Bacteria, fungi, archaea, and viruses are reflective organisms that indicate soil health. Investigating the impact of crude oil pollution on the community structure and interactions among bacteria, fungi, archaea, and viruses in Calamagrostis epigejos soil can provide theoretical support for remediating crude oil pollution in Calamagrostis epigejos ecosystems. In this study, Calamagrostis epigejos was selected as the research subject and subjected to different levels of crude oil addition (0 kg/hm², 10 kg/hm², 40 kg/hm²). Metagenomic sequencing technology was employed to analyze the community structure and diversity of soil bacteria, fungi, archaea, and viruses. Additionally, molecular ecological network analysis was integrated to explore species interactions and ecosystem stability within these microbial communities. The functional profiles of soil microorganisms were elucidated based on data from the KEGG database. Results demonstrated a significant increase in petroleum hydrocarbon content, polyphenol oxidase activity, hydrogen peroxide enzyme activity, and acid phosphatase activity upon crude oil addition, while β-glucosidase content, fiber disaccharide hydrolase content, and tiller number decreased (P < 0.05). Proteobacteria and Actinobacteria were identified as dominant bacterial phyla; Ascomycota, Basidiomycota, and Mucoromycota were found to be dominant fungal phyla; Thaumarchaeota emerged as a dominant archaeal phylum; and Uroviricota represented a dominant viral phylum. The diversity of soil bacterial, fungal, archaeal, and viral communities increased with higher amounts of added crude oil. Ecological network analysis revealed a robust collaborative relationship among bacterial, fungal, archaeal, and viral community species in the control treatment (CK), while strong competitive relationships were observed among these species in the treatments with 10% (F10) and 40% (F40) crude oil concentrations. Structural equation modeling analysis indicated significant positive correlations between fungal community, viral community, enzyme activity, and plant growth; conversely, bacterial and archaeal communities showed significant negative correlations with plant growth (P < 0.05). Correlation analysis identified acid phosphatase as the primary environmental factor influencing soil microbial function. Acid phosphatase levels along with tiller number, aboveground biomass, and petroleum hydrocarbons significantly influenced the fungal community (P < 0.05), while underground biomass had a significant impact on the archaeal community (P < 0.05). Acid phosphatase levels along with cellulose-hydrolyzing enzymes, tiller number, and petroleum hydrocarbons exhibited significant effects on the viral community (P < 0.05). This study investigated variations in bacterial, fungal, archaeal, and viral communities under different crude oil concentrations as well as their driving factors, providing a theoretical foundation for evaluating Calamagrostis epigejos’ potential to remediate crude oil pollution.

Covering about 30% of the global total land area, desert ecosystems have been influenced by warming and nitrogen deposition. However, it remains unclear how desert ecosystems respond to warming and nitrogen deposition. Therefore, we conducted a greenhouse experiment to examine the impacts of N addition and warming on the plant–soil system of Neotrinia splendens, the dominant plant in the desert ecosystem in Northern China. Our findings revealed that low-N dose (N₁) and high-N dose additions (N₂) increased the biomass by 22.83% and 54.23%, respectively; meanwhile, moderate warming (T₂) and severe warming (T₃) decreased the biomass by 39.07% and 45.47%, respectively. N addition did not significantly affect the C:N:P stoichiometry in the plant–soil system. T₂ and T₃ decreased the leaf N content by 17.50% and 16.20%, respectively, and decreased the leaf P content by 10.61% and 45.29%, respectively. This resulted in the plant C:N ratio, C:P ratio, and N:P ratio increasing with warming. Furthermore, warming or N addition not only decreased soil microbial diversity, but also inhibited microbial genera associated with nutrient cycling, such as that of Tumebacillus spp., Bacillus spp., and Mortierella spp.; it additionally influenced important bacterial functions, such as nitrate reduction and ureolysis. Moreover, warming and N addition induced P limitation in the plant–soil system by inhibiting soil microorganisms, such as Mortierella spp. and Bacillus spp., which are associated with P transformation; this was also brought about by increasing the effects of leaf P content on leaf N:P. In conclusion, our results showed that warming and N addition had significant effects on the C:N:P stoichiometry of the plant–soil system through microbial mediation and led to P limitation in the system, regardless of how they affected biomass. Soil microorganisms could mediate the impacts of environmental changes on the plant–soil system. Our findings may provide valuable insights for adjusting vegetation restoration strategies in desert ecosystems under environmental changes.

Soil microorganisms are key indicators of soil health, and it is crucial to investigate the structure and interactions of soil microbial communities among three different provenances of Pennisetum alopecuroides under varying nitrogen fertilizer and temperature levels in Northwest China. This study aims to provide theoretical support for the sustainable use of artificial grassland in this region. Employing a two-factor pot-control experiment with three nitrogen fertilizer treatments and three temperature treatments, a total of all treatments was utilized to examine the composition and abundance of soil microbial communities associated with Pennisetum alopecuroides using high-throughput sequencing, PCR technology, and molecular ecological network analysis. The results revealed that Proteobacteria was the dominant bacterial phylum while Ascomycota was the dominant fungal phylum in the soil samples from three provenances of Pennisetum. Specifically, Proteobacteria exhibited higher abundance in the N3T2 treatment compared to other treatments under N3T2 (25–30°C, 3 g/pot) treatment conditions in Shaanxi and Gansu provinces; similarly, Proteobacteria was more abundant in the N1T2 (25–30°C, 1 g/pot) treatment in Inner Mongolia under N1T2. Moreover, Ascomycota displayed higher abundance than other treatments in both Inner Mongolia and Gansu provinces. Additionally, Pennisetum Ascomycota demonstrated greater prevalence under (25–30°C, 3 g/pot) treatment compared to other treatments; furthermore, Shaanxi’s Pennisetum Ascomycota exhibited increased prevalence under N3T1 (18–23°C, 3 g/pot) treatment compared to other treatments. The richness and diversity of soil microbial communities were significantly influenced by nitrogen fertilizer and temperature changes, leading to notable alterations in their structure. Molecular ecological network analyses revealed strong collaborative relationships among microbial species in Shaanxi Pennisetum and Inner Mongolia Pennisetum under high nitrogen and high temperature treatments, while competitive relationships were observed among microbial species in Gansu Pennisetum under similar conditions. Redundancy analysis indicated that soil pH, total potassium, and total phosphorus were the primary environmental factors influencing microorganisms. In summary, this study offers a theoretical foundation for assessing the sustainable utilization of Pennisetum artificial grasslands in Northwest China by investigating the shifts in soil microbial communities and the driving factors under varying nitrogen fertilizer and temperature levels.

To reveal how the altitude gradient regulates the effects of rhizosphere microbial dynamics on ecosystem multifunctionality in Hylodesmum podocarpum, a field experiment was conducted across four elevation transects (a.s. 896–1805 m) in the Qinling Mountains. The results showed that rhizosphere soil exhibited peak microbial diversity richness at 1805 m (HB4), with bacterial communities showing a strong interspecific cooperative relationship, while the fungal communities showed a competitive relationship. In addition, this study found the assembly process to be different. Bacterial assemblages changed from random processes (HB1, HB2, HB3) to deterministic processes (HB4), whereas fungal assemblages remained stochastic processes across all elevations. Our results also revealed that synergistic interactions among soil carbon, phosphorus, and nitrogen nutrient functions collectively enhanced nutrient-centered soil multifunctionality. Notably, carbon and phosphorus nutrient functions emerged as the primary drivers of soil multifunctionality. Further mechanistic analysis revealed that while soil pH exerted significant control over both carbon and nitrogen nutrient functions, microbial mediation exhibited functional specialization: bacterial communities predominantly regulated carbon cycling, whereas fungal communities played a more comprehensive role in modulating carbon, nitrogen, and phosphorus dynamics along with overall ecosystem multifunctionality. This finding suggested that altitude gradients indirectly affect the characteristics of the microbial community by regulating soil nutrient status, thereby driving changes in ecosystem multifunctionality. This finding provides new insights into how nutrients regulate ecosystem functions through microbial pathways.

Plant restoration strategies are ubiquitously employed for the purposes of soil and water conservation and ecological improvement in forest ecosystems. Despite N and temperature being acknowledged as pivotal factors affecting plant restoration outcomes, their effects on soil fertility, microbial communities, and shrub biomass remain underexplored, particularly in the loess hilly regions of China. Here, we examined the growth patterns and nutrient acquisition abilities of three shrub species, Periploca sepium, Amorpha fruticosa, and Vitex negundo, along with the attendant alterations in soil properties and microbial community composition under controlled greenhouse conditions. Specifically, we imposed three levels of N fertilization (200, 400, and 600 kg ha⁻¹; designated as N1, N2, and N3, respectively) and temperature regimes (18–23, 25–30, and 32–37 °C; labeled T1, T2, and T3, respectively). The results indicated a significant interplay between the combination of N fertilization and temperature significantly affecting shrub growth. Optimal growth conditions, as evidenced by the highest dry biomass accumulation, were identified as N3T1 for A. fruticosa, N1T1 for P. sepium, and N2T2 for V. negundo, with these conditions differentially influencing roots, stems, and leaves. Furthermore, soil microorganisms also responded significantly to the N fertilization and temperature. However, this was largely dependent on shrub species and soil nutrients. For A. fruticosa under N3T1 conditions, Actinobacteria and Basidiomycota abundances correlated strongly with soil C, N, and P contents, while leaf N uptake significantly correlated with the structure of both bacterial and fungal communities. For P. sepium at N1T1, Acidobacteriota was dominant in response to soil N and C, while leaf C uptake and leaf and stem N uptake positively correlated with bacterial and fungal communities, respectively. For V. negundo at N2T2, Chloroflexi had the greatest abundance, responding to the greatest variation in soil N and C, while its stem N uptake was significantly related to the structure of the fungal communities. Thus, our findings underscored the intricate interplay between abiotic factors, shrub growth, soil fertility, and microbial community dynamics, providing insights into the optimization of plant restoration efforts in ecologically sensitive regions.

This study aimed to reveal the effects of crude oil addition on the characteristics of soil microbial communities and ecosystem multifunctionality in Achnatherum splendens and Pennisetum alopecuroides. Specifically, it explored how crude oil addition influences the relationship between soil nutrient regulation, microbial community characteristics, and ecosystem multifunctionality. The results indicated that as crude oil addition increased, the Shannon index and Chao1 index for soil bacteria and fungi in both Achnatherum splendens and Pennisetum alopecuroides increased. Conversely, while the Shannon index for soil archaea in both species increased, the Chao1 index decreased. The ecological network analysis indicated that a strong collaborative relationship existed between species in the soil bacterial communities of Achnatherum splendens and Pennisetum alopecuroides exposed to 10 g/kg crude oil, as well as between species in the soil fungal and archaeal communities of Achnatherum splendens exposed to 40 g/kg crude oil. A strong collaborative relationship was also observed between species in the soil fungal and archaeal communities of Pennisetum alopecuroides exposed to 10 g/kg crude oil. The bacterial and fungal communities exerted a significant direct negative regulatory effect on the soil ecosystem multifunctionality of Achnatherum splendens and Pennisetum alopecuroides, while the archaeal communities had a significant direct positive regulatory effect. Additionally, the multifunctionality index of the soil ecosystem in Achnatherum splendens and Pennisetum showed a significant decline with increasing crude oil addition. This is likely due to the higher toxicity of high-concentration crude oil, which negatively impacts the soil biological community, leading to reduced biodiversity and disruptions in nutrient cycles. This study explores the characteristics of bacterial, fungal, and archaeal communities and ecosystem multifunctionality under different levels of crude oil, which can provide theoretical support for evaluating the restoration of Achnatherum splendens and Pennisetum alopecuroides from crude oil pollution.