Summary
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.
Summary
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.
Agricultural food production is at the base of food and fodder, with fertilization having fundamentally and continuously increased crop yield over the last decades. The performance of crops is ...intimately tied to their microbiome as they together form holobionts. The importance of the microbiome for plant performance is, however, notoriously ignored in agricultural systems as fertilization disconnects the dependency of plants for often plant-beneficial microbial processes. Moreover, we lack a holistic understanding of how fertilization regimes affect the soil microbiome. Here, we examined the effect of a 2-year fertilization regime (no nitrogen fertilization control, nitrogen fertilization, and nitrogen fertilization plus straw amendment) on entire soil microbiomes (bacteria, fungi, and protist) in three common agricultural soil types cropped with maize in two seasons.
We found that the application of nitrogen fertilizers more strongly affected protist than bacterial and fungal communities. Nitrogen fertilization indirectly reduced protist diversity through changing abiotic properties and bacterial and fungal communities which differed between soil types and sampling seasons. Nitrogen fertilizer plus straw amendment had greater effects on soil physicochemical properties and microbiome diversity than nitrogen addition alone. Moreover, nitrogen fertilization, even more together with straw, increased soil microbiome network complexity, suggesting that the application of nitrogen fertilizers tightened soil microbiomes interactions.
Together, our results suggest that protists are the most susceptible microbiome component to the application of nitrogen fertilizers. As protist communities also exhibit the strongest seasonal dynamics, they serve as the most sensitive bioindicators of soil changes. Changes in protist communities might have long-term effects if some of the key protist hubs that govern microbiome complexities as top microbiome predators are altered. This study serves as the stepping stone to promote protists as promising agents in targeted microbiome engineering to help in reducing the dependency on exogenous unsustainably high fertilization and pesticide applications.
Grafting of C7 from the nonparalyzed to the paralyzed side in patients with arm paralysis resulted in greater improvements in power, spasticity, and function at 12 months than rehabilitation therapy ...alone, and functional connection to the ipsilateral cerebral hemisphere developed.
Biological nitrogen fixation plays an important role in nitrogen cycling by transferring atmospheric N2 to plant-available N in the soil. However, the diazotrophic activity and distribution in ...different types of soils remain to be further explored. In this study, 152 upland soils were sampled to examine the diazotrophic abundance, nitrogenase activity, diversity and community composition by quantitative polymerase chain reaction, acetylene reduction assay and the MiSeq sequencing of nifH genes, respectively. The results showed that diazotrophic abundance and nitrogenase activity varied among the three soil types. The diazotrophic community was mainly dominated by Bradyrhizobium, Azospirillum, Myxobacter, Desulfovibrio and Methylobacterium. The symbiotic diazotroph Bradyrhizobium was widely distributed among soils, while the distribution of free-living diazotrophs showed large variation and was greatly affected by multiple factors. Crop type and soil properties directly affected the diazotrophic ɑ-diversity, while soil properties, climatic factors and spatial distance together influenced the diazotrophic community. Network structures were completely different among all three types of soils, with most complex interactions observed in the Red soil. These findings suggest that diazotrophs have various activities and distributions in the three soil types, which played different roles in nitrogen input in agricultural soil in China, being driven by multiple environmental factors.
Chronic pancreatitis (CP) is a chronic inflammatory disease of the pancreas. This study aimed to compare the natural course of alcoholic chronic pancreatitis (ACP) and idiopathic chronic pancreatitis ...(ICP).
CP patients admitted to our center from January 2000 to December 2013 were enrolled. Characteristics were compared between ACP and ICP patients. Cumulative rates of diabetes mellitus (DM), steatorrhea, pancreatic stone, pancreatic pseudocyst, biliary stricture, and pancreatic cancer after the onset and the diagnosis of CP were calculated, respectively. The cumulative rates of DM and steatorrhea after diagnosis of pancreatic stone were also calculated.
A total of 2,037 patients were enrolled. Among them, 19.8% (404/2,037) were ACP and 80.2% (1,633/2,037) were ICP patients. ACP and ICP differs in many aspects, especially in gender, age, smoking, complications, morphology of pancreatic duct, and type of pain. The development of DM, steatorrhea, PPC, pancreatic stone, and biliary stricture were significantly earlier and more common in ACP patients. No significant difference was observed for pancreatic cancer development. There was a rather close correlation between exocrine/endocrine insufficiency and pancreatic stone in ACP patients, which was much less correlated in ICP patients.
The long-term profile of ACP and ICP differs in some important aspects. ACP patients usually have a more severe course of CP. These differences should be recognized in the diagnosis and treatment of CP.
The nickel-rich layered oxide materials have been selected as promising cathode materials for the next generation lithium ion batteries because of their large capacity and comparably high operating ...voltage. However, at high voltage (beyond 4.30 V vs Li/Li+), the members of this family are all suffering from a rapid capacity decay, which was commonly concerned with crystal lattice distortion and related cation disordering. In this work, the quasi-spherical Ni-rich layered LiNi0.6Co0.2Mn0.2O2 (QS-NMC622) material was successfully synthesized through the carbonate co-precipitation method. A coupled measurement, which is a combination of potentiostatic intermittent titration technique (PITT) and in situ X-ray diffraction (XRD), was deployed to simultaneously capture the structural changes and lithium ion diffusion coefficient of QS-NMC622 material during the first cycle. With help of in situ XRD patterns and high-resolution transmission electron microscope (HR-TEM) images, a defective spinel framework of Fd3̅m space group was detected along with a rapid decreasing lattice-parameter c and lattice distortion at deep delithiated state, which causes poor kinetics related to lithium ion mobility. The new-born framework seems to transform and remain as full spinel structure in the parent phase to the end of charge/discharge with high voltage, which could deteriorate both the surface and body structure stability during the subsequent cycles. This established coupled in situ measurement could be applied to simultaneously investigate the structure transformation and kinetics of cathode materials during charge/discharge.
LiNi0.8Co0.1Mn0.1O2 (NCM811) is widely known for its extremely high specific capacity and relatively low cost, which draws extensive attention worldwide. However, poor cycling performance and rate ...capability impose restrictions on its large-scale practical application. Here we report that succinic anhydride (SA) as an additive in carbonate electrolyte significantly enhances the cycling performance and rate capability of Li/NCM811 cells. Capacity retention can reach 93.8% after 400 cycles at 1C rate by adding 3 wt% SA, while the pristine one cannot even endure 100 cycles. Moreover, rate capability can also be optimized to 82.4% of 5C/0.5C capacity ratio. The improvement of electrochemical performance was attributed to the formation of a uniform conductive cathode electrolyte interphase (CEI) layer upon particles. Our results confirm that firstly, the CEI formed by SA can protect active sites on the surface of NCM811 from side reactions. Secondly, the uniform conductive CEI plays a part in inhibiting severe polarization and local overcharge during long cycles. Moreover, the robust CEI layer can suppress the internal cracks, prohibit the irreversible phase transformation and nickel element migration of NCM811.
It is the first time that introducing the green and simple electrolytic additive SA as an electrolytic additive to Li/LiNi0.8Co0.1Mn0.1O2 (NCM811) cells, and greatly improving the cycling performance and the rate capability. SA plays a part in forming a conductive robust cathode electrolyte interphase layer to protect NCM811 particles. Display omitted
•The first time that introducing the green and simple electrolytic additive SA to Li/NCM811 cells.•The loading of active material is about 10 mg cm−2, which is close to the actual system and making results credible.•Employing the tool of “symmetric cell”, indicating that SA mainly works on NCM811 rather than Li metal anode.•Combining multiple experiments to explain the function of SA.•Using in situ XRD characterization to interpret the protection mechanism.
Hierarchical Mn2O3 hollow microspheres of diameter about 6–10 μm were synthesized by solvent-thermal method. When serving as anode materials of LIBs, the hierarchical Mn2O3 hollow microspheres could ...deliver a reversible capacity of 580 mAh g–1 at 500 mA g–1 after 140 cycles, and a specific capacity of 422 mAh g–1 at a current density as high as 1600 mA g–1, demonstrating a good rate capability. Ex situ X-ray absorption near edge structure (XANES) spectrum reveals that, for the first time, the pristine Mn2O3 was reduced to metallic Mn when it discharged to 0.01 V, and oxidized to MnO as it charged to 3 V in the first cycle. Furthermore, the XANES data demonstrated also that the average valence of Mn in the sample at charged state has decreased slowly with cycling number, which signifies an incomplete lithiation process and interprets the capacity loss of the Mn2O3 during cycling.
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