[Objective] To compare the bacterial diversity and community composition between the rhizosphere and non-rhizosphere soil of Gynostemma longipes in different planting regions and reveal the key environmental factors by correlating the bacterial community composition with soil physicochemical properties. The findings are expected to provide a reference for the cultivation and introduction of this plant and lay a basis for exploring the relationship between rhizosphere microorganisms and the chemical component content of G. longipes in different planting regions. [Methods] High-throughput sequencing and soil physicochemical property measurement were employed to compare the bacterial diversity and community composition of G. longipes in different planting regions and reveal the key environmental factors influencing the bacterial community. [Results] A total of 97 085 bacterial amplicon sequence variants (ASVs) were obtained. The bacterial community composition in G. longipes soil showed significant differences among different planting regions (R=0.562, P=0.001) but no significant differences between rhizosphere and non-rhizosphere soil. Proteobacteria (27.40%‒36.67%) and Acidobacteriota (15.60%‒22.19%) were the dominant bacterial phyla. Soil pH, available phosphorus, available potassium, soil organic matter, and alkali-hydrolyzable nitrogen were identified as key environmental factors influencing the bacterial community composition in G. longipes soil. [Conclusion] Based on the sample analysis in this study, the bacterial community diversity and composition of G. longipes varied significantly aross different locations and were closely associated with soil physicochemical properties. This study provides a reference for the cultivation and introduction of G. longipes and gives insights into the relationship between soil microorganisms and secondary metabolite accumulation of G. longipes.

[Objective] To study the effects of drainage on the soil properties and microbial community characteristics in coastal saline-alkali land. [Methods] Soil samples were collected before and after drainage for decreasing salt from the coastal saline-alkali land in Nantong, Jiangsu. The soil pH, nutrient elements (nitrogen, phosphorus, and potassium), enzyme activity, and microbial community structure were analyzed by soil physical and chemical property characterization and high-throughput sequencing. Bioinformatic analysis was conducted to study the correlations between microbial community structure characteristics and soil physical and chemical properties and the possible anaerobic metabolic process. [Results] Drainage for decreasing salt significantly reduced the soil pH and electrical conductivity (EC), while causing the losses of nutrients in the soil to a certain extent. After drainage, the activities of sucrase and peroxidase and the richness and diversity of fungi in the soil increased to a certain extent, while the richness and diversity of bacteria and archaea decreased. Principal component analysis showed that microbial community structure had significantly positive correlations with soil EC and potassium content, while it had significantly negative correlations with catalase and sucrase activities in the soil. Redundancy analysis and functional prediction showed that fungi and archaea were significantly correlated with EC, while archaea may change the community structure by adapting to salinity. [Conclusion] Drainage for decreasing salt reduced the salinity and pH in the soil, which affected the soil properties and microbial community structure.

[Objective] To study the distribution characteristics and enzyme potential of halophilic bacteria in two distinct types of salt lakes located in Xinjiang, China. [Methods] Soil samples were collected from sulfate-type (Qijiaojing) and carbonate-type (Nanhu Alkaline Lake) salt lakes, and their physicochemical properties were analyzed. The diversity, dominant taxa, and enzyme activities of halophilic bacteria were compared between the two salt lakes by Illumina MiSeq and culture experiments. [Results] The physicochemical properties of soil differed significantly between the two salt lakes, and the soil salinity of Qijiaojing salt lake (227.15 mg/g) was higher than that of Nanhu Alkaline Lake (158.61 mg/g). Significant differences were also observed in pH, HCO₃^-, Cl^-, Mg²⁺, and K⁺ content. Spearman correlation analysis revealed positive correlations between Cl^- and Mg²⁺ content and the relative abundance of dominant bacterial genera such as Pontibacter and Bacteroides. Illumina MiSeq results of bacterial 16S rRNA genes indicated that the Simpson and Shannon indexes of Nanhu Alkaline Lake were significantly higher than those of Qijiaojing. Halophilic bacteria belonging to 590 genera of 37 phyla were identified, including Bacteroidota (33.41%), Bacillota (24.71%), Actinomycetota (14.64%), and Pseudomonadota (10.58%). The dominant phylum was Bacteroidota (35.05%) in Nanhu Alkaline Lake, while it was Bacillota (44.66%) in Qijiaojing. The richness of halophilic bacteria in Nanhu Alkaline Lake exceeded that in Qijiaojing, with Pontibacter identified as the dominant genus in both lakes. A total of 1 130 strains were obtained from two salt lakes, belonging to 9 genera, 7 families of 4 phyla, among which Bacillota, Actinomycetota, and Pseudomonadota accounted for 40.53%, 36.81%, and 21.15%, respectively. The results of culture experiments with seven different media indicated that the F6 medium exhibited the highest selectivity towards halophilic microorganisms. Culture experiments demonstrated similar dominant species in both lakes, primarily comprising low-abundant bacteria, such as Nocardiopsis and Bacillus. Enzyme activity screening results revealed that 46.81%, 44.07%, and 20.88% of halophilic bacteria produced esterase, cellulase, and amylase, respectively, with Bacillus exhibiting the highest overall enzyme production capability. [Conclusion] There are significant differences in the halophilic bacterial diversity between sulfate- and carbonate-type salt lakes in Xinjiang. The halophilic bacteria in the carbonate-type Nanhu Alkaline Lake salt lake have higher diversity and exhibit stronger enzyme activities. This investigation contributes valuable insights for the advancement and sustainable utilization of microbial resources and the ecological preservation in salt lakes.

[Objective] To study the influencing factors and mechanism of biogenic gas production in shale. [Methods] The shale in Yulin was chosen as the object of this study, and methanogens specifically enriched by our research team in the preliminary stage were used as functional microbiota. An orthogonal design was adopted to optimize the biogenic gas production conditions. The simulated biogenic gas production characteristics and changes in physical and chemical properties of the shale before and after gas production were comprehensively analyzed by gas chromatography (GC), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy (Ram), and nuclear magnetic resonance spectroscopy (NMR). [Results] The optimal conditions for gas production from shale were as follows: 15% inoculum, a shale particle size of less than 0.125 mm, and an incubation temperature of 35 ℃, under which a cumulative methane yield of 81.22 μmol/g shale was achieved within 50 days. Industrial and elemental analyses conducted before and after gas production revealed that methanogens consumed the organic components of shale to produce methane. XRD results indicated that the inorganic mineral components in shale also contributed to the anaerobic degradation process associated with gas production. FT-IR and Ram results showed that the organic matter in shale was mostly long-chain aliphatic hydrocarbons. During gas production, the carbonyl and ether bonds in some compounds reacted to form intermediate metabolites containing carboxyl groups. After gas production, the D and G peaks in the shale samples were not obvious, indicating that the graphitization degree and maturity of kerogen in the shale increased. In addition, NMR results confirmed that fatty alcohols or fatty amines were utilized by microorganisms in gas production. [Conclusion] Microorganisms can utilize the organic components of the shale to produce gas, while also consuming the inorganic mineral components. This leads to chemical structure organic components, leading to formation of smaller compounds after gas production.

Artemisia desertorum, a dominant xerophyte in the Tengger Desert, possesses exceptional drought resistance, salt tolerance, and sand-fixing capabilities. [Objective] To investigate the diversity of soil microbial communities in the rhizosphere and non-rhizosphere of A. desertorum in the Shapotou Nature Reserve located at the southeastern edge of the Tengger Desert, Ningxia, and the potential interactions between the dominant microbial genera and plants, thus laying a theoretical foundation for ecological restoration in deserts. [Methods] Soil samples were collected from the rhizosphere and non-rhizosphere of A. desertorum, in the plantation cultivated for 42 years of sand fixation, and the sand was collected as the control. Physicochemical properties of each soil sample were measured, and fungal and bacterial communities were analyzed via high-throughput sequencing. [Results] Total nitrogen (TN), available nitrogen (AN), and available potassium (AK) in the rhizosphere and non-rhizosphere soil samples were significantly higher than in shifting sands those in the control (P<0.05). Rhizosphere soil samples also had significantly higher levels of available rhizosphere soils also had significantly higher levels of available phosphorus (AP), AK, soil organic matter (OM), and electrical conductivity (EC) than non-rhizosphere soil samples (P<0.05). Rhizosphere soil samples had slightly higher TN, total phosphorus (TP), AN, and pH than non-rhizosphere soil samples, without significant differences. Bacterial diversity and abundance were higher in non-rhizosphere soil samples, while fungal diversity and abundance were greater in rhizosphere soil samples. Both rhizosphere and non-rhizosphere soil samples had more unique microbial operational taxonomic units (OTUs) than the control. Rhizosphere soil samples contained more fungal OTUs but fewer bacterial OTUs than non-rhizosphere soil samples. Dominant fungal phyla included Ascomycota, Basidiomycota, unclassified fungal phyla, and Rozellomycota, with major fungal genera comprising Candida, Paraphoma, Alternaria, unclassified fungal genera, and Penicillium. Dominant bacterial phyla included Actinobacteriota, Proteobacteria, Bacteroidota, Chloroflexi, and Acidobacteria, with key bacterial genera being Arthrobacter, Nocardioides, Streptomyces, Agromyces, and Sphingomonas. Linear discriminant analysis effect size (LEfSe) identified 212 bacterial taxa and 25 fungal taxa significantly distinguishing rhizosphere soil samples from non-rhizosphere soil samples, with Ascomycota and Proteobacteria being the key taxa. Redundancy analysis showed that OM was the main factor affecting the structure of soil microbial community, positively correlating with Basidiomycota, Acidobacteria, Chloroflexi, and unclassified fungal phyla, while negatively correlating with Ascomycota, Rozellomycota, Actinobacteriota, Proteobacteria, and Bacteroidota. [Conclusion] The cultivation of A. desertorum significantly increased the nutrient levels and fungal diversity and abundance in the rhizosphere soil at the southeastern edge of the Tengger Desert, contributing to soil ecosystem stability. This study offers theoretical insights into regional ecological restoration and provides a scientific basis for restoration scheme optimization and sustainable management of A. desertorum ecosystems.

[Objective] Roseobacter play a significant ecological role in the material cycling and energy flow of marine ecosystems. However, their environmental responses on long time scales and community assembly mechanisms remain unclear. We collected samples over 60 consecutive weeks from the coastal waters near Qingdao to investigate the annual dynamics, environmental responses, and community assembly mechanisms of free-living and particle-associated Roseobacter. [Methods] The 16S rRNA gene amplicon sequencing was performed for the surface seawater samples to reveal the seasonal diversity variations of Roseobacter groups with different lifestyles. Furthermore, the correlations of Roseobacter with various environmental factors and the community assembly mechanisms were explored. [Results] In the surface seawater of the coastal zone, the relative abundance of Roseobacter in total bacteria and archaea exhibited significant seasonal fluctuations (2.64%-34.10%), with being markedly higher in winter and spring than in summer and autumn. Based on the temporal distribution patterns, Roseobacter groups can be classified into summer-autumn, winter-spring, and outbreak growth types. The free-living Roseobacter groups showed more pronounced seasonal patterns, while the particle-associated groups showed higher diversity. Temperature, inorganic nitrogen, and inorganic phosphorus were the main environmental factors influencing Roseobacter diversity, with their explanatory power on particle-associated groups (16.82%) being higher than that on free-living groups (9.06%). In terms of community assembly, deterministic processes had a greater impact on particle-associated Roseobacter groups, indicating that environmental changes had more significant effects on these groups. [Conclusion] This study, by examining the dynamic changes and environmental driving mechanisms of Roseobacter at a fine time scale, reveals their seasonal distribution patterns and provides scientific insights for understanding the spatiotemporal dynamics and ecological functions of this crucial marine bacterial group.

In marine aquaculture, the accumulation of antibiotics such as sulfamethoxazole (SMX) has contributed to the spread of antibiotic-resistant bacteria and genes, posing a serious threat to ecological health. Biological treatment of antibiotic-contaminated wastewater is an essential approach to mitigate these environmental risks. [Objective] To isolate a salt-tolerant strain LS-1 with high SMX degradation efficiency from the sediment of an inshore aquaculture pond, examine the effects of environmental factors on the degradation capacity of this strain, optimize the SMX degradation conditions, elucidate the degradation pathway through product analysis, and evaluate the toxicity of the degradation products. [Methods] The isolated strain was identified by 16S rRNA gene sequencing and phylogenetic analysis. Single factor experiments and response surface methodology were employed to optimize the degradation conditions. GC-MS and the luminescent bacteria test for acute toxicity were adopted to analyze the degradation products and their toxicity. [Results] Strain LS-1 showed 99.79% sequence similarity with Alcaligenes aquatilis strain AS1. Tryptone was determined to be the optimal exogenous carbon source for both growth and SMX degradation. The strain exhibited robust growth across a temperature range of 20‒35 ℃, salinities of 15‰‒35‰, SMX concentrations from 10 to 100 mg/L, and pH 7.0‒9.0. Response surface analysis revealed that SMX concentration, initial pH, and temperature significantly influenced the SMX degradation rate, in descending order of importance. Under optimal conditions (SMX concentration of 33 mg/L, pH 7.4, and 30 ℃), the strain achieved a maximum degradation rate of 60.17% within 48 h. MS results indicated that LS-1 degraded SMX via acetylation and hydroxylation pathways. The results of the luminescent bacteria test for acute toxicity demonstrated a progressive reduction in biological toxicity during the SMX degradation process. [Conclusion] The SMX-degrading strain LS-1 can effectively adapt to marine environmental conditions, reducing SMX-induced toxicity in water. This study highlights the potential of LS-1 for controlling antibiotic pollution in marine aquaculture wastewater.

[Objective] Fusarium oxysporum is a fungal pathogen that causes plant wilt, severely affecting plant growth. Therefore, it is necessary to use appropriate and environmentally friendly biological methods for control of this pathogen. [Methods] We employed the point inoculation method to isolate a marine Bacillus strain antagonistic to Fusarium oxysporum from mangrove soil. The Bacillus strain was identified based on physiological and biochemical characteristics and 16S rRNA gene sequence. The antifungal substance was extracted from the fermentation supernatant, and the inhibitory activity and mechanism of the substance against Fusarium oxysporum were evaluated in vitro. [Results] A Bacillus strain with strong antagonistic activity against Fusarium oxysporum was isolated from mangrove soil and identified as Bacillus velezensis. The antifungal substance secreted by strain K3 exhibited broad-spectrum antimicrobial properties, being effective against both bacteria and fungi. This substance was likely a protein or peptide and had good thermal stability. It showed the minimum inhibitory concentration (MIC) of 1 mg/mL against Fusarium oxysporum, significantly inhibiting spore germination and causing leakage of electrolytes, nucleic acids, and proteins. The treatment with 3×MIC of the antifungal substance for 10 h showed the inhibition rate of 49.85% on the germination of Fusarium oxysporum spores. Moreover, the treated Fusarium oxysporum hyphal cells showed compromised cell integrity, disrupted membrane homeostasis, increased malondialdehyde content, and enhanced activities of superoxide dismutase, peroxidase, and catalase in the membrane. [Conclusion] The antifungal substance produced by B. velezensis K3 isolated from mangrove soil of marine origin exhibits a broad antimicrobial spectrum and strong inhibitory activity against Fusarium oxysporum, with potential commercial application value.

[Objective] To study changes of the bacterial community structure in the Second Drainage Ditch in Ningxia after ecological engineering. [Methods] We employed high-throughput sequencing to study the bacterial community structures in water samples. We explored the factors affecting the bacterial community structure by non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA). [Results] From August 2021 to August 2022, the ammonium nitrogen, total nitrogen (TN), permanganate index, dichromate oxidizability (COD_Cr), and fluoride in the water decreased substantially after the ecological engineering. The dominant bacterial phyla in the water were Proteobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi and the dominant genera included hgcI_clade, SAR11_cladeIII, Limnohabitans, Rhodoferax, and Flavobacterium. The bacterial community structures showed significant differences across different sampling locations. The NMDS results revealed significant variations in the bacterial community structure across different sampling months. The RDA results indicated that total phosphorus (TP), COD_Cr, and pH were the key factors influencing the bacterial community structure. Notably, TP, COD_Cr, and TN together explained the largest variance (8.81%) in the bacterial community structure, followed by TP combined with COD_Cr (-8.05%). [Conclusion] After ecological engineering, the water quality of the Second Drainage Ditch improved, and the bacterial community structure became more diverse. The physicochemical properties of the water strongly influence the distribution and diversity of bacterial communities in the Second Drainage Ditch in Ningxia, which provide a scientific basis for managing the regional water environment.

As global eco-environmental issues have aroused increasing concern, ecological restoration has become a key research topic. As an emerging technology for ecological restoration, aggregate spray-seeding offers significant advantages in vegetation restoration. [Objective] To reveal the relationship between plant community assembly and soil microbial communities during the aggregate spray-seeding restoration process. [Methods] A comprehensive investigation was conducted at plots of various seeding batches on the slopes of Changqin Island in Zhuhai City, focusing on the internal relationships of the structures of pioneer plant communities with soil nutrient content and characteristics of soil fungal and bacterial communities. [Results] The soil fungal community in the aggregate spray-seeding restoration area of Changqin Island was mainly composed of 9 phyla, among which Ascomycota and Basidiomycota were dominant. The soil bacterial community was dominated by Pseudomonadota, Acidobacteriota, and Bacteroidota. The soil fungi of plant pathogens, wood saprotrophs, and endophytes exhibited high abundance, while a large proportion of bacteria were involved in nitrogen cycling. Using the support vector machine method, we identified 24 soil microbial and nutrient indicators related to differences across aggregate spray-seeding batches. The cluster analysis classified the main restoration plants into two groups and the 24 soil-microbial and nutrient indicators into four categories. The inter-group correlation analysis showed significant associations of plant combinations with soil microbial and nutrient indicators. [Conclusion] Substantial differences in community structure and diversity are observed among different aggregate spray-seeding batches. Plant community assembly significantly influences the structures and functions of soil microbial communities. The findings of this study provide essential theoretical support for ecological restoration practices, contributing to the optimization of restoration strategies and enhancing ecosystem stability and sustainability.