Jul 2026· Journal of Hazardous Materials· Vol 514, pp.
142930
· 0 citations· 81 references
Medicine
TL;DR
It is suggested that the presence of bio-MPs may interfere with normal plant-microbe interactions, which is further associated with an imbalance in the rhizosphere ecological microenvironment and may ultimately contribute to impaired plant growth.
Abstract
Microplastics (MPs) pollution already posed a serious threat to human health. Biodegradable (bio) plastics serve as alternatives to traditional plastics. However, the ecological impact of bio-MPs has not been adequately assessed. This study evaluates the effects of two types of bio-MPs (poly (butylene adipate-co-terephthalate) (PBAT) and polylactic acid (PLA)) on plant growth and the rhizosphere soil microenvironment. Exposure to bio-MPs significantly decreased tomato growth, soil enzyme activities, and rhizosphere microbial diversity. In addition, bio-MPs significantly reduced the abundance of beneficial microorganisms (growth-promoting, nutrient cycling, stress resistance) in the rhizosphere soil. The secretion levels of several root exudates decreased significantly, including citric acid, quinic acid, indole, p‑coumaric acid, and flavone. This decrease led to alterations in multiple metabolic pathways: the TCA cycle, the biosynthesis of phenylalanine, tyrosine, and tryptophan, and the phenylpropanoid biosynthesis pathway. Meanwhile, these specific metabolites showed a significant positive correlation with beneficial rhizosphere microorganisms. Compared with traditional MPs, these findings suggests that the presence of bio‑MPs may interfere with normal plant-microbe interactions, which is further associated with an imbalance in the rhizosphere ecological microenvironment and may ultimately contribute to impaired plant growth. In the meantime, the beneficial effects of root exudates on plant resistance against bio‑MP toxicity have also received preliminary confirmation. This finding provides valuable evidence for evaluating the impact of bio-plastics on plant rhizosphere soil health.
Microplastics (MPs) and antibiotics represent escalating emerging contaminants in global agricultural soils, posing substantial threats to crop health and ecosystem functionality worldwide. However, a comprehensive understanding of their joint toxicity and the underlying rhizosphere mechanisms under co-contamination remains elusive, leaving a critical knowledge gap. This study conducted a pot experiment using the globally cultivated peanut (Arachis hypogaea) exposed to polystyrene (PS) or polylactic acid (PLA) MPs (0.25 and 2% w/w) and oxytetracycline (OTC, 10 mg·kg⁻¹), integrating metagenomic sequencing and untargeted metabolomics to elucidate root-zone microecological responses. High-concentration co-exposures significantly suppressed peanut shoot biomass, and OTC was identified as the primary contributor to reduced leaf catalase activity (CAT) (p < 0.01). Metagenomic profiling revealed that co-exposure significantly reshaped the rhizosphere microbiota (R2 = 0.939, p = 0.001), enriching Pseudomonadota while inhibiting Actinobacteriota. Untargeted metabolomics detected 3789 metabolites, revealing that co-exposure significantly regulated the accumulation of defensive flavonoids (taxifolin and daidzin) and stress-responsive steroids (ponasterone A). Particularly, the combined exposure of PLA MPs and OTC induced the most severe metabolic disruption in the rhizosphere, generating 374 differential metabolites compared to the PLA-alone treatment. Procrustes analysis confirmed a tight coupling between microbial communities and metabolomes (M2 = 0.619, p = 0.004). Network analysis further identified key regulatory nodes (Nocardioides and taxifolin) that bridge the associations between the rhizosphere microenvironment and plant growth traits. This study demonstrates that microbial shifts and metabolic adjustments are essential in mediating plant responses to multi-pollutant stress, providing crucial theoretical and mechanistic insights for global agricultural environmental risk assessment under co-contamination scenarios.
Xiaotong Li, Yudong Chen, Jinlong Wang et al.· Ecotoxicology and Environmen...· 0 citations
Microplastics (MPs) pollution caused by agricultural film residues, organic fertilizer application, sewage irrigation, and atmospheric deposition has gradually become an unignorable interference factor to the sustainable development of the rhizosphere soil and crop in farmland. However, their specific impacts on the rhizosphere and crops remain unclear. Therefore, this review focuses on the current knowledge on the response mechanisms of rhizosphere soil and crops to MP contamination. The density of MPs is generally lower than that of soil mineral particles. Their substantial accumulation in soil can significantly reduce both the bulk density (by increasing total porosity) and the particle density (by diluting the heavy solid phase with light plastic components). The introduction of MPs disrupts the normal metabolism of soil bacterial communities; a disruption directly reflected in functional genes associated with carbon cycling. MPs can interfere with the activity of key metabolic enzymes involved in fungal nutrient cycling, thereby disrupting normal energy allocation and material metabolism. Viruses can regulate the turnover and metabolism of microbial communities through lytic and lysogenic cycles, consequently influencing the carbon fate of MPs. The toxicity and underlying mechanisms of MPs on soil fauna primarily manifest in aspects such as feeding behavior, growth and development, oxidative stress, intestinal toxicity, and reproductive toxicity. The direct effects of MPs on plants include physical barriers and mechanical damage, induction of oxidative stress, interference with nutrient uptake, disruption of photosynthesis and carbon metabolism, and disruption of plant hormone networks. This review identifies critical knowledge gaps, particularly regarding crop quality, field-based soil faunal studies, virus-microbe interactions, and degradation products, and proposes future research directions to better understand the risks MPs pose to agricultural sustainability and food safety.
Conventional polyethylene (PE) mulch causes persistent soil plastic pollution; biodegradable mulch films (BMFs) may avoid this, but their effects on sugarcane rhizosphere microbes and yield are unclear.
Using a field trial in Yunnan, we compared polyethylene mulch (PM) with two PBAT/PLA-based biodegradable mulch films (BMFs) differing in thickness (Thick Film, BTK, 0.008 mm; Thin Film, BTH, 0.005 mm). Rhizosphere soil (0–40 cm) physicochemical properties, bacterial (16S) and fungal (18S) communities, predicted microbial functional potentials, and sugarcane agronomic traits were analyzed.
BMFs degradation released organic carbon that significantly altered the rhizosphere microenvironment, increasing soil pH, organic matter, and available potassium relative to PM. These physicochemical changes drove microbial community differentiation. Compared with PM, BMFs increased the relative abundances of
Chloroflexi, Acidobacteria
, and
Basidiomycota
, while decreasing
Actinobacteria
and
Ascomycota
(
p
< 0.05). BMFs also enhanced microbial α-diversity, with bacterial diversity being higher under BTK and fungal diversity under BTH. Neutral model analysis revealed that bacterial community assembly was dominated by stochastic processes; however, BMFs reduced dispersal limitation and strengthened deterministic environmental filtering, particularly under the BTH treatment, due to enhanced microhabitat heterogeneity from faster degradation. These community shifts were associated with enriched predicted sulfur (dsrAB) and nitrogen (nosZ, nif) cycling genes and more complex, cooperative bacterial–fungal interaction networks, with BTH exhibiting higher network complexity and positive interactions. These microbial responses were associated with improved sugarcane performance. Compared with PM, BMFs increased single stalk weight by 8.76%−11.68%, millable stalk number by 4.99%−7.38%, and cane yield by 17.11%−17.40%.
Collectively, our results demonstrate that BMFs, through degradation-driven microhabitat alteration, strengthen deterministic assembly, promote functionally specialized taxa and cooperative networks, and enhance predicted nutrient cycling potentials, thereby improving sugarcane productivity and offering a sustainable alternative to PE mulch.
Qianyuan Duan, Qiang Liu, Xinping Mao et al.· Frontiers in Microbiology· 0 citations
Evidence shows that stress mitigators can reduce MNPs-induced stress by improving rhizosphere microbial communities, increasing plant growth and photosynthetic efficiency, and regulating biochemical, transcriptomic, and metabolomic responses.
Wardah Azhar, Ali Raza Khan, Abdul Salam et al.· Journal of Agricultural and...· 0 citations
The co-occurrence of heavy metal contamination and biodegradable microplastic (polylactic acid, PLA) pollution poses increasing risks to terrestrial plant communities and soil functioning, yet species-specific responses to combined stress remain poorly understood. Cd and microplastics frequently co-occur in agricultural soils, where microplastics can alter cadmium mobility, bioavailability, and transport pathways, potentially modifying metal toxicity and plant stress responses compared with single-pollutant exposure. We investigated the responses of the invasive Bidens pilosa and the native Solanum nigrum grown in monoculture and mixed culture under combined cadmium (Cd) and biodegradable microplastic (PLA) stress by integrating plant growth, photosynthetic performance, oxidative physiology, and rhizosphere biochemical processes. Combined Cd-MP exposure markedly reduced plant growth, chlorophyll content (SPAD), photosystem II efficiency (Fv/Fm), nitrogen accumulation, biomass production, and rhizosphere enzyme activities associated with carbon, nitrogen, and phosphorus cycling. However, B. pilosa maintained greater physiological stability under stress, characterized by higher antioxidant enzyme activities (SOD, CAT, POD), lower reactive oxygen species (H2O2, O2˙-) accumulation, and reduced lipid peroxidation (MDA), whereas S. nigrum exhibited stronger oxidative damage and functional impairment. Multivariate analyses further revealed that root antioxidant capacity was closely associated with rhizosphere microbial enzyme activity, suggesting a root-centered regulatory mechanism linking plant stress tolerance to soil functioning. Overall, the invasive species showed greater tolerance to combined contamination and maintained relatively higher rhizosphere functional activity than the native species, indicating that multi-pollutant stress may alter competitive interactions between invasive and native plants in contaminated environments.
Unknown authors· Physiologia Plantarum : An I...· 0 citations
The use of the tested biostimulant treatments support the use of the tested biostimulants as sustainable crop management tools that preserve rhizosphere microbial communities.
Oumaima Akachoud, Paola Villanueva Rosales, J. Fontaine et al.· Agriculture· 0 citations
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