Diversity and Composition of Soil Acidobacterial Communities in Different Temperate Forest Types of Northeast China

Soil Microbial Community Characteristics and Influencing Factors in Alpine Marsh Wetlands with Different Degradation Levels in Qilian Mountain National Park, Qinghai, China

The microbial community is one of the key indicators for evaluating the health of alpine marsh wetlands, and understanding the composition and health of alpine wetland communities provides a scientific rationale for conservation and restoration efforts. Taking the alpine marsh wetlands in Qilian Mountain National Park, Qinghai Province, as the research object, 27 soil samples (0-30 cm depth) were collected in July 2024 from three types of wetlands: non-degraded (ND), low-level degraded (LD), and heavily degraded (HD). Using high-throughput sequencing, PICRUSt2 functional prediction, nonmetric multidimensional scaling (NMDS), and redundancy analysis (RDA), we analyzed the bacterial community structure and functional characteristics as well as the soil physicochemical properties across different degradation levels and soil depths. Pearson correlation analysis and RDA were used to identify key soil indicators influencing microbial community characteristics. The results showed that (1) compared to ND, the relative abundance of Acidobacteriota increased from 12.3% to 23.7%, and that of Pseudomonadota increased from 28.5% to 35.1% in HD wetlands. Meanwhile, the Shannon index rose from 5.31 in ND to 6.52 in HD, indicating significantly increased microbial community diversity and complexity with wetland degradation (p < 0.05). (2) Vertically, the six major primary metabolic functions gradually weakened with increasing soil depth in all three types of wetlands, the relative abundance of Proteobacteria decreased from 0 to 30 cm, and the α-diversity indices of soil bacteria also declined with depth. (3) Compared to ND, LD and HD showed significantly lower soil moisture content, organic matter, and total organic carbon (p < 0.05), while total potassium and pH increased significantly (p < 0.05). With increasing depth, total nitrogen significantly decreased across all degradation types (p < 0.05). Bacterial diversity, as measured by the Shannon and Simpson indices, showed a significant correlation with several soil properties (moisture, organic matter, total nitrogen, total potassium, cation exchange capacity, and total organic carbon; p < 0.05). Furthermore, pH emerged as a primary environmental driver shaping microbial community structure across different soil depths. These findings offer technical guidance and a theoretical framework for comprehending the degradation and restoration dynamics of alpine marsh wetland ecosystems in the Qilian Mountains.

Effects of Short-Term Straw Return and Manure Fertilization on Soil Microorganisms and Soybean Yield in Parent Material of Degraded Black Soil in Northeast China

Soil erosion has caused the loss of black soil and exposed the soil parent material in the cultivated layer of sloping farmland in Northeast China. Straw return (STR) and manure fertilization (MF) are critical measures to improve soil quality and crop yield. However, the effect of STR and MF on the soil properties of the parent material remains unclear. We conducted a 1-year pot experiment in the field using the soil parent material of degraded black soil to evaluate the effects of STR and MF on soil nutrients, microbial community, and soybean yield. We analyzed these effects using two treatments (STR and MF) in three soybean growth stages (seedling, flowering, and maturity) and a control group (CK). The MF treatment had higher α and β diversity of soil microbial than the CK during all soybean growth stages. Similarly, STR had higher soil microbial α diversity at the maturity stage and lower diversity at the seedling stage. Co-occurrence network analysis suggested that STR and MF increased the proportion of positively correlated edges in soil bacterial and fungal networks compared to the CK. Notably, the treatments enriched beneficial taxa, such as Schizothecium (fungi) and Massilia (bacteria), which are associated with organic matter decomposition and nitrogen cycling. STR and MF significantly improved soil organic matter, total nitrogen, and carbon-nitrogen ratio (p < 0.05). Structural equation modeling (SEM) revealed that STR and MF directly increased soybean yield. This effect was primarily mediated by the significantly higher soil organic matter, total carbon, total nitrogen, and carbon-to-nitrogen ratio in the treatments than in the CK (p < 0.05). In summary, STR and MF improved soil fertility and soil microbial community diversity of degraded black soil. This study provides scientific methods to improve the fertility of degraded black soil and increase soybean production in the short term.

Exploring functional microbiota for uranium sequestration in Zoige uranium mine soil

The Zoige uranium mine is situated in the harsh, cold northern region of Sichuan, characterized by its high altitude and fragile ecosystem. Uncovering the organisms that thrive in such extreme climates, particularly microorganisms, is of paramount importance for advancing bioremediation efforts. Herein, the potential functional microbiota for uranium sequestration in Zoige uranium mine soil was explored using high-throughput sequencing combined with bioinformatics analysis. Analysis of the physicochemical properties of soils showed that the concentration of uranium ranged from 35.20 to 40.62 µg·g-1 around the uranium mine. Bacterial communities differed significantly in soils around the Zoige uranium mine, with the most abundant phyla being Actinobacteria, Proteobacteria, Acidobacteria, Chloroflexi, Gemmatimonadota, Verrucomicrobia, and Firmicutes. Notably, Actinobacteria was considered a biomarker for distinguishing soils with high uranium by linear discriminant analysis effect size. Meanwhile, the correlation analysis demonstrated that Firmicutes and Cyanobacteria were significantly and positively associated with uranium in soil samples, with the correlation coefficients being 0.8601 and 0.7832, respectively. Furthermore, the phylogenetic investigation of communities by reconstruction of unobserved states analysis revealed that the bacterial microbiota was mainly enriched in biosynthesis function in these soils. Interestingly, the abundance of functional genes involved in amino acid biosynthesis increased whereas that related to fatty acid biosynthesis decreased with an increase in uranium content. Taken together, Actinobacteria, Firmicutes, and Cyanobacteria were the potential functional microbiota for uranium sequestration via amino acid and fatty acid biosynthesis pathways in Zoige uranium mine soil. These findings are conducive to obtaining functional strains for developing microbial remediation technologies for uranium contamination.IMPORTANCEBased on the significance of the Zoige uranium mine and its unique ecological environment, this study emphasizes the necessity of in situ bioremediation. Herein, the potential functional microbiota for uranium sequestration in Zoige uranium mine soil was explored using high-throughput sequencing and bioinformatics analysis. Actinobacteria, Firmicutes, and Cyanobacteria were the potential functional microbiota in Zoige uranium mine soils. These microbes interacted and tolerated uranium via amino acid and fatty acid biosynthesis pathways. These findings provide insights into the functional microbiota of uranium sequestration, which are conducive to developing microbial resources and bioremediation technology for treating uranium contamination.

Agricultural soil microbiomes at the climate frontier: Nutrient-mediated adaptation strategies for sustainable farming

The equilibrium transformation of soil microbial community dynamics and succession across various temporal and spatial dimensions plays a critical role in maintaining plant adaptability. Intensive agricultural practices accelerate the succession of plant microbial communities, rendering their restoration function more vulnerable. Climate change, with its variable impacts, affects the resilience of plant microbial communities through regulatory and mediating effects. Investigating the spatiotemporal dynamics of soil microbial communities in the context of climate change offers valuable insights into developing robust and resilient microbial ecosystems. This review examines the regulatory role of soil resources in plant microbial communities, the interactive effects of climate change on soil resource regulation, and the prediction of microbial community structures through resource allocation. Additionally, it explores the mechanisms that sustain ecological resilience in plant microbial community systems, emphasizing the application of the profit-averaging law.

Effects of Different Stand Densities on the Composition and Diversity of Soil Microbiota in a Cunninghamia lanceolata Plantation

As sustainable forest management gains increasing attention, comprehending the impact of stand density on soil properties and microbial communities is crucial for optimizing forest ecosystem functions. This study employed high-throughput sequencing in conjunction with soil physicochemical analysis to assess the effects of stand density on soil physicochemical properties and microbial community characteristics in Chinese fir plantations, aiming to elucidate the influence of density regulation on ecosystem services. Our results suggested that changes in soil physicochemical properties and microenvironmental conditions were key drivers of soil microbial diversity. Total carbon (TC), soluble nitrogen (SN), and light fraction organic matter decreased with increasing stand density, while total potassium (TK) and available phosphorus (AP) concentrations increased. The plot with a density of 900 trees ha-1 exhibited the highest bacterial diversity, in contrast to the plot with 1500 trees ha-1, which showed the lowest. The dominant microbial taxa were similar across different stand retention densities, with Acidobacteria, Proteobacteria, and Chloroflexi being the predominant bacterial phyla and Ascomycota and Basidiomycota being the main fungal groups. Significant positive correlations were observed between soil microbial community structures and environmental factors, particularly with respect to soil phosphorus and nitrogen content. The present study demonstrated that reduced stand densities modulated soil nutrient content and enhanced bacterial diversity, thereby contributing to a more complex and stable soil ecosystem structure. These insights provide a scientific foundation for optimizing the management of Chinese fir plantations, thereby supporting the sustainable development of forest ecosystems.