Average Nucleotide Identity Scores Research Articles

Bifidobacterium fermentum sp. nov. and Bifidobacterium aquikefiricola sp. nov., isolated from water kefir.

Four strains, representing two novel Bifidobacterium species, were isolated from water kefir, a fermented beverage. 16S rRNA gene analysis suggested that the novel species share high identities (98.82-98.89%) with Bifidobacterium aquikefiri LMG 28769T. Complete genomes were assembled with a short- and long-read hybrid sequencing approach. In agreement with the 16S rRNA gene analysis, phylogenetics with 117 marker genes places the novel species closest to B. aquikefiri LMG 28769T as well. The isolates have average nucleotide identity (ANI) scores ranging from 81.46 to 84.84% and digital DNA-DNA hybridization (dDDH) scores from 23.9 to 38.5% with the closest related species, as well as ANI scores between the proposed new species of 80.50%, indicating that the isolates represent two novel species. Matrix-assisted laser desorption/ionization-time of flight chemotaxonomic analysis supported the gene-based taxonomic placement. We propose the names Bifidobacterium fermentum sp. nov. and Bifidobacterium aquikefiricola sp. nov. for these novel species within the Bifidobacterium genus. The proposed type strain B. fermentum WK012_4_13T (= LMG 33104T = DSM 116073T; GenBank accession number GCF_041080835.1) has a genome size of 2.43 Mbp, with a G+C content of 56.00 mol%. The proposed type strain for B. aquikefiricola WK041_4_12T (= LMG 33105T = DSM 116074T; GenBank accession number GCF_041080795.1) has a genome size of 2.36 Mbp and a G+C content of 53.94 mol%. B. fermentum cells are Gram-positive staining, non-motile, non-spore-forming, fructose-6-phosphate phosphoketolase (F6PPK)-positive, catalase- and oxidase-negative and bacillary club shaped. B. aquikefiricola cells are Gram-positive staining, non-motile, non-spore-forming, F6PPK-positive, catalase- and oxidase-negative and square rod shaped.

Discovery of two new actinobacteria, Micromonospora palythoicola sp. nov. and Streptomyces poriticola sp. nov., isolated from marine invertebrates

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 S2-005T = TBRC 18343T and NBRC 116545T) and Streptomyces poriticola sp. nov. (strain C6-003T, =TBRC 17807T and NBRC 116425T). 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 C6-003T displayed significant antimicrobial activity and selective cytotoxicity against human breast cancer MCF-7 cells, with reduced toxicity towards human dermal papilla cells. Micromonospora palythoicola S2-005T 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.

Aquimarina aquimarini sp. nov. and Aquimarina spinulae sp. nov., novel bacterial species with versatile natural product biosynthesis potential isolated from marine sponges.

This study describes two Gram-negative, flexirubin-producing, biofilm-forming, motile-by-gliding and rod-shaped bacteria, isolated from the marine sponges Ircinia variabilis and Sarcotragus spinosulus collected off the coast of Algarve, Portugal. Both strains, designated Aq135T and Aq349T, were classified into the genus Aquimarina by means of 16S rRNA gene sequencing. We then performed phylogenetic, phylogenomic and biochemical analyses to determine whether these strains represent novel Aquimarina species. Whereas the closest 16S rRNA gene relatives to strain Aq135T were Aquimarina macrocephali JAMB N27T (97.8 %) and Aquimarina sediminis w01T (97.1 %), strain Aq349T was more closely related to Aquimarina megaterium XH134T (99.2 %) and Aquimarina atlantica 22II-S11-z7T (98.1 %). Both strains showed genome-wide average nucleotide identity scores below the species level cut-off (95 %) with all Aquimarina type strains with publicly available genomes, including their closest relatives. Digital DNA-DNA hybridization further suggested a novel species status for both strains since values lower than 70 % hybridization level with other Aquimarina type strains were obtained. Strains Aq135T and Aq349T grew from 4 to 30°C and with between 1-5 % (w/v) NaCl in marine broth. The most abundant fatty acids were iso-C17 : 03-OH and iso-C15 : 0 and the only respiratory quinone was MK-6. Strain Aq135T was catalase-positive and β-galactosidase-negative, while Aq349T was catalase-negative and β-galactosidase-positive. These strains hold unique sets of secondary metabolite biosynthetic gene clusters and are known to produce the peptide antibiotics aquimarins (Aq135T) and the trans-AT polyketide cuniculene (Aq349T), respectively. Based on the polyphasic approach employed in this study, we propose the novel species names Aquimarina aquimarini sp. nov. (type strain Aq135T=DSM 115833T=UCCCB 169T=ATCC TSD-360T) and Aquimarina spinulae sp. nov. (type strain Aq349T=DSM 115834T=UCCCB 170T=ATCC TSD-361T).

Spirochaete genome identified in red abalone sample represents a novel genus Candidatus Haliotispira gen. nov. within the order Spirochaetales.

A fully assembled spirochaete genome was identified as a contaminating scaffold in our red abalone (Haliotis rufescens) genome assembly. In this paper, we describe the analysis of this bacterial genome. The assembled spirochaete genome is 3.25 Mb in size with 48.5 mol% G+C content. The proteomes of 38 species were compared with the spirochaete genome and it was discovered to form an independent branch within the family Spirochaetaceae on the phylogenetic tree. The comparison of 16S rRNA sequences and average nucleotide identity scores between the spirochaete genome with known species of different families in Spirochaetia indicate that it is an unknown species. Further, the percentage of conserved proteins compared to neighbouring taxa confirm that it does not belong to a known genus within Spirochaetaceae. We propose the name Candidatus Haliotispira prima gen. nov., sp. nov. based on its taxonomic placement and origin. We also tested for the presence of this species in different species of abalone and found that it is also present in white abalone (Haliotis sorenseni). In addition, we highlight the need for better classification of taxa within the class Spirochaetia.

Xanthomonas citri pv. citri Findings in Citrus Fruits Imported in the Netherlands

Xanthomonas citri pv. citri and pv. aurantifolii are responsible for citrus bacterial canker. The trade of citrus fruit is recognized as one of the seven X. citri pv. citri introduction pathways. Under the current European Union phytosanitary measures, the likelihood of these X. citri pathovars being introduced into the Mediterranean region via infected fruit is rated as unlikely. To closely monitor the commercial trade flow of citrus fruit, imported lots that contained fruits with citrus bacterial canker symptoms were quarantined, and a sample was sent for laboratory analysis. Survey results revealed the presence of viable and highly pathogenic X. citri pv. citri isolates in 97 infected lots between 2013 and 2022, whereas X. citri pv. aurantifolii was never found. These X. citri pv. citri-infected lots primarily concerned Citrus latifolia (64), C. hystrix (17), and C. grandis (11) fruits, mainly from South America but also from several Asian countries. Additionally, a genetic characterization of these X. citri pv. citri isolates demonstrated that, although they originated from different countries, years, and Citrus species, they were all highly related, with average nucleotide identity scores ranging from 99.98 to 100%. These intercepted lots containing symptomatic citrus fruits due to the presence of X. citri pv. citri underlines the importance of continued vigilance by both the exporting and importing countries. Import inspections of the citrus fruit trade flow for the presence of citrus bacterial canker symptoms and subsequent laboratory testing remain significant tools for assessing the long-distance dispersal of X. citri pv. citri.

Halocynthiibacter halioticoli sp. nov., isolated from the viscera of abalone Haliotis discus hannai.

A Gram-stain-negative, rod-shaped, glide, non-flagellated, and facultatively anaerobic bacterial strain, designated as Z654T, was isolated from the gut of abalone Haliotis discus hannai from Rongcheng, Shandong province, China. Cells are 0.2-0.8μm in width and 0.7-3.4μm in length. Cells grew best at 30°C (range, 15-37°C), pH 7.0 (range, 6.0-8.5) and NaCl concentration of 2.0% (w/v) (range, 1-10%). According to the phylogenetic analysis of 16S rRNA gene sequence, the strain belongs to the genus Halocynthiibacter and the closest strain is Halocynthiibacter arcticus KCTC 42129T (97.12%). The genome size of strain Z654T was 3,296,250bp and the DNA G + C content was 54.2mol%. The average nucleotide identity (ANI) scores and digital DNA-DNA hybridization (dDDH) scores with H. arcticus KCTC 42129T were 70% and 14.6-18.2%, respectively. The predominant quinone was Q-10 and the major fatty acids were C18:0, C18:1 ω7c 11-methyl and summed feature 8. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, unidentified aminolipid and unidentifed lipids. Based on the phenotypic, phylogenetic and chemotaxonomic data, strain Z654T was considered to represent a novel species of the genus Halocynthiibacter, for which the name Halocynthiibacte halioticoli sp. nov., is proposed. The type strain is Z654T (= MCCC 1H00503T = KCTC 92003T).

Genome-Wide Comparative Analysis of Lactiplantibacillus pentosus Isolates Autochthonous to Cucumber Fermentation Reveals Subclades of Divergent Ancestry.

Lactiplantibacillus pentosus, commonly isolated from commercial cucumber fermentation, is a promising candidate for starter culture formulation due to its ability to achieve complete sugar utilization to an end pH of 3.3. In this study, we conducted a comparative genomic analysis encompassing 24 L. pentosus and 3 Lactiplantibacillus plantarum isolates autochthonous to commercial cucumber fermentation and 47 lactobacillales reference genomes to determine species specificity and provide insights into niche adaptation. Results showed that metrics such as average nucleotide identity score, emulated Rep-PCR-(GTG)5, computed multi-locus sequence typing (MLST), and multiple open reading frame (ORF)-based phylogenetic trees can robustly and consistently distinguish the two closely related species. Phylogenetic trees based on the alignment of 587 common ORFs separated the L. pentosus autochthonous cucumber isolates from olive fermentation isolates into clade A and B, respectively. The L. pentosus autochthonous clade partitions into subclades A.I, A.II, and A.III, suggesting substantial intraspecies diversity in the cucumber fermentation habitat. The hypervariable sequences within CRISPR arrays revealed recent evolutionary history, which aligns with the L. pentosus subclades identified in the phylogenetic trees constructed. While L. plantarum autochthonous to cucumber fermentation only encode for Type II-A CRISPR arrays, autochthonous L. pentosus clade B codes for Type I-E and L. pentosus clade A hosts both types of arrays. L. pentosus 7.8.2, for which phylogeny could not be defined using the varied methods employed, was found to uniquely encode for four distinct Type I-E CRISPR arrays and a Type II-A array. Prophage sequences in varied isolates evidence the presence of adaptive immunity in the candidate starter cultures isolated from vegetable fermentation as observed in dairy counterparts. This study provides insight into the genomic features of industrial Lactiplantibacillus species, the level of species differentiation in a vegetable fermentation habitat, and diversity profile of relevance in the selection of functional starter cultures.

Cellulosimicrobium fucosivorans is a later heterotypic synonym of Cellulosimicrobium composti.

The taxonomic relationship of Cellulosimicrobium fucosivorans SE3T and Cellulosimicrobium composti BIT-GX5T was re-evaluated. The type strains of the two species shared 99.9 % 16S rRNA gene sequence similarity, and whole genome sequence comparisons showed that the two species shared a 86.3 % digital DNA‒DNA hybridization (dDDH) value, a 98.5 % average nucleotide identity (ANI) score and a 98.2 % average amino acid identity (AAI) value. These values were higher than the recommend novel species recognition threshold values of 16S rRNA gene similarity of 98.6 %, dDDH cutoff value of 70 %, and ANI and AAI cutoff values of 95-96 %. In addition, the phylogenetic tree based on the 16S rRNA gene sequences as well as the phylogenomics tree based on whole genomes supported these two strains being closely related. Based on the principle of priority, we propose that Cellulosimicrobium fucosivorans is a later heterotypic synonym of Cellulosimicrobium composti.

Brenneria bubanii sp. nov., isolated from decaying plant tissues.

Gram-negative, motile, rod-shaped bacterial strains (designated 4F2T and Kf) were isolated from decaying tissues of various deciduous tree species. Phylogenetic analyses based on their 16S rRNA gene sequences showed that the novel isolates belong to the genus Brenneria and showed highest (98.3 %) sequence similarity to Brenneria goodwinii. Isolate 4F2T formed a separate branch on the phylogenetic tree based on concatenated sequences of four housekeeping genes or whole genome sequences, clearly separate from Brenneria goodwinii, suggesting that novel isolates should belong to a novel species. Orthologous average nucleotide identity scores and in silico DNA-DNA hybridization values between isolate 4F2T and type strains of other species in the genus Brenneria were less than 85 and 30 %, respectively, significantly lower than the species boundary cut-off values (95 and 70 %). A negative reaction for β-galactosidase, the ability to use dextrin and maltose as carbon sources, and an inability to use lactose are the main phenotypic characteristics that can be used to differentiate the novel isolates from B. goodwinii. Based on phenotypic and genotypic characteristics, isolates 4F2T and Kf belong to a novel species of the genus Brenneria, for which the name Brenneria bubanii sp. nov. is proposed. The type strain is 4F2T (=NCAIM B 02661T=LMG 32183T).

Cryobacterium zhongshanensis sp. nov., an actinobacterium isolated from Antarctic soil.

A Gram-staining-positive, heterotrophic, non-spore-forming, non-motile, rod-shaped, strain ZS14-85T belonging to the genus Cryobacterium was isolated from soil in Antarctica. Growth was observed in the presence of 0-2% (w/v) NaCl, at pH 7.0-9.0 (optimum, pH 7.0) and 4-30 ℃ (optimum, 20 ℃). Phylogenetic analysis showed that strain ZS14-85T formed a lineage in the genus Cryobacterium. The digital DNA-DNA hybridization (dDDH) values between strain ZS14-85T and its close relatives Cryobacterium psychrotolerans CGMCC 1.5382T, Cryobacterium soli MCCC 1K03549T and Cryobacterium breve NBRC113800T were 22.5, 22.3 and 22.2%, respectively. Orthologous Average Nucleotide Identity (OrthoANI) scores between strain ZS14-85T and C. psychrotolerans CGMCC 1.5382T, C. breve NBRC 113800T and C. soli MCCC1K03549T were 78.7, 78.1 and 77.7%, respectively. The polar lipids of strain ZS14-85T were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), one unidentified glycolipid (GL) and two unidentified lipids (L). The major fatty acids were anteiso-C15:0 (60.7%), iso-C16:0 (17.0%) and anteiso-C17:0 (15.2%). MK-10, MK-11 and MK-9 were the predominant respiratory menaquinones. Based on phenotypic, phylogenetic and genotypic data, a novel species, Cryobacterium zhongshanensis sp. nov. is proposed. The type strain is ZS14-85T (= CCTCC AB 2019396T = KCTC 49384T).

Actinotalea soli sp. nov., isolated from Kubuqi Desert soil.

A Gram-stain positive, facultatively anaerobic, motile rod-shaped strain, BY-33T, was isolated from a soil sample obtained from the Kubuqi Desert, PR China. Phylogenetic analysis based on 16S rRNA gene sequence similarity revealed that strain BY-33T was most closely related to the genus Actinotalea, including Actinotalea ferrariae CF5-4T (98.2 % similarity), 'Actinotalea subterranea' HO-Ch2T (98.0 %), Actinotalea solisilvae THG-T121T (97.6 %), 'Actinotalea bogoriensis' 69B4T (97.5 %), Actinotalea fermentans MT (97.3 %) and 'Actinotalea carbonis' T26T (97.0 %). The strain grew at 0‒37 °C (optimum, 28-30 °C) and pH 6.0-11.0 (optimum, pH 9.0-10.0) and with 0‒8.0 % (w/v) NaCl (optimum, 3.0%) on tryptic soy agar. It had catalase activity, but no oxidase activity. The polar lipids of strain BY-33T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannosides. The major respiratory quinone of strain BY-33T was MK-10 (H4). Its major fatty acids were anteiso-C15 : 0, anteiso-C15 : 1 A and C16 : 0. The genomic DNA G+C content of strain BY-33T was 73.0 mol% based on total genome calculations. The average nucleotide identity scores between the genomic sequences of strain BY-33T and the other species of the genus Actinotalea were found to be low (ANIm <85.0 %, ANIb <77.0 % and OrthoANIu <78.0 %). Furthermore, the digital DNA-DNA hybridization and average amino acid identity values between strain BY-33T and the closely related species ranged from 20.5 to 21.0% and from 62.2 to 72.2 %, respectively. Based on the results of phylogenetic, phenotypic, genotypic and chemotaxonomic analyses, it is concluded that strain BY-33T represents a novel species within the genus Actinotalea, for which the name Actinotalea soli sp. nov. is proposed. The type strain is BY-33T (=CGMCC 1.17460T=KCTC 49362T).

Genome based classification of Streptomyces sp. SUK 48 from fruit of Brasilia sp.

Streptomyces is a filamentous bacteria genus belonging to the Streptomycetaceae family and there are a lot of different species Streptomyces of that have been discovered. Streptomyces sp. SUK 48 is an endophytic bacteria which found in a fruit of Brasilia sp. that located at UKM reserved forest known as Bangi Reserved Forest [1]. This study was conducted to determine the classification of Streptomyces sp. SUK 48 isolated from fruit of Brasilia sp. tree, in genome perspectives [2]. In specific, the objectives of this study were to construct phylogenetic tree for Streptomyces SUK 48, compare genome Streptomyces SUK 48 with other related Streptomyces species genome using bioinformatic tools that can do phylogenomic research and determine Average Nucleotide Identity (ANI) score of Streptomyces sp. SUK 48 as compared to others Streptomyces spp. Based on phylogenetic analysis, Streptomyces SUK 48 have high similarities with Streptomyces malaysiense MUSC 136 with 99.65% pairwise similarity which obtained from BLASTN analysis. While, phylogenomic analysis showed Streptomyces SUK 48 has high similarity with Streptomyces murinus that observed in phylogenomic tree GToTree (Figure 1). Based on the ANI score, it shows that Streptomyces SUK 48 have similarities of 94.14% with Streptomyces murinus from the phylogenomics analysis (Table 1).&#x0D; In conclusion, Streptomyces SUK 48 is a potential novel isolated species.&#x0D;

Metabacillus rhizolycopersici sp. nov., Isolated from the Rhizosphere Soil of Tomato Plants.

A Gram-positive, endospore-forming, rod-shaped and aerobic bacterium, with swarming and swimming motility, designated strain DBTR6T, was isolated from the rhizosphere soil of tomato plants. Strain DBTR6T grew at 20-45℃ (optimum 30-37℃), pH 4-9 (optimum 7-8) and at salinities from 0 to 5% (optimum 1%). Phylogenetic analysis using 16S rRNA gene sequences showed this strain belonged to the genus Metabacillus and was most closely related to Metabacillus litoralis DSM 16303T (98.3%) and Metabacillus sediminilitoris MCCC 1K03777T (98.3%). The DNA G + C content of the genomic DNA was 36.4%. The digital DNA-DNA hybridization value between strain DBTR6T and reference strains M. sediminilitoris MCCC 1K03777T and "M. bambusae" BG109T were less than 70% (26.7% and 26.0%), and the average nucleotide identity score were less than 95% (78.55% and 78.38%), and the Amino Acid Identity values calculated were less than 96% (79.99% and 80.18%), respectively, suggesting that strain DBTR6T represented a novel species in the genus Metabacillus. Chemotaxonomic analysis showed that strain DBTR6T contained MK-7 as the major respiratory quinone. The predominant fatty acids (> 10.0%) were iso-C15:0, anteiso-C15:0 and C16:0. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), glycolipids (GL) and three unidentified lipids (L). Based on the differential physiological properties, biochemical characteristics and genotypic data, strain DBTR6T represents a novel species of the genus Metabacillus, for which the name Metabacillus rhizolycopersici sp. nov. is proposed. The type strain is DBTR6T (= ACCC 61900T = JCM 35080T).

Streptomyces benahoarensis sp. nov. Isolated From a Lava Tube of La Palma, Canary Islands, Spain.

Two Streptomyces strains, labeled as MZ03-37T and MZ03-48, were isolated from two different samples, a mucolite-type speleothem and a microbial mat on the walls of a lava tube from La Palma Island (Canary Islands). Phylogenetic analysis based on concatenated sequences of six housekeeping genes indicated that both strains belonged to the same species. The closest relatives for both strains were Streptomyces palmae CMU-AB204T (98.71%), Streptomyces catenulae NRRL B-2342T (98.35%), and Streptomyces ramulosus NRRL B-2714T (98.35%). Multi-locus sequence analysis (MLSA), based on five house-keeping gene alleles (i.e., atpD, gyrB, recA, rpoB, and trpB), indicated that both isolated strains were closely related to S. catenulae NRRL B-2342T. Whole-genome average nucleotide identity (ANI) scores of both strains were in the threshold value for species delineation with the closest species. Both strains presented a G+C content of 72.1 mol%. MZ03-37T was light brown in substrate and white in aerial mycelium, whereas MZ03-48 developed a black aerial and substrate mycelium. No pigment diffusion was observed in both strains. They grew at 10°C−37°C (optimum 28°C−32°C) and in the presence of up to 15% (w/v) NaCl. MZ03-37T grew at pH 5–10 (optimal 6–9), whereas MZ03-48 grew at pH 4–11 (optimal 5–10). LL-Diaminopimelic acid was the main diamino acid identified. The predominant fatty acids in both strains were iso-C16:0, anteiso-C15:0, C16:0, and iso-C14:0. The major isoprenoid quinones were MK-9(H6) and MK-9(H8), and the main polar lipids were aminolipid, phospholipid, and phosphoglycolipid. In silico analyses for functional annotation predicted the presence of gene clusters involved in resistome mechanisms and in the synthesis of described antimicrobials such as linocin-M18 and curamycin, as well as different genes likely involved in mechanisms for active compound synthesis, both already described and not discovered so far. On the basis of their phylogenetic relatedness and their phenotypic and genotypic features, the strains MZ03-37T and MZ03-48 represented a novel species within the genus Streptomyces, for which the name Streptomyces benahoarensis sp. nov. is proposed. The type strain is MZ03-37T (= CECT 9805 = DSMZ 8002); and MZ03-48 (= CECT 9806 = DSMZ 8011) is a reference strain.

Nocardia noduli sp. nov., a novel actinobacterium with biotechnological potential

A genome-based polyphasic study was undertaken to establish the taxonomic status of an actinobacterium strain isolated from an actinorhizal root nodule. Strain ncl1T was found to have chemotaxonomic, cultural and morphological properties characteristic of members of the genus Nocardia. The strain was closely related to Nocardia aurea in the phylogenetic trees based on 16S rRNA gene and genome sequences. The draft genome of the strain is 8.9 Mbp in size, has a genomic DNA G + C content of 67.0% and was predicted to contain at least 19 biosynthetic gene clusters encoding for specialized metabolites. Strain ncl1T was distinguished from its closest neighbour, N. aurea DSM 103986T, by a broad range of phenotypic properties and by low average nucleotide identity and digital DNA-DNA hybridization scores. Consequently, the strain represents a novel Nocardia species for which the name Nocardia noduli sp. nov. is proposed. The type strain is ncl1T (CECT 30123T = DSM 110878T). The present study provides further evidence that actinorhizal nodules are a source of novel species of Nocardia.

Genome Characterisation of an Isoprene-Degrading Alcaligenes sp. Isolated from a Tropical Restored Forest.

Simple SummaryIsoprene, a volatile hydrocarbon, is the second most abundantly produced climate-active gas, with largely indirect detrimental impacts, such as extending the residence time of the greenhouse gas methane. Isoprene is mainly emitted by plants and can be consumed by a range of microbes inhabiting diverse environments, including soil. Here, the ability of soil bacteria to degrade isoprene was investigated. Soil samples were taken from beneath wild Himalayan cherry trees in a tropical restored forest area, and an Alcaligenes sp. (strain 13f) was isolated. This isolate used isoprene as a sole source of carbon and energy (32.6% of isoprene was consumed in 18 days). A surprising finding from the genome analysis of Alcaligenes sp. strain 13f was that the well-characterised genes and genetic organisation typical of other isoprene-degrading bacteria were not observed. Thus, we propose that this strain uses a different metabolic pathway for isoprene degradation.Isoprene is a climate-active biogenic volatile organic compound (BVOC), emitted into the atmosphere in abundance, mainly from terrestrial plants. Soil is an important sink for isoprene due to its consumption by microbes. In this study, we report the ability of a soil bacterium to degrade isoprene. Strain 13f was isolated from soil beneath wild Himalayan cherry trees in a tropical restored forest. Based on phylogenomic analysis and an Average Nucleotide Identity score of >95%, it most probably belongs to the species Alcaligenes faecalis. Isoprene degradation by Alcaligenes sp. strain 13f was measured by using gas chromatography. When isoprene was supplied as the sole carbon and energy source at the concentration of 7.2 × 105 ppbv and 7.2 × 106 ppbv, 32.6% and 19.6% of isoprene was consumed after 18 days, respectively. Genome analysis of Alcaligenes sp. strain 13f revealed that the genes that are typically found as part of the isoprene monooxygenase gene cluster in other isoprene-degrading bacteria were absent. This discovery suggests that there may be alternative pathways for isoprene metabolism.

Arthrobacter terrae sp. nov., a psychrophilic actinobacterium with multi copies of capA gene isolated from Antarctic soil.

A Gram-staining-positive, non-spore-forming, non-flagellated, ellipsoidal, strain Z1-20T belonging to the genus Arthrobacter was isolated from a soil sample collected from the Zhongshan station, Antarctic. Phylogenetic analysis of the 16S rRNA gene sequences and phylogenetic analysis revealed that strain Z1-20T formed a unique single cluster in the genus Arthrobacter and shared high 16S rRNA sequence similarities of 97.1% and 96.9% with A. glacialis HLT2-12-2T and A. psychrochitiniphilus GP3T, respectively. Values of Digital DNA-DNA hybridization (dDDH) between strain Z1-20T against A. glacialis HLT2-12-2T and A. psychrochitiniphilus GP3T were 20.3% and 13.8%, respectively. Average nucleotide identity (ANI) score between strain Z1-20T against A. glacialis HLT2-12-2T and A. psychrochitiniphilus GP3T were 72.5% and 72.1%, respectively. Genes for the synthesis of the osmoprotectant glycine betaine and higher copies of capA gene encoding cold shock protein were found in genome of Z1-20T that may help Z1-20T in cold-adaptation. Strain Z1-20T comprised lysine as the diagnostic diamino acid. Based on the results of phylogenetic, phenotypic and chemotaxonomic features, strain Z1-20T represents a novel species of a novel taxon of genus Arthrobacter, for which the name Arthrobacter terrae gen. nov., sp. nov. is proposed.

Sutcliffiella deserti sp. nov., isolated from desert soil.

A Gram-stain-positive, facultative anaerobic, motile and rod-shaped bacterial strain, DG-18T, was isolated from desert soil sampled at the Kubuqi Desert in Inner Mongolia, China. Strain DG-18T grew at 4-40 °C (optimum, 25-30 °C), at pH 8.0-10.0 (optimum, pH 9.0) and with 0-8.0 % (w/v) NaCl (optimum 2.0%). 16S rRNA gene sequence analysis placed strain DG-18T within the genus Sutcliffiella of the family Bacillaceae with Sutcliffiella halmapala DSM 8723T (98.2%), Sutcliffiella zhanjiangensis JSM 099021T (97.6%), Sutcliffiella horikoshii DSM 8719T (97.4%), Sutcliffiella catenulata 18CT (96.6 %) and Sutcliffiella cohnii NBRC 15565T (96.5%) as its closest relatives. The major respiratory quinone of strain DG-18T was MK-7 and the major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Its major fatty acids were iso-C15 : 0 and iso-C17 : 1 ω10c. The genomic DNA G+C content of strain DG-18T was 38.7 mol% based on total genome calculations. The average nucleotide identity score between the genomic sequence of strain DG-18T and that of S. halmapala DSM 8723T was 76.7 %. The Genome-to-Genome Distance Calculator showed that the DNA-DNA hybridization value for strain DG-18T and S. halmapala DSM 8723T was 21.8%. Based on the polyphasic taxonomic data, strain DG-18T represents a novel species of the genus Sutcliffiella, for which the name Sutcliffiella deserti sp. nov. is proposed. The type strain is DG-18T (=GDMCC 1.17773T=KCTC 43170T).

Lacisediminihabitans changchengi sp. nov., an actinobacterium isolated from Antarctic swamplands mud.

A Gram-staining-positive, heterotrophic, non-spore-forming, non-motile, short rod-shaped, strain G11-30T belonging to the genus Lacisediminihabitans was isolated from a swampland mud in Antarctica. The strain was identified using a polyphasic taxonomic approach. The strain grew well on R2A agar media and formed no aerial mycelia and no diffusible pigments on any media tested. The chemotaxonomic results showed 2, 4-diaminobutyric acid (DAB) is the diagnostic diamino acid of the peptidoglycan. MK-10 was the predominant respiratory menaquinone. The major phospholipids were phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), unidentified lipid (L) and unidentified glycolipid (GL). The major fatty acids were anteiso-C15:0 (64.5%) and iso-C15:0 (18.7%). A phylogenetic tree based on 16S rRNA gene sequences showed that strain G11-30T formed a lineage in the genus Lacisediminihabitans with the closest phylogenetic Lacisediminihabitans profunda CHu50b-6-2T and Glaciihabitans tibetensis MP203T (97.9%, 97.5% 16S rRNA gene sequence similarity). A phylogenomic tree based on genome sequence of G11-30T, conferred by Type Strain Genome Server (TYGS), separated it from L. profunda CHu50b-6-2T. Strain G11-30T has a complete genome size of 2.59Mb, with a G + C content of 66.2mol%. The digital DNA-DNA hybridization (dDDH) score between strain G11-30T and reference strains L. profunda CHu50b-6-2T and G. tibetensis MP203T were 20.1 and 20.3%, respectively. Concurrently, Average Nucleotide Identity (ANI) score between strain G11-30T against. profunda CHu50b-6-2T and G. tibetensis MP203T were 76.2 and72.5%, respectively. Based on phenotypic, phylogenetic and genotypic data, a novel species, Lacisediminihabitans changchengi sp. nov. is proposed. The type strain is G11-30T (= CCTCC AA 2019080T = KCTC49359T).

Winogradskyella marina sp. nov., isolated from marine sediment.

A Gram-stain-negative, rod-shaped (0.3-0.6 × 0.9-2.2µm), facultatively aerobic, non-motile and yellow-coloured bacterium, designated strain F6397T, was isolated from a marine sediment in Weihai, PR China. Growth of strain F6397T occurred at 4-37°C (optimum, 30-33°C), pH 6.0-9.0 (optimum, 7.5) and in the presence of 1-12% (optimum, 3.0%) (w/v) NaCl. Strain F6397T showed oxidase- and catalase-positive activities. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the strain was assigned to the genus Winogradskyella. Strain F6397T exhibited 95.5-98.1% sequence similarities to recognized species of the genus Winogradskyella. The average nucleotide identity (ANI) scores with Winogradskyella ludwigii HL116T, Winogradskyella litoriviva KMM 6491T and Winogradskyella thalassocola KMM 3907T were 80.1, 78.9 and 82.6%, respectively. The digital DNA-DNA hybridization (dDDH) scores were 23.5, 22.9 and 25.7%, respectively. The genomic DNA G + C content was 33.5mol%. Strain F6397T contained iso-C15:0, iso-C15:1G, iso-C15:0 3-OH and iso-C17:0 3-OH as the predominant fatty acid and MK-6 as the predominant menaquinone. The polar lipid profiles contained phosphatidylethanolamine, three unidentified aminolipids and four unidentified lipids. On the basis of the evidence presented in this study, strain F6397T is considered to represent a novel species of the genus Winogradskyella, for which the name Winogradskyella marina sp. nov. is proposed. The type strain is F6397T (= KCTC 82422T = MCCC 1H00438T).