Response Of Community Structure Research Articles

Mowing mitigates the negative impacts of long-term warming on community composition and niche characteristics of alpine meadow on the Tibetan Plateau

Climate warming and human disturbance are supposed to have significantly impacted the alpine grasslands. However, it is still unclear how human activity affects the community composition and niche characteristics in response to warming. We conducted a two-factorial experiment in an alpine meadow, and set up four treatments: warming, mowing, warming with mowing, and control. Based on the investigation of community composition and niche characteristics, we evaluated the impacts of soil carbon, nitrogen, and phosphorus on species niche overlap. The results showed that mowing significantly increased species richness of Grass, Sedge, Forbs and the importance value of Sedge compared to warming (P < 0.05). The niche breadth of species (>50%) was reduced by warming, but increased under mowing. The niche overlap mainly occurred between Grass and Forbs in warming, while it was evenly distributed among species after mowing, which alleviated the negative effects of warming on interspecific competitiveness. Warming increased the number of species pairs with a niche overlap value >0.9 by 24.15%, while warming with mowing decreased it by 2.7%. The number of species pairs with niche overlap was significantly correlated with soil total nitrogen and soil available nitrogen (P < 0.05). In particular, the species pairs with highly competitive showed a greater dependency on soil nitrogen. Our work highlights that moderate utilization and soil nitrogen are two crucial factors influencing the response of community structure in alpine meadows to future climate change. The study provides an important reference for predicting and addressing the impact of global climate change on adaptive management and grassland protection.

Metabolic cross-feeding interactions modulate the dynamic community structure in microbial fuel cell under variable organic loading wastewaters.

The efficiency of microbial fuel cells (MFCs) in industrial wastewater treatment is profoundly influenced by the microbial community, which can be disrupted by variable industrial operations. Although microbial guilds linked to MFC performance under specific conditions have been identified, comprehensive knowledge of the convergent community structure and pathways of adaptation is lacking. Here, we developed a microbe-microbe interaction genome-scale metabolic model (mmGEM) based on metabolic cross-feeding to study the adaptation of microbial communities in MFCs treating sulfide-containing wastewater from a canned-pineapple factory. The metabolic model encompassed three major microbial guilds: sulfate-reducing bacteria (SRB), methanogens (MET), and sulfide-oxidizing bacteria (SOB). Our findings revealed a shift from an SOB-dominant to MET-dominant community as organic loading rates (OLRs) increased, along with a decline in MFC performance. The mmGEM accurately predicted microbial relative abundance at low OLRs (L-OLRs) and adaptation to high OLRs (H-OLRs). The simulations revealed constraints on SOB growth under H-OLRs due to reduced sulfate-sulfide (S) cycling and acetate cross-feeding with SRB. More cross-fed metabolites from SRB were diverted to MET, facilitating their competitive dominance. Assessing cross-feeding dynamics under varying OLRs enabled the execution of practical scenario-based simulations to explore the potential impact of elevated acidity levels on SOB growth and MFC performance. This work highlights the role of metabolic cross-feeding in shaping microbial community structure in response to high OLRs. The insights gained will inform the development of effective strategies for implementing MFC technology in real-world industrial environments.

Coral responses to a catastrophic marine heatwave are decoupled from changes in total coral cover at a continental scale.

The services provided by the world's coral reefs are threatened by increasingly frequent and severe marine heatwaves. Heatwave-induced degradation of reefs has often been inferred from the extent of the decline in total coral cover, which overlooks extreme variation among coral taxa in their susceptibility and responses to thermal stress. Here, we provide a continental-scale assessment of coral cover changes at 262 shallow tropical reef sites around Australia, using ecological survey data on 404 coral taxa before and after the 2016 mass bleaching event. A strong spatial structure in coral community composition along large-scale environmental gradients largely dictated how coral communities responded to heat stress. While heat stress variables were the best predictors of change in total coral cover, the pre-heatwave community composition best predicted the temporal beta-diversity index (an indicator of change in community composition over time). Indicator taxa in each coral community differed before and after the heatwave, highlighting potential winners and losers of climate-driven coral bleaching. Our results demonstrate how assessment of change in total cover alone may conceal very different responses in community structure, some of which showed strong regional consistency, and may provide a telling outlook of how coral reefs may reorganize in a warmer future.

Harmful Microalgae Exhibit Broad Environmental Adaptability in High-Salinity Area Across the Dafengjiang River Estuary.

Harmful algal blooms (HABs) often occur in estuaries due to their unique environmental heterogeneity, posing significant environmental and human health risks. However, there is limited understanding of the community composition and community-level change points (thresholds) of harmful microalgae in subtropical estuaries. This study explored harmful microalgae community structure and thresholds in the Dafengjiang River estuary using a metabarcoding approach. The results revealed 63 harmful microalgae species, and major species included Guinardia flaccida, Prorocentrum cordatum, Thalassiosira punctigera, Pseudo-nitzschia galaxiae and T. gravida. Nonparametric change-point analysis and threshold indicator taxa analysis (TITAN) showed threshold responses of harmful microalgae community structure to ammonium (57.5-60 μg·L-1), total phosphorus (27.8-28.5 μg·L-1) and dissolved inorganic phosphorus (14.5-28 μg·L-1) along the salinity gradient. Wider environmental thresholds were also found in hypersaline areas. Additionally, Pyrodinium bahamense, Pfiesteria piscicida, Skeletonema tropicum and T. punctigera were sensitive to environmental changes and thus could be used as bioindicators. Overall, our study unveiled diverse abrupt transitions of harmful microalgal communities, providing a risk assessment for human health and ecological safety in subtropical estuary ecosystems.

Temperature sensitivity quandary of soil microbial community structure in Tibetan alpine grasslands: A meta-analysis and field experiment

Soil microorganisms act as the primary decomposers in global terrestrial ecosystems. Whether climate warming will lead to the convergence of the temperature sensitivity of soil microbial community structure and the convergence of the responses of soil microbial community structure to warming remains controversial. This study explored how warming amplitude affected the temperature sensitivity of soil bacteria and fungi community structures, and how it influenced the responses of soil bacteria and fungi community structures to warming on the Qinghai-Tibet Plateau based on meta-analysis and a single-site warming experiment. The temperature sensitivity of soil microbial community structure did not consistently decline with increasing warming magnitude; instead, it even rose, which might be associated with the nonlinear relationships of the warming magnitude with the temperature sensitivity of ecological processes of soil microbial community assembly or the topological parameters of species co-occurrence network. Meta-analysis indicated that responses of soil microbial community to warming were independent of warming amplitude. However, the single-site warming experiment demonstrated that responses of soil microbial community to warming varied with warming amplitude. These inconsistent results might be attributed to distinct spatial scales, grassland types, climatic conditions and warming magnitudes between the single-site experiment and the meta-analysis. Therefore, the temperature sensitivity of soil microbial community and its response to climate warming cannot be simply characterized as monotonically decreasing or increasing in relation to increasing warming magnitude.

Response of Bacterial Community Structure and Function in Rhizosphere Soil on the Photosynthesis of Selected Plant Types C3 and C4 under Bis(2,4,6-tribromophenoxy) Ethane Exposure

This study investigated the response of a bacterial community’s structure and function in the rhizosphere soil of C3 and C4 plants under bis(2,4,6-tribromophenoxy) ethane (BTBPE) exposure. The bacterial community composition was determined using 16S rRNA sequencing, while FAPROTAX and PICRUSt 2 were employed for functional predictions. Results showed significant differences between C3 and C4 plants in terms of bacterial community structure. C3 plants exhibited higher abundances of Proteobacteria, Bacteroidetes at the phylum level and Sphingomicrobium at the genus level, compared to C4 plants. Conversely, C4 plants had higher abundances of Actinobacteria and Patescibacteria at the phylum level and Nocardioides at the genus level. LEfSe and function prediction analyses revealed that the rhizosphere soil bacteria in C3 plants exhibited significantly higher enrichment in nitrogen fixation functions (p &lt; 0.05), whereas C4 plants showed a significantly higher relative abundance of bacteria and functions related to organic pollutant degradation (p &lt; 0.05). These findings suggest that the rhizosphere soil bacteria of C3 plants exhibit a stronger response to BTBPE exposure in nitrogen metabolism-related processes, while C4 plants possess superior biodegradation ability compared to C3 plants.

Changes in Seagrass Community Structure in Response to Sediment Load and Excess Nutrients, and its Implication to Carbon Stocks in the Berau Marine Conservation Area

Changes in Seagrass Community Structure in Response to Sediment Load and Excess Nutrients, and its Implication to Carbon Stocks in the Berau Marine Conservation Area

Nitrogen deposition in the middle-aged and mature coniferous forest: Impacts on soil microbial community structure and function

The impact of nitrogen (N) deposition on soil microbial community structure and function has been a focal point of research; however, the influence of forest age and N form on the microbial response to N deposition has yet not to be fully understood. To address this gap, metagenomic sequencing was utilized to explore the responses of soil microbial community structure and functional genes to five years of N addition in middle-aged and mature coniferous forests in southwest China. Adopting a randomized block design, the experiment included two N forms ((NH4)2SO4 and KNO3) across four levels of addition (0, 10, 20 and 40 kg N ha−1 yr−1). Our findings reveal that the composition of the microbial community structure and functional genes involved in the carbon (C), N, phosphorus (P), and sulphur (S) cycling varied significantly between middle-aged and mature forest (P < 0.001). At the phylum level, the soil microbial community in the mature forest were dominated by Proteobacteria (30.4–38.8 %), Acidobacteriota (8.5–24.1 %), and Chloroflexota (8.1–21.5 %), and the soil microbial community in the middle-aged forest showed a greater presence of Acidobacteriota (28.9–34.0 %) and Actinobacteriota (13.3–19.2 %) with a lower proportion of Chloroflexota (0.4–1.2 %). In both middle-aged and mature forests, functional gene abundance, and the composition of microbial community and functional genes were unaffected by N addition rate (P = 0.793) and N form (P = 0.725). The taxonomic composition of soil microbial community in the mature forest showed a significant positive correlation with soil pH, soil organic carbon (SOC) and total nitrogen (TN) (P < 0.01), while the microbial community composition in the middle-aged forests was not significant correlated with soil pH, SOC and TN (P > 0.05). These findings underscore that N addition in the middle-aged and mature coniferous forest does not significantly impact the soil microbial community structure and function across different N forms and N addition rate, suggesting that soil microorganisms of the forest ecosystem exhibit strong resilience to increased N supply.

Effect of biochar amendment on bacterial community and their role in nutrient acquisition in spinach (Spinacia oleracea L.) grown under elevated CO2

Global climate change is anticipated to shift the soil bacterial community structure and plant nutrient utilization. The use of biochar amendment can positively influence soil bacterial community structure, soil properties, and nutrient use efficiency of crops. However, little is known about the underlying mechanism and response of bacterial community structure to biochar amendment, and its role in nutrient enhancement in soil and plants under elevated CO2. Herein, the effect of biochar amendment (0, 0.5, 1.5%) on soil bacterial community structure, spinach growth, physiology, and soil and plant nutrient status were investigated under two CO2 concentrations (400 and 600 μmol mol−1). Findings showed that biochar application 1.5% (B.2.E) significantly increased the abundance of the bacterial community responsible for growth and nutrient uptake i.e. Firmicutes (42.25%) Bacteroidetes (10.46%), and Gemmatimonadetes (125.75%) as compared to respective control (CK.E) but interestingly abundance of proteobacteria decreased (9.18%) under elevated CO2. Furthermore, the soil available N, P, and K showed a significant increase in higher biochar-amended treatments under elevated CO2. Spinach plants exhibited a notable enhancement in growth and photosynthetic pigments when exposed to elevated CO2 levels and biochar, as compared to ambient CO2 conditions. However, there was variability observed in the leaf gas exchange attributes. Elevated CO2 reduced spinach roots and leaves nutrient concentration. In contrast, the biochar amendment (B2.E) enhanced root and shoot Zinc (494.99%–155.33%), magnesium (261.15%–183.37%), manganese (80.04%–152.86%), potassium (576.24%–355.17%), calcium (261.88%–165.65%), copper (325.42%–282.53%) and iron (717.63%–177.90%) concentration by influencing plant physiology and bacterial community. These findings provide insights into the interaction between plant and bacterial community under future agroecosystems in response to the addition of biochar contributing to a deeper understanding of ecological dynamics.

Winter cover crops and irrigation alter soil microbial community composition in an arid cropping system

Cover cropping is a well-established strategy to improve soil health, especially in arid and semi-arid agricultural systems. Benefits to soil health are often mediated via effects of cover crops on soil microbial community structure, function and diversity, crucial for regulating soil biogeochemical cycles, eventually promoting agricultural sustainability. However, limited water availability is a major constraint for both cover crop growth and soil microbial activity. This study sought to characterize and elucidate the shifts in soil microbial community structure in response to different cover crops and differential irrigation treatments using phospholipid fatty acid (PLFA) profiling in southern New Mexico. We tested five cover crop treatments: Pisum sativum (Australian winter pea), Hordeum vulgare cv. Stockford (barley), Brassica juncea cv. Caliente 199 (brown mustard), a three-way mix, and a fallow control — in combination with irrigation treatments of one, two, or three irrigation applications — in a split-plot design over two years. Zea mays (sweet corn) was grown as the summer cash crop. We collected soil samples just after cover crop planting in the fall of 2018, following second year cover crop termination but during Z. mays growth in June 2020, and after the second season of Z. mays growth in October 2020. Differential irrigation treatments did not lead to consistent patterns of change under any cover crop or irrigation treatment. However, PLFA parameters in cover cropped compared to winter fallow plots tended to decrease under one and three irrigations but increased with two irrigations. Changes were more common for bacterial than for fungal PLFA biomarkers, and more common in B. juncea and H. vulgare cover crops than in P. sativa or the mix. It is important to note that, while cover crop effects were inconsistent, cover cropping did lead to some shifts in PLFA biomarkers, even in the short two-year period of cover cropping.

Response of soil nematode community structure and metabolic footprint to nitrogen addition in alfalfa fields on the Loess Plateau

Nematodes serve as key indicators of soil health in ecological studies. Therefore, the current study examined the community structure and metabolic footprint of soil nematodes in alfalfa fields across varying levels of N supply in the semi-arid Loess Plateau. The findings offer theoretical guidance for the sustainable management of artificial alfalfa grasslands in this region. The research was based on alfalfa fields with different N application rates (0, 50, 100, 150 kg/ha2) as the research object, The shallow plate method was used to separate and extract soil nematodes, identify soil nematode groups, calculate ecological function index and metabolic footprint, and identify indicator species. A total of 6346 nematodes were isolated in this study, belonging to 27 genera and 19 families. Notably, the plant parasitic nematode Helicotylenchus was predominant. As N addition increased, the plant parasitic index (PPI) increased significantly. A N50 application significantly enhanced the soil nematode diversity index (H\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext{H}$$\\end{document}) and the free-living index (MI). The findings showcased a noticeable decrease in disturbance within the N50 soil nematode community. This resulted in a mature and stable community structure primarily attributed to the heightened abundance of omnivorous/predatory nematodes. Across various N levels, soil nematode communities underwent significant alterations in the soil food web structure through shifts in their metabolic footprint. Future strategies should focus on refining N management practices and integrating sustainable approaches like crop rotation and pest management. These efforts will contribute to guidelines ensuring artificial alfalfa grasslands lasting health and productivity.

Seasonal response of soil microbial community structure and life history strategies to winter snow cover change in a temperate forest

Snow cover provides a thermally stable and humid soil environment and thereby regulates soil microbial communities and biogeochemical cycling. A warmer world with large reductions in snow cover and earlier spring snowmelt may disrupt this stability and associated ecosystem functioning. Yet, little is known about the response of soil microbial communities to decreased snowpack and potential carry-over effects beyond the snow cover period. Herein, we tested this response by conducting a snowpack manipulation experiment (control, addition, and removal) in a temperate forest. Our results showed that fungi were more sensitive to changes in snowpack. Thicker snowpack increased the diversity of fungi, but had weak effects on the diversity of bacteria in winter. Thickening snow cover promoted the ratio of fungi to bacteria abundance across the year, and such relative increase in fungi abundance was largely driven by Basidiomycota phyla (Agaricomycetes class). Increased snowpack decreased soil nitrate concentration, and produced carry-over biogeochemical effects evidenced by increased summer β-1,4-glucosidase and N-acetyl-β-glucosaminidase activities. On a seasonal scale, microbial biomass peaked at both winter and summer; winter microbial community was fungi dominated, while bacteria dominated in summer. The abundances of bacterial phyla had greater seasonal variation than fungal phyla. Specifically, Actinobacteria had greater dominance in winter than in summer, while Acidobacteria, Proteobacteria, and Verrucomicrobia had greater abundance in summer than in winter. Microbial high yield-resource acquisition-stress tolerance life history strategies showed significant seasonal tradeoffs, i.e., resource acquisition and stress tolerance strategies dominated in summer, while high yield strategy dominated in winter. Overall, our findings underline that climate-induced reductions in snow cover can disrupt soil biogeochemical cycling also beyond the snow cover period due to shifts in soil microbial community structure and life history strategies.

Soils of two Antarctic Dry Valleys exhibit unique microbial community structures in response to similar environmental disturbances

BackgroundIsolating the effects of deterministic variables (e.g., physicochemical conditions) on soil microbial communities from those of neutral processes (e.g., dispersal) remains a major challenge in microbial ecology. In this study, we disturbed soil microbial communities of two McMurdo Dry Valleys of Antarctica exhibiting distinct microbial biogeographic patterns, both devoid of aboveground biota and different in macro- and micro-physicochemical conditions. We modified the availability of water, nitrogen, carbon, copper ions, and sodium chloride salts in a laboratory-based experiment and monitored the microbial communities for up to two months. Our aim was to mimic a likely scenario in the near future, in which similar selective pressures will be applied to both valleys. We hypothesized that, given their unique microbial communities, the two valleys would select for different microbial populations when subjected to the same disturbances.ResultsThe two soil microbial communities, subjected to the same disturbances, did not respond similarly as reflected in both 16S rRNA genes and transcripts. Turnover of the two microbial communities showed a contrasting response to the same environmental disturbances and revealed different potentials for adaptation to change. These results suggest that the heterogeneity between these microbial communities, reflected in their strong biogeographic patterns, was maintained even when subjected to the same selective pressure and that the ‘rare biosphere’, at least in these samples, were deeply divergent and did not act as a reservoir for microbiota that enabled convergent responses to change in environmental conditions.ConclusionsOur findings strongly support the occurrence of endemic microbial communities that show a structural resilience to environmental disturbances, spanning a wide range of physicochemical conditions. In the highly arid and nutrient-limited environment of the Dry Valleys, these results provide direct evidence of microbial biogeographic patterns that can shape the communities’ response in the face of future environmental changes.

Temporal temperature shifts govern the population succession of picoeukaryotes and picocyanobacteria in a coastal ecosystem

Picophytoplankton are vital components of the marine microbial food web. Being the smallest in the phytoplankton group, their short life cycles make them excellent bioindicators of environmental conditions. Given this, an investigation was conducted at the Kandla Port ecosystem (Latitude 23º 01' N; Longitude 70º 13' E) in the state of Gujarat, India to assess the response of picophytoplankton community structure to temporal and spatial environmental conditions. The sampling was conducted in July 2015, October-November 2015, and February 2016 at twenty-six stations. The results revealed a wide annual temperature range due to the study site's proximity to the Tropic of Cancer. The salinity ranged up to 40 while the turbulence caused by the macrotides resulted in highly turbid waters, especially during July due to precipitation. The picophytoplankton community was represented by picocyanobacteria (three sub-groups of Synechococcus) and picoeukaryotes (three sub-groups including Cryptophytes). The picocyanobacteria were abundant during the less turbid, warmer October-November period and lower during the cooler February period. The dominant Synechoccocus groups are associated positively with NH4+ and negatively with PO43-. The Cryptophytes were present during the warm and cool periods indicating tolerance to a wide range of temperature, salinity, and light. Their positive correlation with PO43- and NH4+ concentrations during February and October-November, respectively suggests a causal relationship. The picoeukaryotic group dominated the picophytoplankton community during the cooler period (February). The relative importance of the two picophytoplankton groups changed throughout the year exhibiting temporal niche segregation and hence establishing their role as bioindicators of temperature.

Response of soil microbial community structure and function to the sewage leakage: A case study of a 25-year-old cesspool

Providing many millions of rural households with decentralized sanitation facilities remains challenging. In undeveloped areas, cesspools have still been widely used due to technologically simple and low-cost. However, the influence of cesspools on the surrounding soil remains unclear. In this study, we investigated the influence of a 25-year-old household cesspool on soil physicochemical factors, microbial community composition and function, pathogens and antibiotic resistance genes (ARGs). Soil at the depth around the sewage liquid level (D70) was mostly disturbed where TOC, NO3–N and TP was increased to 16.8 g/kg, 18.2 mg/kg and 1.02 mg/kg respectively. Correspondingly, the element cycling genes of carbon fixation, methanotrophy, nitrogen fixation, ammonia oxidation, and nitrate reduction etc., were increased at D70. Notably, human derived pathogens such as Enterobacter, Salmonella, Pseudomonas aeruginosa, Klebsiella pneumoniae, Prevotella, and Vibrio were highly enriched by 5–10 folders in D70, indicating the potential health risk to human. Mantel tests suggested that EC, TP, pH, NH3–N and particularly NO3–N are important factors that influence the microbial community and element cycling genes in cesspool-affected soil. Overall, this study revealed the impact of household cesspool leakage on the surrounding soil and provided information for the selection and construction of basic sanitation facilities in poor regions.

Land use/cover drive functional patterns of bacterial communities in sediments of a subtropical river, China

The bacterial community in sediment serves as an important indicator for assessing the environmental health of river ecosystems. However, the response of bacterial community structure and function in river basin sediment to different land use/cover changes has not been widely studied. To characterize changes in the structure, composition, and function of bacterial communities under different types of land use/cover, we studied the bacterial communities and physicochemical properties of the surface sediments of rivers. Surface sediment in cropland and built-up areas was moderately polluted with cadmium and had high nitrogen and phosphorus levels, which disrupted the stability of bacterial communities. Significant differences in the α-diversity of bacterial communities were observed among different types of land use/cover. Bacterial α-diversity and energy sources were greater in woodlands than in cropland and built-up areas. The functional patterns of bacterial communities were shown that phosphorus levels and abundances of pathogenic bacteria and parasites were higher in cropland than in the other land use/cover types; Urban activities have resulted in the loss of the denitrification function and the accumulation of nitrogen in built-up areas, and bacteria in forested and agricultural areas play an important role in nitrogen degradation. Differences in heavy metal and nutrient inputs driven by land use/cover result in variation in the composition, structure, and function of bacterial communities.

A review of factors affecting the soil microbial community structure in wetlands.

Microbial community in wetland soils is crucial for maintaining the stability of the wetland ecosystem. Nevertheless, the soil microbial community is sensitive to the environmental stress in wetlands. This leads to the possibility that the microbial community structure may be influenced by environmental factors. To gain an in-depth understanding in the response of microbial community structure in wetland soils under different environmental factors, this review comprehensively explores the factors of natural conditions (e.g., different types of wetland, soil physical and chemical properties, climate conditions), biological factors (e.g., plants, soil animals), and human activities (e.g., land use, soil pollution, grazing). Those factors can affect microbial community structure and activities in wetland soils through different ways such as (i) affecting the wetland soil environment in which soil microorganisms survived in, (ii) influencing the available nutrients (e.g., carbon, nitrogen) required for microbial activity, and (iii) the direct effects on soil microorganisms (toxicity or promotion of resistant species). This review can provide references for the conservation of microbial diversity in wetland soils, the maintenance of wetland ecosystem balance, and the wetland ecological restoration.

Differential Responses of Bacterial and Fungal Community Structure in Soil to Nitrogen Deposition in Two Planted Forests in Southwest China in Relation to pH

Increased nitrogen deposition profoundly impacts ecosystem nutrient cycling and poses a significant ecological challenge. Soil microorganisms are vital for carbon and nutrient cycling in ecosystems; however, the response of soil microbial communities in subtropical planted coniferous forests to nitrogen deposition remains poorly understood. This study carried out a four-year nitrogen addition experiment in the subtropical montane forests of central Yunnan to explore the microbial community dynamics and the primary regulatory factors in two coniferous forests (P. yunnanensis Franch. and P. armandii Franch.) under prolonged nitrogen addition. We observed that nitrogen addition elicited different responses in soil bacterial and fungal communities between the two forest types. In P. yunnanensis Franch. plantations, nitrogen supplementation notably reduced soil bacterial α-diversity but increased fungal diversity. In contrast, P. armandii Franch. forests showed the opposite trends, indicating stand-specific differences. Nitrogen addition also led to significant changes in soil nutrient dynamics, increasing soil pH in P. yunnanensis Franch. forests and decreasing it in P. armandii Franch. forests. These changes in soil nutrients significantly affected the diversity, community structure, and network interactions of soil microbial communities, with distinct responses noted between stands. Specifically, nitrogen addition significantly influenced the β-diversity of fungal communities more than that of bacterial communities. It also reduced the complexity of bacterial interspecies interactions in P. yunnanensis Franch. forests while enhancing it in P. armandii Franch. forests. Conversely, low levels of nitrogen addition improved the stability of fungal networks in both forest types. Using random forest and structural equation modeling, soil pH, NH4+-N, and total nitrogen (TN) were identified as key factors regulating bacterial and fungal communities after nitrogen addition. The varied soil nutrient conditions led to different responses in microbial diversity to nitrogen deposition, with nitrogen treatments primarily shaping microbial communities through changes in soil pH and nitrogen availability. This study provides essential insights into the scientific and sustainable management of subtropical plantation forest ecosystems.

High-rate pig manure substitution enhances comammox Nitrospira abundance and diversity in the Cinnamomum camphora coppice planting soils

Comammox Nitrospira represents a groundbreaking discovery in nitrogen cycle research, showcasing its remarking ability for complete ammonia oxidation, which challenges prior conceptions of nitrification. In this study, we examined the response of comammox Nitrospira gene abundance, diversity, and community structure to different rates of pig manure substitution (0 %, 25 %, 50 %, 75 %, and 100 %) in subtropical agroforestry soils. The abundance of ammonia-oxidizing microorganisms was assessed by qPCR, whereas the diversity and structure of comammox Nitrospira were determined by high-throughput sequencing. Our findings revealed that pig manure substitution led to an increase in soil pH, available phosphorus (AP), comammox Nitrospira abundance, and diversity within soils under Cinnamomum camphora coppice planting. Soil pH and AP were the primary factors influencing the diversity and community structure of comammox Nitrospira. Moreover, pig manure substitution significantly influenced the composition of comammox Nitrospira, notably by increasing the relative abundance of clade A.2.1 while reducing that of clade A.2.2. However, pig manure substitution did not exert a significant impact on net nitrification rates, suggesting bacterial relative abundances were more sensitive to manure substitution compared to the underlying biogeochemical processes. Overall, our results offer new insights into the response of comammox Nitrospira to different rates of pig manure substitution in Cinnamomum camphora coppice planting soils, highlighting the pivotal role of soil AP and pH as the key determinants shaping comammox Nitrospira diversity and community structure.

Soil fungal community structure and function response to rhizoma perennial peanut cultivars

BackgroundCrop-associated microorganisms play a crucial role in soil nutrient cycling, and crop growth, and health. Fine-scale patterns in soil microbial community diversity and composition are commonly regulated by plant species or genotype. Despite extensive reports in different crop or its cultivar effects on the microbial community, it is uncertain how rhizoma peanut (RP, Arachis glabrata Benth.), a perennial warm-season legume forage that is well-adapted in the southern USA, affects soil microbial community across different cultivars.ResultsThis study explored the influence of seven different RP cultivars on the taxonomic composition, diversity, and functional groups of soil fungal communities through a field trial in Marianna, Florida, Southern USA, using next-generation sequencing technique. Our results showed that the taxonomic diversity and composition of the fungal community differed significantly across RP cultivars. Alpha diversity (Shannon, Simpson, and Pielou’s evenness) was significantly higher in Ecoturf but lower in UF_Peace and Florigraze compared to other cultivars (p < 0.001). Phylogenetic diversity (Faith’s PD) was lowest in Latitude compared to other cultivars (p < 0.0001). The dominant phyla were Ascomycota (13.34%), Mortierellomycota (3.82%), and Basidiomycota (2.99%), which were significantly greater in Florigraze, UF_Peace, and Ecoturf, respectively. The relative abundance of Neocosmospora was markedly high (21.45%) in UF_Tito and showed large variations across cultivars. The relative abundance of the dominant genera was significantly greater in Arbrook than in other cultivars. There were also significant differences in the co-occurrence network, showing different keystone taxa and more positive correlations than the negative correlations across cultivars. FUNGuild analysis showed that the relative abundance of functional guilds including pathogenic, saprotrophic, endophytic, mycorrhizal and parasitic fungi significantly differed among cultivars. Ecoturf had the greatest relative abundance of mycorrhizal fungal group (5.10 ± 0.44), whereas UF_Peace had the greatest relative abundance of endophytic (4.52 ± 0.56) and parasitic fungi (1.67 ± 0.30) compared to other cultivars.ConclusionsOur findings provide evidence of crop cultivar’s effect in shaping fine-scale fungal community patterns in legume-based forage systems.Graphical abstract