Sirt3 restricts tumor initiation via promoting LONP1 deacetylation and K63 ubiquitination.

BACKGROUND: Sirtuin 3 (Sirt3) is a controversial regulator of carcinogenesis. It residents in the mitochondria and gradually decays during aging. In this study, we tried to investigate the role of Sirt3 in carcinogenesis and to explore its involvement in metabolic alteration. METHODS: We generated conditional intestinal epithelium Sirt3-knockout mice by crossing ApcMin/+; Villin-Cre with Sirt3fl/fl (AVS) mice. The deacetylation site of Lon protease-1 (LONP1) was identified with Mass spectrometry. The metabolic flux phenotype was determined by Seahorse bioanalyzer. RESULTS: We found that intestinal epithelial cell-specific ablation of Sirt3 promotes primary tumor growth via stabilizing mitochondrial LONP1. Notably, we newly identified that Sirt3 deacetylates human oncogene LONP1 at N terminal residue lysine 145 (K145). The LONP1 hyperacetylation-mutant K145Q enhances oxidative phosphorylation to accelerate tumor growth, whereas the deacetylation-mutant K145R produces calorie-restriction like phenotype to restrain tumorigenesis. Sirt3 deacetylates LONP1 at K145 and subsequently facilitates the ESCRT0 complex sorting and K63-ubiquitination that resulted in the degradation of LONP1. Our results sustain the notion that Sirt3 is a tumor-suppressor to maintain the appropriate ubiquitination and degradation of oncogene LONP1. CONCLUSION: Sirt3 represents a targetable metabolic checkpoint of oncogenesis, which produces energy restriction effects via maintaining LONP1 K145 deacetylation and subsequent K63 ubiquitination.

Phosphorus Fertilization Boosts Mineral-Associated Soil Organic Carbon Formation Associated with Phagotrophic Protists.

Long-term fertilization affects soil organic C accumulation. A growing body of research has revealed critical roles of bacteria in soil organic C accumulation, particularly through mineral-associated organic C (MAOC) formation. Protists are essential components of soil microbiome, but the relationships between MAOC formation and protists under long-term fertilization remain unclear. Here, we used cropland soil from a long-term fertilization field trial and conducted two microcosm experiments with 13C-glucose addition to investigate the effects of N and P fertilizations on MAOC formation and the relationships with protists. The results showed that long-term fertilization (especially P fertilization) significantly (P < 0.05) increased 13C-MAOC content. Compared with P-deficient treatment, P replenishment enriched the number of protists (mainly Amoebozoa and Cercozoa) and bacteria (mainly Acidobacteriota, Bacteroidota, and Gammaproteobacteria), and significantly (P < 0.001) promoted the abundances of bacterial functional genes controlling C, N, P, and S metabolisms. The community composition of phagotrophic protists prominently (P < 0.001) correlated with the bacterial community composition, bacterial functional gene abundance, and 13C-MAOC content. Co-occurrence networks of phagotrophic protists and bacteria were more connected in soil with the N inoculum added than in soil with the NP inoculum added. P replenishment strengthened bacterial 13C assimilation (i.e., 13C-phospholipid fatty acid content), which negatively (P < 0.05) correlated with the number and relative abundance of phagotrophic Cercozoa. Together, these results suggested that P fertilization boosts MAOC formation associated with phagotrophic protists. Our study paves the way for future research to harness the potential of protists to promote belowground C accrual in agroecosystems.

Dahuang Fuzi Baijiang decoction restricts progenitor to terminally exhausted T cell differentiation in colorectal cancer.

Obesity increases the risk of colorectal cancer (CRC) by 30%. The obese tumor microenvironment compromises antitumor immunity by eliciting exhausted T cells (Tex). Hypothesizing that Dahuang Fuzi Baijiang decoction (DFB) is a combined classical prescription from the "Synopsis of Prescriptions of the Golden Chamber". We first determined that DFB regresses tumor growth in high-fat diet-induced obese mice by expanding the TIM3- subset with intermediate expression of programmed cell death-1 (PD-1int TIM3- ) and restricting the PD-1hi TIM3+ subset. Transcription factor 1 (TCF1) is highly expressed in the PD-1int TIM3- subset but is absent in PD-1hi TIM3+ cells. We next confirmed that progenitor PD-1int TCF+ cells robustly produce tumor necrosis factor-α (TNFα) and interferon-γ, whereas terminally differentiated PD-1int TCF+ cells have defects in generating TNFα. With transgenic ob/ob mice, we found that DFB produces cooperative efficacy with anti-PD-1 (αPD-1) by limiting the PD-1hi Tim3+ subset and amplifying the PD-1int TCF+ population. Finally, we defined the recombinant chemokine C-C-motif receptor 2 (CCR2)+ CD8+ subset as terminal Tex and identified that the differentiation from progenitor to terminal Tex is driven, at least in part, by the chemokine (C-C motif) ligand 2 (CCL2)/CCR2 axis. The CCR2 inhibitor enhances the response to αPD-1 by promoting the counts of progenitor Tex. Altogether, DFB dampens CCL2 and preserves progenitor Tex in the obese microenvironment to restrain CRC progression. These findings provide unambiguous evidence that the traditional Chinese formula DFB can prevent tumor progression by modulating adaptive immunity and establish a strong rationale for further clinical verification.

Controllable 3D Porous Ni Current Collector Coupled with Surface Phosphorization Enhances Na Storage of Ni3 S2 Nanosheet Arrays.

3D porous Ni is fabricated via an easily scalable electroless plating method using a dynamic template formed through in-situ hydrogen bubbles. The pore size in the range of several micrometers is controllable through adjusting the Ni2+ depositing rate and hydrogen bubbles releasing rate. The Ni3 S2 nanosheet arrays anode is then grown on the unique 3D porous Ni current collector followed by subsequent surface phosphorization. The tremendous interconnected pores and rich voids between the Ni3 S2 nanosheet arrays cannot only provide rapid transferring channels for Na+ , but also accommodate volumetric changes of the Ni3 S2 electrode during cycling, guaranteeing the integrity of the active material. In addition, the surface phosphorized layer enhances the electronic conductivity through providing an electron transport highway along the 3D Ni3 S2 , NiP2 layer, and 3D porous Ni current collector, and simultaneously stabilizes the electrode/electrolyte interphase as a protecting layer. Because of these merits, the phosphorized 3D porous Ni3 S2 (3D P-Ni3 S2 ) electrode is capable of delivering an ultra-stable capacity of 387.5 mAh g-1 at 0.1 A g-1 , and a high capacity retention of 85.3% even at a high current density of 1.6 A g-1 .

LncRNA NKILA integrates RXFP1/AKT and NF-κB signalling to regulate osteogenesis of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are previously found to have potential capacity to differentiate into osteocytes when exposed to specific stimuli. However, the detailed molecular mechanism during this progress remains largely unknown. In the current study, we characterized the lncRNA NKILA as a crucial positive regulator for osteogenesis of MSCs. NKILA attenuation significantly inhibits the calcium deposition and alkaline phosphatase activity of MSCs. More interestingly, we defined that NKILA is functionally involved in the regulation of RXFP1/PI3K-AKT and NF-κB signalling. Knockdown of NKILA dramatically down-regulates the expression of RXFP1 and then reduces the activity of AKT, a downstream regulator of RXFP1 signalling which is widely accepted as an activator of osteogenesis. Moreover, we identify NF-κB as another critical regulator implicated in NKILA-mediated osteogenic differentiation. Inhibition of NF-κB can induce the expression of RUNX2, a master transcription factor of osteogenesis, in a HDAC2-mediated deacetylation manner. Thus, this study illustrates the regulatory function of NKILA in osteogenesis through distinct signalling pathways, therefore providing a new insight into searching for new molecular targets for bone tissue repair and regeneration.

Effects of micro-/nano-hydroxyapatite and phytoremediation on fungal community structure in copper contaminated soil.

Micro-/nano-hydroxyapatite (MHA/NHA) has been used to reduce the concentration of available heavy metals and increase soil pH in the remediation of heavy metal-contaminated soils. However, little is known about the effects of MHA and NHA on soil fungal communities and function. In this study, fungal community composition was characterized from copper-contaminated soils amended with MHA, NHA and three other classic amendments combined with Elsholtzia splendens during a 3-year immobilization experiment. High-throughput sequencing results showed that applications of MHA increased the richness and diversity of the fungal community, which was opposite the results of NHA. SIMPER analysis indicated that both the relative abundance of fungi associated with biosorption and plant growth promotion increased, whereas the relative abundance of fungi related to bioleaching and potential pathogens decreased after applying MHA. Redundancy (RDA) analysis revealed that the soil pH was a crucial environmental factor in the succession of fungal communities. In addition, the results of functional prediction via FUNGuild suggested that the application of MHA had the potential to reduce the risk of pathogens infecting animals and plants in the soil but that NHA had some environmental risks. Overall, fungal community showed a synergistic effect of immobilization with the test amendments, and MHA was better for the remediation of heavy metal-contaminated soils than the other test amendments.

Environment and geographic distance differ in relative importance for determining fungal community of rhizosphere and bulk soil.

Rhizospheric fungi play major roles in both natural and agricultural ecosystems. However, little is known about the determinants of their diversity and biogeographic patterns. Here, we compared fungal communities in rhizosphere and bulk soils of wheat fields in the North China Plain. The rhizosphere had a lower fungal diversity (observed OTUs and Chao1) than bulk soil, and a distinct fungal community structure in rhizosphere compared with bulk soil. The relative importance of environmental factors and geographic distance for fungal distribution differed between rhizosphere and bulk soil. Environmental factors were the primary cause of variations in total fungal community and major fungal phyla in bulk soil. By contrast, fungal communities in soils loosely attached to roots were predictable from both environmental factors and influences of geographic distance. Communities in soils tightly attached to roots were mainly determined by geographic distance. Our results suggest that both contemporary environment processes (present-day abiotic and biotic environment characters) and historical processes (spatial isolation, dispersal limitation occurred in the past) dominate variations of fungal communities in wheat fields, but their relative importance of all these processes depends on the proximity of fungal community to the plant roots.

Effect of blood biochemical factors on nontraumatic necrosis of the femoral head : Logistic regression analysis.

OBJECTIVE: This case-control study aimed to identify the risk factors of nontraumatic necrosis of the femoral head (NONFH). METHODS: In all, 242 patients with NONFH treated at the hip disease research center of our hospital between March 2012 and October 2015 were included. After excluding 19 patients with tumor or tuberculosis, 223 patients were enrolled. Controls comprised 223 healthy persons selected from our hospital database. Single-factor variance analysis and t test were performed to select the index of statistical significance. The 95% confidence interval (95% CI) and normal range of the selected indicators were compared, and abnormal related indexes were selected from the femoral head necrosis group. The selected indicators were based on the increase or decrease to locate the risk indicators and render their corresponding assignment. Logistic regression analysis of the risk factors was performed after the assignment. RESULTS: The necrotic group of patients with decreased carbon dioxide combining power (CO2CP), increased total cholesterol, increased low-density lipoprotein, and decreased high-density lipoprotein levels had statistically significant partial regression coefficient values and the odds ratios were 73.5 (95% CI 24.59-219.74), 7.15 (3.51-14.85), 633.07 (121.7-3304.78), and 20.11 (9.36-43.8), respectively, indicating that these are strong risk factors for NONFH. CONCLUSIONS: Abnormal lipid metabolism is a strong risk factor of NONFH. Lipid examination can be used as a screening tool for NONFH in high-risk populations, for alcoholism, and many hormone applications. The decreased CO2CP was associated with NONFH, and bone microcirculation was considered to possibly lead various conditions such as ischemia and hypoxia-related bone metabolic acidosis. However, further study is needed.

Carbon constrains fungal endophyte assemblages along the timberline.

The alpha diversity of foliar fungal endophytes (FEs) in leaves of Betula ermanii in a subalpine timberline ecotone on Changbai Mountain, China increased with elevation. There were also significant differences in beta diversity along the elevation gradient. Among the environmental variables analysed, leaf carbon significantly increased with elevation, and was the most significant environmental factor that constrained the alpha and beta diversity in the FE communities. Tree height and the cellulose, lignin, and carbon/nitrogen ratio of the leaves also affected the FE assemblages. When controlled for the effects of elevation, leaf carbon was still the main driver of changes in evenness, Shannon diversity and FE community composition. The results offered clues of the carbon acquisition strategy of the foliar FEs across this cold terrain. There was strong multicollinearity between both annual precipitation and temperature, with elevation (|Pearson r| > 0.986), so the effects of these climatic variables were impossible to separate; however, they may play key roles, and the direct effects of both warrant further investigation. As pioneer decomposers of leaf litter, variations in diversity and community composition of FE measured here may feedback and influence carbon cycling and dynamics in these forest ecosystems.

Fungal community composition in soils subjected to long-term chemical fertilization is most influenced by the type of organic matter.

Organic matter application is a widely used practice to increase soil carbon content and maintain soil fertility. However, little is known about the effect of different types of organic matter, or the input of exogenous species from these materials, on soil fungal communities. In this study, fungal community composition was characterized from soils amended with three types of organic matter over a 30-year fertilization experiment. Chemical fertilization significantly changed soil fungal community composition and structure, which was exacerbated by the addition of organic matter, with the direction of change influenced by the type of organic matter used. The addition of organic matter significantly increased soil fungal richness, with the greatest richness achieved in soils amended with pig manure. Importantly, following addition of cow and pig manure, fungal taxa associated with these materials could be found in the soil, suggesting that these exogenous species can augment soil fungal composition. Moreover, the addition of organic matter decreased the relative abundance of potential pathogenic fungi. Overall, these results indicate that organic matter addition influences the composition and structure of soil fungal communities in predictable ways.

Legume rhizodeposition promotes nitrogen fixation by soil microbiota under crop diversification.

Biological nitrogen fixation by free-living bacteria and rhizobial symbiosis with legumes plays a key role in sustainable crop production. Here, we study how different crop combinations influence the interaction between peanut plants and their rhizosphere microbiota via metabolite deposition and functional responses of free-living and symbiotic nitrogen-fixing bacteria. Based on a long-term (8 year) diversified cropping field experiment, we find that peanut co-cultured with maize and oilseed rape lead to specific changes in peanut rhizosphere metabolite profiles and bacterial functions and nodulation. Flavonoids and coumarins accumulate due to the activation of phenylpropanoid biosynthesis pathways in peanuts. These changes enhance the growth and nitrogen fixation activity of free-living bacterial isolates, and root nodulation by symbiotic Bradyrhizobium isolates. Peanut plant root metabolites interact with Bradyrhizobium isolates contributing to initiate nodulation. Our findings demonstrate that tailored intercropping could be used to improve soil nitrogen availability through changes in the rhizosphere microbiome and its functions.

Spatial and temporal dynamics of the bacterial community under experimental warming in field-grown wheat.

Climate change may lead to adverse effects on agricultural crops, plant microbiomes have the potential to help hosts counteract these effects. While plant-microbe interactions are known to be sensitive to temperature, how warming affects the community composition and functioning of plant microbiomes in most agricultural crops is still unclear. Here, we utilized a 10-year field experiment to investigate the effects of warming on root zone carbon availability, microbial activity and community composition at spatial (root, rhizosphere and bulk soil) and temporal (tillering, jointing and ripening stages of plants) scales in field-grown wheat (Triticum aestivum L.). The dissolved organic carbon and microbial activity in the rhizosphere were increased by soil warming and varied considerably across wheat growth stages. Warming exerted stronger effects on the microbial community composition in the root and rhizosphere samples than in the bulk soil. Microbial community composition, particularly the phyla Actinobacteria and Firmicutes, shifted considerably in response to warming. Interestingly, the abundance of a number of known copiotrophic taxa, such as Pseudomonas and Bacillus, and genera in Actinomycetales increased in the roots and rhizosphere under warming and the increase in these taxa implies that they may play a role in increasing the resilience of plants to warming. Taken together, we demonstrated that soil warming along with root proximity and plant growth status drives changes in the microbial community composition and function in the wheat root zone.

Dosage effects of organic manure on bacterial community assemblage and phosphorus transformation profiles in greenhouse soil.

Manure is a potential substitute for chemical phosphate fertilizer, especially in intensive agriculture, such as greenhouse farming, but the associations between soil phosphorus (P) availability and the soil microbial community under manure application instead of chemical phosphate fertilizers are still rarely addressed. In this study, a field experiment in greenhouse farming with manure application instead of chemical phosphate fertilizers was established, including five treatments: a control with conventional fertilization and chemical phosphate fertilizer substitution treatments using manure as the sole P resource at 25% (0.25 Po), 50% (0.50 Po), 75% (0.75 Po), and 100% (1.00 Po) of the control. Except for 1.00 Po, all the treatments applied with manure harbored similar levels of available P (AP) as the control. Most of the bacterial taxa involved in P transformation were enriched in manure treatments. Treatments of 0.25 Po and 0.50 Po significantly enhanced bacterial inorganic P (Pi) dissolution capacity, while 0.25 Po decreased bacterial organic P (Po) mineralization capacity. In contrast, the 0.75 Po and 1.00 Po treatments significantly decreased the bacterial Pi dissolution capacity and increased the Po mineralization capacity. Further analysis revealed that the changes in the bacterial community were significantly correlated with soil pH, total carbon (TC), total nitrogen (TN), and AP. These results revealed the dosage effect of the impact of manure on soil P availability and microbial P transformation capacity and emphasized that an appropriate dosage of organic manure is important in practical production.

Self-healing of surface defects on Zn electrode for stable aqueous zinc-ion batteries via manipulating the electrode/electrolyte interphases.

The reversibility and stability of aqueous zinc-ion batteries are largely limited by inevitable parasitic reactions at the interface and uncontrollable dendrite growth. Inspired by self-healing smart electronic materials, we propose a confinement strategy with gelatin, an amphiphilic macromolecule, as additive to regulate the deposition behavior of Zn ions and utilize the dendrites to fill the surface defects formed by inevitable interfacial parasitic reactions. Absorbed gelatin molecules impede H2O reaching Zn electrode surface to enhance the anticorrosion behavior and adjust the local pH value, which is a "smart" way to stabilize the electrode/electrolyte interphase. Additionally, the confined effect of absorbed gelatin molecules on Zn2+ and "electrostatic shield" formed from positive charged -CN3H5+ suppress 2D diffusion and accumulation of Zn2+, guiding Zn continuously depositing inside the defect during electrochemical cycling, then self-healing of electrode surface defects is achieved. Under the synergetic effects of these merits, Zn electrode demonstrates almost unchangeable surface after soaking in the electrolyte for 10 days, and stably cycle more than 1100 h at 0.5 mA cm-2 and 1300 h at 3.0 mA cm-2 in symmetric cell. In addition, the full batteries using the base electrolyte with 0.5 and 1.0 g/L gelatin can stably cycle for 3000 cycles.

Dynamic variation of bacterial community assemblage and functional profiles during rice straw degradation.

Bacteria is one of the most important drivers of straw degradation. However, the changes in bacterial community assemblage and straw-decomposing profiles during straw decomposition are not well understood. Based on cultivation-dependent and independent technologies, this study revealed that the "common species" greatly contributed to the dynamic variation of bacterial community during straw decomposition. Twenty-three functional strains involved in straw decomposition were isolated, but only seven were detected in the high-throughput sequencing data. The straw decomposers, including the isolated strains and the agents determined by functional prediction, constituted only 0.024% (on average) of the total bacterial community. The ecological network showed that most of the identified decomposers were self-existent without associations with other species. These results showed that during straw composition, community assembly might be greatly determined by the majority, but straw decomposition functions might be largely determined by the minority and emphasized the importance of the rare species in community-specific functions.

Responses of Nitrous Oxide Emissions and Bacterial Communities to Experimental Freeze-Thaw Cycles in Contrasting Soil Types.

Nitrous oxide (N2O) pulse emissions are detected in soils subjected to freeze-thaw cycles in both laboratory and field experiments. However, the mechanisms underlying this phenomenon are poorly understood. In this study, a laboratory incubation experiment that included freeze-thaw cycles (FTC), freezing (F) and control (CK) treatments was performed on three typical Chinese upland soils, namely, fluvo-aquic soil (FS), black soil (BS) and loess soil (LS). A higher similarity in soil properties and bacterial community structure was discovered between FS and LS than between FS and BS or LS and BS, and the bacterial diversity of FS and LS was higher than that of BS. FTC significantly increased the denitrification potential and the proportion of N2O in the denitrification gas products in FS and LS but decreased the denitrification potential in BS. Accordingly, with the increasing number of freeze-thaw cycles, the bacterial community composition in the FTC treatments in FS and LS diverged from that in CK but changed little in BS. Taxa that responded to FTC or correlated with denitrification potential were identified. Taken together, our results demonstrated that the effects of FTC on N2O emissions are soil-type-dependent and that the shift in the microbial community structure may contribute to the elevated N2O emissions.

Resource-dependent biodiversity and potential multi-trophic interactions determine belowground functional trait stability.

BACKGROUND: For achieving long-term sustainability of intensive agricultural practices, it is pivotal to understand belowground functional stability as belowground organisms play essential roles in soil biogeochemical cycling. It is commonly believed that resource availability is critical for controlling the soil biodiversity and belowground organism interactions that ultimately lead to the stabilization or collapse of terrestrial ecosystem functions, but evidence to support this belief is still limited. Here, we leveraged field experiments from the Chinese National Ecosystem Research Network (CERN) and two microcosm experiments mimicking high and low resource conditions to explore how resource availability mediates soil biodiversity and potential multi-trophic interactions to control functional trait stability. RESULTS: We found that agricultural practice-induced higher resource availability increased potential cross-trophic interactions over 316% in fields, which in turn had a greater effect on functional trait stability, while low resource availability made the stability more dependent on the potential within trophic interactions and soil biodiversity. This large-scale pattern was confirmed by fine-scale microcosm systems, showing that microcosms with sufficient nutrient supply increase the proportion of potential cross-trophic interactions, which were positively associated with functional stability. Resource-driven belowground biodiversity and multi-trophic interactions ultimately feedback to the stability of plant biomass. CONCLUSIONS: Our results indicated the importance of potential multi-trophic interactions in supporting belowground functional trait stability, especially when nutrients are sufficient, and also suggested the ecological benefits of fertilization programs in modern agricultural intensification. Video Abstract.

The overlap of soil and vegetable microbes drives the transfer of antibiotic resistance genes from manure-amended soil to vegetables.

Livestock manure, as a major source of antibiotic resistance genes (ARGs), could further transfer ARGs from soil to vegetables when it's used as fertilizer in field and then pose threat to human health. Meanwhile, manure inputs and vegetable planting also affect soil bacterial communities, but these effects on the transmission of ARGs from soil to vegetable is still lacking. Here, lettuce and endive were cultivated in manure-amended soils using pot experiment. The distribution of bacterial community, ARGs and intI1 gene were studied in manure-amended soil and vegetable roots and leaves at harvest. High-throughput sequencing analysis demonstrated that planting vegetables exerted significant effect on soil bacterial communities, which partly explained the decrease of certain ARGs and the intI1 gene in planted soil than in control soil. ARGs in vegetable and soil were interconnected. The bacterial community compositions among root endophyte, leaf endophyte, and phyllosphere were varied by Hierarchical clustering analysis. Higher abundance of shared bacterial taxa was found between root endophytes and soil microbes, which could lead to a relative higher detection frequency of ARGs in root endophyte. Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes were dominant in the plant endophyte and phyllosphere microbes and had intensive correlations with ARGs. Taken together, our findings provided valuable insights into the role of bacterial community structure in the dissemination of ARGs from manure-amended soil to vegetables.

Lowered Cd toxicity, uptake and expression of metal transporter genes in maize plant by ACC deaminase-producing bacteria Achromobacter sp.

In this study, an ACC deaminase-producing bacterial strain Achromobacter sp. A1 was isolated from maize rhizosphere soil, characterized and evaluated for the effects on cadmium (Cd) immobilization in solution/rhizosphere, physiological characteristics and the tissue Cd contents in maize and the molecular mechanisms involved by hydroponic and pot experiments. ACC deaminase activity of strain A1 was significantly enhanced by Cd addition and Cd concentration decreased (55.54-63.62%) in solution supplemented with various Cd concentrations. Strain A1 significantly increased the maize dry weights (30.77-105%) and chlorophyll content (7.46-14.46%), decreased MDA content (25.16-36.87%) and ethylene production (20.93-35.86%) in hydroponic experiment. Strain A1 significantly reduced the above-ground tissue Cd uptake by 12.64-33.68% and 42-48% in hydroponic and pot experiments, reduced the DTPA-extractable Cd content and elevated invertase, urease and catalase activity in rhizosphere soils. In addition, the expression levels of Cd transporter genes HMA3 and Nramp5 were significantly reduced in root and shoot after strain A1 inoculation. These results indicate that strain A1 has great potential for application as a novel and environmentally friendly inoculant to immobilize Cd and reduce maize Cd uptake in Cd-contaminated environments, and will improve the understanding of the relative molecular mechanisms underlying the response to strain A1 in maize plant.

Changes in phosphorus mobilization and community assembly of bacterial and fungal communities in rice rhizosphere under phosphate deficiency.

Rhizosphere microorganisms are closely associated with phosphorus (P) uptake in plants and are considered potential agents to mitigate P shortage. However, the mechanisms of rhizospheric microbial community assembly under P deficiency have yet to be elucidated. In this study, bacterial and fungal communities in rice rhizosphere and their P mobilization potential under high (+P) and low (-P) concentrations of P were investigated. Bacterial and fungal community structures were significantly different between -P and +P treatments. And both bacterial and fungal P-mobilizing taxa were enriched in-P treatment; however, the proportion of P-mobilizing agents in the fungal community was markedly greater than that in the bacterial community. A culture experiment confirmed that microbial phosphate solubilizing capacity was significantly higher in -P treatment compared with that in +P treatment. -P treatment lowered bacterial diversity in rice rhizosphere but increased fungal diversity. Further analysis demonstrated that the contribution of deterministic processes in governing bacterial community assembly was strengthened under P deficiency but was largely weakened in shaping the fungal community. These results highlighted that enriching P-mobilizing microbes in the rhizosphere is a vital way for rice to cope with P deficiency, and that fungi contribute considerably to P mobilization in rice rhizosphere. Findings from the study provide novel insights into the assembly of the rhizosphere microbiome under P deficiency and this will facilitate the development of rhizosphere microbial regulation strategies to increase nutrient uptake in plants.