Description of Massilia rubra sp. nov., Massilia aquatica sp. nov., Massilia mucilaginosa sp. nov., Massilia frigida sp. nov., and one Massilia genomospecies isolated from Antarctic streams, lakes and regoliths

Disentangling microbial coupled fillers mechanisms for the permeable layer optimization process in multi-soil-layering systems

The multi-soil-layering (MSL) systems is an emerging solution for environmentally-friendly and cost-effective treatment of decentralized rural domestic wastewater. However, the role of the seemingly simple permeable layer has been overlooked, potentially holding the breakthroughs or directions to addressing suboptimal nitrogen removal performance in MSL systems. In this paper, the mechanism among diverse substrates (zeolite, green zeolite and biological ceramsite) coupled microorganisms in different systems (activated bacterial powder and activated sludge) for rural domestic wastewater purification was investigated. The removal efficiencies performed by zeolite coupled with microorganisms within 3 days were 93.8% for COD, 97.1% for TP, and 98.8% for NH4+-N. Notably, activated sludge showed better nitrification and comprehensive performance than specialized nitrifying bacteria powder. Zeolite attained an impressive 89.4% NH4+-N desorption efficiency, with a substantive fraction of NH4+-N manifesting as exchanged ammonium. High-throughput 16S rRNA gene sequencing revealed that aerobic and parthenogenetic anaerobic bacteria dominated the reactor, with anaerobic bacteria conspicuously absent. And the heterotrophic nitrification-aerobic denitrification (HN-AD) process was significant, with the presence of denitrifying phosphorus-accumulating organisms (DPAOs) for simultaneous nitrogen and phosphorus removal. This study not only raises awareness about the importance of the permeable layer and enhances comprehension of the HN-AD mechanism in MSL systems, but also provides valuable insights for optimizing MSL system construction, operation, and rural domestic wastewater treatment.

Bacterial diversity and geomicrobiology of Winter Wonderland ice cave, Utah, USA

The Winter Wonderland ice cave, located at an elevation of 3140 m above sea level in the Uinta Mountains of northern Utah, USA, maintains a constant sub-zero temperature. Seasonal snowmelt and rain enter the cave, freeze on the surface of the existing ice, and contribute to a 3-m-thick layered ice mass. This ice mass contains organic matter and cryogenic cave carbonates (CCCs) that date back centuries. In this study, samples of ice, liquid water, and exposed CCCs were collected to examine the bacterial communities within the cave and to determine if these communities vary spatially and between sample types. Flow cytometry showed that cell counts are an order of magnitude higher in liquid water samples than in ice. Epifluorescence microscopy and scanning electron microscopy imaging revealed potential coccoid and bacillus microbial morphologies in water samples and putative cells or calcite spherules in the CCCs. The diversity of bacteria associated with soil, identified through sequence-based analysis, supports the hypothesis that water enters the cave by filtering through soil and bedrock. A differential abundance of bacterial taxa was observed between sample types, with the greatest diversity found in CCCs. This supports a geomicrobiological framework where microbes aggregate in the water, sink into a concentrated layer, and precipitate out of the ice with the CCCs, thereby reducing the cell counts in the ice. These CCCs may provide essential nutrients for the bacteria or could themselves be products of biomineralization.

Differential Reshaping of Skin and Intestinal Microbiota by Stocking Density and Oxygen Availability in Farmed Gilthead Sea Bream (Sparus aurata): A Behavioral and Network-Based Integrative Approach

Fish were kept for six weeks at three different initial stocking densities and water O2 concentrations (low-LD, 8.5 kg/m3 and 95-70% O2 saturation; medium-MD, 17 kg/m3 and 55-75% O2 saturation; high-HD, 25 kg/m3 and 60-45% O2 saturation), with water temperature increasing from 19 °C to 26-27 °C. The improvement in growth performance with the decrease in stocking density was related to changes in skin and intestinal mucosal microbiomes. Changes in microbiome composition were higher in skin, with an increased abundance of Alteromonas and Massilia in HD fish. However, these bacteria genera were mutually exclusive, and Alteromonas abundance was related to a reactive behavior and systemic growth regulation via the liver Gh/Igf system, while Massilia was correlated to a proactive behavior and a growth regulatory transition towards muscle rather than liver. At the intestinal level, microbial abundance showed an opposite trend for two bacteria taxa, rendering in a low abundance of Reyranella and a high abundance of Prauserella in HD fish. This trend was correlated with up-regulated host gene expression, affecting the immune response, epithelial cell turnover, and abiotic stress response. Most of the observed responses are adaptive in nature, and they would serve to infer new welfare indicators for increased stress resilience.

Biotechnological potential of psychrotolerant methylobacteria isolated from biotopes of Antarctic oases

Ten strains of psychrotolerant methylotrophic bacteria were isolated from the samples collected in Larsemann and Bunger Hills (Antarctica). Most of the isolates are assigned to the genus Pseudomonas, representatives of the genera Janthinobacterium, Massilia, Methylotenera and Flavobacterium were also found. Majority of isolates were able to grow on a wide range of sugars, methylamines and other substrates. Optimal growth temperatures for the isolated strains varied from 6 °C to 28 °C. The optimal concentration of NaCl was 0.5-2.0%. The optimal pH values of the medium were 6-7. It was found that three strains synthesized indole-3-acetic acid on a medium with L-tryptophan reaching 11-12 μg/ml. The values of intracellular carbohydrates in several strains exceeded 50 μg/ml. Presence of calcium-dependent and lanthanum-dependent methanol dehydrogenase have been shown for some isolates. Strains xBan7, xBan20, xBan37, xBan49, xPrg27, xPrg48, xPrg51 showed the presence of free amino acids. Bioprospection of Earth cryosphere for such microorganisms has a potential in biotechnology.

Arbuscular mycorrhizal fungi drive bacterial community assembly in halophyte Suaeda salsa

Halophytes inhabit saline soils, wherein most plants cannot grow, therefore, their ecological value is outstanding. Arbuscular mycorrhizal (AM) fungi can reconstruct microbial communities to assist plants with stress tolerance. However, little information is available on the microbial community assembly of AM fungi in halophytes. A pot experiment was conducted to investigate the effects of AM fungi on rhizosphere bacterial community structure and soil physiochemical characteristics in the halophyte Suaeda salsa at 0, 100, and 400 mM NaCl. The results demonstrated that AM fungi increased soil alkaline phosphatase (ALP) activity at the three NaCl concentrations, and decreased available P, available K, and the activity of soil catalase (CAT) at 100 mM NaCl. AM fungi decreased the Shannon index of the community at 0 and 100 mM NaCl and increased Sobs index at 400 mM NaCl. Regarding the bacterial community structure, AM fungi substantially decreased the abundance of Acidobacteria phylum at 0 and 100 mM NaCl. AM fungi significantly increased the abundance of genus Ramlibacter, an oxyanion-reducing bacteria that can clean out reactive oxygen species (ROS). AM fungi recruited the genera Massilia and Arthrobacter at 0 and 100 mM NaCl, respectively. Some strains in the two genera have been ascribed to plant growth promoting bacteria (PGPB). AM fungi increased the dry weight and promoted halophyte growth at all three NaCl levels. This study supplements the understanding that AM fungi assemble rhizosphere bacterial communities in halophytes.

Taxonomic Diversity and Functional Traits of Soil Bacterial Communities under Radioactive Contamination: A Review

Studies investigating the taxonomic diversity and structure of soil bacteria in areas with enhanced radioactive backgrounds have been ongoing for three decades. An analysis of data published from 1996 to 2024 reveals changes in the taxonomic structure of radioactively contaminated soils compared to the reference, showing that these changes are not exclusively dependent on contamination rates or pollutant compositions. High levels of radioactive exposure from external irradiation and a high radionuclide content lead to a decrease in the alpha diversity of soil bacterial communities, both in laboratory settings and environmental conditions. The effects of low or moderate exposure are not consistently pronounced or unidirectional. Functional differences among taxonomic groups that dominate in contaminated soil indicate a variety of adaptation strategies. Bacteria identified as multiple-stress tolerant; exhibiting tolerance to metals and antibiotics; producing antioxidant enzymes, low-molecular antioxidants, and radioprotectors; participating in redox reactions; and possessing thermophilic characteristics play a significant role. Changes in the taxonomic and functional structure, resulting from increased soil radionuclide content, are influenced by the combined effects of ionizing radiation, the chemical toxicity of radionuclides and co-contaminants, as well as the physical and chemical properties of the soil and the initial bacterial community composition. Currently, the quantification of the differential contributions of these factors based on the existing published studies presents a challenge.

The silicon regulates microbiome diversity and plant defenses during cold stress in Glycine max L

Introduction

With climate change, frequent exposure of bioenergy and food crops, specifically soybean (Glycine max L.), to low-temperature episodes is a major obstacle in maintaining sustainable plant growth at early growth stages. Silicon (Si) is a quasi-essential nutrient that can help to improve stress tolerance; however, how Si and a combination of cold stress episodes influence plant growth, plant physiology, and microbiome diversity has yet to be fully discovered.

Methods

The soybean plants were exposed to cold stress (8-10°C) with or without applying Si, and the different plant organs (shoot and root) and rhizospheric soil were subjected to microbiome analysis. The plant growth, physiology, and gene expression analysis of plant defenses during stress and Si were investigated.

Results and discussion

We showed that cold stress significantly retarded soybean plants' growth and biomass, whereas, Si-treated plants showed ameliorated negative impacts on plant growth at early seedling stages. The beneficial effects of Si were also evident from significantly reduced antioxidant activities - suggesting lower cold-induced oxidative stress. Interestingly, Si also downregulated critical genes of the abscisic acid pathway and osmotic regulation (9-cis-epoxy carotenoid dioxygenase and dehydration-responsive element binding protein) during cold stress. Si positively influenced alpha and beta diversities of bacterial and fungal microbiomes with or without cold stress. Results showed significant variation in microbiome composition in the rhizosphere (root and soil) and phyllosphere (shoot) in Si-treated plants with or without cold stress exposures. Among microbiome phyla, Proteobacteria, Bacteroidota, and Ascomycota were significantly more abundant in Si treatments in cold stress than in control conditions. For the core microbiome, we identified 179 taxa, including 88 unique bacterial genera in which Edaphobacter, Haliangium, and Streptomyces were highly abundant. Enhanced extracellular enzyme activities in the cold and Si+cold treatments, specifically phosphatase and glucosidases, also reflected the microbiome abundance. In conclusion, this work elucidates cold-mediated changes in microbiome diversity and plant growth, including the positive impact Si can have on cold tolerance at early soybean growth stages - a step toward understanding crop productivity and stress tolerance.

DOM hydrophilic components of organic fertilizers increased the soil nitrogen retention capacity and succession of the microbial community

Introduction

Application of organic fertilizers affects soil properties and microbial communities, which in turn alters soil N transformation processes. Unfortunately, it is not clear how the difference in the character of the organic fertilizer DOM affects the soil nitrogen retention capacity and its microbial processes.

Methods

According to the principle of equal nutrients, the treatments of chemical fertilizer alone (treatment CF), chemical fertilizer with organic fertilizer DOM hydrophilic components (treatment H), and chemical fertilizer with organic fertilizer DOM hydrophobic components (treatment P) were set up, where the characteristics of soil nitrogen transformation and changes in microbial community structure were studied with soil culture conditions for 24 days.

Results

It was discovered that the addition of organic fertilizer DOM components (H and P) slowed nitrification rate and increased protease activity resulting in a higher NH4+-N content compared to the CF treatment. The DOM addition (H and P) increased the microbial biomass nitrogen (MBN) levels in the soil and increased the soil nitrogen pool capacity.

Conclusions

Moreover, the carbon use efficiency of the hydrophilic components is higher than that of the hydrophobic components, resulting in its further increase in nitrogen reservoir capacity and higher nitrogen retention capacity. Network analysis showed that the addition of organic fertilizer DOM hydrophilic components increased network complexity and synergy between microorganisms. In combination with random forest analysis, it was shown that Sphingomonas and Massilia were key species influencing soil nitrogen retention capacity and nitrogen availability characteristics.

Key genes of electron transfer, the nitrogen cycle and tetracycline removal in bioelectrochemical systems

BACKGROUND

Soil microbial fuel cells (MFCs) can remove antibiotics and antibiotic resistance genes (ARGs) simultaneously, but their removal mechanism is unclear. In this study, metagenomic analysis was employed to reveal the functional genes involved in degradation, electron transfer and the nitrogen cycle in the soil MFC.

RESULTS

The results showed that the soil MFC effectively removed tetracycline in the overlapping area of the cathode and anode, which was 64% higher than that of the control. The ARGs abundance increased by 14% after tetracycline was added (54% of the amplified ARGs belonged to efflux pump genes), while the abundance decreased by 17% in the soil MFC. Five potential degraders of tetracycline were identified, especially the species Phenylobacterium zucineum, which could secrete the 4-hydroxyacetophenone monooxygenase encoded by EC 1.14.13.84 to catalyse deacylation or decarboxylation. Bacillus, Geobacter, Anaerolinea, Gemmatirosa kalamazoonesis and Steroidobacter denitrificans since ubiquinone reductase (encoded by EC 1.6.5.3), succinate dehydrogenase (EC 1.3.5.1), Coenzyme Q-cytochrome c reductase (EC 1.10.2.2), cytochrome-c oxidase (EC 1.9.3.1) and electron transfer flavoprotein-ubiquinone oxidoreductase (EC 1.5.5.1) served as complexes I, II, III, IV and ubiquinone, respectively, to accelerate electron transfer. Additionally, nitrogen metabolism-related gene abundance increased by 16% to support the microbial efficacy in the soil MFC, and especially EC 1.7.5.1, and coding the mutual conversion between nitrite and nitrate was obviously improved.

CONCLUSIONS

The soil MFC promoted functional bacterial growth, increased functional gene abundance (including nitrogen cycling, electron transfer, and biodegradation), and facilitated antibiotic and ARG removal. Therefore, soil MFCs have expansive prospects in the remediation of antibiotic-contaminated soil. This study provides insight into the biodegradation mechanism at the gene level in soil bioelectrochemical remediation.

Bioplastic (poly-3-hydroxybutyrate)-producing Massilia endophytica sp. nov., isolated from Cannabis sativa L. 'Cheungsam'

A rod-shaped, motile, Gram-negative bacterial strain named DM-R-R2A-13T was isolated from the plant Cannabis sativa L. 'Cheungsam'. The phylogenetic analysis of the 16S rRNA gene sequence revealed that strain DM-R-R2A-13T belongs to the family Oxalobacteraceae and is closely related to members of the genus Massilia, with Massilia flava (97.58% sequence similarity) and Massilia armeniaca (97.37% sequence similarity) being the closest members. The digital DNA-DNA hybridization (dDDH) values between strain DM-R-R2A-13T and Massilia flava CGMCC 1.10685T and Massilia armeniaca ZMN-3Twere 22.2% and 23.3%, while the average nucleotide identity (ANI) values were 78.85% and 79.63%, respectively. The DNA G+C content was measured to be 64.6 mol%. Moreover, the bacterium was found to contain polyhydroxyalkanoate (PHA) granules based on transmission electron microscopy, indicating its potential to produce bioplastic. Genome annotation revealed the presence of PHA synthase genes (phaC, phaR, phaP, and phaZ), and the biopolymer was identified as poly-3-hydroxybutyrate (PHB) based on nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) analyses. Using maltose as a carbon source, the strain produced PHB of up to 58.06% of its dry cell weight. Based on the phenotypic, chemotaxonomic, and phylogenetic characteristics, it has been determined that DM-R-R2A-13T represents a novel species belonging to the genus Massilia. As such, the name Massilia endophytica sp. nov. is proposed for this newly identified species. The type strain is DM-R-R2A-13T (= KCTC 92072T = GDMCC 1.2920T).

Hydrogel-potassium humate composite alleviates cadmium toxicity of tobacco by regulating Cd bioavailability

Cadmium (Cd) removal from soil to reduce Cd accumulation in plants is essential for agroecology, food safety, and human health. Cd enters plants from soil and affects plant growth and development. Hydrogels can easily combine with Cd, thereby altering its bioavailability in soil. However, few studies have evaluated the effects of hydrogel on the complex phytotoxicity caused by Cd uptake in plants and the microbial community structure. Herein, a new poly (acrylic acid)-grafted starch and potassium humate composite (S/K/AA) hydrogel was added to soil to evaluate its impact on tobacco growth and the soil microenvironment. The results indicate that the addition of S/K/AA hydrogel can significantly improve the biomass, chlorophyll (Chl) content, and photosynthetic capacity of tobacco plants during Cd stress conditions, and decrease Cd concentration, probably by affecting Cd absorption through the expression of Cd absorption transporters (e.g., NRAMP5, NRAMP3, and IRT1). Moreover, the application of S/K/AA hydrogel not only reduced the accumulation of reactive oxygen species (ROS), but also reduced the antioxidant activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), suggesting that S/K/AA hydrogel alleviates Cd toxicity via a non-antioxidant pathway. Notably, we further analyzed the effectiveness of the hydrogel on microbial communities in Cd-contaminated soil and found that it increased the Cd-tolerant microbial community (Arthrobacter, Massilia, Streptomyces), enhancing the remediation ability of Cd-contaminated soil and helping tobacco plants to alleviate Cd toxicity. Overall, our study provides primary insights into how S/K/AA hydrogel affects Cd bioavailability and alleviates Cd toxicity in plants.

Genome-wide and constrained ordination-based analyses of EC code data support reclassification of the species of Massilia La Scola et al. 2000 into Telluria Bowman et al. 1993, Mokoshia gen. nov. and Zemynaea gen. nov

Based on genome-wide data, Massilia species belonging to the clade including Telluria mixta LMG 11547T should be entirely transferred to the genus Telluria owing to the nomenclatural priority of the type species Telluria mixta. This results in the transfer of 35 Massilia species to the genus Telluria. The presented data also supports the creation of two new genera since peripherally branching Massilia species are distinct from Telluria and other related genera. It is proposed that 13 Massilia species are transferred to Mokoshia gen. nov. with the type species designated Mokoshia eurypsychrophila comb. nov. The species Massilia arenosa is proposed to belong to the genus Zemynaea gen. nov. as the type species Zemynaea arenosa comb. nov. The genome-wide analysis was well supported by canonical ordination analysis of Enzyme Commission (EC) codes annotated from genomes via pannzer2. This new approach was performed to assess the conclusions of the genome-based data and reduce possible ambiguity in the taxonomic decision making. Cross-validation of EC code data compared within canonical plots validated the reclassifications and correctly visualized the expected genus-level taxonomic relationships. The approach is complementary to genome-wide methodology and could be used for testing sequence alignment based data across genetically related genera. In addition to the proposed broader reclassifications, invalidly described species 'Massilia antibiotica', 'Massilia aromaticivorans', 'Massilia cellulosiltytica' and 'Massilia humi' are described as Telluria antibiotica sp. nov., Telluria aromaticivorans sp. nov., Telluria cellulosilytica sp. nov. and Pseudoduganella humi sp. nov., respectively. In addition, Telluria chitinolytica is reclassified as Pseudoduganella chitinolytica comb. nov. The use of combined genome-wide and annotation descriptors compared using canonical ordination clarifies the taxonomy of Telluria and its sibling genera and provides another way to evaluate complex taxonomic data.

Dynamic distribution of Massilia spp. in sewage, substrate, plant rhizosphere/phyllosphere and air of constructed wetland ecosystem

Introduction

Massilia bacteria are widely distributed and have various ecological functions. Preliminary studies have shown that Massilia is the dominant species in constructed wetland ecosystems, but its species composition and distribution in constructed wetlands are still unclear.

Methods

In this paper, the in-house-designed primers were used to construct a 16S rDNA clone library of Massilia. The RFLP sequence analysis method was used to analyze the diversity of Massilia clone library and the composition of Massilia in sewage, substrate, plant rhizosphere, plant phyllosphere and air in a constructed wetland sewage treatment system. Redundancy analysis (RDA) and canonical correspondence analysis (CCA) were used to analyze the correlation between environmental factors and the population characteristics of Massilia in the corresponding environment. The dominant species of Massilia were analyzed for differences.

Results

The results showed that the 16S rDNA clone library in primer 5 worked well. According to the clone library diversity index analysis, the richness of Massilia varied significantly in different environments in different seasons, where the overall summer and autumn richness was higher than that in the spring and winter. The relative abundance of 5 Massilia in the constructed wetland ecosystem was greater than 1% in all samples, which were M. alkalitolerans, M. albidiflava, M. aurea, M. brevitalea, and M. timonae. The seasonal variation of dominant genera was significantly correlated with environmental factors in constructed wetlands.

Discussion

The above results indicated that the species of Massilia were abundant and widely distributed in the constructed wetland ecosystem, and there were significant seasonal differences. In addition, the Massilia clone library of constructed wetland was constructed for the first time in this study and the valuable data of Massilia community structure were provided, which was conducive to the further study of microbial community in constructed wetland.

Structure Determination of Lipid A with Multiple Glycosylation Sites by Tandem MS of Lithium-Adducted Negative Ions

FLATn is a tandem mass spectrometric technique that can be used to rapidly generate spectral information applicable for structural elucidation of lipids like lipid A from Gram-negative bacterial species from a single bacterial colony. In this study, we extend the scope and capability of FLATn by tandem MS fragmentation of lithium-adducted molecular lipid A anions and fragments (FLATn-Li) that provides additional structural and diagnostic data from FLATn samples allowing for the discrimination of terminal phosphate modifications in a variety of pathogenic and environmental species. Using FLATn-Li, we elucidated the lipid A structure from several bacterial species, including novel structures from arctic bacterioplankton of the Duganella and Massilia genera that favor 4-amino-4-deoxy-l-arabinopyranose (Ara4N) modification at the 1-phosphate position and that demonstrate double glycosylation with Ara4N at the 1 and 4' phosphate positions simultaneously. The structures characterized in this work demonstrate that some environmental psychrophilic species make extensive use of this structural lipid A modification previously characterized as a pathogenic adaptation and the structural basis of resistance to cationic antimicrobial peptides. This observation extends the role of phosphate modification(s) in environmental species adaptation and suggests that Ara4N modification can functionally replace the positive charge of the phosphoethanolamine modification that is more typically found attached to the 1-phosphate position of modified lipid A.

Dynamics of dominant rhizospheric microbial communities responsible for trichlorfon absorption and translocation in maize seedlings

In this study, the available phosphorus (AP) and TCF concentrations in soils and maize (Zea mays) seedling tissues were measured in response to escalating TCF concentrations during 216 hr of culture. Maize seedlings growth considerably enhanced soil TCF degradation, reaching the highest of 73.2% and 87.4% at 216 hr in 50 and 200 mg/kg TCF treatments, respectively, and increased AP contents in all the seedling tissues. Soil TCF was majorly accumulated in seedling roots, reaching maximum concentration of 0.017 and 0.076 mg/kg in TCF-50 and TCF-200, respectively. The hydrophilicity of TCF might hinder its translocation to the aboveground shoot and leaf. Using bacterial 16 S rRNA gene sequencing, we found that TCF addition drastically lessened bacterial community interactions and hindered the complexity of their biotic networks in rhizosphere than in bulk soils, leading to the homogeneity of bacterial communities that were resistant or prone to TCF biodegradation. Mantel test and redundancy analysis suggested a significant enrichment of dominant species Massilia belonging to Proteobacteria phyla, which in turn affecting TCF translocation and accumulation in maize seedling tissues. This study provided new insight into the biogeochemical fate of TCF in maize seedling and the responsible rhizobacterial community in soil TCF absorption and translocation.

Microbial communities and their roles in the Cenozoic sulfurous oil reservoirs in the Southwestern Qaidam Basin, Western China

The latest discovery of sulfurous natural gas marked a breakthrough in the Cenozoic natural gas exploration in the southwestern margin of Qaidam Basin. The 16S rRNA analyses were performed on the crude oil samples from H₂S-rich reservoirs in the Yuejin, Shizigou and Huatugou profiles, to understand the sulfurous gas origin, which was also integrated with carbon and hydrogen isotopes of alkane and sulfur isotopes of H₂S collected from the Yingxiongling Area. Results show that the microorganisms in samples can survive in the hypersaline reservoirs, and can be classified into multiple phyla, including Proteobacteria, Planctomycetes, Firmicutes, Bacteroidetes, and Haloanaerobiaeota. Methanogens are abundant in all of the three profiles, while sulfate-reducing bacteria are abundant in Yuejin and Huatugou profiles, contributing to the methane and H₂S components in the natural gas. The carbon, hydrogen and sulfur isotopes of sulfurous natural gas in the Yingxiongling Area show that the natural gas is a mixture of coal-type gas and oil-type gas, which was primarily derived from thermal degradation, and natural gas from the Yuejin and Huatugou profiles also originated from biodegradation. The isotopic analysis agrees well with the 16S rRNA results, i.e., H₂S-rich natural gas from the Cenozoic reservoirs in the southwest margin of the Qaidam Basin was primarily of thermal genesis, with microbial genesis of secondary importance.

Genomic and phenotypic characterization of a red-pigmented strain of Massilia frigida isolated from an Antarctic microbial mat

The McMurdo Dry Valleys of Antarctica experience a range of selective pressures, including extreme seasonal variation in temperature, water and nutrient availability, and UV radiation. Microbial mats in this ecosystem harbor dense concentrations of biomass in an otherwise desolate environment. Microbial inhabitants must mitigate these selective pressures via specialized enzymes, changes to the cellular envelope, and the production of secondary metabolites, such as pigments and osmoprotectants. Here, we describe the isolation and characterization of a Gram-negative, rod-shaped, motile, red-pigmented bacterium, strain DJPM01, from a microbial mat within the Don Juan Pond Basin of Wright Valley. Analysis of strain DJMP01's genome indicates it can be classified as a member of the Massilia frigida species. The genome contains several genes associated with cold and salt tolerance, including multiple RNA helicases, protein chaperones, and cation/proton antiporters. In addition, we identified 17 putative secondary metabolite gene clusters, including a number of nonribosomal peptides and ribosomally synthesized and post-translationally modified peptides (RiPPs), among others, and the biosynthesis pathway for the antimicrobial pigment prodigiosin. When cultivated on complex agar, multiple prodiginines, including the antibiotic prodigiosin, 2-methyl-3-propyl-prodiginine, 2-methyl-3-butyl-prodiginine, 2-methyl-3-heptyl-prodiginine, and cycloprodigiosin, were detected by LC-MS. Genome analyses of sequenced members of the Massilia genus indicates prodigiosin production is unique to Antarctic strains. UV-A radiation, an ecological stressor in the Antarctic, was found to significantly decrease the abundance of prodiginines produced by strain DJPM01. Genomic and phenotypic evidence indicates strain DJPM01 can respond to the ecological conditions of the DJP microbial mat, with prodiginines produced under a range of conditions, including extreme UV radiation.

Massilia agrisoli sp. nov., isolated from rhizospheric soil of banana

A Gram-stain-negative, aerobic, short rod-shaped and motile novel bacterial strain, designated MAHUQ-52^T, was isolated from the rhizospheric soil of a banana plant. Colonies grew at 10-35 °C (optimum, 28 °C), pH 6.0-9.5 (optimum, pH 7.0-7.5), and in the presence of 0-1.0 % NaCl (optimum 0 %). The strain was positive for catalase and oxidase tests, as well as hydrolysis of gelatin, casein, starch and Tween 20. Based on the results of phylogenetic analysis using 16S rRNA gene and genome sequences, strain MAHUQ-52^T clustered together within the genus Massilia. Strain MAHUQ-52^T was closely related to Massilia soli R798^T (98.6 %) and Massilia polaris RP-1-19^T (98.3 %). The novel strain MAHUQ-52^T has a draft genome size of 4 677 454 bp (25 contigs), annotated with 4193 protein-coding genes, 64 tRNA and 19 rRNA genes. The genomic DNA G+C content was 63.0 %. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MAHUQ-52^T and closely related type strains were ≤88.4 and 35.8 %, respectively. The only respiratory quinone was ubiquinone-8. The major fatty acids were identified as C_16 : 0 and summed feature 3 (C_15 : 0 iso 2-OH and/or C_16 : 1  ω7c). Strain MAHUQ-52^T contained phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol as the major polar lipids. On the basis of dDDH and ANI values, as well as genotypic, chemotaxonomic and physiological data, strain MAHUQ-52^T represents a novel species within the genus Massilia, for which the name Massilia agrisoli sp. nov. is proposed, with MAHUQ-52^T (=KACC 21999^T=CGMCC 1.18577^T) as the type strain.

Pseudomonas petrae sp. nov. isolated from regolith samples in Antarctica

A polyphasic taxonomic approach was used to characterize the four strains P2653^T, P2652, P2498, and P2647, isolated from Antarctic regolith samples. Initial genotype screening performed by PCR fingerprinting based on repetitive sequences showed that the isolates studied formed a coherent cluster separated from the other Pseudomonas species. Identification results based on 16S rRNA gene sequences showed the highest sequence similarity with Pseudomonas graminis (99.7%), which was confirmed by multilocus sequence analysis using the rpoB, rpoD, and gyrB genes. Genome sequence comparison of P2653^T with the most related P. graminis type strain DSM 11363^T revealed an average nucleotide identity of 92.1% and a digital DNA-DNA hybridization value of 46.6%. The major fatty acids for all Antarctic strains were C_16:0, Summed Feature 3 (C_16:1ω7c/C_16:1ω6c) and Summed Feature 8 (C_18:1ω7c/C_18:1ω6c). The predominant respiratory quinone was Q-9, and the major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol. The regolith strains could be differentiated from related species by the absence of arginine dihydrolase, ornithine and lysine decarboxylase and by negative tyrosine hydrolysis. The results of this polyphasic study allowed the genotypic and phenotypic differentiation of four analysed strains from the closest related species, which confirmed that the strains represent a novel species within the genus Pseudomonas, for which the name Pseudomonas petrae sp. nov. is proposed with P2653^T (CCM 8850^T = DSM 112068^T = LMG 30619^T) as the type strain.

Massilia phyllostachyos sp. nov., Isolated from the Roots of Moso Bamboo in China

A Gram-negative, strictly aerobic, motile, and rod-shaped bacterial strain G4R7^T was isolated from the roots of moso bamboo (Phyllostachys edulis) in Zhejiang, Hangzhou Province, China. After comparing 16S rRNA gene sequences, strain G4R7^T exhibited the highest similarities with Massilia neuiana PTW21^T (98.3%), followed by M. agri K-3-1^T (98.3%), M. consociate CCUG 58010^T (97.7%), M. niastensis 5516S-1^T (97.7%) and M. yuzhufengensis ZD1-4^T (97.6%). The phylogenetic analysis revealed that strain G4R7^T belonged to the genus Massilia. The draft genome of strain G4R7^T was 5.81 Mb, and the G+C content was 64.4%. The average nucleotide identity values between G4R7^T and another related member of the genus Massilia ranged from 76.6 to 87.2%, and the digital DNA-DNA hybridization ranged from 20.7 to 27.9%. Strain G4R7^T grew at 15-37 °C (optimum 25-30 °C) and pH 6.0-9.0 (optimum pH 7.0) in the presence of 0-3% (w/v) NaCl (optimum 0%). The respiratory quinone was Q-8, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and aminophospholipid. The major cellular fatty acids were C_10:0 3OH, C_12:0, C_12:0 2OH, and C_16:0, summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c). As per the data from chemotaxonomic, phylogenetic, and phenotypic evidence, strain G4R7^T represents a new species of genus Massilia, for which the name Massilia phyllostachyos sp. nov. is proposed. The type strain is G4R7^T (=ACCC 61911^T=GDMCC 1.2961^T=JCM 35225^T).

Studying Plant-Insect Interactions through the Analyses of the Diversity, Composition, and Functional Inference of Their Bacteriomes

As with many other trophic interactions, the interchange of microorganisms between plants and their herbivorous insects is unavoidable. To test the hypothesis that the composition and diversity of the insect bacteriome are driven by the bacteriome of the plant, the bacteriomes of both the plant Datura inoxia and its specialist insect Lema daturaphila were characterised using 16S sRNA gene amplicon sequencing. Specifically, the bacteriomes associated with seeds, leaves, eggs, guts, and frass were described and compared. Then, the functions of the most abundant bacterial lineages found in the samples were inferred. Finally, the patterns of co-abundance among both bacteriomes were determined following a multilayer network approach. In accordance with our hypothesis, most genera were shared between plants and insects, but their abundances differed significantly within the samples collected. In the insect tissues, the most abundant genera were Pseudomonas (24.64%) in the eggs, Serratia (88.46%) in the gut, and Pseudomonas (36.27%) in the frass. In contrast, the most abundant ones in the plant were Serratia (40%) in seeds, Serratia (67%) in foliar endophytes, and Hymenobacter (12.85%) in foliar epiphytes. Indeed, PERMANOVA analysis showed that the composition of the bacteriomes was clustered by sample type (F = 9.36, p < 0.001). Functional inferences relevant to the interaction showed that in the plant samples, the category of Biosynthesis of secondary metabolites was significantly abundant (1.4%). In turn, the category of Xenobiotics degradation and metabolism was significantly present (2.5%) in the insect samples. Finally, the phyla Proteobacteria and Actinobacteriota showed a pattern of co-abundance in the insect but not in the plant, suggesting that the co-abundance and not the presence−absence patterns might be more important when studying ecological interactions.

Himalayan Microbiomes for Agro-environmental Sustainability: Current Perspectives and Future Challenges

The Himalayas are one of the most mystical, yet least studied terrains of the world. One of Earth's greatest multifaceted and diverse montane ecosystems is also one of the thirty-four global biodiversity hotspots of the world. These are supposed to have been uplifted about 60-70 million years ago and support, distinct environments, physiography, a variety of orogeny, and great biological diversity (plants, animals, and microbes). Microbes are the pioneer colonizer of the Himalayas that are involved in various bio-geological cycles and play various significant roles. The applications of Himalayan microbiomes inhabiting in lesser to greater Himalayas have been recognized. The researchers explored the applications of indigenous microbiomes in both agricultural and environmental sectors. In agriculture, microbiomes from Himalayan regions have been suggested as better biofertilizers and biopesticides for the crops growing at low temperature and mountainous areas as they help in the alleviation of cold stress and other biotic stresses. Along with alleviation of low temperature, Himalayan microbes also have the capability to enhance plant growth by availing the soluble form of nutrients like nitrogen, phosphorus, potassium, zinc, and iron. These microbes have been recognized for producing plant growth regulators (abscisic acid, auxin, cytokinin, ethylene, and gibberellins). These microbes have been reported for bioremediating the diverse pollutants (pesticides, heavy metals, and xenobiotics) for environmental sustainability. In the current perspectives, present review provides a detailed discussion on the ecology, biodiversity, and adaptive features of the native Himalayan microbiomes in view to achieve agro-environmental sustainability.

Duganella vulcania sp. nov., Rugamonas fusca sp. nov., Rugamonas brunnea sp. nov. and Rugamonas apoptosis sp. nov., isolated from subtropical streams, and phylogenomic analyses of the genera Janthinobacterium, Duganella, Rugamonas, Pseudoduganella and Massilia

Six Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and motile strains (FT81WT, FT82W, FT107W, FT3ST, LX20WT and LX47WT) sharing high 16S rRNA gene sequence similarities with species of the genera Janthinobacterium (97.0–98.3 %), Duganella (96.3–98.8 %), Rugamonas (97.8–98.6 %), Pseudoduganella (96.8–97.5 %) and Massilia (94.5–98.6 %) were isolated from subtropical streams in PR China. The phylogenetic trees reconstructed using the 16S rRNA gene sequences indicated that the species of above five genera often mix together, indicating that the taxonomic statuses of some species were questionable. Phylogenomic reconstruction based on 369 single-copy orthologous clusters indicated that the species of the genus Janthinobacterium form a distinct cluster, strains FT81WT, FT82W and FT107W form a tight cluster with the species of the genus Duganella , and strains FT3ST, LX20WT and LX47WT form a tight cluster with the species of genus Rugamonas , and the species of genus Pseudoduganella form a tight cluster with Massilia guangdongensis , Massilia ginsengisoli , Massilia rivuli , Massilia namucuonensis , Massilia aquatica sensu Lu et al., Massilia buxea , Massilia armeniaca , Massilia plicata , Massilia flava , Massilia lurida , Massilia dura , Massilia lutea , Massilia umbonata , Massilia albidiflava and Massilia violacea . It should be noted that Massilia aquatica Lu et al. 2020 non Massilia aquatica Holochová et al. 2020 is a later homonym and an illegitimate name. The GTDB Release 202 also supported the proposal that M. guangdongensis , M. ginsengisoli , M. rivuli , M. namucuonensis , M. aquatica sensu Lu et al., M. buxea , M. armeniaca , M. plicata , M. flava , M. lurida , M. dura , M. lutea , M. umbonata , M. albidiflava and M. violacea should be transferred into the genus Pseudoduganella . The calculated pairwise orthologous average nucleotide identity by usearch (OrthoANIu) values were between 95.0 % and 95.6 % among strains FT81WT, FT82W and FT107W, but were less than 91.5 % among strains FT3ST, LX20WT, LX47WT and other related strains. Combining the results of phylogenomic analyses, phenotypic, biochemical and genotypic characteristics, strains FT81WT, FT82W and FT107W should represent a novel species of the genus Duganella , and strains FT3ST, LX20WT and LX47WT should represent three novel species of the genus Rugamonas , for which the names Duganella vulcania sp. nov. (type strain FT81WT=GDMCC 1.1679T =KACC 21471T), Rugamonas fusca sp. nov. (type strain FT3ST=GDMCC 1.1907T =KACC 21952T), Rugamonas brunnea sp. nov. (type strain LX20WT=GDMCC 1.1911T =KACC 21956T) and Rugamonas apoptosis sp. nov. (type strain LX47WT=GDMCC 1.1914T =KACC 21959T) are proposed.

Duganella dendranthematis sp. nov. and Massilia forsythiae sp. nov., isolated from flowers

Two aerobic, Gram-stain-negative, motile, mesophilic, rod-shaped and catalase-positive bacterial strains designated AF9R3T and GN2-R2T were isolated from flowers collected in the Republic of Korea. Strain AF9R3T grew at 4–33 °C, pH 4.0–9.0 and with 0–1 % NaCl (w/v), and strain GN2-R2T grew at 10–33 °C, pH 4.0–9.0 and with 0–1 % NaCl (w/v). Phylogenetic analysis on the basis of 16S rRNA gene sequences indicated that strains AF9R3T and GN2-R2T belonged to the genera Duganella and Massilia , respectively, showing high sequence similarity to Duganella levis CY42WT (99.4 %) and Massilia putida 6 NM-7T (98.0 %), respectively. Both strains contained summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c) and C16 : 0 as the major fatty acids, and ubiquinone Q-8 as the predominant quinone. Strain AF9R3T had diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, and strain GN2-R2T comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid as the major polar lipids. Orthologous average nucleotide identity and digital DNA–DNA hybridization values of strain AF9R3T to its closest relative D. levis CY42WT were 92.6 and 56.5 %, and those of strain GN2-R2T to its closest relative M. putida 6 NM-7T were 81.4 and 24.8 %. Based on genotypic and phenotypic data, strains AF9R3T and GN2-R2T are considered to represent novel species of the genus Duganella and Massilia , respectively, for which the names Duganella dendranthematis sp. nov. (type strain AF9R3T=KACC 21258T=NBRC 114510T) and Massilia forsythiae sp. nov. (type strain GN2-R2T=KACC 21261T=NBRC 114511T) have been proposed.

Characterisation of Waterborne Psychrophilic Massilia Isolates with Violacein Production and Description of Massilia antarctica sp. nov

A group of seven bacterial strains producing blue-purple pigmented colonies on R2A agar was isolated from freshwater samples collected in a deglaciated part of James Ross Island and Eagle Island, Antarctica, from 2017–2019. The isolates were psychrophilic, oligotrophic, resistant to chloramphenicol, and exhibited strong hydrolytic activities. To clarify the taxonomic position of these isolates, a polyphasic taxonomic approach was applied based on sequencing of the 16S rRNA, gyrB and lepA genes, whole-genome sequencing, rep-PCR, MALDI-TOF MS, chemotaxonomy analyses and biotyping. Phylogenetic analysis of the 16S rRNA gene sequences revealed that the entire group are representatives of the genus Massilia. The closest relatives of the reference strain P8398T were Massilia atriviolacea, Massilia violaceinigra, Massilia rubra, Massilia mucilaginosa, Massilia aquatica, Massilia frigida, Massilia glaciei and Massilia eurypsychrophila with a pairwise similarity of 98.6–100% in the 16S rRNA. The subsequent gyrB and lepA sequencing results showed the novelty of the analysed group, and the average nucleotide identity and digital DNA–DNA hybridisation values clearly proved that P8398T represents a distinct Massilia species. After all these results, we nominate a new species with the proposed name Massilia antarctica sp. nov. The type strain is P8398T (= CCM 8941T = LMG 32108T).

Massilia soli sp. nov., isolated from soil

A Gram-stain-negative, catalase- and oxidase-positive and aerobic bacterium, designated strain R798T, was isolated from soil in South Korea. Cells were motile rods by means of a single polar flagellum. Growth of strain R798T was observed at 15–35 °C (optimum, 25–30 °C), pH 5.0–8.0 (optimum, 6.0) and 0–1.5 % NaCl (optimum, 0.3 %). Strain R798T contained ubiquinone-8 as the sole isoprenoid quinone, summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c) and C16 : 0 as the major fatty acids and phosphatidylglycerol and phosphatidylethanolamine as the major polar lipids. The DNA G+C content of strain R798T calculated from the whole genome sequence was 63.3 mol%. Phylogenetic analyses based on the 16S rRNA gene and whole genome sequences revealed that strain R798T formed a distinct phyletic lineage within the genus Massilia . Strain R798T was most closely related to Massilia eurypsychrophila B528-3T with a 98.0 % 16S rRNA gene sequence similarity. Average nucleotide identity and digital DNA–DNA hybridization values between strain R798T and the type strain of M. eurypsychrophila were 79.2 and 22.7 %, respectively. Based on the phenotypic, chemotaxonomic and molecular analyses, strain R798T represents a novel species of the genus Massilia , for which the name Massilia soli sp. nov. is proposed. The type strain is R798T (=KACC 22114T=JCM 34601T).

Draft Genome Sequences of the Three Massilia Strains AB1, ST3, and ZL223

To increase the genomic data available for antibiotic discovery, three independently isolated antibiotic-producing Massilia strains were sequenced. No more than 84% average nucleotide identity was shared with publicly available Massilia genomes, and a low similarity of predicted biosynthetic gene clusters to known clusters was found.