While straw incorporation is a recognized beneficial practice for utilizing renewable biomass, contributing to soil organic matter accrual, and enhancing agricultural sustainability, the complex multi-trophic microbial responses to different straw return strategies and their subsequent mediation of soil carbon dynamics remain incompletely understood. Here, we conducted a field experiment in croplands of the Northeast China Plain, comparing straw removal (CK), crushed straw incorporation (ST), and biochar amendment (BC) treatments. Both straw and biochar incorporation increased the soil organic carbon contents (biochar: +12.5%, p < 0.0001; straw return: +7.3%, p < 0.05), but through contrasting pathways, BC treatment enhanced particulate organic carbon (POC) (+31.4% vs control, p < 0.01) while decreasing mineral-associated organic carbon (MAOC) (-8.7%, vs control, p < 0.05). A converse pattern was observed in the ST treatment (POC:-18%, p > 0.05, MAOC: marginal non-significant increase). Both BC and ST treatments reduced the alpha diversity of the integrated microbial community and the complexity of the multi-trophic interaction network (indicated by reduced edge numbers and graph density). Additionally, more frequent cross-trophic associations (CTAs) were observed in BC and ST treatments. The proportion of negative within-trophic associations (WTAs) was negatively correlated with MAOC, whereas the proportion of CTAs was positively correlated with MAOC. Our findings reveal that extracellular enzyme activities, hierarchical interactions, and network complexity collectively shaped MAOC accumulation. Thus, we propose a mechanistic framework where multi-trophic microbial interactions-rather than taxonomic diversity alone-govern soil carbon stabilization in croplands.

Edaphic antibiotic resistance genes (ARGs) have garnered worldwide concern, yet mechanisms by which specific microbial taxa drive ARG variation under anthropogenic stress remain unclear. Here we show how opportunistic and sensitive taxa contribute to ARG propagation in soil microcosms exposed to conventional (polyethylene, PE) or biodegradable (polybutylene adipate terephthalate, PBAT) microplastics and four-generation tetracyclines. Compared with PBAT-only, the total abundance of ARGs increases progressively in soils co-exposed to PBAT and tetracyclines, ranging from 1.17-fold for the first-generation tetracycline to 2.87-fold for the fourth-generation tetracycline. Tetracycline and multidrug ARGs are markedly enriched under PBAT combined with high-generation tetracyclines, particularly fourth-generation omadacycline. This ARG proliferation coincides with generational enrichment of opportunistic taxa, whereas sensitive taxa exhibited weak or negative correlations. Molecular docking simulations reveal that enhanced resistance potential of opportunistic taxa stems from stronger binding affinities between resistance proteins and high-generation tetracyclines. These findings highlight the pivotal role of opportunistic microbes in ARG dissemination under biodegradable microplastics and newer antibiotic generations, advancing our mechanistic understanding of resistance proliferation in soil ecosystems. Strong binding of resistance proteins to high-generation tetracyclines exacerbates antibiotic resistance gene spread in soil exposed to biodegradable polybutylene adipate terephthalate and tetracyclines, based on soil microcosm experiments.

Although biochar (BC) is widely used as a catalyst support, the mechanisms by which it modulates redox cycles at transition metal centers remain insufficiently understood. Herein, a cobalt ferrite (CoFe2O4)-BC composite was synthesized to activate hydrogen peroxide (H2O2) and peroxymonosulfate (PMS) for norfloxacin (NOR) degradation. The CoFe2O4-BC/PMS system achieved efficient NOR removal at near-neutral pH with negligible metal leaching (Fe < 0.01 mg/L; Co < 0.20 mg/L). Electrochemical analyses demonstrate that the CoFe2O4-BC composite synergistically enhances both charge transfer kinetics and mass transport. Mechanistic analysis identified BC as a critical electron shuttle, accelerating the rate-limiting Fe(II)/Fe(III) and Co(II)/Co(III) redox cycles to sustain Fenton-like reactions. Density functional theory (DFT) calculations indicate that hydroxyl radical (OH) and sulfate radical (SO4-) primarily attack the piperazine and benzene rings of NOR. Degradation proceeded via carbonyl addition and piperazine ring cleavage, yielding partial mineralization to fluoride (18.6%) and nitrate (2.93%). Validated in natural water matrices, the system demonstrated excellent stability and adaptability. Ultimately, this work offers a robust strategy for antibiotic remediation and provides theoretical insights into unlocking the full potential of heterogeneous Fenton-like catalysis.

The plastisphere, defined as a unique niche for microbial colonization of plastic debris, is a recognized hotspot for antibiotic resistance genes (ARGs), yet the internal biological mechanisms driving this enrichment remain unclear. We hypothesize that quorum sensing (QS), a key bacterial communication process, actively drives the ARG dissemination within this environment. Using a continuous-flow tubular column system with polystyrene and polylactic acid microplastics, we manipulated QS with an exogenous signaling molecule (3OC6-HSL) and a quorum quenching (QQ) enzyme. Metagenomic analysis revealed that QS activation significantly increased the abundance of ARGs and mobile genetic elements (MGEs), while QQ had the opposite effect. Mechanistically, we show that QS promotes horizontal gene transfer by enhancing biofilm formation and bacterial conjugation, primarily within Gammaproteobacteria. Moreover, QS activation altered the plastisphere virome, increasing the proportion of virulent phages and ARG-carrying viral sequences, suggesting enhanced transduction. Our results establish QS as a key regulator of ARG proliferation in the complex plastisphere communities and highlight quorum quenching strategies as a novel approach to mitigate the spread of antibiotic resistance in microplastic-laden environments.

Microplastics (MPs) and polycyclic aromatic hydrocarbons (PAHs) are two prominent classes of environmental contaminants that frequently co-exist in aquatic sediments, yet their co-occurrence patterns in coastal small watersheds remain poorly understood. This study provides the first integrated assessment of MPs and PAHs in the Houxi River watershed, a typical coastal small watershed in southeastern China, by simultaneously sampling water, surface sediments, and riparian soils across 18 sites spanning the upstream reservoir area (Zone A), midstream rural-urban transition zone (Zone B), and downstream urbanized area (Zone C). MPs were detected at a 100% detection rate across all three media. The mean abundance of MPs in water, sediments, and soil was 3.65 +/- 0.51 n/L, 354.56 +/- 18.22 n/kg, and 1509.55 +/- 69.90 n/kg, respectively. MPs were predominantly small-sized (< 0.5 mm, > 70%), fragment-shaped (> 50%), and composed of polyethylene (PE, > 50%). The total concentrations of 16 US EPA priority PAHs (Σ-16 PAHs) in surface sediments ranged from 115.02 to 807.27 ng/g (mean: 371.33 ng/g), with 4-ring and 5-ring PAHs being the dominant components (each > 25%), indicating primarily pyrogenic sources. PAH diagnostic ratios further confirmed mixed combustion origins dominated by biomass and fossil fuel burning. Both MPs and PAHs exhibited a pronounced upstream-to-downstream increasing gradient, strongly linked to the intensity of anthropogenic activities along the urbanization continuum. Spearman correlation analysis revealed a significant positive correlation between sediment MP abundance and Σ-16 PAHs concentrations (r_s = 0.91, p < 0.001), suggesting shared anthropogenic sources and potential synergistic accumulation mechanisms. Risk assessment using the polymer-specific hazard index (H) and pollution load index (PLI) indicated that MPs posed a low-risk (Level I) but were approaching Level II thresholds. Sediment quality guidelines (SQGs) assessment showed that PAH ecological risks were predominantly between the Rare Effect Level (REL) and Threshold Effect Level (TEL), with localized exceedances to the Occasional Effect Level (OEL) at downstream sites, particularly for benzo[a]pyrene (BaP, 44.4% of sites reaching OEL). The co-occurrence of MPs and PAHs in sediments raises concerns about combined ecological risks, as the dominant polymer types (PE and PP) have demonstrated high sorption affinities for PAHs in laboratory studies. These findings provide critical baseline data for understanding the coupled behavior of emerging and legacy contaminants in coastal small watersheds and inform integrated pollution management strategies for land-sea coordinated environmental governance.

Nanoscale zero-valent iron (nZVI) has been proposed as a material to mitigate the rebound of antibiotic resistance genes (ARGs) during composting maturation. However, the mechanisms underlying ARGs reduction and the associated environmental risk mitigation remain unclear. In this study, two co-composting treatments were conducted: one with nZVI and one without nZVI as the control. The results indicated that the abundance of ARGs in the control increased by 3.05-fold, whereas in the nZVI treatment, ARGs were reduced by 60.62%. The reduction of ARGs in the nZVI treatment was primarily observed during the maturation phase of composting, with a 90.29% decrease compared to the control. Notably, the high-risk ARGs were significantly diminished by 83.42% in the nZVI treatment relative to the control. nZVI facilitated a substantial reduction in the abundance of potential pathogenic bacteria, achieving a 98.02% decrease. The key high-risk ARGs were ermB, tetM, and tetW. In the nZVI treatment, the reduction of ermB was mainly associated with the decreased abundance of mobile genetic elements (MGEs), while the reduction of tetM and tetW were more closely associated with the decreased abundance of pathogens. Overall, these results suggest that nZVI can improve compost safety by limiting ARG rebound and reducing potential pathogenic bacteria, although its long-term environmental safety still requires further evaluation.

Ingestion of microplastics (MPs) is a critical exposure pathway for MP-associated hydrophobic organic contaminants (HOCs), yet the fraction that becomes bioaccessible during digestion remains poorly constrained, particularly when accounting for realistic absorption kinetics and dietary matrices. Here, we present a physiologically based in vitro digestion model incorporating sequential gastric, small-intestinal, and colonic phases with a polydimethylsiloxane (PDMS) sink to simulate gut-wall absorption. We quantified the bioaccessibility of seven polychlorinated biphenyls (PCBs) from various MP polymers (HDPE, LDPE, PET, PP, PS, PVC) and size fractions (15-300 mesh) in the presence of common food components (cellulose, edible oil, protein, starch). Bioaccessibility was strongly size-dependent; smaller MPs yielded markedly higher desorption, whereas the largest size fractions released only 14.3-36.8% of the loaded PCBs. Rubbery polymers (e.g., PE) released PCBs more readily than glassy polymers (e.g., PVC) due to higher chain mobility. Notably, the digestive matrix significantly modulated these vector effects. Co-ingested dietary fat suppressed bioaccessibility by 21.0-65.7% for the hydrophobic congeners, whereas proteins and carbohydrates slightly enhanced release via micellar solubilization. These results demonstrate that the carrier effect of MPs is dynamically influenced by particle characteristics and dietary context, providing essential parameters for refining human health risk assessments.

Ciprofloxacin (CIP), a veterinary antibiotic in swine wastewater is an emerging contaminant with low concentration but significant environmental risk. Its inhibitory effects on biological treatment systems and the proliferation of antibiotic resistance genes have raised widespread public concern. An expanded granular sludge bed reactor was coupled with an anaerobic membrane bioreactor (EGSB-AnMBR) to treat swine wastewater containing CIP. During 320 days operation, the EGSB-AnMBR system achieved over 98.6 % chemical oxygen demand (COD) removal efficiency and 61.4 %-100 % CIP removal efficiency. During the initial operation phase, sludge adsorption served as the primary mechanism for CIP removal, whereas biodegradation became dominant in the last operational phase. 16S rRNA gene high-throughput sequencing analysis revealed that under CIP stress, the abundance of CIP-resistant Spirochaetota increased from 4.7 % to 9.5 %, whereas Patescibacteria abundance progressively decreased from 72.7 % to 15.7 %. Metagenomic analysis demonstrated microbes in anaerobic granular sludge (AnGS) achieved "defense-efflux" by activating macB/evgS efflux pumps while suppressing tetA, whereas membrane biofilm (MB) developed a "storage-retention" strategy through synergistic effects of tetA and evgS. This EGSB-AnMBR system exhibits promising application potential for swine wastewater treatment and antibiotic control, providing significant support for livestock pollution management.

Per- and polyfluoroalkyl substances (PFAS) have become a well-known class of anthropogenic pollutants in coastal regions. It is known that PFAS primarily enter the sea from nearshore sources, dry deposition, and wet deposition. However, the contribution of offshore sources to PFAS pollution in the sea remains poorly understood. Our study aims to investigate the occurrence of 74 PFAS across 15 groups in a coastal region of eastern China and to characterize their spatial distribution by focusing on the critical roles of both nearshore and offshore sources. Results revealed that 26 PFAS were detected in the coastal region (i.e., Ou River and Wenzhou Bay), with detection frequencies ranging from 4.3% to 100.0%. Notably, over 10 PFAS were detected for the first time in the region, such as perfluorooctane sulfonamide (FOSA), hexafluoropropylene oxide dimer acid (HFPO-DA), and 6:2 fluorotelomer sulfonic acid (6:2 FTSA), among others. The concentrations of detected PFAS ranged from 0.0018 to 76.31 ng/L, with perfluorooctanoic acid (PFOA) as the dominant congener. Spatial analysis indicated that the nearshore area was more severely polluted compared to the offshore area, with specific hotspots identified near industrialized areas. However, the distribution of certain PFAS, such as perfluorobutane sulfonic acid (PFBS) and perfluoro-3,6-dioxaheptanoic acid (PFDHA), exhibited a contrasting pattern, with higher concentrations observed in the offshore area and near island perimeters. These findings suggest that PFAS pollution in Wenzhou Bay originates from both nearshore and offshore sources, highlighting a complex interplay between nearshore and island-related activities.

Pharmaceuticals and personal care products (PPCPs) have received widespread attention owing to their negative effects on the health of ecosystems. While numerous studies monitored the usage of PPCPs, and ignored the systematical investigation of the discarded PPCPs. Here, we collected leachate from 73 landfills across China and detected 52 target PPCPs. A total of 42 PPCPs were detected in 73 landfills in China with a concentration distribution of 10-3-103 μg/L, of which 93 % of the PPCPs had mean concentrations higher than the safe concentrations for antimicrobial resistance selection. The mean concentrations of the top three PPCPs were caffeine (CF), lincomycin (LIN), and acetaminophen (ACET). Gross domestic product, population density, and precipitation were the most dominant factors affecting CF, LIN, and ACET in leachate, whose concentrations remarkably decreased with landfill age. In contrast, the concentrations of hydrophobic PPCPs such as ketoprofen, carbamazepine, diclofenac, sulfadimidine, and erythromycin, were significantly higher in old leachate. Precipitation, hydrophilicity, and pH were the most important factors affecting the occurrence of the hydrophobic PPCPs in leachate. High concentrations of PPCPs in landfill leachate were also detected in economically or densely populated countries worldwide. For the first time, it was found that the concentration of hydrophobic PPCPs increased in old leachate, in contrast to the traditional understanding of decreasing the concentration of PPCPs owing to the biodegradation during landfill.

Despite the crucial ecological roles of bacterial, fungal and archaeal communities in rivers and lakes, their interactions and dynamic changes in large, hydrologically-connected river–lake systems remain poorly understood. This study investigated the biogeographic patterns, assembly processes and co-occurrence network characteristics of bacterial, fungal and archaeal communities in the middle reaches of Yangtze River (MYR) and its two largest connected lakes, Dongting Lake (DTL) and Poyang Lake (PYL). Our results revealed significant spatial heterogeneity in microbial diversity and composition, with higher sedimentary microbial diversity in lakes than in the river. Stochastic processes, particularly dispersal limitation, dominated community assembly across all habitats. β-NRI analysis showed that deterministic processes were more influential for planktonic bacterial and archaeal communities in the lakes. Co-occurrence network analysis demonstrated that inter-domain cooperation was prevalent in PYL, whereas intra-domain interactions were more common in MYR and DTL, reflecting distinct hydrological connectivity. Keystone taxa differed between rivers and lakes, with rare taxa prevailing in MYR and both rare and abundant taxa contributing in lakes. Our findings highlight how connectivity and flow dynamics fundamentally shape microbial ecology, providing insights into for the management and conservation of large river–lake ecosystems.

Advanced oxidation processes (AOPs) are pivotal in the degradation of recalcitrant and toxic organic pollutants in water and wastewater. While extensive research has optimized AOPs performance through various experimental parameters, the impact of groundwater matrices on electron transfer processes (ETP) remains inadequately addressed. The mechanism of the ETP is the oxidation of organic complexes and the reduction of peracetic acid catalyst complexes resulting from the co-adsorption of organic compounds and peracetic acid by the catalyst. Therefore, the oxidation potential of sulfamethoxazole and the reduction potential of the AC600/ PAA* complex are affected by the groundwater matrix, which in turn affects the kinetic process of the ETP system. This study investigates the role of groundwater matrices in the AC600/PAA system, revealing how these matrices influence ETP efficiency. We demonstrate that weakly acidic and neutral conditions enhance ETP, while chloride ions (Cl-) facilitate electron transfer and bicarbonate ions (HCO3-) inhibit it. Notably, the presence of humic acid at concentrations below 10 mg/L positively correlates with increased electron transfer rates, indicating robust adaptability to natural organic matter. Contrary to traditional views, our findings highlight that ETP efficiency is significantly improved in real groundwater matrices, suggesting a substantial advantage over conventional radical-based degradation pathways. This research provides critical insights into optimizing AOPs performance in environmental contexts, laying the groundwork for future advancements in electron transfer technology for organic pollutant degradation.

The widespread occurrence of antibiotics in wastewater aroused serious attention. UV-based advanced oxidation processes (UV-AOPs) are powerful technologies in removing antibiotics in wastewater, which include UV/catalyst, UV/H2O2, UV/Fenton, UV/persulfate, UV/chlorine, UV/ozone, and UV/peracetic acid. In this review, we collated recent advances in application of UV-AOPs for the abatement of fluoroquinolones (FQs) as widely used class of antibiotics. Representative FQs of ciprofloxacin, norfloxacin, ofloxacin, and enrofloxacin were most extensively studied in the state-of-art studies. The evolvement of gas-state and solid-state UV light sources was presented and batch and continuous flow UV reactors were compared towards practical applications in UV-AOPs. Generally, degradation of FQs followed the pseudo-first order kinetics in UV-AOPs and strongly affected by the operating factors and components of water matrix. Participation of reactive species and transformation mechanisms of FQs were compared among different UV-AOPs. Challenges and future prospects were pointed out for providing insights into the practical application of UV-AOPs for antibiotic remediation in wastewater.

Microbial communities in many ecosystems are suffering a wide range of environmental stressors induced by anthropogenic perturbations. While the impacts of a single stressor have been extensively estimated in numerous studies, the responses of microbial communities to multiple environmental stressors simultaneously are still poorly understood. In the current study, we investigated the taxonomic diversity, community resistance, and co- occurrence interaction of soil bacterial communities treated with different numbers of environmental stressors by conducting 136 microcosms. We found that the richness and Shannon diversity of the soil community decreased significantly from 1430 to 6.54 in the mono-factor treatments to 920 and 5.77 in the hepta-factor treatments. The counts of nodes and edges of the soil microbial networks decreased with the increasing stressor number, potentially indicating that multiple stressors can reduce the network size. Multiple stressors increased the community resistance potential to environmental disturbance. Additionally, the network cohesion suggested that the cooperative and competitive behaviors between microorganisms were induced by multiple stressors. The observation could be potentially due to the enrichment of the generalists by multiple environmental stressors. Although only a handful of stressors were included, our study still indicated that multiple environmental stressors would lead to diversity loss via deterministic processes.

Through a systematic review of literature references from 2007 to 2022, we compiled a comprehensive national dataset comprising over 67,000 records and covering information on 129 antibiotics detected in the surface water and sediments of China’s major rivers. Our analysis revealed notably high antibiotic concentrations in the Liaohe and Yellow Rivers. Among the antibiotics examined, sulfonamides, quinolones, and tetracyclines exhibited relatively high median concentrations in river water. Regional distribution analysis highlighted increased antibiotic levels in Shandong and Tianjin compared to other areas. Partial least squares path modeling revealed that animal production and pollution discharge positively influenced antibiotic levels in river water, whereas natural and socioeconomic factors had negative impacts. Based on the ecological risk assessment, we formulated a prioritized national list of antibiotics, with sulfonamides having the largest number of entries, followed by quinolones. Importantly, our analysis revealed a declining trend in antibiotic concentrations and the associated risk levels across China during the study period. This study not only enhances our understanding of antibiotic distribution in China's water systems, but also contributes to the development of a scientifically sound approach for prioritizing antibiotics. Ultimately, these findings will inform targeted antibiotic management and control strategies. Environmental implication Antibiotics, posing threats to ecosystems and human health, exhibit pseudo-persistence in the environment. we compiled a national dataset of over 67,000 records on antibiotics, our study scrutinized antibiotic distribution in China's major river water and sediment. Through this analysis, we identified key factors influencing distribution patterns and crafted a national priority ranking for antibiotics. These findings deepen our understanding of antibiotic presence and contribute to the development of targeted management strategies aimed at minimizing environmental impact.

Iron-based nanoparticles (Fe-NPs) exhibit promising potential for soil remediation. However, their toxic effects on plants have also been reported. Typical Fe-NPs have been introduced into soil–plant systems to examine their possible nanotoxicity and other impacts on plants, while Fe-NPs have been added to pollutant–soil–plant systems to evaluate their performance as remediation agents. Mixed opinions and results have been reported regarding interactions between Fe-NPs and soil or plants. Here, meta-analysis was conducted to evaluate the effects of Fe-NPs on plant morphological and physiological characteristics in soil–plant and pollutant–soil–plant systems. Interestingly, morphological characteristics (dry and fresh weight) were significantly improved by Fe-NPs in both soil–plant and pollutant–soil–plant systems. In terms of plant physiological characteristics, Fe-NPs exerted negative effects on plant pigments in soil–plant systems, but positive effects in pollutant–soil–plant systems. In addition, Fe-NPs greatly increased the Fe contents and decreased the pollutant contents of plants. This study also provides a comprehensive review of the positive and negative effects of Fe-NPs on soil-plant systems and summarizes the pollutant remediation mechanisms of Fe-NPs in soil–plant systems. The results underscore the potential of Fe-NPs in agricultural applications and the future development of food safety.

Tetracyclines (TCs) have been widely detected in agricultural soil due to their widespread use in animal husbandry. The impact of low-generation TCs, i.e., the first- and second- generations, on soil ecosystem has attracted widespread attention. However, the dynamic response of soil microbial community to high-generation TCs, i.e., the third- and fourth- generations, remains largely unknown. Herein, we characterized the variations in the composition, diversity and succession of microbial community and the proliferation of antibiotic resistance genes (ARGs) under the stress of four generations of TCs in brown soil and red soil. The results demonstrated that the exposure of low- and high- generation TCs consistently decreased the alpha diversity and stimulated the succession rate of microbial community in soil. High-generation TCs strongly shifted microbial community composition by reducing community resilience. The complexity of microbial networks and cross-module associations were strengthened to cope with the stress of high-generation TCs in soil. The abundance of ARGs was exacerbated by 1.75 times in response to the fourth-generation TCs compared to control in brown soil. The potential bacterial hosts of ARGs were more diverse in brown soil exposed to high-generation TCs, but the dominant hosts were not changed. These results highlight the potential ecological risk of the newly developed antibiotics, which is helpful for a comprehensive risk assessment of emerging contaminants.

Using peracetic acid-based non-radical oxidation processes (PAA-based NOPs) effectively removes organic micropollutants in water treatment. PAA-based NOPs merits encompass the selective oxidation of organic contaminants, facilitated by the mildness of the non-radical active species generated, and a heightened tolerance to diverse water matrices. However, research on this topic is still in its infancy, and current studies have different perspectives and interpretations. In this study, we provide a comprehensive summary and examination of the mechanisms of four PAA-based NOPs, discussing their activation mechanisms, influencing factors, identification methods, and oxidation characteristics. Additionally, we examine the triggering mechanism and provide recommendations for controlling and regulating the occurrence of PAA-based NOPs. Finally, we highlight the potential applications and future challenges of PAA-based NOPs in aquatic environments. Through the analysis of relevant evidence, this study provides valuable insights into PAA-based NOPs, contributing to developing novel water treatment solutions.

The increasing accumulation of microplastics in agricultural soils potentially threatens crop safety and quality. However, studies regarding the molecular mechanisms underlying the effects of conventional and biodegradable microplastics on plant growth remain limited. Herein, we estimated the effects of biodegradable polybutylene adipate terephthalate, poly (butylene succinate), polylactic acid, and conventional non-biodegradable polyethylene and polystyrene microplastics (at a concentration of 1% [w/w]) on the growth and physiological performance of maize (Zea mays L.). In addition, we studied the molecular mechanisms underlying the effects of these microplastics on maize. Exposure to microplastics induced the production of antioxidant enzymes and antioxidants at varying levels in the maize. While the maize antioxidant systems were induced against biodegradable microplastic exposure, maize photosynthesis was relatively more important for conventional microplastic treatments. Additionally, metabolomics and transcriptomic analyses revealed that the pathways of secondary metabolite biosynthesis, photosynthesis, energy metabolism, and carbohydrate metabolism were regulated by biodegradable and conventional microplastics. Specifically, microplastics induced the plant hormone signal transduction and mitogen-activated protein kinase signaling pathways. Our results further indicated that microplastics could impact the plant through changing the soil environmental variables or altering the soil microbial communities. This study provides a molecular-scale perspective on the responses of crops to microplastic contamination, and these findings will contribute to the ecological risk assessment of biodegradable and conventional microplastics.

The increasing accumulation of microplastics in agricultural soils potentially threatens crop safety and quality. However, studies regarding the molecular mechanisms underlying the effects of conventional and biodegradable microplastics on plant growth remain limited. Herein, we estimated the effects of biodegradable polybutylene adipate terephthalate, poly (butylene succinate), polylactic acid, and conventional nonbiodegradable polyethylene and polystyrene microplastics (at a concentration of 1% [w/w]) on the growth and physiological performance of maize (Zea mays L.). In addition,we studied the molecular mechanisms underlying the effects of these microplastics on maize. Exposure to microplastics induced the production of antioxidant enzymes and antioxidants at varying levels in the maize. While the maize antioxidant systems were induced against biodegradable microplastic exposure, maize photosynthesis was relatively more important for conventional microplastic treatments. Additionally, metabolomics and transcriptomic analyses revealed that the pathways of secondary metabolite biosynthesis, photosynthesis, energy metabolism, and carbohydrate metabolism were regulated by biodegradable and conventional microplastics. Specifically, conventional microplastics induced the plant hormone signal transduction and mitogen-activated protein kinase signaling pathways. Our results provide a molecular-scale perspective on the responses of crops to microplastic contamination, and these findings will contribute to the ecological risk assessment of biodegradable and conventional microplastics.