 60, 60 and 50 μg for Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Echerichia coli, Pseudomonas aeruginosa and Mycobacterium abscessus respectively. The effects of compound 1 were studied on bacterial membrane structure using scanning electron microscopy. The results indicated a membrane-disrupting mechanism, resulting in the dysfunction of the cytoplasmic membrane structure and cell death of the pathogenic bacterial strains. Kinetics of growth of the test organisms was also analysed and indicated 2-methylheptylisonicotinate 1 as a bactericidal agent. Furthermore, we have studied the binding affinity of 1 towards different membrane proteins of pathogenic bacteria by in silico analysis., Conclusions: 2-methylheptylisonicotinate was isolated from M. auratinigra, a rare actinobacterial strain possessing antibacterial activity through a membrane-disrupting mechanism, and has MICs similar to standard antibiotic neomycin sulphate. It is the first report about a strain of M. auratinigra, isolated from Indo-Burma biodiversity hotspot of North-east India with new antimicrobial activities. In silico studies have also supported these results performed on various membrane targets of pathogenic bacteria., Significance and Impact of the Study: The antibacterial potential of M. auratinigra is reported for the first time. The results indicate the possible use of 2-methylheptylisonicotinate as a source of antibacterial agent against dreaded human pathogens., (© 2016 The Society for Applied Microbiology.)

A diversity study on the presence of strains representing the genus Micromonospora in Pisum sativum nodules collected from Cañizal (Spain) has provided evidence of the high number of isolates that might represent novel species. In the present work, we have characterized three of these isolates: GUI23T, GUI43T and GUI63T. Phenotypic and genotypic analyses confirmed that all strains represent novel species of the genus Micromonospora with the following proposed names: Micromonospora ureilytica sp. nov., type strain GUI23T (=CECT 9022T=DSM 101692T), Micromonospora noduli sp. nov., type strain GUI43T (=CECT 9020T=DSM 101694T), and Micromonospora vinacea sp. nov., type strain GUI63T (=CECT 9019T=DSM 101695T).

The novel actinomycete, strain CH3-3T, was isolated from mangrove sediment collected from Chonburi Province, Thailand. On the basis of its spore morphology and chemotaxonomic characteristics, the strain belonged to the genus Micromonospora. It contained meso-diaminopimelic acid, glucose, mannose, xylose, ribose and rhamnose in the whole-cell hydrolysate, MK-10(H4), MK-10(H6) and MK-10(H8) as major menaquinones, and iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0 as major cellular fatty acids. blast analysis of 16S rRNA gene sequences revealed that the strain showed highest similarity with Micromonospora palomenae NEAU-CX1T (98.97 %) and Micromonospora coxensis 2-30-b(28)T (98.97 %). Based on phylogenetic tree analysis of the 16S rRNA gene sequence, the strain formed a cluster with M. palomenae NEAU-CX1T, Micromonospora halophytica DSM 43171T, M. coxensis 2-30-b(28)T and Micromonospora purpureochromogenes DSM 43821T. On the basis of phenotypic differences and DNA-DNA relatedness evidence, strain CH3-3T could be clearly distinguished from the closely related species of the genus Micromonospora and represents a novel species of the genus Micromonospora for which the name Micromonospora sediminis sp. nov. is proposed. The type strain is CH3-3T (=JCM 18523T=PCU 350T=TISTR 2396T).

A total of 218 actinobacteria strains were isolated from wild perennial liquorice plants Glycyrrhiza glabra L. and Glycyrrhiza. inflate BAT. Based on morphological characteristics, 45 and 32 strains from G. inflate and G. glabra, respectively, were selected for further analyses. According to 16S rRNA sequence analysis, most of the strains belonged to genus Streptomyces and a few strains represented the rare actinobacteria Micromonospora, Rhodococcus and Tsukamurella. A total of 39 strains from G. inflate and 27 strains from G. glabra showed antimicrobial activity against at least one indicator organism. The range of the antimicrobial activity of the strains isolated from G. glabra and G. inflate was similar. A total of 34 strains from G. inflate and 29 strains from G. glabra carried at least one of the genes encoding polyketide synthases, non-ribosomal peptide synthetase and FADH2-dependent halogenase. In the type II polyketide synthase KSα gene phylogenetic analysis, the strains were divided into two major clades: one included known spore pigment production-linked KSα sequences and other sequences were linked to the production of different types of aromatic polyketide antibiotics. Based on the antimicrobial range, the isolates that carried different KSα types were not separated from each other or from the isolates that did not carry KSα. The incongruent phylogenies of 16S rRNA and KSα genes indicated that the KSα genes were possibly horizontally transferred. In all, the liquorice plants were a rich source of biocontrol agents that may produce novel bioactive compounds.

A Micromonospora strain, designated DS3186(T), isolated from sediment collected from the Black Sea off the Yason Peninsula, Ordu, Turkey, was examinated using a polyphasic approach. The strain was found to have chemotaxonomic, morphological and phylogenetic properties consistent with its clasification in the genus Micromonospora. A comparative 16S rRNA gene sequence analysis showed that the strain was closely related to the type strains of Micromonospora olivasterospora (99.0 %), Micromonospora equina (98.8 %), Micromonospora rhizosphaerae (98.8 %) and Micromonospora viridifaciens (98.8 %); low levels of DNA-DNA relatednes were found between the isolate and the M. olivasterospora and M. rhizosphaerae strains. Corresponding phylogenetic analysis based on partial gyrB gene sequences showed that strain DS3186(T) formed a subclade with the type strains of Micromonospora eburnea, M. equina, Micromonospora narathiwatensis and M. viridifaciens. Strain DS3186(T) was distinguished from its close phylogenetic neighbours using a combination of chemotaxonomic, morphological and physiological properties. Consequently, it is proposed that strain DS3186(T) represents a novel Micromonospora species for which the name Micromonospora yasonensis sp. nov. is proposed. The type strain is DS3186(T) (=DSM 45980(T) = KCTC 29433(T)).

Three novel actinobacterial strains, GUI2(T), GUI42 and CR21 isolated from nodular tissues and the rhizosphere of a sweet pea plant collected in Cañizal, Spain were identified according to their 16S rRNA gene sequences as new members of the genus Micromonospora. The closest phylogenetic members were found to be Micromonospora saelicesensis (99.2%) "Micromonospora zeae" (99.1%), "Micromonospora jinlongensis" (99%), Micromonospora lupini (98.9%) and Micromonospora zamorensis (98.8%). To resolve their full taxonomic position, four additional genes (atpD, gyrB, recA, rpoB) were partially sequenced and compared to available Micromonospora type strain sequences. DNA-DNA hybridization, BOX-PCR and ARDRA profiles confirmed that these strains represent a novel genomic species. All strains contained meso-diaminopimelic and hydroxy-diaminopimelic acids in their cell wall. Their fatty acid profiles comprised iso-C15:0, iso-C16:0 and anteiso-C15:0 as major components. The polar lipids diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol were found in the type strain GUI2(T) which also contained MK-10(H4) as the major menaquinone. Physiological and biochemical characteristics also differentiated the new isolates. Based on the integration of the above studies, strains GUI2(T), GUI42 and CR21 represent a novel Micromonospora species and we propose the name Micromonospora luteifusca sp. nov. The type strain is GUI2(T) (=CECT 8846(T); =DSM 100204(T))., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

A novel actinomycete strain 2803GPT1-18(T) was isolated from a composite mangrove soil sample collected from Beihai, Guangxi province, China. Phylogenetic analysis of the 16S rRNA gene sequence of strain 2803GPT1-18(T) indicated high similarity with 'Micromonospora harpali' NEAU-JC6(T) (99.2 %), Micromonospora haikouensis 232617(T) (99.1 %), Micromonospora wenchangensis 2602GPT1-05(T) (99.1 %), Micromonospora schwarzwaldensis HKI0641(T) (99.1 %). The gyrB gene sequence analysis also indicated that strain 2803GPT1-18(T) should be assigned to the genus Micromonospora but different from any established Micromonospora species. The strain harbored meso-DAP and glycine as major cell wall amino acids, MK-10(H6) (53.5 %), MK-9(H6) (25.1 %) and MK-9(H4) (13.4 %) as predominant menaquinones. The characteristic whole cell sugars are arabinose, xylose, glucose, galactose and mannose. The polar lipid profile comprises phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol and unidentified polar lipids. The major cellular fatty acids present are iso-C16:0 (44.2 %) and iso-C15:0 (12.4 %). The DNA G+C content is 71.2 mol%. Furthermore, a combination of DNA-DNA relatedness and some physiological and biochemical properties indicated that the novel strain could be readily distinguished from the closely related species. On the basis of these phenotypic and genotypic data, strain 2803GPT1-18(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora mangrovi sp. nov. is proposed. The type strain is 2803GPT1-18(T) (=CCTCC AA2012012(T) = DSM45761(T)).

An actinomycete strain SL3-70(T) was isolated from a rice field and characterised using a polyphasic approach. The morphological and chemotaxonomical characteristics of strain SL3-70(T) indicate that it belongs to the genus Micromonospora. The phylogenetic analysis of the nearly complete 16S rRNA gene sequence revealed that strain SL3-70(T) is a member of the genus Micromonospora, and is closely related to Micromonospora echinaurantica DSM 43904(T) (99.1 % 16S rRNA gene sequence similarity) and Micromonospora kangleipakensis MBRL 34(T) (98.8 %). DNA-DNA relatedness between strain SL3-70(T) and its relatives ranged from 21.2 % ± 0.6 to 38.7 % ± 0.4. The results obtained from our study indicate that strain SL3-70(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora soli sp. nov. is proposed. The type strain is SL3-70(T) (=BCC 67268(T); =NBRC 110009(T)).

A novel actinomycete, designated strain NEAU-gq11(T), was isolated from wolfberry root (Lycium chinense Mill) and characterized using a polyphasic approach. Strain NEAU-gq11(T) was observed to form rough-surfaced spores that borne singly on the substrate hyphae but aerial mycelia were not developed. The organism showed closest 16S rRNA gene sequence similarity to Micromonospora saelicesensis Lupac 09(T) (99.4%), and phylogenetically clustered with M. chokoriensis 2-19/6(T) (99.3%), 'M. zeae' NEAU-gq9(T) (99.3%), M. violae NEAU-zh8(T) (99.1%), 'M. jinlongensis' NEAU-GRX11(T) (99.1%), M. zamorensis CR38(T) (99.0%), M. taraxaci NEAU-P5(T) (98.9%) and M. lupini Lupac 14N(T) (98.6%). Phylogenetic analysis based on the gyrB gene sequences also indicated that the isolate clustered with the above type strains except M. violae NEAU-zh8(T). The cell-wall peptidoglycan consisted of meso-diaminopimelic acid and glycine. The major menaquinones were MK-9(H8), MK-10(H6) and MK-10(H2). The phospholipid profile contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The major fatty acid was iso-C16:0. Furthermore, some physiological and biochemical properties and low DNA-DNA relatedness values enabled the strain to be differentiated from members of closely related species. Therefore, it is proposed that strain NEAU-gq11(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora lycii sp. nov. is proposed. The type strain is NEAU-gq11(T) (=CGMCC 4.7149(T)=DSM 46703(T)).

A novel actinomycete, designated strain 2902at01T was isolated from soil collected at a mangrove forest in Zhanjiang, Guangdong province, China. The strain was identified using a polyphasic classification method. The 16S rRNA gene sequence of strain 2902at01T showed the highest similarity to Micromonospora equina Y22T (98.3 %) and Micromonospora pattaloongensis TJ2-2T (98.1 %). Phylogenetic analysis based on the gyrB gene sequence also clearly showed that the strain was different from any previously discovered species of the genus Micromonospora. The characteristic whole-cell sugars were ribose and xylose. The cell-wall hydrolysates contained alanine, asparagine, glycine and meso-diaminopimelic acid. MK-10(H6) and MK-10(H8) were the major menaquinones of the novel strain. The predominant fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0. The characteristic polar lipids of strain 2902at01T were phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and diphosphatidylglycerol. The DNA G+C content was 70.2 mol%. DNA-DNA hybridization data combined with other physiological and biochemical features could distinguish strain 2902at01T from the reference strains M. equina Y22T and M. pattaloongensis TJ2-2 T. On the basis of these phenotypic and genotypic data, strain 2902at01T represents a novel species of the genus Micromonospora, for which the name Micromonospora zhanjiangensis sp. nov. is proposed. The type strain is 2902at01T ( = CCTCC AA2014018T = DSM 45902T).

The novel actinomycete strain PWB-003T, which produced fluostatins B and C antibiotics, was isolated from nearshore sediment collected from Panwa Cape, Phuket Province, Thailand. Data from the present polyphasic study indicated that strain PWB-003T represented a member of the genus Micromonospora. It produced single spores on substrate mycelia and contained meso-diaminopimelic acid in the cell-wall peptidoglycan. Whole-cell hydrolysate contained ribose, xylose, arabinose, mannose and glucose. The predominant menaquinone was MK-10 (H4). Cellular fatty acids comprised C18 : 1ω9c, iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0 and iso-C17 : 0. On the basis of 16S rRNA gene sequence similarity analysis, the novel strain was closely related to Micromonospora eburnea LK2-10T (99.38 %), Micromonospora chaiyaphumensis MC5-1T (99.16 %), Micromonospora yangpuensis FXJ6.011T (98.97 %), Micromonospora echinaurantiaca DSM 43904T (98.97 %), Micromonospora pallida DSM 43817T (98.97 %), Micromonospora sagamiensis DSM 43912T and Micromonospora auratinigra JCM 12357T (both 98.97 %). The G+C content of the DNA was 74.5 mol%. DNA-DNA relatedness values among strain PWB-003T and related type strains ranged from 11.3 ± 1.3 to 38.8 ± 1.1 %. On the basis of these observations, strain PWB-003T could be distinguished from its closely related type strains and is considered to represent a novel species of the genus Micromonospora, for which the name Micromonospora fluostatini sp. nov. (type strain PWB-003T = JCM 30529T = PCU 341T = TISTR 2345T) is proposed.

An actinomycete, strain K55T, was isolated from a composite soil sample from a nickel mine,collected from Yueyang, Shaanxi Province, PR China. Strain K55T showed 16S rRNA gene sequence similarities of 98.73 %–98.51 % to species of the genus Micromonospora, including Micromonospora haikouensis 232617T, Micromonospora coxensis 2-30-b(28)T, Micromonospora wenchangensis 2602GPT1-05T, Micromonospora matsumotoense IMSNU22003T, Micromonospora maoerensis NEAU-MES19T, and Micromonospora humi P0402T. This strain harboured meso-diaminopimelic acid, alanine and glycine as the major cell-wall amino acids, xylose and glucose as the characteristic whole-cell sugars, and iso-C15 : 0(20.53 %),iso-C17 : 0 (12.74 %), iso-C16 : 0 (12.15 %), anteiso-C17 : 0 (7.97 %), C17 : 1ω8c(7.49 %) and C17 : 0 (6.63 %) as the dominant fatty acids. The major menaquinones were MK-10(H4) and MK-10(H6). The phospholipid profile comprised phosphatidylethanolamine,diphosphatidylglycerol, phosphatidylinositol, phosphatidylglycerol and unknown phosphoglycolipids. The DNA G+C content was 71.4 mol%. A comprehensive analysis ofseveral physiological and biochemical traits and DNA–DNA relatedness indicated that strainK55T was different from closely related species. These phenotypic, genotypic and chemotaxonomic data suggest that strain K55T represents a novel species of the genus Micromonospora, for which the name Micromonospora nickelidurans sp. nov., is proposed. The type strain is K55T (5JCM 30559T5ACCC19713T).

A novel actinobacterial strain, designated strain NEAU-JM2(T), was isolated from volcanic sediment collected from Longwan, Jilin province, north China and characterized using a polyphasic approach. The strain was found to have morphological and chemotaxonomic characteristics typical of the members of the genus Micromonospora. Phylogenetic analysis of the16S rRNA gene sequence also indicated that strain NEAU-JM2(T) should be classified in the genus Micromonospora and showed that close relatives are Micromonospora maoerensis NEAU-MES19(T) (99.5 %) and Micromonospora matsumotoense JCM 9104(T) (98.8 %). However, phylogenetic analysis based on the gyrB gene sequence showed that the isolate forms a separate subclade away from the close relatives in the neighbour-joining tree and also recovered with the maximum-likelihood algorithm. The low level of DNA-DNA relatedness allowed the isolate to be differentiated from M. maoerensis NEAU-MES19(T) and M. matsumotoense JCM 9104(T). Furthermore, strain NEAU-JM2(T) could also be distinguished from its close phylogenetic relatives by cultural and physiological characteristics. Therefore, it is proposed that strain NEAU-JM2(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora vulcania sp. nov. is proposed. The type strain is NEAU-JM2(T) (=CGMCC 4.7144(T) = DSM 46711(T)).

Two novel actinobacteria, strains NEAU-CX1(T) and NEAU-JC6(T), were isolated from nymphs of stinkbug (Palomena viridissima Poda) and a beetle (Harpalus sinicus Hope), respectively, collected from Harbin, Heilongjiang Province, China. A polyphasic study was carried out to establish the taxonomic positions of these strains. The phylogenetic analysis based on 16S rRNA gene sequence of strain NEAU-CX1(T) showed it to be most closely related to Micromonospora coxensis JCM 13248(T) (99.3 % sequence similarity), Micromonospora purpureochromogenes DSM 43821(T) (99.1 %) and Micromonospora halophytica JCM 3125(T) (98.6 %), and that of strain NEAU-JC6(T) to Micromonospora haikouensis DSM 45626(T) (99.3 %), Micromonospora carbonacea JCM 3139(T) (99.1 %) and Micromonospora krabiensis JCM 12869(T) (99.1 %). The phylogenetic analysis based on gyrB gene sequence of strain NEAU-CX1(T) showed it to be most closely related to M. purpureochromogenes DSM 43821(T) (98.0 % sequence similarity), and that of strain NEAU-JC6(T) to M. haikouensis DSM 45626(T) (99.0 %) and M. carbonacea JCM 3139(T) (98.0 %). A combination of DNA-DNA hybridization results and cultural and physiological properties indicated that the two strains can be distinguished from their closest phylogenetic relatives. Thus, strains NEAU-CX1(T) and NEAU-JC6(T) represent two novel species of the genus Micromonospora, for which the names Micromonospora palomenae sp. nov. and Micromonospora harpali sp. nov. are proposed. The type strains are NEAU-CX1(T) (=CGMCC 4.7175(T) = JCM 30056(T)) and NEAU-JC6(T) (=CGMCC 4.7173(T) = JCM 30055(T)).

An endophytic actinobacterial strain, CS1-12(T), was isolated from a leaf of Costus speciosus. Single spores were observed directly on the substrate mycelia. The cell-wall peptidoglycan of this strain exhibited meso-diaminopimelic acid and 3-OH-meso-diaminopimelic acid. Arabinose, glucose, ribose, xylose and rhamnose were detected as whole-cell sugars. The diagnostic phospholipids of this strain were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The predominant menaquinones were MK-10(H6), MK-10(H8), MK-9(H4) and MK-10(H4). The main components of the cellular fatty acids (>10%) were iso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and anteiso-C15 : 0. The G+C content of the genomic DNA was 72.8 mol%. 16S rRNA gene sequence analysis data showed that strain CS1-12(T) should be classified in the genus Micromonospora and that it is closely related to Micromonospora fulviviridis DSM 43906(T) (99.3%). The physiological, biochemical and chemotaxonomic properties, including the DNA-DNA hybridization results, indicated that strain CS1-12(T) could be judged a novel species of the genus Micromonospora , for which the name Micromonospora costi sp. nov. is proposed. The type strain is CS1-12(T) ( =BCC 58124(T) =NBRC 109518(T))., (© 2015 IUMS.)

A novel actinomycete, designated strain NEAU-P5(T), was isolated from dandelion root (Taraxacum mongolicum Hand.-Mazz.). Strain NEAU-P5(T) showed closest 16S rRNA gene sequence similarity to Micromonospora chokoriensis 2-19/6(T) (99.5%), and phylogenetically clustered with Micromonospora violae NEAU-zh8(T) (99.3%), M. saelicesensis Lupac 09(T) (99.0%), M. lupini Lupac 14N(T) (98.8%), M. zeae NEAU-gq9(T) (98.4%), M. jinlongensis NEAU-GRX11(T) (98.3%) and M. zamorensis CR38(T) (97.9%). Phylogenetic analysis based on the gyrB gene sequence also indicated that the isolate clustered with the above type strains except M. violae NEAU-zh8(T). The cell-wall peptidoglycan consisted of meso-diaminopimelic acid and glycine. The major menaquinones were MK-9(H8), MK-9(H6) and MK-10(H2). The phospholipid profile contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The major fatty acids were C(16:0), iso-C(15:0) and C(17:0). Furthermore, some physiological and biochemical properties and low DNA-DNA relatedness values enabled the strain to be differentiated from members of closely related species. Therefore, it is proposed that strain NEAU-P5(T) represents a novel species of the genus Micromonospora, for which the name Micromonospora taraxaci sp. nov. is proposed. The type strain is NEAU-P5(T) (=CGMCC 4.7098(T) = DSM 45885(T)).

The Judicial Commission affirms that the combination Micromonospora aurantiaca Sveshnikova et al. 1969 (Approved Lists 1980) may not serve as the correct name of the taxon because Rule 12b states that no specific or Subspecific epithets within the same genus may be the same if based on different types and the specific epithet aurantiaca in Micromonospora aurantiaca Sveshnikova et al. 1969 (Approved Lists 1980) is the same as the subspecific epithet aurantiaca in Micromonospora carbonacea subsp. aurantiaca Luedemann and Brodsky 1964 (Approved Lists 1980) and the latter has priority. According to Rule 53, the duplication of the same specific or subspecific epithet based on different types creates an illegitimate epithet with the principle of priority determining which is to be replaced as specified in Rule 54. The replacement of the specific epithet aurantiaca in Micromonospora aurantiaca Sveshnikova et al. 1969 (Approved Lists 1980) also requires that the authorship of the original authors is retained. However, action of this nature requires that the original epithet is maintained in the original combination. There currently appears to be no mechanisms where such action can be taken., (IUMS.)

Endophytic microorganisms live inside plants for at least part of their life cycle. According to their life strategies, bacterial endophytes can be classified as "obligate" or "facultative". Reports that members of the genus Micromonospora, Gram-positive Actinobacteria, are normal occupants of nitrogen-fixing nodules has opened up a question as to what is the ecological role of these bacteria in interactions with nitrogen-fixing plants and whether it is in a process of adaptation from a terrestrial to a facultative endophytic life. The aim of this work was to analyse the genome sequence of Micromonospora lupini Lupac 08 isolated from a nitrogen fixing nodule of the legume Lupinus angustifolius and to identify genomic traits that provide information on this new plant-microbe interaction. The genome of M. lupini contains a diverse array of genes that may help its survival in soil or in plant tissues, while the high number of putative plant degrading enzyme genes identified is quite surprising since this bacterium is not considered a plant-pathogen. Functionality of several of these genes was demonstrated in vitro, showing that Lupac 08 degraded carboxymethylcellulose, starch and xylan. In addition, the production of chitinases detected in vitro, indicates that strain Lupac 08 may also confer protection to the plant. Micromonospora species appears as new candidates in plant-microbe interactions with an important potential in agriculture and biotechnology. The current data strongly suggests that a beneficial effect is produced on the host-plant.

Biotic interactions can improve agricultural productivity without costly and environmentally challenging inputs. Micromonospora strains have recently been reported as natural endophytes of legume nodules but their significance for plant development and productivity has not yet been established. The aim of this study was to determine the diversity and function of Micromonospora isolated from Medicago sativa root nodules. Micromonospora-like strains from field alfalfa nodules were characterized by BOX-PCR fingerprinting and 16S rRNA gene sequencing. The ecological role of the interaction of the 15 selected representative Micromonospora strains was tested in M. sativa. Nodulation, plant growth and nutrition parameters were analyzed. Alfalfa nodules naturally contain abundant and highly diverse populations of Micromonospora, both at the intra- and at interspecific level. Selected Micromonospora isolates significantly increase the nodulation of alfalfa by Ensifer meliloti 1021 and also the efficiency of the plant for nitrogen nutrition. Moreover, they promote aerial growth, the shoot-to-root ratio, and raise the level of essential nutrients. Our results indicate that Micromonospora acts as a Rhizobia Helper Bacteria (RHB) agent and has probiotic effects, promoting plant growth and increasing nutrition efficiency. Its ecological role, biotechnological potential and advantages as a plant probiotic bacterium (PPB) are also discussed.

A novel actinomycete, designated strain NEAU-zh8(T), was isolated from a root of Viola philippica Car collected in China and characterized using a polyphasic approach. 16S rRNA gene sequence similarity studies showed that strain NEAU-zh8(T) belongs to the genus Micromonospora, being most closely related to Micromonospora chokoriensis 2-9(6)(T) (99.9 %), Micromonospora saelicesensis Lupac 09(T) (99.3 %) and Micromonospora lupini Lupac 14N(T) (99.0 %). gyrB gene analysis also indicated that strain NEAU-zh8(T) should be assigned to the genus Micromonospora. The cell-wall peptidoglycan consisted of meso-diaminopimelic acid and glycine. The major menaquinones were MK-10(H4), MK-10(H2) and MK-10(H6). The phospholipid profile contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The major fatty acids were iso-C15:0, C16:0 and C17:0 10-methyl. A combination of DNA-DNA hybridization results and some physiological and biochemical properties indicated that strain NEAU-zh8(T) could be readily distinguished from the closest phylogenetic relatives. Therefore, it is proposed that strain NEAU-zh8(T) represents a novel Micromonospora species, for which the name Micromonospora violae sp. nov. is proposed. The type strain is NEAU-zh8(T) (=CGMCC 4.7102(T)=DSM 45888(T)).

A total of 74 actinomycete isolates were cultivated from two marine sponges, Geodia barretti and Phakellia ventilabrum collected at the same spot at the bottom of the Trondheim fjord (Norway). Phylogenetic analyses of sponge-associated actinomycetes based on the 16S rRNA gene sequences demonstrated the presence of species belonging to the genera Streptomyces, Nocardiopsis, Rhodococcus, Pseudonocardia and Micromonospora. Most isolates required sea water for growth, suggesting them being adapted to the marine environment. Phylogenetic analysis of Streptomyces spp. revealed two isolates that originated from different sponges and had 99.7% identity in their 16S rRNA gene sequences, indicating that they represent very closely related strains. Sequencing, annotation, and analyses of the genomes of these Streptomyces isolates demonstrated that they are sister organisms closely related to terrestrial Streptomyces albus J1074. Unlike S. albus J1074, the two sponge streptomycetes grew and differentiated faster on the medium containing sea water. Comparative genomics revealed several genes presumably responsible for partial marine adaptation of these isolates. Genome mining targeted to secondary metabolite biosynthesis gene clusters identified several of those, which were not present in S. albus J1074, and likely to have been retained from a common ancestor, or acquired from other actinomycetes. Certain genes and gene clusters were shown to be differentially acquired or lost, supporting the hypothesis of divergent evolution of the two Streptomyces species in different sponge hosts.