Incineration fly ash, a hazardous waste from municipal solid and hazardous waste incineration, contains heavy metals, soluble chlorides, and dioxins. A full-scale 'water washing + low-temperature thermal decomposition (LTD)' process for the treatment of incineration fly ash was evaluated in this study, which was conducted in a 20,000-ton/year project in Yancheng, China. Bench-scale tests were used to optimize washing parameters (30 min, 1:3 solid-to-liquid ratio, pH 6, 50-70°C) and LTD conditions (400°C, 45 min), achieving 99.5% dioxin removal - from 440.26 ng TEQ/kg in raw ash to 2.02 ng TEQ/kg. A significant reduction in heavy metal leaching was confirmed during full-scale operation. The treated fly ash was utilized in hollow brick production by mixing with cement, aggregates, and water in a mass ratio of 5:1:4:1, followed by moulding and curing. Additionally, crystalline salt was generated that met industrial standards, while hollow bricks were manufactured in compliance with GB/T 15229-2011 (compressive strength MU 10.0). This integrated technology facilitates the harmless treatment (via detoxification) of hazardous fly ash and the resource recovery of byproducts, thereby addressing the shortcomings of conventional landfilling and high-energy consumption processes. The approach establishes a scalable technical framework for the management of incineration fly ash, thereby contributing to the advancement of circular economy and environmental sustainability objectives.

Antimicrobial resistance (AMR) is a global public health challenge, and risk assessments based solely on gene abundance often underestimate the immediacy of resistance dissemination. This study presented a carrier-centric framework integrating metagenomic and metatranscriptomic profiling with deep learning–based identification of mobile genetic elements, applied to a full-scale constructed wetland (CW). CW overall reduced ARG burdens, with genomic abundance in plants, sediments, and water decreasing by 98.5%, 80.9%, and 88.8%, respectively. However, transcriptional activity showed an opposite trend, with sediments exhibiting the highest ARG expression, highlighting their pivotal role in the persistence and dissemination of resistance. In sediments, phage-mediated expression increased sharply from 4.0% to 92.5%, exceeding plasmid-associated levels by ~276-fold, revealing a low-abundance but high-activity residual risk pattern. Furthermore, 16 of the 310 recovered nonredundant MAGs were identified as phage hosts, 11 of which were potentially pathogenic, antibiotic-resistant bacteria (PARB) and were more active in sediments than in water or plants. These findings indicate that transduction within high-density, biofilm-associated niches constitutes a key terminal risk source. In addition, sediment acts as a high-risk reservoir where redox and ionic gradients, together with residual lomefloxacin and other antibiotics, enhance phage infectious activity and the accumulation of ARGs. Through cross-compartment transmission along the sediment–water interface, these phage-associated and PARB populations continuously seed the overlying water. It is recommended that ARG risk assessment shift from static abundance to an activity-aware, carrier- and host-resolved approach, prioritizing sediment-targeted transcript monitoring and phage transduction early warning to support risk mitigation in CW.

Rice is a major food crop in China, and paddy fields are an important agricultural source of greenhouse gas (GHG) emissions. Achieving high yields while reducing GHG emissions is essential for national food security and agricultural carbon mitigation. Water-management during the rice season is widely used to reduce methane (CH4) emissions; however, evidence of its effectiveness, particularly with respect to yield responses and CH4 emissions before and after transplanting, remains inconsistent. To address this gap, we evaluated two tillage practices before transplanting and two irrigation regimes during the early tillering stage: aerobic tillage with controlled irrigation (AC), aerobic tillage with flooding (AF), conventional tillage with controlled irrigation (CC), and conventional tillage with flooding (CF, control). Field experiments were conducted in a high-latitude rice-growing region in China in 2024 and 2025. Across the two years of study, aerobic tillage significantly increased average rice yield by 6.3%, whereas controlled irrigation caused a slight decline. Compared with the CF, the AC treatment markedly reduced the peak dissolved CH4 flux after the first drainage event by 66.4%–71.2% and lowered cumulative CH4 emissions by 42.1%–51.7%. Consequently, AC achieved the lowest global warming potential (GWP) and yield-scaled GWP (GHGI). These reductions were associated with a significantly greater abundance of methanotrophic genes under AC. In addition, aerobic tillage reduced average soil dissolved organic carbon (DOC) during the tillering stage by 11.8% across two study years. Overall, integrating aerobic tillage with controlled irrigation during the tillering stage provides an effective strategy for reducing CH4 emissions while maintaining high yield and improving water-use efficiency in rice production.

In this study, celery stalks were pretreated with different durations (0-150 s) of high-humidity hot air impingement blanching (HHAIB), followed by far-infrared radiation assisted pulsed vacuum freeze-drying (FIR-PVFD) at 60, 65, and 70 °C. The effects of HHAIB on the physicochemical properties, composition and transformation of phenolic compounds, volatile components, and antioxidant capacity of FIR-PVFD-dried celery stalks were systematically investigated. The results showed that HHAIB not only effectively reduced the counts of total mesophilic aerobic bacteria (TMAB) and total yeast and mold (TYM), but also decreased the relative activities of polyphenol oxidase (PPO) and lipoxygenase (LOX) by more than 91% after 90 s of treatment. HHAIB altered the cellular structure of celery stalks, shortened the drying time by 29.33-41.43%, and improved their hydration properties. HHAIB pretreatment promoted the conversion of bound phenolics to free phenolics in celery stalks, with significant increases in the contents of p-coumaric acid, apigenin, graveobioside A, and other components. The total free phenolic content increased by 56.99%, thus HHAIB enhanced the antioxidant activity. An electronic nose and sensory evaluation revealed that HHAIB-pretreated celery stalks better retained the characteristic herbal and pungent notes. GC-MS results indicated that HHAIB treatment optimized the aroma profile by regulating the contents and composition of terpenes, aldehydes, ketones, alcohols, and aromatic compounds.

Water management significantly impacts methane (CH4) emissions from paddy fields and cadmium (Cd) accumulation in rice grains through often opposing mechanisms, presenting a complex challenge in optimizing practices to simultaneously mitigate both issues. Through comprehensive field observations across four irrigation regimes over three consecutive planting seasons (i.e., the late rice, early rice, and late rice), along with a pot experiment, we developed an innovative strategy that effectively reduces CH4 emissions and Cd levels while maintaining optimal rice yields. The CTFG treatment—an optimized approach combining controlled irrigation (CI) during rice tillering stage with continuous flooding (CF) during rice grain-filling stage—demonstrated remarkable consistent efficacy over the three seasons. Compared to high-yielding irrigation practice, this regime achieved a 33 % reduction in CH4 emissions and a 42 % decrease in Cd content in brown rice, without compromising rice yield. Furthermore, when benchmarked against specialized irrigation regimes, CTFG outperformed a Cd-minimizing regime by reducing CH4 emissions by 39 % and surpassed a CH4-reducing regime by lowering Cd levels in brown rice by 40 %, while maintaining comparable performance in each targeted area. Mechanistic studies revealed that the tillering and grain-filling stages play pivotal roles in regulating CH4 emissions and Cd content, respectively. CI implementation during tillering stage effectively suppressed methanogen activity while enhancing methanotroph populations, thereby significantly reducing CH4 emissions. Conversely, CF during grain-filling stage decreased soil redox potential and promoted sulfate-reducing bacteria, consequently limiting Cd mobility and its subsequent uptake by rice plants. The results of pot experiments further demonstrated the positive effect of CTFG regime in reducing emissions and cadmium levels, thereby confirming the efficacy of this approach. These findings provide valuable scientific insights for developing more sustainable rice production systems through optimized water management strategies. The CTFG approach represents a significant advancement in balancing environmental protection and food safety concerns in rice cultivation.

Context: Water management plays a crucial role in determining rice yield, methane (CH4) emissions from paddy fields, and cadmium (Cd) level in rice grains. Controlled irrigation can significantly reduce CH4 emissions from paddy fields, but may increase Cd level in rice grain and decrease yield through excessive drought. To innovate water management practices is urgent to achieve the synergistic goals of higher yields while lowering both CH4 emissions and Cd level. Objective: The objective of this study was to investigate the effects of optimized irrigation coupled with dense planting on rice yield, CH4 emissions, and grain Cd content, along with their underlying mechanisms. Methods: Therefore, we conducted a three-consecutive-season field experiment, including four treatments: CK (local high-yield irrigation strategy), OPT0 (Optimized irrigation strategy with equivalent planting density to the CK), OPT15, and OPT30 (Optimized irrigation strategy with 15% and 30% increases in planting density of the CK, respectively). Results: Relative to CK, the OPT15 and OPT30 treatments significantly enhanced rice yields by 15% and 26%, respectively, while concurrently reducing CH4 emissions by 50% and 45%, and lowering Cd contents in brown rice by 30% and 33%. Although the OPT0 treatment significantly reduced CH4 emissions and Cd accumulation compared to CK, it caused an 8% yield reduction. Mechanistically, dense planting combined with irrigation optimization improved rice yield by enhancing the number of effective panicles per unit area. Simultaneously, the co-improvement of methanogens and sulfate-reducing bacteria at rice tillering stage under optimized irrigation may reduce CH4 emissions and Cd level. Conclusions: This study demonstrates that dense planting combined with optimized irrigation synergistically enhances rice yield while reducing CH4 emissions and grain Cd levels. Implications: Our findings can offer scientific support and technical solutions for developing food safety, low-carbon, and high-yielding rice cropping systems in Southern China and other similar regions.

Greenhouse gas emission inventories specifically target anthropogenic components. Consequently, internationally recognized accounting methodologies deduct natural background emissions when quantifying nitrous oxide from croplands and methane (CH4) from flooded lands. However, in compiling paddy CH4 emission inventories, the entirety of CH4 emitted from rice paddies is currently accounted for as anthropogenic contribution from rice cultivation. Here, through synthesis of empirical research, meta-analysis of published literatures, and model simulations, we analyzed the origins and cultivation history of rice paddies in China, key drivers of CH4 emissions, and fundamental accounting methodologies used in inventory compilation. The goal was to isolate and estimate the natural and anthropogenic contributions to CH4 emissions from rice paddies in China. Our results reveal that rice paddies possess dual attributes of both wetlands and croplands. Their CH4 emissions comprise both natural and anthropogenic components and should not be wholly attributed to human activities. Paddy CH4 emissions were found to be approximately 72.2% to 123.6% of those from their adjacent natural wetlands, indicating that converting low-lying lands and marshes to rice cultivation does not necessarily increase CH4 emissions. Global wetland restoration practices further demonstrate that water management regimes mimicking paddy field conditions during the growing season (groundwater depth 0-20 cm) optimally balance CH4 mitigation with soil carbon sequestration and biodiversity conservation, underscoring the rice cultivation potential as a climate-smart land-use practice. Estimates based on machine learning models suggest that natural emissions constitute more than 36% of total paddy CH4 fluxes, a proportion too significant to ignore. Therefore, analogous to the IPCC accounting methodologies for nitrous oxide from croplands and CH4 from flooded lands, natural background emissions should be deducted when compiling paddy CH4 inventories. As a responsible global leader in rice production, China should proactively shape international discourse on CH4 inventory compilation and mitigation strategies. We propose initiating methodological updates and foundational data enhancement by: (1) Strengthening theoretical research to refine accounting methodologies and ensure scientific rigor in inventories; (2) Enhancing foundational data collection through intensified in-situ monitoring and improved model estimation to reduce inventory uncertainty; and (3) Fostering international collaboration and exchange to elevate the influence of China and other major rice-producing nations in shaping global standards for paddy CH4 accounting and inventory compilation, thereby synergistically advancing carbon mitigation and sequestration actions in rice ecosystems.

Methane (CH4) and nitrous oxide (N2O) are the two most important greenhouse gases following carbon dioxide (CO2). However, existing research on the relationship between rice plant morphological traits and GHG emissions remains relatively limited, often focusing only on individual or a few plant characteristics. To address this research gap, a field experiment was conducted in Chongqing from April to August 2024. Five locally promoted hybrid rice varieties, which are widely cultivated in the region, were selected as experimental materials. The CH4 and N2O emissions of these varieties throughout their entire growth cycle were continuously monitored using the static chamber-gas chromatography method. Concurrently, the morphological traits of both the above-ground components and root systems of the rice plants were quantified.The results revealed significant varietal differences in CH4 and N2O emissions. CH4 emissions followed a unimodal trend, peaking during the panicle emergence to full heading stage. In contrast, N2O emissions peaked after field drainage and drying. Cumulative CH4 emissions ranged from 314.6 to 443.4 kg·ha-1, with the variety ‘Qxiangyou 352’ exhibiting significantly lower emissions than the others. Cumulative N2O emissions ranged from -0.049 to 0.165 kg·ha-1, showing no significant differences among varieties. Correlation analysis indicated that CH4 flux was highly significantly positively correlated with plant height, leaf area index (LAI), aboveground dry biomass, and root dry biomass, but highly significantly negatively correlated with root oxidation activity (ROA). Similarly, N2O flux was highly significantly positively correlated with plant height, LAI, root volume, and root dry biomass, and significantly negatively correlated with ROA. Overall, ‘Qxiangyou 352’ not only achieved a relatively high yield of 11.2 t·ha-1, but also demonstrated the lowest global warming potential (GWP) of 8.8 t CO2e·ha-1 and the lowest greenhouse gas intensity (GHGI) of 0.8 t CO2e·t-1, highlighting its promising low-carbon and high-yield characteristics.

Fe(III)-reducing bacteria, consisting of different species with varying cell numbers in the environment, are present, together with redox-active electron shuttles and both dissolved and solid Fe(III) species. However, the effect of electron shuttles and Fe(III)-organic-matter(Fe(III)-OM) complexes on microbial Fe(III) reduction is mainly based on a few early isolated model strains. Due to variations in experimental methods among different researchers, it remains unclear whether these two types of compounds influence different Fe(III)-reducing bacteria differently at varying cell numbers. To address this question, we conducted cell suspension experiments with Shewanella oneidensis MR-1, Aeromonas sp. CD and Aeromonas sp. XH, and evaluated reduction rates of Fe(III)-citrate and ferrihydrite with or without AQDS at three different inoculum concentrations. Our results showed that electron shuttles promoted Fe(III) reduction to different extents among these bacteria, along with varying ratios of the rates of Fe(III)-OM reduction and ferrihydrite reduction. Furthermore, cell numbers also influenced the impact of electron shuttle on Fe(III) reduction; ferrihydrite reduction rates were not increasing proportionally with increasing inoculum concentrations when electron shuttles were present. Comparative genomics suggested that differences in the identity of the Fe(III) reductase and the type of Fe(III)-chelators potentially synthesized probably led to these varied promotional effects. These results highlight the significant differences between model and nonmodel Fe(III)-reducing bacteria, suggesting that the presence of Fe(III)-OM complexes and electron shuttles may determine the presence and abundances of certain Fe(III)-reducing bacteria in different environments.

Phyllosphere microorganisms play a vital role in enhancing the adaptability and functionality of their host plants. Although the effects of phyllosphere microbial communities on host functional traits and their association with host phylogeny has been widely investigated, it remains unclear whether host selection consistently drives the assembly of these communities. In this study, bacterial and fungal communities on the surfaces of 734 leaf samples were characterized using bacterial and fungal amplicon sequencing. These microbial communities were associated with 42 plant species native to the Gurbantunggut Desert, a representative temperate desert located in Central Asia. The research assessed the relative contributions of plant-related factors, abiotic environmental variables (such as climate and soil), and spatial components to the observed variation in phyllosphere microbial communities, and further inferred the topological structure of plant-microbe interaction networks. The results indicate that plant phylogeny, plant functional traits, abiotic environment conditions, and spatial factors account for variations in the bacterial community composition (36.4 %, 4.6 %, 1.0 %, and 0.1 %, respectively) and the fungal community composition (28.6 %, 3.0 %, 1.5 %, and 1.2 %, respectively), following a hierarchical trend of plant phylogeny > plant functional traits > abiotic environment > space. Plant phylogeny and functional traits play a central role in shaping the assembly of phyllosphere microbial communities, indicating that plant filtering effects significantly influence microbial composition. Analysis of plant-microbe interactions reveals distinct preferences of microbial taxa for plant hosts across different taxonomic levels and geographic regions. Bipartite network analysis further illustrates that plant-microbe networks are highly specialized and modular, with plant-fungal networks exhibiting greater host specificity compared to plant-bacterial networks. Collectively, these findings underscore plant filtering as the primary determinant of microbial community assembly in the desert phyllosphere and provide valuable insights into the macroecological patterns shaping plant-microbe interactions in arid ecosystems.

IntroductionIn high-latitude area, climate change has brought about recurrent chilling stress that adversely impacts the sustainable production of rice and alters the distribution of carbon (C) and nitrogen (N) in paddy ecosystems. A comprehensive understanding of how the paddy ecosystem’s C and N allocation responds to low-temperature stress during critical growth stages remains elusive.MethodsA rice pot experiment of two varieties combined with 13C and 15N isotope labelling method was conducted to evaluate how low temperature stress at heading stage affects rice yield, and above- and belowground C and N partitioning.Results and DiscussionLow-temperature stress significantly reduced rice grain yield of JN809 (sensitive to low-temperature stress) and J88 (tolerant to low-temperature stress) varieties by 27.6% and 21.4%, respectively, This stress tendency increased C and N accumulation in rice stems and leaves, while concurrently decreasing C and N accumulation in panicles. Specifically, under low-temperature stress, the 13C isotope content in stems and leaves was found to be 14.0% and 19.0% higher than in the control treatment, while the 13C and 15N isotope contents in their panicles were 29.3% and 22.5% lower, respectively. The low-temperature tolerant variety (J88) demonstrated a reduced effect of low-temperature stress on rice yield and C, N allocation due to efficient resource reallocation and stress tolerance mechanisms. The findings of this study provide a foundation for developing rice breeding and cultivation techniques that can enhance rice resilience and adaptability to climate change. Additionally, it informs strategies to optimize C and N sequestration practices in rice fields, ensuring high yields and efficient resource utilization.

Two yellow-pigmented, Gram-stain-negative, aerobic, motile and rod-shaped bacterial strains, designated RHCKP32T and RRHST58T, were isolated from the citrus leaves in Renhua County, a famous planting area located in Guangdong Province, China. Phylogenomic analysis showed that they belonged to the genus Pantoea, and strain RHCKP32T was most closely related to Pantoea deleyi LMG 24200T, while strain RRHST58T showed the closest relationship to Pantoea septica LMG 5345T. The overall genomic relatedness analysis showed that strains RHCKP32T and RRHST58T shared 84.3‒94.6 and 89.5‒94.5% average nucleotide identity and 32.0‒58.0 and 38.5‒58.2% digital DNA-DNA hybridization with their closely related type strains, respectively, which were all below the suggested threshold values for novel species delimitation. They both took ubiquinone 8 (Q-8) as the predominant respiratory quinone and C16:0, C17:0 cyclo, summed feature 2 (C14:0 3-OH and/or iso-C16:1 I), summed feature 3 (C16:1  ω7c and/or C16:1  ω6c) and summed feature 8 (C18:1  ω7c and/or C18:1  ω6c) as their major fatty acids. The genomic DNA G+C contents of strains RHCKP32T and RRHST58T were 57.33 and 58.77 mol%, respectively. Based on the phenotypic, phylogenetic and chemotaxonomic analyses, they should be considered as two novel species of the genus Pantoea, for which the names Pantoea phosphatilytica sp. nov. and Pantoea phyllosphaerae sp. nov. are proposed with RHCKP32T (=GDMCC 1.2672T=JCM 34793T) and RRHST58T (=GDMCC 1.2673T=JCM 34797T) as the type strains, respectively. In addition, they showed the ability to solubilize inorganic phosphates and produce siderophores, for which the maximum soluble phosphorus concentrations could reach 510.03±7.11 and 506.47±3.08 mg l-1 for strains RHCKP32T and RRHST58T after 5 days of inoculation in liquid National Botanical Research Institute's (NBRIP) medium, respectively, and the corresponding relative siderophore production was 21.25±2.23 and 10.20±0.15 percent siderophore unit after 2 days of inoculation in nutrient broth, implicating they might have potential application in promoting plant growth.

Microbes evolved ArsR transcriptional repressors to regulate genes involved in arsenic detoxification, resistance, and biotransformations. ArsRs are homodimers, with cysteine residues from each subunit forming either intrasubunit or intersubunit arsenic binding sites. Here, we identified an ArsR from Arcticibacter tournemirensis R1 (AtArsR) with three vicinal cysteine pairs in each monomer. AtArsR has one high-affinity site for As(III)/MAs(III) and a second site with a high affinity for MAs(III) but lower affinity for As(III). In A. tournemirensis R1, analysis of gene expression showed that AtArsR and its regulated genes are induced to significantly higher levels by As(III) compared with an ars operon controlled by a more typical ArsR. AtArsR responds to both As(III)/MAs(III), but not As(V)/MAs(V). AtArsR has a binding affinity for As(III) that is higher than that of ArsR with a single arsenic binding site per subunit. Cells of Escherichia coli expressing AtArsR exhibited increased arsenic accumulation. Mutating two of the three cysteine pairs decreased the level of accumulation. Our results indicate that cysteines from each pair contribute to two binding sites for As(III) and MAs(III), suggesting that AtArsR provides an evolutionary advantage for competition in high arsenic environments. AtArsR is a promising candidate for engineering enhanced arsenic accumulation, which is a viable strategy for arsenic bioremediation.

Trivalent arsenicals, such as arsenite [As(III)] and methylarsenite [MAs(III)], are highly toxic and commonly found in anoxic environments. Similarly, antimony (Sb), a toxic metalloid present in the environment, triggers the activation of numerous genes in microorganisms to resist, transform, and efflux it. This study focuses on the arsZ' gene from the trivalent metalloids-resistant Ensifer adhaerens strain ST2 and its role in mitigating antimonite [Sb(III)] toxicity. The introduction of arsZ' into Escherichia coli AW3110 provided resistance to Sb(III) but not MAs(III). Crucial cysteine residues, Cys95 and Cys109 in ArsZ', were found to be essential for Sb(III) resistance. The disruption of arsZ' in E. adhaerens resulted in decreased tolerance to Sb(III) but not As(III). Exposure to Sb(III) in the ΔarsZ' mutant strain ST2Δars'Z led to a significant rise in reactive oxygen species production and a decline in catalase activity, indicating oxidative stress. Particularly, Sb(III) induced glutathione reductase activity. These discoveries shed light on a novel detoxification pathway for Sb(III) in bacteria and underscore the potential of soil bacteria like strain ST2 in mitigating Sb(III) toxicity for future bioremediation endeavors.

Context: Continuous cropping is widely practiced to maximize economic benefits and land utilization, but it often leads to outbreaks of soil-borne diseases, posing significant challenges to crop production and sustainable use of farmland soil. To sustain soil fertility and productivity in continuous cropping system, various fertilization strategies have been explored. However, the relationship between fertilization and soil microbial communities, particularly concerning soil-borne diseases, remains poorly understood. Objective: This study aims to investigate the mechanism of optimized fertilization in mitigating soil-borne diseases by comparing the responses of bulk and rhizosphere soils to different fertilizer applications. Methods: We investigated the effects of fertilization methods on soil chemical properties, microbial communities, early blight and yields through a six-year continuous potato cropping experiment, including optimized fertilization (NPK), farmer fertilization practice (FP), nutrient omissions, and application of agricultural organic materials. Results: NPK alleviated early blight in potatoes and slowed down yield reduction by 33.9 %. NPK with corn straw or sheep manure increased particulate organic matter (POM), reduced the disease index (2.25% and 3.80%, respectively), and had more significant effect on fungal community in bulk soil (R2 = 0.45, P = 0.002) than rhizosphere soil. The results demonstrated that optimized fertilization facilitated carbon accumulation in bulk soil and nitrogen fixation in rhizosphere soil. Moreover, the impacts of nitrogen, phosphorus, or potassium on microbial communities differed between bulk and rhizosphere soils, largely due to the responses of POM. We identified POM as a key factor influencing soil-borne diseases and demonstrated its relationship with disease suppression. Conclusions: Optimized fertilization was found to mitigate early blight and reduce yield loss by increasing POM, a key factor influencing soil-borne diseases and balancing fungal communities in continuous cropping soils. Significance: Our research sheds light on the mechanism of optimized fertilization in abating soil-borne diseases, which remained elusive in prior studies. For the first time, we identified and demonstrated the strong association between POM and soil-borne disease. These findings highlight the crucial, yet often overlooked, role of bulk soil quality in suppressing soil-borne disease and provide valuable insights into cultivating disease-suppressing soils.

This study assessed the environmental risks and regional variations associated with using titanium gypsum in road construction. It revealed that the conventional HJ/T299-2007 leaching method underestimates heavy metal leaching rates from titanium gypsum by approximately 1%, potentially leading to an underestimation of environmental risks. Further analysis indicated that Pb, Ni, As, Cd, and Zn leach from titanium gypsum road materials to varying extents, while Mn poses a notable exceedance risk with an 11% probability of surpassing limits and a maximum exceedance factor of 1.8. Significant disparities in regulatory thresholds for titanium gypsum pollutants were observed among 11 provinces along the Yangtze River, with the highest threshold (Qinghai) nearly five times greater than the lowest (Jiangxi). Rainfall was identified as a key contributor to these regional differences. The findings suggest that traditional assessment methods underestimate titanium gypsum risks and highlight the need for enhanced national solid waste evaluation frameworks. Additionally, given the substantial regional risk variations, differentiated management strategies are recommended.

Phyllosphere microorganisms play a vital role in supporting host plant health and adaptability. Although previous research on the effects of host performance and their phylogenetic associations on phyllosphere microbial communities has predominantly focused on tropical, subtropical, and temperate forestry ecosystems, the responses of these microbial communities to plant phylogeny and functional traits in temperate desert environments remains poorly understood. In this study, we conducted a quantitative analysis of bacterial and fungal community structures in the phyllosphere of 39 plant species from the Gurbantunggut Desert, a typical temperate desert in Central Asia. Variation partitioning analysis revealed that plant phylogeny, leaf physicochemical properties, and leaf morphological characteristics collectively explained the variation in phyllosphere microbial communities. Specifically, these factors accounted for 19.26%, 14.53%, and 2.32% of the variance in bacterial communities, and 11.55%, 8.36%, and 2.19% of the variance in fungal communities, respectively. A significant hierarchical pattern emerged: plant phylogeny > leaf physicochemical properties > leaf morphological characteristics, highlighting the dominant role of plant filtering effects in community assembly. Linear mixed-effects model analysis further confirmed the significant influence of multiple plant attributes, including phylogeny and functional traits, on microbial community structure. Plant-microbe interaction analysis revealed distinct host preferences of microbial taxa across different plant taxonomic levels. Co-evolutionary analysis also indicated a significant phylogenetic association between host plants and their phyllosphere amplicon sequence variants (ASVs). Overall, our findings demonstrate that plant attributes, particularly plant phylogeny and functional traits, are key factors driving the assembly of phyllosphere microbial communities in deserts. This study provides new insights into species coexistence mechanisms in fragile habitats and enhances our understanding of plant-microbe interactions in global desert ecosystem.

Arsenic biomethylation plays a critical role in modulating environmental arsenic toxicity yet remains understudied in the phylum Bacteroidetes. Here, we characterize HeArsM, a methyltransferase from the soil bacterium Hymenobacter edaphi, which effectively methylates arsenite [As(III)] into various species. We demonstrated that this activity is primarily supported by the thioredoxin (Trx)-thioredoxin reductase (TR)-NADPH system, which is significantly more effective than alternative reductants such as glutathione/glutaredoxin (GSH/Grx), cysteine, or tris(2-carboxyethyl)phosphine (TCEP). Site-directed mutagenesis identified Cys23, Cys48, and Cys143 as essential for catalysis, with Cys143 uniquely required for monomethylarsenite [MMAs(III)] methylation. Structural modeling using AlphaFold and energy minimization supports a thiol-disulfide exchange mechanism as the basis for arsenic methylation. These findings provide mechanistic insight into arsenic detoxification in Bacteroidetes and highlight H. edaphi as a model for understanding microbial arsenic cycling in terrestrial environments.

Rice yield and quality decline due to excessive fertiliser use is problematic in China. To increase rice grain filling and improve rice yield and quality, a nitrogen reduction and density increase study in 2023 and 2024 was imposed on a long-term experimental field. The four treatments adopted for the study were normal nitrogen and normal density (CK), normal nitrogen and increased density (NN+ID), reduced nitrogen in panicle fertiliser and increased density (RPN+ID), and reduced nitrogen in basal fertiliser and increased density (RBN+ID). RPN+ID and RBN+ID, respectively, produced a 3.0% and 5.1% higher yield than CK in both years. The mean grain filling rate (Va) of superior grains in RBN+ID increased by 12.5%, while the mean grain filling rate (Va) of inferior grains in the RPN+ID treatment increased by 4.2% with respect to CK. RPN+ID caused 0.4%, 9.6%, and 13.3% decline in the brown rice rate, chalkiness degree, and chalkiness rate, respectively, while RBN+ID triggered 0.4%, 7.2%, and 11.0% decline in the brown rice rate, chalkiness degree, and chalkiness rate, respectively. RPN+ID stimulated 4.2% and 3.1% increases in flavour and straight-chain amylose values, respectively. Whereas a 20% reduction in basal nitrogen fertiliser and a 32% increase in density improved the yield and appearance quality of rice, a 20% reduction in nitrogen fertiliser at the panicle stage and a 32% increase in density promoted a higher steaming flavour quality. Therefore, an appropriate reduction in nitrogen fertiliser while simultaneously increasing rice density has a significant impact on rice quality, fertiliser pollution reduction, and is a theoretical basis for rice yield and quality improvement in Northeast China.