Biofilm development on fractured rock in oligotrophic nitrate-rich groundwater: An in-situ bioreactor study

Biofilms drive all biogeochemical processes and represent the main mode of existence for active microbial life. Many past studies examined biofilm formation under static and eutrophic conditions, but those conditions are not representative of typical groundwater environments. In this study, we developed in situ bioreactors and methodologies to examine the influence of subsurface properties such as redox condition and lithology on the properties of naturally formed biofilms in two adjacent wells, a 30-m deep well completed in alluvium and a 120-m deep well in gneiss bedrock. The bulk chemistry of groundwater from the wells was similar, with neutral pH and abundant nitrate (21.9-24.6 mg/L), but redox conditions differed with depth (alluvial: oxic, gneiss bedrock: anoxic). Microbial community analysis revealed distinct clustering of biofilm community composition with the groundwater environment. Biofilm communities were consistently assembled by deterministic processes whereas planktonic communities had a higher influence of stochastic processes. Alluvial biofilms exhibited more diverse communities mainly composed of organotrophic aerobes capable of nitrate utilization. Bedrock biofilms indicated similar community compositions with groundwater where anaerobic denitrifiers coupled with sulfur oxidizers were dominant. Visualization and biomass quantification revealed distinct morphologies and development of biofilm along rock types and groundwater environments. Biofilm on gneiss surface had more biomass and formed a thin layered structure, compared to sandstone biofilm which had a randomly distributed pattern, implying that the morphology of biofilm was governed by the properties of the rock. Attached to unattached (planktonic) microbe ratios ranged from 3.9 × 103 to 1.2 × 104: 1 in the gneiss surface and 3.4 × 102 to 4.2 × 102: 1 in the sandstone surface in bedrock groundwater environment. Taken together, this study advances our understanding of subsurface biomass abundance and demonstrates that the in-situ bioreactors are effective for cultivating and analyzing of subsurface biofilms. Based on the specific field conditions tested, we found that biofilm can form stably on fractured rock surfaces within a year, with groundwater redox conditions shaping community composition and rock types determining biofilm volume and morphology. The methodologies presented here can be extended to other subsurface environments with varying groundwater geochemistry and lithology, which will help further refine estimates of microbial life and its role in subsurface ecosystems.

Microbial analyses of infectious keloids on the anterior chest-a case-control study

Some studies have confirmed that pathogens can cause infection through bacterial cultures on the surface of infectious keloids. However, further exploration of the comparison between infectious and non-infectious keloids and the bacterial flora of infectious foci is lacking. To investigate the differential flora of purulent secretions on the surface of infectious keloids compared to non-infectious keloids and to determine the microbial composition within the infectious foci. This case-control study involved 17 patients and obtained swab specimens from the surface of keloids in two groups, and from the infectious foci in the infectious group. Bacterial composition was analyzed using 16S ribosomal RNA sequencing. There were no statistical differences in the general condition of patients between the two groups. The presence of the phylum Actinobacteriota, and the orders Propionibacteriales and Corynebacteriales, as well as the genus Taibaiella, was greater on the surface of keloids in the infectious group. The most prevalent genera in infective sites were Staphylococcus, Peptoniphilus, and Cutibacterium. Microbial-associated gene pathways indicated a correlation with inflammation and tumor-like growth in keloids. There is a connection between infectious keloids and microorganisms, providing insights for predicting and treating keloid infections.

Dynamics of PHA-Accumulating Bacterial Communities Fed with Lipid-Rich Liquid Effluents from Fish-Canning Industries

The biosynthesis of polyhydroxyalkanoates (PHAs) from industrial wastes by mixed microbial cultures (MMCs) enriched in PHA-accumulating bacteria is a promising technology to replace petroleum-based plastics. However, the populations' dynamics in the PHA-accumulating MMCs are not well known. Therefore, the main objective of this study was to address the shifts in the size and structure of the bacterial communities in two lab-scale sequencing batch reactors (SBRs) fed with fish-canning effluents and operated under non-saline (SBR-N, 0.5 g NaCl/L) or saline (SBR-S, 10 g NaCl/L) conditions, by using a combination of quantitative PCR and Illumina sequencing of bacterial 16S rRNA genes. A double growth limitation (DGL) strategy, in which nitrogen availability was limited and uncoupled to carbon addition, strongly modulated the relative abundances of the PHA-accumulating bacteria, leading to an increase in the accumulation of PHAs, independently of the saline conditions (average 9.04 wt% and 11.69 wt%, maximum yields 22.03 wt% and 26.33% SBR-N and SBR-S, respectively). On the other hand, no correlations were found among the PHAs accumulation yields and the absolute abundances of total Bacteria, which decreased through time in the SBR-N and did not present statistical differences in the SBR-S. Acinetobacter, Calothrix, Dyella, Flavobacterium, Novosphingobium, Qipengyuania, and Tsukamurella were key PHA-accumulating genera in both SBRs under the DGL strategy, which was revealed as a successful tool to obtain a PHA-enriched MMC using fish-canning effluents.

Enrichment of a denitratating microbial community through kinetic limitation

Denitratation, or the intentionally engineered accumulation of nitrite (NO₂^-) from selective reduction of nitrate (NO₃^-), can be combined with downstream anammox to reduce chemical and energy use associated with conventional nitrification and denitrification. This study aimed to enrich a denitratating microbial community capable of significant NO₂^- accumulation by applying added kinetic limitation to an already stoichiometrically-limited, glycerol-driven denitratation process. Operation at solids residence time, SRT=3.0 d, resulted in optimal denitratation performance and a microbial community dominated by NO₃^--respirers, noted by one order of magnitude lower total copy numbers of nirS and nirK gene transcripts compared to longer SRTs. Selective NO₃^- reduction to NO₂^- was achieved at all SRTs although longer SRTs (less kinetic limitation) supported microbial communities more capable of full denitrification as described by a lower NO₂^- accumulation ratio (NAR=42±5%) and higher steady-state nitrous oxide (1.5 mg/L N₂O-N) accumulation. Shorter SRTs (more kinetic limitation) led to higher observed yields (Y=0.63 mg-COD/mg-COD) with more electrons dedicated for cell synthesis (f_s=0.56±0.10), which potentially contributed to the accumulation of NO₃^-. Enrichment of a denitratating-dominant microbial community by optimizing kinetic limitation operating parameters could support significant NO₂^- accumulation and reduce chemical and energy use for biological nitrogen removal when combined with downstream anammox.

Genetically Modified Sugarcane Intercropping Soybean Impact on Rhizosphere Bacterial Communities and Co-occurrence Patterns

Strategies involving genes in the dehydration-responsive element binding (DREB) family, which participates in drought stress regulation, and intercropping with legumes are becoming prominent options in promoting sustainable sugarcane cultivation. An increasing number of studies focusing on root interactions in intercropping systems, particularly involving transgenic crops, are being conducted to better understand and thus, harness beneficial soil microbes to enhance plant growth. We designed experiments to investigate the characteristics of two intercropping patterns, soybean with wild-type (WT) sugarcane and soybean with genetically modified (GM) Ea-DREB2B-overexpressing sugarcane, to assess the response of the rhizosphere microbiota to the different cropping patterns. Bacterial diversity in the rhizosphere microbial community differed between the two intercropping pattens. In addition, the biomass of GM sugarcane that intercropped with soybean was significantly improved compared with WT sugarcane, and the aboveground biomass and root biomass of GM soybean intercropping sugarcane increased by 49.15 and 46.03% compared with monoculture. Furthermore, a beneficial rhizosphere environment for the growth of Actinobacteria was established in the systems intercropped with GM sugarcane. Improving the production mode of crops by genetic modification is a key strategy to improving crop yields and provides new opportunities to further investigate the effects of intercropping on plant roots and soil microbiota. Thus, this study provides a basis for selecting suitable sugarcane-soybean intercropping patterns and a theoretical foundation for a sustainable sugarcane production.

Taibaiella lutea sp. nov., Isolated from Ubiquitous Weedy Grass

An aerobic, Gram-stain-negative, non-motile and rod-shaped bacterial strain, designated as KVB11^T was isolated from the root of plant Setaria viridis near Dongguk University. Phylogenetic analysis indicated that strain KVB11^T belonged to the genus Taibaiella of the family Chitinophagaceae. Comparative 16S rRNA gene analysis indicated that the strain KVB11^T has closest similarities to Taibaiella smilacinae PTJT-5 ^T (96.6%) and Taibaiella yonginensis THG-SC4^T (96.4%). Strain KVB11^T grew optimally at 25-28°C, at pH 7.0 and tolerates NaCl upto 1% (w/v) NaCl. Flexirubin-type pigments were present. Phylogenetic and phylogenomic trees based on 16S rRNA gene sequences and genomic sequences demonstrated that strain KVB11^T formed a distinct branch with all seven type strains of genus Taibaiella. MK-7 was identified as the predominant isoprenoid quinone. The polar lipid were phosphatidylethanolamine, one unidentified aminophosphoglycolipid, one unidentified aminoglycolipid and two unidentified phosphoglycolipids. C_15:0 (28.3%), iso-C_15:1 G (28.5%) and iso-C_17:0 3-OH (10.5%) were the major fatty acids of the strain KVB11^T. The DNA G + C content of the genomic DNA of novel isolate was determined to be 38.9%. The above results clearly confirmed that strain KVB11^T represents a novel species of the genus Taibaiella, for which the name Taibaiella lutea sp. nov. is proposed. The type strain is KVB11^T (= KACC 19904 ^T = NBRC 113690 ^T).

Enhanced biodegradation of crude oil in soil by a developed bacterial consortium and indigenous plant growth promoting bacteria

AIMS

This study aimed to develop an efficient, cost-effective and eco-friendly bacterial consortium to degrade petroleum sludge.

METHODS AND RESULTS

Four bacterial strains belonging to genera Acinetobacter and Pseudomonas were selected to constitute three different consortia based on their initial concentration. The highest degradation rate (78%) of 1% (v/v) crude oil after 4 weeks of incubation was recorded when the concentration of biosurfactant (BS) producing isolate was high. Genes, such as alkB, almA, cyp153, pah-rhdGN, nah, phnAC and cat23 were detected using the polymerase chain reaction method and their induction levels were optimal at pH 7·0. A crude oil sludge was artificially constituted, and its bacterial composition was investigated using 16S rRNA gene amplicon sequencing. The results showed that the soil bacterial community was dominated by plant growth-promoting bacteria (PGPB) after crude oil treatment.

CONCLUSIONS

Our findings indicate the decontamination of the crude oil contaminated soil was more effective in the presence of both the constituted consortium and PGPB compared to the presence of PGPB alone.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study showed that the PGPB (Taibaiella) present in petroleum uncontaminated soil can promote the soil decontamination. The addition of both efficient hydrocarbon-degrading and BS producing bacteria is also necessary to improve the decontamination.

Deciphering the Root Endosphere Microbiome of the Desert Plant Alhagi sparsifolia for Drought Resistance-Promoting Bacteria

Drought is among the most destructive abiotic stresses limiting crop growth and yield worldwide. Although most research has focused on the contribution of plant-associated microbial communities to plant growth and disease suppression, far less is known about the microbes involved in drought resistance among desert plants. In the present study, we applied 16S rRNA gene amplicon sequencing to determine the structure of rhizosphere and root endosphere microbiomes of Alhagi sparsifolia Compared to those of the rhizosphere, endosphere microbiomes had lower diversity but contained several taxa with higher relative abundance; many of these taxa were also present in the roots of other desert plants. We isolated a Pseudomonas strain (LTGT-11-2Z) that was prevalent in root endosphere microbiomes of A. sparsifolia and promoted drought resistance during incubation with wheat. Complete genome sequencing of LTGT-11-2Z revealed 1-aminocyclopropane-1-carboxylate deaminases, siderophore, spermidine, and colanic acid biosynthetic genes, as well as type VI secretion system (T6SS) genes, which are likely involved in biofilm formation and plant-microbe interactions. Together, these results indicate that drought-enduring plants harbor bacterial endophytes favorable to plant drought resistance, and they suggest that novel endophytic bacterial taxa and gene resources may be discovered among these desert plants.IMPORTANCE Understanding microbe-mediated plant resistance to drought is important for sustainable agriculture. We performed 16S rRNA gene amplicon sequencing and culture-dependent functional analyses of Alhagi sparsifolia rhizosphere and root endosphere microbiomes and identified key endophytic bacterial taxa and their genes facilitating drought resistance in wheat. This study improves our understanding of plant drought resistance and provides new avenues for drought resistance improvement in crop plants under field conditions.

Microbial recycling cells: First steps into a new type of microbial electrochemical technologies, aimed at recovering nutrients from wastewater

The aim of this work were to study terracotta-based porous air-water separators (4 mm thickness) in microbial recycling cells (MRCs) fed with cow manure (CM), swine manure (SM) and dairy wastewater (DW). Over 125 days, besides the removal of 60-90% of soluble-COD, considerable fractions of the main macronutrients (C, N, P, K, Fe, Mn, Ca, Mg) were removed from the wastewater and deposited on the terracotta separators as both inorganic salts and biomass deposits. Water evaporation at air-water interface as well as the high cathodic pH (10-12), induced by oxygen reduction to OH^-, were the predominant factors leading to precipitation. The separators were saturated of up to 10 g per kg of terracotta of the main macronutrients, with negligible concentrations of the main inorganic contaminants. These materials could be directly reused as nutrients-enriched solid conditioners for agricultural soils.

Taibaiella helva sp. nov., isolated from farmland soil in China

A yellow-coloured bacterial strain, designated F-4T, was isolated from a farmland soil sample from Qianshan, Anhui province, China. Strain F-4T was Gram-stain-negative, strictly aerobic, oval-shaped, motile (by gliding) and non-spore-forming. Growth occurred at 20–35 °C (optimum, 30 °C), at pH 6.0–8.0 (pH 7.0) and with 0–1.0 % (w/v) NaCl (0 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain F-4T belonged to the genus Taibaiella . 16S rRNA gene sequence similarity values between strain F-4T and the type strains of the three recognized species of the genus Taibaiella , Taibaiella koreensis KACC 17171T, Taibaiella soli KCTC 42277T and Taibaiella chishuiensis JCM 19637T, were 98.1, 96.4 and 95.9 %, respectively. The predominant respiratory quinone was MK-7, with MK-8 as a minor component. The major polar lipids of strain F-4T were three unidentified lipids, two unidentified aminolipids, three unidentified phospholipids, an unidentified aminophospholipid and phosphatidylethanolamine. The major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0. The G+C content of the genomic DNA based on total genome calculations was 51.3 mol%. The major polyamine of strain F-4T was homospermidine. The average nucleotide identity and the digital DNA–DNA hybridization values for draft genomes between strain F-4T and strain THG-DT86T were 79.8 and 22.6 %, respectively. On the basis of the genotypic and phenotypic data presented here, strain F-4T represents a novel species of the genus Taibaiella , for which the name Taibaiella helva sp. nov. is proposed. The type strain is F-4T (=KCTC 62442T=CGMCC 1.13562T).

Edaphocola aurantiacus gen. nov., sp. nov., a new member of the family Chitinophagaceae isolated from wetland soil in South Korea

A short rod-shaped, yellow-orange pigmented, strictly aerobic bacterium, designated as strain H2^T, was isolated from the wetland soil of Halla Mountain, Jeju-island, South Korea. Growth was observed at temperatures of 10-30 °C (optimum at 25-30 °C), pH of 6-8 (optimum at pH 7), and salt concentrations of 0-1% (w/v) NaCl (optimum at 0%). The strain H2^T was found to be a catalase and oxidase-positive, non-motile, Gram-negative bacterium. On the basis of 16S rRNA gene sequence similarity and phylogenetic analysis, strain H2^T was found to be related to the members of the Chitinophagaceae family, being closely related to Taibaiella chishuiensis AY17^T (94.3% sequence similarity). The major polar lipids are phosphatidylethanolamine and glycolipid. Strain H2^T contained MK-7 as the only menaquinone as well as iso-C_15:0, iso-C_15:1 G and iso-C_17:0 3-OH as the major fatty acids (> 15%). The DNA G+C content of strain H2^T was determined to be 48.3 mol%. Based on the phylogenetic, phenotypic characteristics and chemotaxonomic analysis data, strain H2^T (= KCTC 62115^T = JCM 32353^T) should be classified as representative of a novel species of a novel genus within the family Chitinophagaceae, for which the name Edaphocola aurantiacus gen. nov., sp. nov., is proposed.

Nemorella caseinilytica gen. nov., sp. nov., isolated from forest soil

Two novel strains, J116-2^T and J116-1, were isolated from forest soil and were taxonomically characterized by a polyphasic approach. Both strains were yellow-coloured, Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacteria. The strains were non-sporulating, catalase-positive and oxidase-negative. Strains J116-2^T and J116-1 were able to grow at 20-32 °C, pH 6.0-8.5, and 0-0.5 % (w/v) NaCl concentration. Based on 16S rRNA gene sequence analyses, strains J116-2^T and J116-1 formed a distinct lineage within the family Chitinophagaceae of the phylum Bacteroidetes and were closely related to genera Taibaiella (89.86-89.30 % sequence similarity), Falvihumibacter (89.20-89.06 %), Filimonas (89.06 %) and Chitinophaga(89.01-88.77 %). The pairwise sequence similarity between strains J116-2^T and J116-1 was found to be 99.86 %. Flexirubin-type pigments were absent in both strains. The only respiratory quinone was menaquinone-7 (MK-7); the major polar lipid was phosphatidylethanolamine; the predominant polyamine was homospermidine; and the major fatty acids were C15 : 0iso, C15 : 1iso G and C17 : 0iso 3-OH. The genomic DNA G+C content values of strains J116-2^T and J116-1 were 51.1 and 50.9 mol%, respectively. On the basis of phenotypic, genotypic and phylogenetic analysis, strain J116-2^T represents a novel species of a new genus in the family Chitinophagaceae, for which the name Nemorella caseinilytica gen. nov., sp. nov. is proposed. The type strain of Nemorella caseinilytica is J116-2^T (=KEMB 9005-550^T=KACC 19168^T=NBRC 112827^T).

Edaphobaculum flavum gen. nov., sp. nov., a member of family Chitinophagaceae, isolated from grassland soil

A yellow-coloured, Gram-stain-negative, non-motile, rod-shaped, strictly aerobic bacterium, designated 1-116^T, was isolated from Erdos grassland soil of Inner Mongolia, PR China. Phylogenetic analysis based on 16S rRNA genes showed that strain 1-116^T was a member of family Chitinophagaceae and exhibited the highest similarities to Taibaiella koreensis THG-DT86^T (90.1 %) and Flavihumibacter solisivae 3-3^T (90.0 %), while the similarities to the other Chitinophagaceae type strains were lower than 90.0 %. Strain 1-116^T grew at 16-33 °C (optimum 28 °C), pH 6.0-9.0 (optimum 7.0-8.0) and 0-0.5 % NaCl (w/v; optimum without NaCl). A flexirubin-type pigment was present. The DNA G+C content was 43.2 mol% and the only quinone present was menaquinone-7. The only polyamine detected was sym-homospermidine [30.7 µmol (g dry weight)^-1] and the predominant fatty acids were iso-C15 : 0 (20.8 %), iso-C15 : 1 G (25.1 %), summed feature 4 (anteiso-C17 : 1 B and/or iso-C17 : 1 I; 13.8 %) and iso-C17 : 0 3-OH (13.2 %). The major polar lipids were phosphatidylethanolamine, three unidentified lipids, an unidentified aminophospholipid and an unidentified glycolipid. On the basis of the polyphasic analyses, strain 1-116^T represents a novel genus and species in the family Chitinophagaceae, for which the name Edaphobaculum flavum gen. nov., sp. nov., is proposed. The type strain of Edaphobaculum flavum is 1-116^T (=CCTCC AB 2017054=KCTC 52843).

Nitrate effects on chromate reduction in a methane-based biofilm

The effects of nitrate (NO₃^-) on chromate (Cr(VI)) reduction in a membrane biofilm reactor (MBfR) were studied when CH₄ was the sole electron donor supplied with a non-limiting delivery capacity. A high surface loading of NO₃^- gave significant and irreversible inhibition of Cr(VI) reduction. At a surface loading of 500 mg Cr/m²-d, the Cr(VI)-removal percentage was 100% when NO₃^- was absent (Stage 1), but was dramatically lowered to < 25% with introduction of 280 mg N m^-2-d NO₃^- (Stage 2). After ∼50 days operation in Stage 2, the Cr(VI) reduction recovered to only ∼70% in Stage 3, when NO₃^- was removed from the influent; thus, NO₃^- had a significant long-term inhibition effect on Cr(VI) reduction. Weighted PCoA and UniFrac analyses proved that the introduction of NO₃^- had a strong impact on the microbial community in the biofilms, and the changes possibly were linked to the irreversible inhibition of Cr(VI) reduction. For example, Meiothermus, the main genus involved in Cr(VI) reduction at first, declined with introduction of NO₃^-. The denitrifier Chitinophagaceae was enriched after the addition of NO₃^-, while Pelomonas became important when nitrate was removed, suggesting its potential role as a Cr(VI) reducer. Moreover, introducing NO₃^- led to a decrease in the number of genes predicted (by PICRUSt) to be related to chromate reduction, but genes predicted to be related to denitrification, methane oxidation, and fermentation increased.

Pantoea alhagi, a novel endophytic bacterium with ability to improve growth and drought tolerance in wheat

A novel strain LTYR-11Z^T that exhibited multiple plant growth promoting (PGP) traits was isolated from the surface-sterilized leaves of Alhagi sparsifolia Shap. (Leguminosae), which reprsents one of the top drought tolerant plants in north-west China. Phylogenetic analysis of 16S rRNA gene sequences and multilocus sequence analysis based on partial sequences of atpD, gyrB, infB and rpoB genes revealed that strain LTYR-11Z^T was a member of the genus Pantoea, with Pantoea theicola NBRC 110557^T and Pantoea intestinalis DSM 28113^T as the closest phylogenetic relatives. The results of DNA–DNA hybridization, phenotypic tests and fatty acid analysis confirmed that strain LTYR-11Z^T represents a novel species of the genus Pantoea, for which we propose the name Pantoea alhagi sp. nov. Confocal microscopy observation revealed that strain LTYR-11Z^T effectively colonizes the rhizoplane of both Arabidopsis and wheat. Strain LTYR-11Z^T was able to promote the growth of wheat enhancing its resistance to drought stress. Strain LTYR-11Z^T led to increased accumulation of soluble sugars, decreased accumulation of proline and malondialdehyde (MDA), and decreased degradation of chlorophyll in leaves of drought-stressed wheat. Our findings will contribute to the development of a novel biotechnological agent to improve the adaptation of crop plants to drought in arid ecosystems.

Genome-Based Taxonomic Classification of Bacteroidetes

The bacterial phylum Bacteroidetes, characterized by a distinct gliding motility, occurs in a broad variety of ecosystems, habitats, life styles, and physiologies. Accordingly, taxonomic classification of the phylum, based on a limited number of features, proved difficult and controversial in the past, for example, when decisions were based on unresolved phylogenetic trees of the 16S rRNA gene sequence. Here we use a large collection of type-strain genomes from Bacteroidetes and closely related phyla for assessing their taxonomy based on the principles of phylogenetic classification and trees inferred from genome-scale data. No significant conflict between 16S rRNA gene and whole-genome phylogenetic analysis is found, whereas many but not all of the involved taxa are supported as monophyletic groups, particularly in the genome-scale trees. Phenotypic and phylogenomic features support the separation of Balneolaceae as new phylum Balneolaeota from Rhodothermaeota and of Saprospiraceae as new class Saprospiria from Chitinophagia. Epilithonimonas is nested within the older genus Chryseobacterium and without significant phenotypic differences; thus merging the two genera is proposed. Similarly, Vitellibacter is proposed to be included in Aequorivita. Flexibacter is confirmed as being heterogeneous and dissected, yielding six distinct genera. Hallella seregens is a later heterotypic synonym of Prevotella dentalis. Compared to values directly calculated from genome sequences, the G+C content mentioned in many species descriptions is too imprecise; moreover, corrected G+C content values have a significantly better fit to the phylogeny. Corresponding emendations of species descriptions are provided where necessary. Whereas most observed conflict with the current classification of Bacteroidetes is already visible in 16S rRNA gene trees, as expected whole-genome phylogenies are much better resolved.

Rhizobium gei sp. nov., a bacterial endophyte of Geum aleppicum

A bacterial strain, designated as ZFJT-2T, was isolated from the stem of Geum aleppicum Jacq. collected from Taibai Mountain in Shaanxi Province, north-west China. Cells of strain ZFJT-2T were Gram-stain-negative, strictly aerobic, rod-shaped and motile by means of a single polar flagellum. The major fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, 11-methyl C18 : 1ω7c and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), and the DNA G+C content was 58.3 mol% (HPLC). Phylogenetic analyses based on 16S rRNA gene sequences showed that strain ZFJT-2T was a member of the genus Rhizobium and was most closely related to Rhizobium giardinii KACC 10720T (98.6 % similarity) and Rhizobium herbae CCBAU 83011T (98.5 %). The low levels of sequence similarity found between the atpD, recA and glnII gene sequences of strain ZFJT-2T and those of recognized species of the genus Rhizobium (no more than 94.4, 87.2 and 89.5 %, respectively) indicated that it may represent a separate species of the genus Rhizobium. The DNA-DNA relatedness values for strain ZFJT-2T with respect to R. giardinii KACC 10720T and R. herbae CCBAU 83011T were 17.6 and 41.9 %, respectively. On the basis of phenotypic, phylogenetic and genotypic data, strain ZFJT-2T is considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium gei sp. nov. is proposed. The type strain is ZFJT-2T (=CCTCC AB 2013015T=KCTC 32301T=LMG 27603T).

Chitin Mixed in Potting Soil Alters Lettuce Growth, the Survival of Zoonotic Bacteria on the Leaves and Associated Rhizosphere Microbiology

Chitin is a promising soil amendment for improving soil quality, plant growth, and plant resilience. The objectives of this study were twofold. First, to study the effect of chitin mixed in potting soil on lettuce growth and on the survival of two zoonotic bacterial pathogens, Escherichia coli O157:H7 and Salmonella enterica on the lettuce leaves. Second, to assess the related changes in the microbial lettuce rhizosphere, using phospholipid fatty acid (PLFA) analysis and amplicon sequencing of a bacterial 16S rRNA gene fragment and the fungal ITS2. As a result of chitin addition, lettuce fresh yield weight was significantly increased. S. enterica survival in the lettuce phyllosphere was significantly reduced. The E. coli O157:H7 survival was also lowered, but not significantly. Moreover, significant changes were observed in the bacterial and fungal community of the lettuce rhizosphere. PLFA analysis showed a significant increase in fungal and bacterial biomass. Amplicon sequencing showed no increase in fungal and bacterial biodiversity, but relative abundances of the bacterial phyla Acidobacteria, Verrucomicrobia, Actinobacteria, Bacteroidetes, and Proteobacteria and the fungal phyla Ascomycota, Basidiomycota, and Zygomycota were significantly changed. More specifically, a more than 10-fold increase was observed for operational taxonomic units belonging to the bacterial genera Cellvibrio, Pedobacter, Dyadobacter, and Streptomyces and to the fungal genera Lecanicillium and Mortierella. These genera include several species previously reported to be involved in biocontrol, plant growth promotion, the nitrogen cycle and chitin degradation. These results enhance the understanding of the response of the rhizosphere microbiome to chitin amendment. Moreover, this is the first study to investigate the use of soil amendments to control the survival of S. enterica on plant leaves.

Filimonas endophytica sp. nov., isolated from surface-sterilized root of Cosmos bipinnatus

A Gram-stain-negative, yellow, motile by gliding, filamentous bacterium, designated SR 2-06T, was isolated from surface-sterilized root of garden cosmos. 16S rRNA gene sequence analysis indicated that SR 2-06T was related most closely to Filimonas lacunae YT21T of the family Chitinophagaceae at a sequence similarity of 96.90 %, while levels of similarity to other related taxa were less than 93.08 %. Strain SR 2-06T exhibited similar features to F. lacunae in that it contained MK-7 as the major respiratory quinone, and iso-C15 : 1 G, iso-C15 : 0 and a summed feature consisting of C16 : 1ω6c and/or C16 : 1ω7c as the major fatty acids. However, strain SR 2-06T was distinguished from F. lacunae using a combination of physiological and biochemical properties. The cellular polar lipids were phosphatidylethanolamine, unknown aminophospholipids, unknown aminolipids, an unknown phospholipid and unidentified polar lipids. The DNA G+C content was 46.0 mol%. The phenotypic and phylogenetic evidence clearly indicates that strain SR 2-06T represents a novel species of the genus Filimonas, for which the name Filimonas endophytica sp. nov. is proposed. The type strain is SR 2-06T ( = KCTC 42060T = JCM 19844T).

Sphingomonas hylomeconis sp. nov., isolated from the stem of Hylomecon japonica

A yellow-pigmented bacterium, designated strain GZJT-2T, was isolated from the stem of Hylomecon japonica (Thunb.) Prantl et Kündig collected from Taibai Mountain in Shaanxi Province, north-west China. Cells of strain GZJT-2T were Gram-reaction-negative, strictly aerobic, rod-shaped, non-spore-forming and non-motile. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GZJT-2T was a member of the genus Sphingomonas, with sequence similarities of 92.1-96.9 % to type strains of recognized species of the genus Sphingomonas (92.1 % to Sphingomonas oligoaromativorans SY-6T and 96.9 % to Sphingomonas oligophenolica JCM 12082T). Strain GZJT-2T contained ubiquinone-10 (Q-10) as the predominant respiratory quinone and sym-homospermidine as the major polyamine. The major cellular fatty acids were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C14 : 0 2-OH. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, sphingoglycolipid, four unidentified phospholipids, an unidentified aminolipid and four unidentified lipids were detected in the polar lipid profile. The DNA G+C content was 62.5 ± 0.3 mol%. On the basis of data from phenotypic, phylogenetic and DNA-DNA relatedness studies, strain GZJT-2T is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas hylomeconis sp. nov. is proposed. The type strain is GZJT-2T ( = CCTCC AB 2013304T = KCTC 42739T).

Sphingobium endophyticus sp. nov., isolated from the root of Hylomecon japonica

A yellow-pigmented bacterium, designated strain GZGR-4(T), was isolated from the root of Hylomecon japonica (Thunb.) Prantl et Kündig collected from Taibai Mountain in Shaanxi Province, north-west China. Cells of strain GZGR-4(T) were Gram-negative, rod-shaped, strictly aerobic, non-endospore-forming and non-motile. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GZGR-4(T) is a member of the genus Sphingobium, exhibiting the highest sequence similarity to Sphingobium aromaticiconvertens DSM 12677(T) (97.3 %). 16S rRNA gene sequence similarities between strain GZGR-4(T) and the type strains of other Sphingobium species with validly published names ranged from 93.4-96.5 %. The predominant respiratory quinone of strain GZGR-4(T) was ubiquinone-10 (Q-10) and the major cellular fatty acids were summed feature 8 (comprising C18:1 ω7c and/or C18:1 ω6c), summed feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c), C16:0 and C14:0 2-OH. Spermidine was the major polyamine. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid, one unidentified phosphoglycolipid, one unidentified phospholipid, one unidentified aminolipid and one unidentified lipid. The DNA G+C content was 63.6 mol%. DNA-DNA relatedness for strain GZGR-4(T) with respect to its closest phylogenetic relative S. aromaticiconvertens DSM 12677(T) was 22.6 ± 5.3 %. On the basis of the polyphasic taxonomic data presented, strain GZGR-4(T) is considered to represent a novel species of the genus Sphingobium, for which the name Sphingobium endophyticus sp. nov. is proposed. The type strain is GZGR-4(T) (=CCTCC AB 2013305(T) = KCTC 32447(T)).

Sphingomonas gei sp. nov., isolated from roots of Geum aleppicum

A yellow-pigmented bacterium, designated strain ZFGT-11(T), was isolated from roots of Geum aleppicum Jacq. collected from Taibai Mountain in Shaanxi Province, north-west China, and was subjected to a taxonomic study by using a polyphasic approach. Cells of strain ZFGT-11(T) were Gram-stain-negative, strictly aerobic rods that were surrounded by a thick capsule and were motile by means of a single polar flagellum. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain ZFGT-11(T) was a member of the genus Sphingomonas and was closely related to Sphingomonas naasensis KACC 16534(T) (97.6% similarity), Sphingomonas kyeonggiense JCM 18825(T) (96.8%), Sphingomonas asaccharolytica IFO 15499(T) (96.7%) and Sphingomonas leidyi DSM 4733(T) (96.6%). The predominant respiratory quinone was ubiquinone-10 (Q-10) and the major cellular fatty acids were summed feature 8 (comprising C(18 : 1)ω7c and/or C(18 : 1)ω6c), C(17 : 1)ω6c, C(14 : 0) 2-OH, C(16 : 0) and C(15 : 0) 2-OH. The major polyamine of strain ZFGT-11(T) was sym-homospermidine. Phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, sphingoglycolipid, two unidentified aminoglycolipids, two unidentified phospholipids and two unidentified lipids were detected in the polar lipid profile. The DNA G+C content was 66.8 mol%. DNA-DNA relatedness for strain ZFGT-11(T) with respect to its closest phylogenetic relative S. naasensis KACC 16534(T) was 26.2±4.8% (mean±SD). On the basis of data from the present polyphasic taxonomic study, strain ZFGT-11(T) is considered to represent a novel species of the genus Sphingomonas , for which the name Sphingomonas gei sp. nov. is proposed. The type strain is ZFGT-11(T) ( = CCTCC AB 2013306(T) = KCTC 32449(T) = LMG 27608(T)).

Hydrobacter penzbergensis gen. nov., sp. nov., isolated from purified water

A Gram-negative, oxidase- and catalase-positive bacterium, designated strain EM 4(T), which varied in shape from rod-shaped to curved or helical with frequently observed bulb-shaped protuberances, was isolated from purified water. 16S rRNA gene sequence analysis indicated that the novel strain belongs to the family Chitinophagaceae within the phylum Bacteroidetes; the closest relative among bacterial species with validly published names was determined to be Sediminibacterium salmoneum NBRC 103935(T), with 93.4 % sequence identity. The main fatty acids of strain EM 4(T) were iso-C15 : 0, iso-C15 : 1 and iso-C17 : 0 3-OH. The polar lipid profile consisted of phosphatidylethanolamine, aminolipids, aminophospholipids and unknown lipids; the quinone system consisted of menaquinone MK-7. 16S rRNA gene sequence analysis and the polar lipid and fatty acid profiles suggest that the strain represents a novel genus and species, for which the name Hydrobacter penzbergensis gen. nov., sp. nov. is proposed. The type strain of Hydrobacter penzbergensis is strain EM 4(T) ( = DSM 25353(T) = CCUG 62278(T)).

Rhizobacter bergeniae sp. nov., isolated from the root of Bergenia scopulosa

A yellowish-pigmented bacterium, designated strain PLGR-1(T), was isolated from the root of Bergenia scopulosa collected from Taibai Mountain in Shaanxi Province, north-west China, and was subjected to a taxonomic study by using a polyphasic approach. Cells of strain PLGR-1(T) were Gram-stain-negative, strictly aerobic, rod-shaped, non-spore-forming and motile with a single polar flagellum. Growth occurred at 7-33 °C (optimum, 25-28 °C), at pH 5.0-10.0 (optimum, pH 6.0-7.0) and with 0-0.5 % (w/v) NaCl (optimum, 0 %). The predominant respiratory quinone was ubiquinone-8 (Q-8) and the major cellular fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). The major polyamines were putrescine and 2-hydroxyputrescine and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content was 69.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain PLGR-1(T) belonged to the class Betaproteobacteria and formed a tight phyletic lineage with members of the genus Rhizobacter. Strain PLGR-1(T) was most closely related to Rhizobacter dauci DSM 11587(T) and Rhizobacter fulvus DSM 19916(T), with 16S rRNA gene sequence similarities of 98.5 and 98.0 %, respectively. The DNA-DNA relatedness values between strain PLGR-1(T) and the type strains of Rhizobacter dauci and Rhizobacter fulvus were 46.3 and 14.7 %, respectively. Based on the phenotypic, phylogenetic and genotypic data, strain PLGR-1(T) is considered to represent a novel species of the genus Rhizobacter, for which the name Rhizobacter bergeniae sp. nov. is proposed. The type strain is PLGR-1(T) ( = CCTCC AB 2013018(T) = KCTC 32299(T) = LMG 27607(T)).

Asticcacaulis endophyticus sp. nov., a prosthecate bacterium isolated from the root of Geum aleppicum

A strictly aerobic, light-yellow-coloured, stalked bacterium, designated strain ZFGT-14(T), was isolated from the root of Geum aleppicum Jacq. collected from Taibai Mountain in Shaanxi province, north-west China, and was subjected to a taxonomic study using a polyphasic approach. This novel isolate grew at 7-33 °C (optimum 25-28 °C) and pH 6.0-10.0 (optimum pH 7.0-8.0). Flexirubin-type pigments were not produced. Cells were Gram-stain-negative, rod-shaped and motile with a single polar flagellum. The predominant respiratory quinone was Q-10. The major cellular fatty acids were summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0, C19 : 0 cyclo ω8c and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and the major polar lipids were phosphatidylglycerol and glycolipids. The DNA G+C content was 57.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZFGT-14(T) was most closely related to the genus Asticcacaulis and had low sequence similarity (95.0-95.9 %) with all species with validly published names within the genus Asticcacaulis. Based on the phenotypic, phylogenetic and genotypic data, strain ZFGT-14(T) is considered to represent a novel species of the genus Asticcacaulis, for which the name Asticcacaulis endophyticus sp. nov. is proposed. The type strain is ZFGT-14(T) ( = CCTCC AB 2013012(T) = KCTC 32296(T) = LMG 27605(T)).

Flavihumibacter solisilvae sp. nov., isolated from forest soil

A Gram-stain-positive, strictly aerobic, yellow colony-forming bacterium, designated strain 3-3(T), was isolated from forest soil of Bac Kan Province in Vietnam. Cells were non-motile rods without gliding motility, showing oxidase- and catalase-positive reactions. Growth was observed at 20-37 °C (optimum, 28 °C) and pH 5.5-9.5 (optimum, pH 7.5). The major cellular fatty acids were iso-C(15 : 0), iso-C(15 : 1) G and summed feature 3 (comprising C(16 : 1)ω6c and/or C(16 : 1)ω7c). Strain 3-3(T) contained phosphatidylethanoamine, three unidentified aminolipids and three unidentified lipids. The G+C content of the genomic DNA was 49.5 mol% and the only isoprenoid quinone detected was menaquinone 7 (MK-7). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 3-3(T) formed a tight phylogenetic lineage with Flavihumibacter petaseus T41(T) with a bootstrap value of 100%. Strain 3-3(T) was related most closely to F. petaseus T41(T) with 97.3% 16S rRNA gene sequence similarity and the level of DNA-DNA relatedness between the two was 9.4±1.2%. Based on phenotypic, chemotaxonomic and molecular features, strain 3-3(T) represents a novel species of the genus Flavihumibacter, for which the name Flavihumibacter solisilvae sp. nov. is proposed. The type strain is 3-3(T) ( = KACC 17917(T) = JCM 19891(T)).

Solirubrobacter taibaiensis sp. nov., isolated from a stem of Phytolacca acinosa Roxb

A white-coloured bacterium, designated strain GTJR-20(T), was isolated from a stem of Phytolacca acinosa Roxb. collected from Taibai Mountain in Shaanxi Province, north-west China, and was subjected to a taxonomic study by using a polyphasic approach. The novel isolate was found to grow optimally at 28-30 °C, at pH 7.5-8.0 and in the absence of NaCl. Cells were observed to be Gram-stain positive, strictly aerobic, rod-shaped and non-motile. The predominant respiratory quinone was identified as MK-7(H4) and the major cellular fatty acids were identified as iso-C16:0 (35.8 %), C18:1 ω9c (17.7 %), C17:1 ω6c (11.0 %), C17:1 ω8c (7.8 %) and C18:3 ω6c (6, 9, 12) (7.2 %). The DNA G+C content was determined to be 71.6 mol %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GTJR-20(T) is a member of the genus Solirubrobacter and is closely related to Solirubrobacter phytolaccae GTGR-8(T) (16S rRNA gene sequence similarity, 98.4 %), Solirubrobacter soli KCTC 12628(T) (97.8 %), Solirubrobacter pauli KCTC 9974(T) (97.7 %) and Solirubrobacter ginsenosidimutans KCTC 19420(T) (97.6 %). No other recognized bacterial species showed more than 94.6 % 16S rRNA gene sequence similarity to the novel isolate. DNA-DNA relatedness values for strain GTJR-20(T) with respect to its closely related neighbours S. phytolaccae GTGR-8(T), S. soli KCTC 12628(T), S. pauli KCTC 9974(T) and S. ginsenosidimutans KCTC 19420(T) were 48.3 ± 8.6, 21.3 ± 5.2, 36.8 ± 6.2 and 36.0 ± 5.5 %, respectively. Based on the phenotypic, phylogenetic and genotypic data, strain GTJR-20(T) is considered to represent a novel species of the genus Solirubrobacter, for which the name Solirubrobacter taibaiensis sp. nov. is proposed. The type strain is GTJR-20(T) (=CCTCC AB 2013308(T) = KCTC 29222(T)).

Taibaiella chishuiensis sp. nov., isolated from freshwater

A Gram-reaction-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, AY17T, was isolated from the Chishui River in Guizhou Province, South-west China. Strain AY17T grew optimally at pH 7.0 and 20 °C. Flexirubin-type pigments were produced. 16S rRNA gene sequence analysis indicated that strain AY17T belonged to the family Chitinophagaceae within the phylum Bacteroidetes; the closest phylogenetic relative was Taibaiella smilacinae PTJT-5T (95.3% gene sequence similarity). The DNA G+C content was 49.5 mol%. Strain AY17T contained MK-7 as the predominant respiratory quinone and phosphatidylethanolamine as the major polar lipid. The major fatty acids were iso-C15:0, iso-C15:1G and iso-C17:0 3-OH. On the basis of phylogenetic, phenotypic and genetic data, strain AY17T was classified as representing a novel species of the genus Taibaiella, for which the name Taibaiella chishuiensis sp. nov. is proposed. The type strain is AY17T (=CGMCC 1.12700T=JCM 19637T).

Pseudoxanthomonas gei sp. nov., a novel endophytic bacterium isolated from the stem of Geum aleppicum

A Gram stain-negative, strictly aerobic, rod-shaped, non-motile and deep-yellow-coloured bacterial strain, designated ZFJR-3(T), was isolated from the stem of Geum aleppicum Jacq. collected from Taibai Mountain in Shaanxi Province, north-west China, and characterized by using a polyphasic approach. The novel isolate grew optimally at 25-28 °C and in the absence of NaCl. Flexirubin-type pigments were produced. The predominant respiratory quinone was ubiquinone-8 (Q-8) and the major cellular fatty acids were iso-C15:0 (29.2 %), iso-C16:0 (18.5 %), summed feature 9 (comprising iso-C17:1 ω9c and/or C16:0 10-methyl; 8.8 %), C16:1 ω7c alcohol (8.8 %), iso-C11:0 3-OH (6.9 %) and iso-C11:0 (6.8 %). The DNA G+C content was 66.1 mol %. The only polyamine was spermidine and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain ZFJR-3(T) belongs to the genus Pseudoxanthomonas and was most closely related to Pseudoxanthomonas yeongjuensis KCTC 22757(T) (16S rRNA gene sequence similarity, 99.0 %) and Pseudoxanthomonas sacheonensis KCTC 22080(T) (98.0 %). The levels of 16S rRNA gene sequence similarity with respect to other Pseudoxanthomonas species with validly published names were less than 96.5 %. DNA-DNA relatedness values for strain ZFJR-3(T) with respect to its closely related neighbours P. yeongjuensis KCTC 22757(T) and P. sacheonensis KCTC 22080(T) were 48.7 and 36.3 %, respectively. Based on the phenotypic, phylogenetic and genotypic data, strain ZFJR-3(T) is considered to represent a novel species of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas gei sp. nov. is proposed. The type strain is ZFJR-3(T) (=CCTCC AB 2013020(T) =KCTC 32298(T)).

Crenotalea thermophila gen. nov., sp. nov., a member of the family Chitinophagaceae isolated from a hot spring

A thermophilic aerobic bacterium designated strain STH-1-Y1(T) was isolated from sulfur-turf in a Japanese hot spring (Okuhodaka hot spring, Gifu Pref.). Colonies of strain STH-1-Y1(T) were yellow and low convex morphology with a slightly irregular fringe. Cells were slender long rods, 0.4-0.6 µm wide and 1.2-3.0 µm long. The isolate was an obligate aerophilic organism, and could not grow by fermentation or nitrate respiration. The isolate had a thermophilic trait, and could grow at 35-60 °C and pH 5.5-7.5; maximum growth occurred at 55 °C and pH 7.0 with a doubling time of 1.9 h. The Biolog and API tests suggested that strain STH-1-Y1(T) was able to use various sugars such as glucose, lactose, mannose, maltose, trehalose, cellobiose and sucrose, but could not use sugar alcohols other than glycerol, i.e. adonitol, arabitol, erythritol, inositol, mannitol, sorbitol and xylitol. Lactate and glutamate could be used, but other fatty acids, i.e. acetate, citrate, propionate and succinate could not. Gelatin, casein, starch and glycogen were hydrolysed, but neither chitin nor agar was degraded. Cells lacked flexirubin and showed oxidase and catalase activities. The major respiratory quinone was menaquinone-7 (MK-7), and major cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, iso-C17 : 0 and anteiso-C15 : 0. No unsaturated fatty acids were detected. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain STH-1-Y1(T) was closely related to the family Chitinophagaceae within the phylum Bacteroidetes. However, the isolate was evenly distant from all members in this family with sequence similarities of 87-89 %. These significantly low sequence similarities strongly suggested that strain STH-1-Y1(T) represents a novel species in a new genus of the family Chitinophagaceae within the phylum Bacteroidetes. Based on phenotypic and phylogenetic characteristics, the name Crenotalea thermophila gen. nov., sp. nov. is proposed. The type strain of the type species is STH-1-Y1(T) ( = JCM 11541(T) = DSM 14807(T)).

Taibaiella koreensis sp. nov., isolated from soil of a ginseng field

A Gram-staining-negative, strictly aerobic, motile (by gliding), non-spore-forming and rod-shaped bacterial strain, designated THG-DT86(T), was isolated from soil of a ginseng field of Pocheon province in the Republic of Korea and its taxonomic position was investigated by a polyphasic approach. Growth occurred at 10-35 °C, at pH 6.5-8.5 and with 0-1.5 % (w/v) NaCl on trypticase soy agar. Flexirubin-type pigments were found to be present. On the basis of 16S rRNA gene sequence similarity, strain THG-DT86(T) was shown to belong to the genus Taibaiella and was related to Taibaiella smilacinae PTJT-5(T) (95.3 %). The G+C content of the genomic DNA was 50.1 mol%. The only isoprenoid quinone detected in strain THG-DT86(T) was menaquinone-7 (MK-7) and the only polyamine was homospermidine. The predominant fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 0, iso-C15 : 1 G and iso-C17 : 0, and the major polar lipids were phosphatidylethanolamine, an unidentified aminophosphoglycolipid and an unidentified aminophospholipid. Phenotypic data and phylogenetic inference supported the affiliation of strain THG-DT86(T) to the genus Taibaiella, and a number of biochemical tests differentiated strain THG-DT86(T) from the recognized species of the genus Taibaiella. Therefore, the novel isolate represents a novel species, for which the name Taibaiella koreensis sp. nov. is proposed, with THG-DT86(T) as the type strain ( = KACC 17171(T) = JCM 18823(T)).

Solirubrobacter phytolaccae sp. nov., an endophytic bacterium isolated from roots of Phytolacca acinosa Roxb

A Gram-staining-positive, strictly aerobic, rod-shaped, non-motile, non-spore-forming bacterial strain, designated GTGR-8(T), which formed white colonies, was isolated from roots of Phytolacca acinosa Roxb. collected from Taibai Mountain in Shaanxi Province, north-west China. Strain GTGR-8(T) grew optimally at 28-30 °C, at pH 7.0-8.0 and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain GTGR-8(T) was a member of the genus Solirubrobacter and was closely related to Solirubrobacter pauli B33D1(T) (98.9% similarity), Solirubrobacter ginsenosidimutans BXN5-15(T) (97.0%) and Solirubrobacter soli Gsoil 355(T) (96.9%). No other recognized bacterial species showed more than 94.2% 16S rRNA gene sequence similarity to the novel isolate. The only respiratory quinone of strain GTGR-8(T) was MK-7(H4) and the major fatty acids (>5%) were iso-C16 : 0, C18 : 1ω9c, C17 : 1ω8c, C18 : 3ω6c (6,9,12) and C17 : 1ω6c. The DNA G+C content was 71.0 mol%. DNA-DNA relatedness for strain GTGR-8(T) with respect to its closest relatives, S. pauli KCTC 9974(T) and S. ginsenosidimutans KCTC 19420(T), was 52.5 and 24.5%, respectively. Based on phenotypic, phylogenetic and genotypic data, strain GTGR-8(T) is considered to represent a novel species in the genus Solirubrobacter, for which the name Solirubrobacter phytolaccae sp. nov. is proposed. The type strain is GTGR-8(T) ( = CCTCC AB 2013011(T) = KCTC 29190(T)).