Closest Phylogenetic Neighbours Research Articles

Novel oceanic cyanobacterium isolated from Bangaram island with profound acid neutralizing ability is proposed as Leptolyngbya iicbica sp. nov. strain LK

An acid-neutralizing, filamentous, non-heterocytous, marine cyanobacterium named 'LK' has been isolated from the seashore of Bangaram Island, an atoll of Lakshadweep, India, and is described here as a novel species. LK has been characterized using morphological, ecological, and genomic features. Based on 16S rRNA, whole-genome sequencing, and marker gene-based analysis, LK has been identified as a new species. LK clustered with Leptolyngbya-like strains belonging to the LPP group but diverged from Leptolyngbya sensu stricto, indicating the polyphyletic nature of the Leptolyngbya genus. Leptolyngbya sp. SIOISBB and Halomicronema sp. CCY15110 were identified as LK's two closest phylogenetic neighbors in various phylogenetic studies. The analysis of 16S rRNA, ITS secondary structures, and genome relatedness indices such as AAI, ANI, and gANI strongly support LK as a novel species of the Leptolyngbya genus. The mechanism behind acid neutralization in LK has been delineated, attributing it to a surface phenomenon most likely due to the presence of salts of calcium, magnesium, sodium, and potassium. We name LK as Leptolyngbya iicbica strain LK which is a novel species with prominent acidic pH-neutralizing properties.

Comparative genomics of plant growth promoting phosphobacteria isolated from acidic soils.

Despite being one of the most abundant elements in soil, phosphorus (P) often becomes a limiting macronutrient for plants due to its low bioavailability, primarily locked away in insoluble organic and inorganic forms. Phosphate solubilizing and mineralizing bacteria, also called phosphobacteria, isolated from P-deficient soils have emerged as a promising biofertilizer alternative, capable of converting these recalcitrant P forms into plant-available phosphates. Three such phosphobacteria strains-Serratia sp. RJAL6, Klebsiella sp. RCJ4, and Enterobacter sp. 198-previously demonstrated their particular strength as plant growth promoters for wheat, ryegrass, or avocado under abiotic stresses and P deficiency. Comparative genomic analysis of their draft genomes revealed several genes encoding key functionalities, including alkaline phosphatases, isonitrile secondary metabolites, enterobactin biosynthesis and genes associated to the production of indole-3-acetic acid (IAA) and gluconic acid. Moreover, overall genome relatedness indexes (OGRIs) revealed substantial divergence between Serratia sp. RJAL6 and its closest phylogenetic neighbours, Serratia nematodiphila and Serratia bockelmanii. This compelling evidence suggests that RJAL6 merits classification as a novel species. This in silico genomic analysis provides vital insights into the plant growth-promoting capabilities and provenance of these promising PSRB strains. Notably, it paves the way for further characterization and potential application of the newly identified Serratia species as a powerful bioinoculant in future agricultural settings.

Anaerolentibacter hominis gen. nov. sp. nov., Diplocloster hominis sp. nov. and Pilosibacter fragilis gen. nov. sp. nov., isolated from human faeces.

Three Gram-positive, obligately anaerobic bacterial strains, namely CSJ-1T, CSJ-3T, and CSJ-4T, were isolated from faeces of healthy persons. They were characterized through a combination of whole-genome sequencing, phenotypic traits, and metabolomic analysis. The genome sizes of CSJ-1T, CSJ-4T, and CSJ-3T were 3.3, 3.8, and 6.1 Mbp, with DNA G+C contents of 47.2, 48.3, and 48.8 mol%, respectively. Strain CSJ-3T was identified as representing a novel species, Diplocloster hominis (type strain CSJ-3T=CGMCC 1.18033T=JCM 36512T) of the genus Diplocloster. The 16S rRNA gene sequence similarity and whole genome average nucleotide identity (gANI) of CSJ-4T to its closest related species, Diplocloster modestus ASD 4241T, were 98.3 and 91.4 %, respectively. Comparative analysis of 16S rRNA gene sequences showed 91.6 % similarity between CSJ-1T and its closest phylogenetic neighbour, Catenibacillus scindens DSM 106146T, and 93.3 % similarity between CSJ-4T and its closest relative strain, Clostridium fessum SNUG30386T. Based on the polyphasic taxonomic results, we proposed two novel genera and three novel species. Strain CSJ-1T was identified as representing a novel species of novel genus, Anaerolentibacter hominis gen. nov. sp. nov. (type strain CSJ-1T=CGMCC 1.18046T=JCM 36511T) of the family Lachnospiraceae, and strain CSJ-4T was identified as representing a novel species of novel genus Pilosibacter fragilis gen. nov. sp. nov. (type strain CSJ-4T=CGMCC 1.18026T= JCM 36513T) of the family Clostridiaceae.

Aquincola agrisoli sp. nov., isolated from rhizospheric soil of eggplant and in silico genome mining for the prediction of biosynthetic gene clusters.

A Gram-stain negative, aerobic, rod-shaped, motile and flagellated novel bacterial strain, designated MAHUQ-54T, was isolated from the rhizospheric soil of eggplant. The colonies were observed to be light pink coloured, smooth, spherical and 0.2-0.6 mm in diameter when grown on R2A agar medium for 2 days. MAHUQ-54T was able to grow at 15-40 °C, at pH 5.5-9.0 and in the presence of 0-0.5 % NaCl (w/v). The strain gave positive results for both catalase and oxidase tests. The strain was positive for hydrolysis of l-tyrosine, urea, Tween 20 and Tween 80. On the basis of the results of 16S rRNA gene sequence comparisons, the isolate was identified as a member of the genus Aquincola and is closely related to Aquincola tertiaricarbonis L10T (98.8 % sequence similarity) and Leptothrix mobilis Feox-1T (98.2 %). MAHUQ-54T has a draft genome size of 5 994 516 bp (60 contigs), annotated with 5348 protein-coding genes, 45 tRNA and 5 rRNA genes. The average nucleotide identity (ANI) and digital DNA-DNA hybridisation (dDDH) values between MAHUQ-54T and its closest phylogenetic neighbours were 75.8-83.3 and 20.8-25.3 %, respectively. In silico genome mining revealed that MAHUQ-54T has a significant potential for the production of novel natural products in the future. The genomic DNA G+C content was determined to be 70.4 %. The predominant isoprenoid quinone was ubiquinone-8. The major fatty acids were identified as C16 : 0, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). On the basis of dDDH, ANI value, genotypic analysis, chemotaxonomic and physiological data, strain MAHUQ-54T represents a novel species within the genus Aquincola, for which the name Aquincola agrisoli sp. nov. is proposed, with MAHUQ-54T (=KACC 22001T = CGMCC 1.18515T) as the type strain.

Revisiting the phylogenetic status of a field crab (Decapoda, Brachyura) from Chelari, Malappuram District (Kerala, India): an integrative approach through morphological and molecular taxonomy

Abstract The phylogeny of field crabs has been under profuse discussion for several decades. At this juncture, this paper reassesses the “decades old” phylogenetic status of an edible field crab, hitherto referred to as Paratelphusa hydrodromous, inhabiting the paddy fields of Chelari village (Kerala, India). After Alcock’s (1910) description, there has hardly been any serious attempt at ascertaining its precise taxonomic status. Through an integrated approach, using parsimony analysis and molecular methods, the present study reveals the candidate form’s (species’) closer affinity to the genus Oziotelphusa. Comparison of morphological and molecular characteristics with its closest phylogenetic neighbours (O. biloba, O. wagrakarowensis, O. kerala and O. aurantia) has shown that the candidate form is a taxonomically distinct entity, qualified to be considered as an unreported species; its suggested revised nomenclature is Oziotelphusa chelarensis, reminiscent of the village Chelari. Further, the paper views the relevance of this taxonomic study from conservational angles as well.

Whole genome sequencing of Streptomyces antnestii sp. nov. with a potency to become an industrial strain.

Streptomyces Strain San01 is isolated from the soil of ant-nest found in the tea estate of Darjeeling, India. The morphology, biochemical, as well as the molecular characteristics, proved that San01 belonged to the genus Streptomyces. The average nucleotide identity (ANI) value between the genome sequence of the studied strain and its closest phylogenetic neighbors were very low and also could be distinguished from its closest neighbour with broad range of phenotypic data. The draft genome sequence of isolate San01 (NZ_RZYA00000000.1) was estimated to be 9.12 Mbp in size with 71.2% of GC content and it encompasses 39 biosynthetic gene clusters that emphasize the biotechnological potential of this isolate.Based on the phenotypic, genetic and genomic data, isolate San01 (=JCM 34633 = NCTC 14543) merits to be recognized as a type strain of a novel species and hereby propose the name Streptomyces antnestii sp. nov. Incidentally, this is the first report on Streptomyces genomes from Darjeeling, India.

Frankia nepalensis sp. nov., a non-infective non-nitrogen-fixing isolate from root nodules of Coriaria nepalensis Wall

Strains CN4T, CN6, CN7 and CNm7 were isolated from root nodules of Coriaria nepalensis from Murree in Pakistan. They do not form root nodules on C. nepalensis nor on Alnus glutinosa although they deformed root hairs of Alnus. The colonies are bright red-pigmented, the strains form hyphae and sporangia but no N2-fixing vesicles and do not fix nitrogen in vitro. The peptidoglycan of strain CN4T contains meso-diaminopimelic acid; whole cell sugars consist of ribose, mannose, glucose, galactose and rhamnose. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two unknown lipids represent the major polar lipids; MK-9(H4) and MK-9(H6) are the predominant menaquinones (>15 %), and iso-C16 : 0 and C17 : 1ω8c are the major fatty acids (>15 %). The results of comparative 16S rRNA gene sequence analyses indicated that strain CN4T is most closely related to Frankia saprophytica CN 3T. An MLSA phylogeny using amino acids sequences of AtpD, DnaA, FtsZ, Pgk and RpoB, assigned the strain to cluster 4 non-nodulating species, close to F. saprophytica CN 3T , Frankia asymbiotica M16386T and Frankia inefficax EuI1cT with 0.04 substitutions per site, while that value was 0.075 with other strains. Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between CN4T and all species of the genus Frankia with validly published names were below the defined threshold for prokaryotic species demarcation, with dDDH and ANI values at or below 27.8 and 83.7 %, respectively. The four strains CN4T, CN6, CN7 and CNm7 had dDDH (98.6–99.6 %) and ANI values that grouped them as representing a single species. CN4T has a 10.76 Mb genome. CN4T was different from its close phylogenetic neighbours with validly published names in being red-pigmented, in having several lantibiotic-coding clusters, a carbon monoxide dehydrogenase cluster and a clustered regularly interspaced short palindromic repeats (CRISPR) cluster. The results of phenotypic, physiological and phylogenomic analyses confirmed the assignment of strain CN4T (=DSM 114740T = LMG 32595T) to a novel species, with CN4T as type strain, for which the name Frankia nepalensis sp. nov. is proposed.

Psychrobacillus antarcticus sp. nov., a psychrotolerant bioemulsifier producer isolated from King George Island, Antarctica.

A Gram-stain-positive rod, psychrotolerant, aerobic and bioemulsifier-producing strain, denoted as Val9T, was isolated from soil sampled at Vale Ulman, King George Island, Antarctica. The strain grew at up to 30 °C (optimum, 15 °C), at pH 6-9 (optimum, pH 8) and with up to 5 % w/v NaCl (optimum, 3 %). The strain was motile and positive for catalase, oxidase and H2S. It did not hydrolyse starch, casein or gelatin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Val9T belonged to the genus Psychrobacillus and was closely related to Psychrobacillus psychrotolerans DSM 11706T (99.9 % similarity), Psychrobacillus psychrodurans DSM 11713T (99.8 %) and Psychrobacillus glaciei PB01T (99.2 %). Digital DNA-DNA hybridization and average nucleotide identity values were lower than 37.3 and 85.5 %, respectively, with the closest phylogenetic neighbours. The DNA G+C content of strain Val9T calculated from the complete genome sequence was 36.6 mol%. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 1ω11c. Menaquinone-8 was the major respiratory quinone. The peptidoglycan type was A4β l-Orn-d-glu. The novel strain contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol as predominant polar lipids. Based on 16S rRNA phylogenetic and multilocus sequence analyses (recA, rpoB and gyrB), as well as phylogenomic, chemotaxonomic and phenotypic tests, we demonstrate that strain Val9T represents a novel species of the genus Psychrobacillus, for which the name Psychrobacillus antarcticus sp. nov. is proposed. The type strain is Val9T (=DSM 115096T=CCGB 1952T=NRRL B-65674T).

Candidatus Kirkpatrickella diaphorinae gen. nov., sp. nov., an uncultured endosymbiont identified in a population of Diaphorina citri from Hawaii

Diaphorina citri is the hemipteran pest and vector of a devastating bacterial pathogen of citrus worldwide. In addition to the two core bacterial endosymbionts of D. citri, Candidatus Carsonella ruddii and Candidatus Profftella armatura, the genome of a novel endosymbiont and as of yet undescribed microbe was discovered in a Hawaiian D. citri population through deep sequencing of multiple D. citri populations. Found to be closely related to the genus Asaia in the family Acetobacteraceae by 16S rRNA gene sequence analysis, it forms a sister clade along with other insect-associated 16S rRNA gene sequences from uncultured bacterium found associated with Aedes koreicus and Sogatella furcifera. Multilocus sequence analysis confirmed the phylogenetic placement sister to the Asaia clade. Despite the culturable Asaia clade being the closest phylogenetic neighbour, attempts to culture this newly identified bacterial endosymbiont were unsuccessful. On the basis of these distinct genetic differences, the novel endosymbiont is proposed to be classified into a candidate genus and species ‘Candidatus Kirkpatrickella diaphorinae’. The full genome was deposited in GenBank (accession number CP107052; prokaryotic 16S rRNA OP600170).

Macromonas nakdongensis sp. nov., Isolated from Freshwater and Characterization of Bacteriophage BK-30P-The First Phage That Infects Genus Macromonas.

A Gram-stain-negative, non-motile, non-pigmented, rod-shaped bacterium was isolated from a freshwater sample of Nakdong River in South Korea and designated as strain BK-30T. An analysis of the 16S rRNA gene sequence of strain BK-30T revealed its closest phylogenetic neighbors were members of the genus Macromonas. Specifically, the strain formed a robust clade with Macromonas bipunctata DSM 12705T, sharing 98.4% similarity in their 16S rRNA gene sequences. The average nucleotide identity value between strain BK-30T and M. bipunctata DSM 12705T was 79.8%, and the genome-to-genome distance averaged 21.3%, indicating the representation of a novel genomic species. Strain BK-30T exhibited optimum growth at 30 °C and pH 7.0, in the absence of NaCl. The major respiratory isoprenoid quinone identified was ubiquinone-8 (Q-8). The principal fatty acids detected were C16:1ω7c and/or C16:1ω6c (49.6%), C16:0 (27.5%), and C18:1ω7c and/or C18:1 ω6c (9.2%). The DNA G+C content of the strain was determined to be 67.3 mol%. Based on these data, we propose a novel species within the genus Macromonas, named Macromonas nakdongensis sp. nov., to accommodate the bacterial isolate. Strain BK-30T is designated as the type strain (=KCTC 52161T = JCM 31376T = FBCC-B1). Additionally, we present the isolation and complete genome sequence of a lytic phage infecting strain BK-30T, named BK-30P. This bacteriophage is the first reported to infect Macromonas, leading us to propose the name "Macromonasphage".

Novosphingobium beihaiensis sp. nov., a novel pesticide-tolerant bacterium isolated from mangrove sediments.

A novel Novosphingobium species, designated strain B2638T, was isolated from mangrove sediments which was collected from Beibu Gulf, Beihai, P. R. China. The isolate could grow in the presence of chlorpyrifos. Phylogenetic analysis based on 16S rRNA gene sequence revealed that the isolate belonged to the genus Novosphingobium, showing 99.9% sequence similarity with N. decloroationis 502str22T and less than 98% similarity with other type strain of species of this genus. Molecular typing by BOX-PCR divided strain B2638T and N. declorationis 502str22T into two clusters and indicated that they were not identical. Genomic comparison referenced by values of the DNA-DNA hybridization (dDDH) and the average nucleotide identity (ANI) between strain B2638T and its close phylogenetic neighbors were 20.0-29.5% and 75.3-85.3%, respectively, that were lower than proposed thresholds for bacterial species delineation. The major fatty acids (> 10%) were identified as C18:1 ω7c, C17:1 iso ω9c and C16:0. The main polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, phosphatidyl glycerol, unidentified lipid and unidentified aminolipid. Results from phenotypic, chemotaxonomic and genotypic analyses proposed that strain B2638T (= MCCC 1K07406T = KCTC 72968T) is represented a novel species in the genus Novosphingobium, for which the names Novosphingobium beihaiensis sp. nov. is proposed.

Genomic Analysis of a Novel Antarctic Bacterium, Cyrobacterium sp.SO2 Provides Insights into its Genomic Potential for Production of Antimicrobial Compounds

A novel strain of Cryobacterium designated as SO2, was isolated from the Antarctic. Hence, this study was undertaken to gain further insight into the antimicrobial compounds and secondary metabolites produced by Cryobacterium sp. SO2. It was found that strain SO2 is a Gram-positive that exhibits an irregular rod shape, which formed yellow to orange pigmented colonies on semi-solid media. Strain SO2 grows at temperatures ranging from 4 to 25 ºC. It has a complete genomic size of 4.097 Mb. SO2 has a DNA G+C content of 68.43%, and genomic annotation showed that the genome contained 3,862 CDS, 10 rRNA, 55 tRNA and 1 tm-RNA. Phylogenetic and OrthoANI analysis suggested Cryobacterium sp. strains SO1, N22, TMB1-8, LW097, TMN39-1, C. zongtaiiTMN-42, C. arcticumPAMC27867 and C. soli GCJ02 as its closest phylogenetic neighbour. Genome annotation shows that strain SO2 confers β-lactamase class A, cephalosporin-C deacetylases, and 27 drug-resistance encoding genes, and allows resistance to ceftazidime. Functional annotation identifies 28.74% of predicted genes are of unknown functions. Genome mining indicates that there are six putative secondary metabolite gene clusters in strain SO2. They are made up of RRE-containing, terpene, beta-lactone, T3PKS, NAPAA, and 2dos. This finding shows strain SO2 harbours genes that may be involved in the production of compounds with antibacterial and antioxidant activities.

Stakelama marina sp. nov., isolated from seawater of the Tangyin hydrothermal field in the Okinawa Trough.

A Gram-stain-negative, strictly aerobic, rod-shaped and non-flagellated marine bacterium, designated strain LXI357T, was isolated from deep-sea water sampled at the Tangyin hydrothermal field in the Okinawa Trough. The growth temperature range was 20-45 °C (optimum, 28 °C). Strain LXI357T was also able to grow at pH 5.0-7.5 (optimum, pH 6.0-7.0) and in the presence of 0.5-11 % (optimum, 7%, w/v) NaCl. Strain LXI357T was oxidase-negative and catalase-positive. The predominant fatty acids were C18 : 1 ω7c and C16 : 0. The major polar lipids of strain LXI357T contained phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phospholipid, sphingoglycolipid, diphosphatidylglycero and an unidentified aminolipid. Based on the results of 16S rRNA gene sequence analysis, strain LXI357T belonged to the genus Stakelama and was most closely related to Stakelama flava CBK3Z-3T (96.28%, 16S rRNA gene sequence similarity), followed by Stakelama algicida Yeonmyeong 1-13T (95.67%), Stakelama pacifica JLT832T (95.46%) and Sphingosinicella vermicomposti YC7378T (95.43%). Genome relatedness between strain LXI357T and Stakelama flava CBK3Z-3T was computed using average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity, with values of 76.02, 20.9 and 71.1 %, respectively. The genomic DNA G+C content of strain LXI357T is 64.1 mol%. In addition, strain LXI357T has multiple genes related to sulphur metabolism, including genes encoding for the Sox system. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished strain LXI357T from its closest phylogenetic neighbours. According to the results of polyphasic analyses, strain LXI357T is considered to represent a novel species of the genus Stakelama, for which the name Stakelama marina sp. nov. is proposed. The type strain is LXI357T (=MCCC 1K06076T=KCTC 82726T).

Paraburkholderia tagetis sp. nov., a novel species isolated from roots of Tagetes patula enhances the growth and yield of Solanum lycopersicum L. (tomato).

A multifunctional, Gram-stain-negative, aerobic, motile by flagella, short-rod shaped bacteria, designated strain RG36T was isolated from roots of marigold plant (Tagetes patula) sampled at Dongguk University, Republic of Korea. A 16S rRNA sequences indicated that the closest phylogenetic neighbors were Paraburkholderia acidiphila 7Q-K02T (99.0%) and Paraburkholderia sacchari IPT101T (98.9%) of the family Burkholderiaceae. The draft genome size was 8.52 Mb (63.7% GC). The genome contained 7,381 coding sequences. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of strain RG36T with its most closely related species were only 83.1-88.7 and 27.6-36.7%, respectively. Strain RG36T contained Q-8 as the major respiratory quinone and its main fatty acids (>10%) were C16:0, C17:0 cyclo, C19:0 cyclo ω8c, and summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c). Strain RG36T accumulates polyhydroxybutyrates (PHB) and exhibits multiple plant growth-promoting properties including production of indole-3-acetic acid (IAA), siderophores, protease, phosphate solubilization, and harboring gene clusters for its multifunctional properties. A pot experiment was conducted to evaluate the effect of PGPR on the growth of Solanum lycopersicum L. (Tomato). Result also confirmed the ability of strain RG36T to promote tomato plant growth, especially it increases the yield of tomatoes. Structural assessment of the bioplastic by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and GC-MS spectroscopy, which confirmed the structure of the polymer as PHB. Our study revealed the potential of strain RG36T to promote the growth of tomato plant and fruit yield by stimulating the various phytohormones, which could be use as bio-fertilizers to reduce the use of chemical fertilizers and promotes sustainable agricultural production. The phenotypic, chemotaxonomic and phylogenetic data, and genome analysis showed that strain RG36T represents a novel species of the genus Paraburkholderia, for which the name Paraburkholderia tagetis sp. nov. is proposed. The type strain is RG36T (=KACC 22685T = TBRC 15696T).

Mining metagenomes reveals diverse antibiotic biosynthetic genes in uncultured microbial communities

Pathogens resistant to antimicrobials form a significant threat to public health worldwide. Tackling multidrug-resistant pathogens via screening metagenomic libraries has become a common approach for the discovery of new antibiotics from uncultured microorganisms. This study focuses on capturing nonribosomal peptide synthase (NRPS) gene clusters implicated in the synthesis of many natural compounds of industrial relevance. A NRPS PCR assay was used to screen 2976 Escherichia coli clones in a soil metagenomic library to target NRPS genes. DNA extracts from 4 clones were sequenced and subjected to bioinformatic analysis to identify NRPS domains, their phylogeny, and substrate specificity.Successfully, 17 NRPS-positive hits with a biosynthetic potential were identified. DNA sequencing and BLAST analysis confirmed that NRPS protein sequences shared similarities with members of the genus Delftia in the Proteobacteria taxonomic position. Multiple alignment and phylogenetic analysis demonstrated that clones no. 15cd35 and 15cd37 shared low bootstrap values (54%) and were distantly far from close phylogenetic neighbors. Additionally, NRPS domain substrate specificity has no hits with the known ones; hence, they are more likely to use different substrates to produce new diverse antimicrobials. Further analysis confirmed that the NRPS hits resemble several transposon elements from other bacterial taxa, confirming its diversity. We confirmed that the analyses of the soil metagenomic library revealed a diverse set of NRPS related to the genus Delftia. An in-depth understanding of those positive NRPS hits is a crucial step for genetic manipulation of NRPS, shedding light on alternative novel antimicrobial compounds that can be used in drug discovery and hence supports the pharmaceutical sector.

A nostoxanthin-producing bacterium, Sphingomonas nostoxanthinifaciens sp. nov., alleviates the salt stress of Arabidopsis seedlings by scavenging of reactive oxygen species.

A novel, nostoxanthin-producing, endophytic bacterium, designated as AK-PDB1-5T, was isolated from the needle-like leaves of the Korean fir (Abies koreana Wilson) collected from Mt. Halla in Jeju, South Korea. A 16S rRNA sequence comparison indicated that the closest phylogenetic neighbors were Sphingomonas crusticola MIMD3T (95.6%) and Sphingomonas jatrophae S5-249T (95.3%) of the family Sphingomonadaceae. Strain AK-PDB1-5T had a genome size of 4,298,284 bp with a 67.8% G + C content, and digital DNA-DNA hybridization and OrthoANI values with the most closely related species of only 19.5-21% and 75.1-76.8%, respectively. Cells of the strain AK-PDB1-5T were Gram-negative, short rods, oxidase- and catalase-positive. Growth occurred at pH 5.0-9.0 (optimum pH 8.0) in the absence of NaCl at 4-37°C (optimum 25-30°C). Strain AK-PDB1-5T contained C14:0 2OH, C16:0 and summed feature 8 as the major cellular fatty acids (> 10%), while sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, phospholipids and lipids were found to be the major polar lipids. The strain produces a yellow carotenoid pigment; natural products prediction via AntiSMASH tool found zeaxanthin biosynthesis clusters in the entire genome. Biophysical characterization by ultraviolet-visible absorption spectroscopy and ESI-MS studies confirmed the yellow pigment was nostoxanthin. In addition, strain AK-PDB1-5T was found significantly promote Arabidopsis seedling growth under salt conditions by reducing reactive oxygen species (ROS). Based on the polyphasic taxonomic analysis results, strain AK-PDB1-5T was determined to be a novel species in the genus Sphingomonas with the proposed name Sphingomonas nostoxanthinifaciens sp. nov. The type strain is AK-PDB1-5T (= KCTC 82822T = CCTCC AB 2021150T).

Corynebacterium megadyptis sp. nov. with two subspecies, Corynebacterium megadyptis subsp. megadyptis subsp. nov. and Corynebacterium megadyptis subsp. dunedinense subsp. nov. isolated from yellow-eyed penguins.

Novel Corynebacterium strains, 3BT and 7BT, were isolated from the oral cavities of young chicks of yellow-eyed penguins (hoiho), Megadyptes antipodes. A polyphasic taxonomic characterization of these strains revealed chemotaxonomic, biochemical and morphological features that are consistent with those of the genus Corynebacterium. The 16S rRNA gene sequence similarity values between the strains and their closest phylogenetic neighbour, Corynebacterium ciconiae CCUG 47525T were 99.07 %, values that are in line with their phylogenomic positions within the evolutionary radiation of the genus Corynebacterium. Digital DNA-DNA hybridization values and average nucleotide identities between the genome sequences of the two strains and related Corynebacterium species were well below the defined threshold values (70 and 95-96 %, respectively) for prokaryotic species delineation. The genome size of these strains varied between 2.45-2.46 Mb with G+C content 62.7-62.9 mol%. Strains 3BT and 7BT were Gram-stain positive bacilli that were able to grow in presence of 0-10 % (w/v) NaCl and at temperature ranging between 20-37 °C. The major fatty acids (>15 %) were C16 : 0 and C18 : 1 ω9c, and the mycolic acid profile included 32-36 carbon atoms. We propose that these strains represent a novel species, Corynebacterium megadyptis sp. nov. with 3BT (=DSM 111184T=NZRM 4755T) as the type strain. Phylogenomically, strains 3BT and 7BT belong to two lineages with subtle differences in MALDI-TOF spectra, chemotaxonomic profiles and phenotypic properties. The fatty acid profile of strain 3BT contains C18 : 0 as a predominant type (>15 %), which is a minor component in strain 7BT. Strain 7BT can oxidize N-acetyl-d-glucosamine, l-serine, α-hydroxy-butyric acid, l-malic acid, l-glutamic acid, bromo-succinic acid and l-lactic acid, characteristics not observed in strain 3BT. Therefore, we propose that these strains represent two subspecies, namely Corynebacterium megadyptis subsp. megadyptis subsp. nov. (type strain, 3BT=DSM 111184T=NZRM 4755T) and Corynebacterium megadyptis subsp. dunedinense subsp. nov. (type strain, 7BT=DSM 111183T=NZRM 4756T).

Arthrobacter hankyongi sp. nov., Isolated From Wet Land.

A Gram-staining-positive, catalase positive and oxidase negative, non-motile, non-flagellated, and oval-shaped bacterium, was designated as I2-34T, isolated from wetland in Soul South Korea. Colonies were round, entire, raised, and cream colored after two days of incubation on R2A agar plates at 25°C. Based on genomes (both 16S rRNA gene and draft genome) sequence analysis, strain I2-34T belongs to the genus Arthrobacter and was most closely related to Arthrobacter deserti YIM CS25T (98.0%). The strain I2-34T had a circular genome with length of 5,186,447 base pairs (67 contigs) and 4830 total genes. Out of 4696 were protein-coding genes, 54 tRNA and 4 rRNA genes. The chemotaxonomic analysis indicates iso-C16:0, anteiso-C15:0, and anteiso-C17:0 as major fatty acids, phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), and two unidentified glycolipids (GL1, GL2) as major polar lipids. The predominant quinone was MK-8(H2). The peptidoglycan type was A3α with an. L-Lys-L-Ala interpeptide bridge. Thus, the experimental data demonstrated here show that the novel isolate shares the similar major fatty acids, major polar lipid PG, DPG, and GLs, major and major quinone MK8-(H2) with the described members of the genus Arthrobacter. However, the low 16S rRNA gene sequence (98.0%), and some physiological and biochemical characteristics differentiate the I2-34T from its closest phylogenetic neighbors. As a result, the isolate represents a novel species in within the genus Arthrobacter and family Micrococcaceae for which the name Arthrobacter hankyongi sp. nov. is proposed. The type strain is I2-34T (= KACC 22217T, LMG 32197T).

Paenibacillus agilis sp. nov., Paenibacillus cremeus sp. nov. and Paenibacillus terricola sp. nov., isolated from rhizosphere soils.

Members of the genus Paenibacillus are well known for their metabolic versatility and great application potential in plant growth promotion. Three novel bacterial strains, designated N4T, JC52T and PR3T, were isolated from rhizosphere soils and characterized by using a polyphasic taxonomic approach. The 16S rRNA gene sequence phylogenetic and phylogenomic analysis revealed that the three strains belonged to the genus Paenibacillus and formed three independent branches distinct from all reference strains. The results of DNA-DNA hybridization (DDH) and average nucleotide identity (ANI) analyses between the three strains and their relatives further demonstrated that the three strains represented different novel genospecies. Strain N4T exhibited the highest similarity, ANI and digital DDH values with Paenibacillus assamensis DSM 18201T (99.0/87.5/33.9 %) and Paenibacillus insulae DS80T (97.2/-/18.2±1.2 %). Values for JC52T with Paenibacillus validus NBRC 15382T were 96.9, 73.3 and 19.6 %, and with Paenibacillus rigui JCM 16352T were 96.1, 72.1 and 19.3 %. Values for PR3T with Paenibacillus ginsengiterrae DCY89T were 98.2, - and 31.8±1.5 %, with Paenibacillus cellulosilyticus ASM318225v1T were 97.8, 83.3 and 26.7 %, and with Paenibacillus kobensis NBRC 15729T were 97.6, 75.7 and 20.4 %. Cells of the three novel bacterial strains were Gram-positive, spore-forming, motile and rod-shaped. The novel species contained anteiso-C15 : 0 and MK-7 as the predominant fatty acid and menaquinone, respectively. The novel strains have numerous similar known clusters of non-ribosomal peptide synthetases, siderophores, lanthipeptide, lassopeptide-like bacillibactin, paeninodin and polyketide-like chejuenolide A/B lankacidin C. Based on the distinct morphological, physiological, chemotaxonomic and phylogenetic differences from their closest phylogenetic neighbours, we propose that strains N4T, JC52T and PR3T represent novel species of the genus Paenibacillus, with the names Paenibacillus agilis sp. nov. (=KACC 19717T=JCM 32775T), Paenibacillus cremeus sp. nov. (=KACC 21221T=NBRC 113867T) and Paenibacillus terricola sp. nov. (=KACC 21455T=NBRC 114385T), respectively.

Characterization of three Stenotrophomonas strains isolated from different ecosystems and proposal of Stenotrophomonas mori sp. nov. and Stenotrophomonas lacuserhaii sp. nov.

Members of the genus Stenotrophomonas, and particularly Stenotrophomonas maltophilia, are opportunistic human pathogens, but not enough research has evaluated the identification of environmental Stenotrophomonas spp. However, most Stenotrophomonas spp. serves as plant-probiotic bacteria.In this study, we obtained and characterized three Stenotrophomonas strains from different ecosystems. Based on phenotypic differences, chemotaxonomic properties, ANI and dDDH identity values, and phylogenetic analyses, two novel Stenotrophomonas species are proposed for the strains identified here. The encoding genes related to plant-growth promotion in the genomes of the newly recovered Stenotrophomonas spp. were retrieved. Follow-on experiments confirmed that these strains produced the important plant hormone IAA. Thus, these Stenotrophomonas spp. could considerably contribute to shaping and maintaining ecological stability in plant-associated environments, particularly while acting as plant-probiotic microorganisms.