Microbial species pool-mediated diazotrophic community assembly in crop microbiomes during plant development.

Plant-associated diazotrophs strongly relate to plant nitrogen (N) supply and growth. However, our knowledge of diazotrophic community assembly and microbial N metabolism in plant microbiomes is largely limited. Here we examined the assembly and temporal dynamics of diazotrophic communities across multiple compartments (soils, epiphytic and endophytic niches of root and leaf, and grain) of three cereal crops (maize, wheat, and barley) and identified the potential N-cycling pathways in phylloplane microbiomes. Our results demonstrated that the microbial species pool, influenced by site-specific environmental factors (e.g., edaphic factors), had a stronger effect than host selection (i.e., plant species and developmental stage) in shaping diazotrophic communities across the soil-plant continuum. Crop diazotrophic communities were dominated by a few taxa (~0.7% of diazotrophic phylotypes) which were mainly affiliated with Methylobacterium, Azospirillum, Bradyrhizobium, and Rhizobium. Furthermore, eight dominant taxa belonging to Azospirillum and Methylobacterium were identified as keystone diazotrophic taxa for three crops and were potentially associated with microbial network stability and crop yields. Metagenomic binning recovered 58 metagenome-assembled genomes (MAGs) from the phylloplane, and the majority of them were identified as novel species (37 MAGs) and harbored genes potentially related to multiple N metabolism processes (e.g., nitrate reduction). Notably, for the first time, a high-quality MAG harboring genes involved in the complete denitrification process was recovered in the phylloplane and showed high identity to Pseudomonas mendocina. Overall, these findings significantly expand our understanding of ecological drivers of crop diazotrophs and provide new insights into the potential microbial N metabolism in the phyllosphere.IMPORTANCEPlants harbor diverse nitrogen-fixing microorganisms (i.e., diazotrophic communities) in both belowground and aboveground tissues, which play a vital role in plant nitrogen supply and growth promotion. Understanding the assembly and temporal dynamics of crop diazotrophic communities is a prerequisite for harnessing them to promote plant growth. In this study, we show that the site-specific microbial species pool largely shapes the structure of diazotrophic communities in the leaves and roots of three cereal crops. We further identify keystone diazotrophic taxa in crop microbiomes and characterize potential microbial N metabolism pathways in the phyllosphere, which provides essential information for developing microbiome-based tools in future sustainable agricultural production.

Promoting CO2 electroreduction to CO by a graphdiyne-stabilized Au nanoparticle catalyst.

The electrochemical CO2 reduction reaction (CO2RR) gives an ideal approach for producing valuable chemicals, offering dual benefits in terms of environmental preservation and carbon recycling. In this work, a strong synergistic effect is constructed by adopting electron-rich graphdiyne (GDY) as the supporting matrix, which significantly stabilizes the Au active sites and boosts the CO2RR process. The as-prepared GDY-supported Au nanoparticles (Au/GDY) exhibit excellent CO2RR performance, with an extremely high faradaic efficiency of 94.6% for CO as well as good stability with continuous electrolysis for 36 hours. The superior activity and stability of the Au/GDY catalyst can be attributed to the electronic interaction between Au nanoparticles and the GDY substrate, resulting in enhanced electron transfer rates and a stable network of catalytically active sites that ultimately promote the CO2RR.

Coffee consumption and periodontitis: a Mendelian Randomization study.

BACKGROUND: Coffee is one of the most consumed beverages in the world, coffee consumption has been growing in the United States over the past 20 years. Periodontitis is defined by the pathologic loss of the periodontal ligament and destruction of the connective tissue attachment and alveolar bone loss and is related to different systemic diseases and conditions. However, the causality has remained unclarified, thus we regarded discovering the causal relationship between coffee consumption and the liability to periodontitis as the objective of the study. METHODS: Coffee consumption was subdivided into binary coffee consumption and continuous coffee consumption to refine the study design. Genetic instruments were stretched from the MRC-IEU's (MRC Integrative Epidemiology Unit) output from the GWAS pipeline using phesant-derived variables based on the UK Biobank, the Gene-Lifestyle Interactions in Dental Endpoints (GLIDE) project, and the joint meta-analysis of a recent GWAS. The IVW (Inverse Variance Weighted) was regarded as the primary method to estimate the causality, a scatter plot revealed the intuitive result, and tests for stability were also carried out. RESULTS: An effect of continuous coffee consumption on the risk of periodontitis was found, with per SD of coffee consumed increases, the risk of periodontitis rises by 1.04% (Odds Ratio of IVW is 1.0104), while the effect of binary coffee consumption on periodontitis did not meet the requirement of indicating a strong causal association, neither were the reverse causality analyses. CONCLUSIONS: The study indicated the causality of continuous coffee consumption to the risk of periodontitis with a relatively small scale of effect estimate and no strong evidence for an effect of binary coffee-consuming behavior on periodontitis. There was also no intensive evidence suggesting reverse causality.

2-Furoic acid associated with the infection of nematodes by Dactylellina haptotyla and its biocontrol potential on plant root-knot nematodes.

Dactylellina haptotyla is a typical nematode-trapping fungus that has garnered the attention of many scholars for its highly effective lethal potential for nematodes. Secondary metabolites play an important role in D. haptotyla-nematode interactions, but which metabolites perform which function remains unclear. We report the metabolic functions based on high-quality, chromosome-level genome assembly of wild D. haptotyla YMF1.03409. The results indicate that a large variety of secondary metabolites and their biosynthetic genes were significantly upregulated during the nematode-trapping stage. In parallel, we identified that 2-furoic acid was specifically produced during nematode trapping by D. haptotyla YMF1.03409 and isolated it from fermentation production. 2-Furoic acid demonstrated strong nematicidal activity with an LD50 value of 55.05 µg/mL against Meloidogyne incognita at 48 h. Furthermore, the pot experiment showed that the number of galls of tomato root was significantly reduced in the experimental group treated with 2-furoic acid. The considerable increase in the 2-furoic acid content during the infection process and its virulent nematicidal activity revealed an essential synergistic effect during the process of nematode-trapping fungal infection. IMPORTANCE Dactylellina haptotyla have significant application potential in nematode biocontrol. In this study, we determined the chromosome-level genome sequence of D. haptotyla YMF1.03409 by long-read sequencing technology. Comparative genomic analysis identified a series of pathogenesis-related genes and revealed significant gene family contraction events during the evolution of D. haptotyla YMF1.03409. Combining transcriptomic and metabolomic data as well as in vitro activity test results, a compound with important application potential in nematode biocontrol, 2-furoic acid, was identified. Our result expanded the genetic resource of D. haptotyla and identified a previously unreported nematicidal small molecule, which provides new options for the development of plant biocontrol agents.

Soil biodiversity supports the delivery of multiple ecosystem functions in urban greenspaces.

While the contribution of biodiversity to supporting multiple ecosystem functions is well established in natural ecosystems, the relationship of the above- and below-ground diversity with ecosystem multifunctionality remains virtually unknown in urban greenspaces. Here we conducted a standardized survey of urban greenspaces from 56 municipalities across six continents, aiming to investigate the relationships of plant and soil biodiversity (diversity of bacteria, fungi, protists and invertebrates, and metagenomics-based functional diversity) with 18 surrogates of ecosystem functions from nine ecosystem services. We found that soil biodiversity across biomes was significantly and positively correlated with multiple dimensions of ecosystem functions, and contributed to key ecosystem services such as microbially driven carbon pools, organic matter decomposition, plant productivity, nutrient cycling, water regulation, plant-soil mutualism, plant pathogen control and antibiotic resistance regulation. Plant diversity only indirectly influenced multifunctionality in urban greenspaces via changes in soil conditions that were associated with soil biodiversity. These findings were maintained after controlling for climate, spatial context, soil properties, vegetation and management practices. This study provides solid evidence that conserving soil biodiversity in urban greenspaces is key to supporting multiple dimensions of ecosystem functioning, which is critical for the sustainability of urban ecosystems and human wellbeing.

Grazing and ecosystem service delivery in global drylands.

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide. Increasing grazing pressure reduced ecosystem service delivery in warmer and species-poor drylands, whereas positive effects of grazing were observed in colder and species-rich areas. Considering interactions between grazing and local abiotic and biotic factors is key for understanding the fate of dryland ecosystems under climate change and increasing human pressure.

The oncological and obstetric results of radical trachelectomy as a fertility-sparing therapy in early-stage cervical cancer patients.

PURPOSE: This study explored the oncological and obstetric results of radical trachelectomy (RT) in early-stage cervical cancer patients. METHODS: A retrospective analysis was conducted the oncological and obstetric results of 23 patients with early cervical cancer (stages IA2-IB3; International Federation of Gynecology and Obstetrics, 2018) who underwent RT in The Maternal and Child Health Care Hospital of Guiyang, China, from October 2004 to September 2018. RESULTS: 23 patients had cervical tumors of the squamous cell carcinoma histological type. All 23 patients retained reproductive function. The mean follow-up time was 112.87 ± 55.75 (36-199) months. The median tumor size was 2.00 ± 1.35 cm (imperceptible to the eyes 5.00 cm). No recurrence was observed in any of the patient cases. Among the patients with a tumor size > 4 cm (up to 5 cm), three patients who wished to preserve fertility accepted RT following neoadjuvant chemotherapy The pregnancy outcomes were as follows: 8 cases (47.06%) out of 17 cases who attempting pregnancy conceived 12 times.First-trimester abortion and the voluntary abandonment of pregnancy occurred in 4 cases (33.33%), respectively, one patient performed deliberate termination at 24 weeks of gestation. Second-trimester abortion occurred in three cases (25.0%) for chorioamnionitis. Premature delivery at 32 weeks occurred in one case (8.33%). CONCLUSION: Radical trachelectomy is a safe and effective treatment for women with early-stage cervical cancer preserving fertility biology. Patients with a cervical tumor sized > 4 cm can be pregnant after neoadjuvant chemotherapy and RT. Accordingly, this treatment is worthy of further exploration.

Water deficit affects inter-kingdom microbial connections in plant rhizosphere.

The frequency and severity of drought are increasing due to anthropogenic climate change and are already limiting cropping system productivity in many regions around the world. Few microbial groups within plant microbiomes can potentially contribute towards the fitness and productivity of their hosts under abiotic stress events including water deficits. However, microbial communities are complex and integrative work considering the multiple co-existing groups of organisms is needed to better understand how the entire microbiome responds to environmental stresses. We hypothesize that water deficit stress will differentially shape bacterial, fungal, and protistan microbiome composition and influence inter-kingdom microbial interactions in the rhizospheres of corn and sugar beet. We used amplicon sequencing to profile bacterial, fungal, and protistan communities in corn and sugar beet rhizospheres grown under irrigated and water deficit conditions. The water deficit treatment had a stronger influence than host species on bacterial composition, whereas the opposite was true for protists. These results indicate that different microbial kingdoms have variable responses to environmental stress and host factors. Water deficit also influenced intra- and inter-kingdom microbial associations, wherein the protist taxa formed a separate cluster under water deficit conditions. Our findings help elucidate the influence of environmental and host drivers of bacterial, fungal, and protistan community assembly and co-occurrence in agricultural rhizosphere environments.

Archaea is more important than bacteria in driving soil stoichiometry in phosphorus deficient habitats.

Phosphorus deficiency is a critical limit on the cycling of carbon (C), nitrogen (N) and phosphorus (P) in forest ecosystems. Despite the pivotal roles of microbes in driving the biogeochemical cycling of C/N/P, our knowledge on the relationships of soil bacteria and archaea to P deficiency in forest ecosystems remains scarce. Here, we studied 110 acidic soils (average pH 4.5) collected across 700-km subtropical forests with a gradient of available phosphorus (AP) ranging from 0.21 to 17.6 mg/kg. We analyzed the soil C/N/P stoichiometry and studied soil bacterial and archaeal diversity/abundance via high throughput sequencing and qPCR approaches. Our results show that soil P decoupled with N or C when below 3 mg/kg but coupled with C and N when above 3 mg/kg. Archaeal diversity and abundance were significantly higher in low AP (< 3 mg/kg) soils than in high AP (>3 mg/kg) soils, while bacterial were less changed. Compared with bacteria, archaea are more strongly related with soil stoichiometry (C:N, C:P, N:P), especially when AP was less than 3 mg/kg. Taxonomic and functional composition analysis further confirmed that archaeal rather than bacterial taxonomic composition was significantly related with functional composition of microbial communities. Taken together, our results show that archaea are more important than bacteria in driving soil stoichiometry in phosphorus deficient habitats and suggest a niche differentiation of soil bacteria and archaea in regulating the soil C/N/P cycling in subtropical forests.

Activities and metabolomics of Cordyceps gunnii under different culture conditions.

Many active metabolites have been identified from various species of the fungal genus Cordyceps. A predominant species of this genus is Cordyceps gunnii, but there are limited reports on the active ingredients from this species. This study aimed to conduct activity assays and metabolome analysis on extracts of C. gunnii obtained under different culture conditions. Five different solid media were selected to culture the mycelium of C. gunnii and the metabolites were extracted with organic solvents; concurrently, the wild stroma and host complexes of C. gunnii were extracted by ethyl acetate. Extracts were subsequently assayed for various biological activities and were analyzed by untargeted metabolomics. There were significant differences in the activities and metabolites of C. gunnii extracts from different culture conditions and from wild stroma and host complexes. The extracts of stroma and host complexes and mycelia cultured on WGA medium for 21 days exhibited similar effective inhibitory activity against five cell lines. A total of 51 metabolites were annotated and included various structural types. The literatures indicate that most of the identified compounds have a variety of different biological activities. These findings provide the basis for further systematic excavation of C. gunnii and improved utilization of this fungal species.

Soil initial bacterial diversity and nutrient availability determine the rate of xenobiotic biodegradation.

Understanding the relative importance of soil microbial diversity, plants and nutrient management is crucial to implement an effective bioremediation approach to xenobiotics-contaminated soils. To date, knowledge on the interactive effects of soil microbiome, plant and nutrient supply on influencing biodegradation potential of soils remains limited. In this study, we evaluated the individual and interactive effects of soil initial bacterial diversity, nutrient amendments (organic and inorganic) and plant presence on the biodegradation rate of pyrene, a polycyclic aromatic hydrocarbon. Initial bacterial diversity had a strong positive impact on soil biodegradation potential, with soil harbouring higher bacterial diversity showing ~ 2 times higher degradation rates than soils with lower bacterial diversity. Both organic and inorganic nutrient amendments consistently improved the degradation rate in lower diversity soils and had negative (inorganic) to neutral (organic) effect in higher diversity soils. Interestingly, plant presence/type did not show any significant effect on the degradation rate in most of the treatments. Structural equation modelling demonstrated that initial bacterial diversity had a prominent role in driving pyrene biodegradation rates. We provide novel evidence that suggests that soil initial microbial diversity, and nutrient amendments should be explicitly considered in the design and employment of bioremediation management strategies for restoring natural habitats disturbed by organic pollutants.

Unveiling the visible-light-driven photodegradation pathway and products toxicity of tetracycline in the system of Pt/BiVO4 nanosheets.

The antibiotics pollution has currently captured increasing concerns due to its potential hazards to the environment and human health. The development of efficient and viable techniques for the removal of antibiotics is one of the research hotspots in fields of wastewater treatment and pharmaceutical industry. Although the photodegradation of antibiotics is widely studied, the evolution and toxicity of degradation intermediates have been rarely documented. Herein, Pt nanoparticles (NPs) decorated BiVO4 nanosheets (Pt/BiVO4 NSs) that exhibit excellent tetracycline (TC) photodegradation activity and stability have been prepared. Especially, the TC degradation efficiency reaches ca. 88.5% after 60 min under visible light irradiation, which is superior to most of the metal loaded two-dimensional photocatalysts reported hitherto. The excellent photocatalytic activity is attributable to the enhanced light absorption capacity and charge separation efficiency in Pt/BiVO4 NSs. h+, •O2- and •OH are the main active species for TC degradation, resulting in three possible degradation pathways. Furthermore, we first verify that TC solutions treated by Pt/BiVO4 NSs are harmless to Escherichia coli K-12 and various bacteria in natural rivers, which would not stimulate Escherichia coli to produce antibiotics resistance genes (ARGs). This work develops an environmentally friendly photodegradation strategy using Pt/BiVO4 NSs with potentials for efficient remediation of antibiotics pollution in wastewater.

Plant developmental stage drives the differentiation in ecological role of the maize microbiome.

BACKGROUND: Plants live with diverse microbial communities which profoundly affect multiple facets of host performance, but if and how host development impacts the assembly, functions and microbial interactions of crop microbiomes are poorly understood. Here we examined both bacterial and fungal communities across soils, epiphytic and endophytic niches of leaf and root, and plastic leaf of fake plant (representing environment-originating microbes) at three developmental stages of maize at two contrasting sites, and further explored the potential function of phylloplane microbiomes based on metagenomics. RESULTS: Our results suggested that plant developmental stage had a much stronger influence on the microbial diversity, composition and interkingdom networks in plant compartments than in soils, with the strongest effect in the phylloplane. Phylloplane microbiomes were co-shaped by both plant growth and seasonal environmental factors, with the air (represented by fake plants) as its important source. Further, we found that bacterial communities in plant compartments were more strongly driven by deterministic processes at the early stage but a similar pattern was for fungal communities at the late stage. Moreover, bacterial taxa played a more important role in microbial interkingdom network and crop yield prediction at the early stage, while fungal taxa did so at the late stage. Metagenomic analyses further indicated that phylloplane microbiomes possessed higher functional diversity at the early stage than the late stage, with functional genes related to nutrient provision enriched at the early stage and N assimilation and C degradation enriched at the late stage. Coincidently, more abundant beneficial bacterial taxa like Actinobacteria, Burkholderiaceae and Rhizobiaceae in plant microbiomes were observed at the early stage, but more saprophytic fungi at the late stage. CONCLUSIONS: Our results suggest that host developmental stage profoundly influences plant microbiome assembly and functions, and the bacterial and fungal microbiomes take a differentiated ecological role at different stages of plant development. This study provides empirical evidence for host exerting strong effect on plant microbiomes by deterministic selection during plant growth and development. These findings have implications for the development of future tools to manipulate microbiome for sustainable increase in primary productivity. Video Abstract.

Generalist Taxa Shape Fungal Community Structure in Cropping Ecosystems.

Fungi regulate nutrient cycling, decomposition, symbiosis, and pathogenicity in cropland soils. However, the relative importance of generalist and specialist taxa in structuring soil fungal community remains largely unresolved. We hypothesized that generalist fungi, which are adaptable to various environmental conditions, could potentially dominate the community and become the basis for fungal coexisting networks in cropping systems. In this study, we identified the generalist and habitat specialist fungi in cropland soils across a 2,200 kms environmental gradient, including three bioclimatic regions (subtropical, warm temperate, and temperate). A few fungal taxa in our database were classified as generalist taxa (~1%). These generalists accounted for >35% of the relative abundance of all fungal populations, and most of them are Ascomycota and potentially pathotrophic. Compared to the specialist taxa (5-17% of all phylotypes in three regions), generalists had a higher degree of connectivity and were often identified as hub within the network. Structural equation modeling provided further evidence that after accounting for spatial and climatic/edaphic factors, generalists had larger contributions to the fungal coexistence pattern than habitat specialists. Taken together, our study provided evidence that generalist taxa are crucial components for fungal community structure. The knowledge of generalists can provide important implication for understanding the ecological preference of fungal groups in cropland systems.

Global homogenization of the structure and function in the soil microbiome of urban greenspaces.

The structure and function of the soil microbiome of urban greenspaces remain largely undetermined. We conducted a global field survey in urban greenspaces and neighboring natural ecosystems across 56 cities from six continents, and found that urban soils are important hotspots for soil bacterial, protist and functional gene diversity, but support highly homogenized microbial communities worldwide. Urban greenspaces had a greater proportion of fast-growing bacteria, algae, amoebae, and fungal pathogens, but a lower proportion of ectomycorrhizal fungi than natural ecosystems. These urban ecosystems also showed higher proportions of genes associated with human pathogens, greenhouse gas emissions, faster nutrient cycling, and more intense abiotic stress than natural environments. City affluence, management practices, and climate were fundamental drivers of urban soil communities. Our work paves the way toward a more comprehensive global-scale perspective on urban greenspaces, which is integral to managing the health of these ecosystems and the well-being of human populations.

Rare taxa maintain the stability of crop mycobiomes and ecosystem functions.

Plants harbour highly diverse mycobiomes which sustain essential functions for host health and productivity. However, ecological processes that govern the plant-mycobiome assembly, interactions and their impact on ecosystem functions remain poorly known. Here we characterized the ecological role and community assembly of both abundant and rare fungal taxa along the soil-plant continuums (rhizosphere, phyllosphere and endosphere) in the maize-wheat/barley rotation system under different fertilization practices at two contrasting sites. Our results indicate that mycobiome assembly is shaped predominantly by compartment niche and host species rather than by environmental factors. Moreover, crop-associated fungal communities are dominated by few abundant taxa mainly belonging to Sordariomycetes and Dothideomycetes, while the majority of diversity within mycobiomes are represented by rare taxa. For plant compartments, the abundant sub-community is mainly determined by stochastic processes. In contrast, the rare sub-community is more sensitive to host selection and mainly governed by deterministic processes. Furthermore, our results demonstrate that rare taxa play an important role in fungal co-occurrence network and ecosystem functioning like crop yield and soil enzyme activities. These results significantly advance our understanding of crop mycobiome assembly and highlight the key role of rare taxa in sustaining the stability of crop mycobiomes and ecosystem functions.

Host selection shapes crop microbiome assembly and network complexity.

Plant microbiomes are essential to host health and productivity but the ecological processes that govern crop microbiome assembly are not fully known. Here we examined bacterial communities across 684 samples from soils (rhizosphere and bulk soil) and multiple compartment niches (rhizoplane, root endosphere, phylloplane, and leaf endosphere) in maize (Zea mays)-wheat (Triticum aestivum)/barley (Hordeum vulgare) rotation system under different fertilization practices at two contrasting sites. Our results demonstrate that microbiome assembly along the soil-plant continuum is shaped predominantly by compartment niche and host species rather than by site or fertilization practice. From soils to epiphytes to endophytes, host selection pressure sequentially increased and bacterial diversity and network complexity consequently reduced, with the strongest host effect in leaf endosphere. Source tracking indicates that crop microbiome is mainly derived from soils and gradually enriched and filtered at different plant compartment niches. Moreover, crop microbiomes were dominated by a few dominant taxa (c. 0.5% of bacterial phylotypes), with bacilli identified as the important biomarker taxa for wheat and barley and Methylobacteriaceae for maize. Our work provides comprehensive empirical evidence on host selection, potential sources and enrichment processes for crop microbiome assembly, and has important implications for future crop management and manipulation of crop microbiome for sustainable agriculture.

Nitrogen-fixing trees in mixed forest systems regulate the ecology of fungal community and phosphorus cycling.

The fungal community plays an important role in forest ecosystems via the provision of resources to plant nutrition and productivity. However, the ecology of the fungal network and its relationship with phosphorus (P) dynamics remain poorly understood in mixed forest plantations. Here, we analyzed the fungal community using the amplicon sequencing in plantations of pure Eucalyptus grandis, with (E + N) and without N fertilization (E), besides pure Acacia mangium (A), and in a consortium of E. grandis and A. mangium (E + A), at 27 and 39 months after planting. We analyzed chemical, physical and biochemical soil and litter attributes related to P cycling, and the fungal community structure to find out if mixed plantations can increase fungal connections and to identify their role in the P dynamics in the soil-litter system. Soil organic fraction (OF), phosphorus in OF, total-P and acid phosphatase activity were significantly higher in E + A and A treatments regardless of the sampling period. Total N and P, richness, and Shannon diversity of the fungi in the litter was significantly higher in the treatments E + A and A. The fungal community structure in litter differed between treatments and sampling periods, and E + A showed an intermediate structure between the two pure treatments (E) and (A). E + A correlated highly with P dynamics when evaluated by both Pearson and redundancy analyses, particularly in the litter layer. Co-occurrence networks of fungal taxa became simpler in pure E. grandis plantations, whereas mixed system (E + A) showed a more connected and complex network. Our findings provide novel evidence that mixed forest plantations promote positive responses in the fungal community connections, which are closely related to P availability in the system, prominently in the litter layer. This indicates that the litter layer represents a specific niche to improve nutrient cycling by fungi in mixed forest ecosystems.

Multiple elements of soil biodiversity drive ecosystem functions across biomes.

The role of soil biodiversity in regulating multiple ecosystem functions is poorly understood, limiting our ability to predict how soil biodiversity loss might affect human wellbeing and ecosystem sustainability. Here, combining a global observational study with an experimental microcosm study, we provide evidence that soil biodiversity (bacteria, fungi, protists and invertebrates) is significantly and positively associated with multiple ecosystem functions. These functions include nutrient cycling, decomposition, plant production, and reduced potential for pathogenicity and belowground biological warfare. Our findings also reveal the context dependency of such relationships and the importance of the connectedness, biodiversity and nature of the globally distributed dominant phylotypes within the soil network in maintaining multiple functions. Moreover, our results suggest that the positive association between plant diversity and multifunctionality across biomes is indirectly driven by soil biodiversity. Together, our results provide insights into the importance of soil biodiversity for maintaining soil functionality locally and across biomes, as well as providing strong support for the inclusion of soil biodiversity in conservation and management programmes.

Large-scale patterns of soil antibiotic resistome in Chinese croplands.

Soil is a vital reservoir of antibiotic resistance genes (ARGs), but we still know little about their distribution in cropland soils and the main driving forces. Here we performed an investigation for ARGs patterns in 105 cropland soils (planted with maize, peanut or soybean) along a 2, 200 km transect in China using high-throughput quantitative PCR approaches. Totally, 204 ARGs were detected, with a higher diversity found in central China than that in northeast and south China. The most abundant (top 50%) and highly shared (present in >50% samples) ARGs regarded as core resistome were dominated by multidrug resistance genes such as oprJ, acrA-05 and acrA-04. Regressive analyses revealed that the relative abundance of total ARGs and core resistome both had significant relationships with mobile genetic elements (MGEs). Anthropogenic factors including the consumption of plastic films and soil properties including heavy metals showed good correlations with the diversity of ARGs. Structural equation modelling analysis further explained that anthropogenic factors were the main forces shaping the ARGs patterns. These findings highlight the importance of human activities in shaping soil antibiotic resistome in the croplands, providing potential management strategies to mitigate the dissemination of ARGs to humans via food chain.