The environmental prevalence of the tire wear-derived emerging pollutant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) has increasingly raised public concern. However, knowledge of the adverse effects of 6PPD-Q on soil fauna is scarce. In this study, we elucidated its impact on soil fauna, specifically on the earthworm Eisenia fetida. Our investigation encompassed phenotypic, multi-omics, and microbiota analyses to assess earthworm responses to a gradient of 6PPD-Q contamination (10, 100, 1000, and 5000 mu g/kg dw soil). Post-28-day exposure, 6PPD-Q was found to bioaccumulate in earthworms, triggering reactive oxygen species production and consequent oxidative damage to coelomic and intestinal tissues. Transcriptomic and metabolomic profiling revealed several physiological perturbations, including inflammation, immune dysfunction, metabolic imbalances, and genetic toxicity. Moreover, 6PPD-Q perturbed the intestinal microbiota, with high dosages significantly suppressing microbial functions linked to metabolism and information processing (P < 0.05). These alterations were accompanied by increased mortality and weight loss in the earthworms. Specifically, at an environmental concentration of 6PPD-Q (1000 mu g/kg), we observed a substantial reduction in survival rate and physiological disruptions. This study provides important insights into the environmental hazards of 6PPD-Q to soil biota and reveals the underlying toxicological mechanisms, underscoring the need for further research to mitigate its ecological footprint.

The hazelnut weevil larvae (Curculio dieckmanni) is a major pest of nut weevils, spending part of its life cycle in the soil and causing significant damage to hazelnut crops. Moreover, its concealed feeding behavior complicates effective control with chemical insecticides. The entomopathogenic nematode Steinernema carpocapsae, which efficiently kills weevil larvae, offers a promising biological control agent. To investigate the molecular responses of hazelnut weevil larvae to nematode infection, we employed integrated transcriptomic and proteomic analyses following infection by S. carpocapsae. Our results revealed substantial alterations in gene expression, particularly the upregulation of immune-related transcripts such as antimicrobial peptides (AMPs) and stress-responsive proteins like heat shock protein 70 (HSP70). Furthermore, significant metabolic reprogramming occurred, marked by the downregulation of carbohydrate metabolic pathways and activation of energy conservation mechanisms. Although we observed an overall correlation between mRNA and protein expression levels, notable discrepancies highlighted the critical roles of post-transcriptional and post-translational regulatory processes. Collectively, these findings advance our understanding of the molecular interaction between insect hosts and pathogenic nematodes and contribute valuable knowledge for enhancing the effectiveness of EPN-based pest management strategies.

Cadmium (Cd) is a toxic, non-essential heavy metal, with significant stress to plants such as soybean (Glycine max). High Cd concentration in the soil inhibits various stages of soybean growth, including seed germination, vegetative growth, and the reproduction stage. Phosphate, a vital macronutrient, has been shown to alleviate Cd-induced stress; however, the molecular mechanisms remain poorly understood. This study aimed to explore the interactive effects of Cd and phosphate on soybeans at the physiological, transcriptomic, and metabolic levels using a multi-omics approach. Experiments were conducted where soybean plants were treated with different concentrations of Cd and phosphate. The results indicated that Cd stress significantly reduced plant height, photosynthetic rate, and transpiration rate, while phosphorus application mitigated these effects, reducing Cd absorption in both roots and shoots. Furthermore, antioxidant enzyme activities (superoxide dismutase, catalase, and peroxidase) were significantly enhanced by phosphate under Cd stress, which scavenged reactive oxygen species (ROS) generated by cadmium, thereby protecting cells from oxidative stress damage. Transcriptome and metabolome analyses revealed substantial changes in gene expression and metabolite profiles in response to Cd and phosphate treatments. Notably, phosphorus treatment induced the up-regulation of genes involved in stress response, root development, and metal transport, while altering metabolic pathways related to phenolic acids, flavonoids, and lipids. This research provided new insights into the molecular mechanism by which phosphorus enhanced the activity of antioxidant enzymes, thereby improving the plant's antioxidant defense capacity and reducing the toxic effects of cadmium in soybeans, offering potential strategies for enhancing crop resilience against heavy metal contamination.

Titanium dioxide nanoparticles (TiO2 NPs) have been widely used in agriculture, which increased the risk to soilplant systems. Studies have demonstrated that TiO2 NPs can induce phytotoxicity. However, the toxicity mechanisms, particularly under the stress of TiO2 NPs with different crystalline forms, remain inadequately reported. In this study, we combined transcriptomics and metabolomics to analyze the toxicity mechanisms in rice (Oryza sativa L.) under the stress of anatase (AT) or rutile (RT) TiO2 NPs (50 mg/kg, 40 days). The length (decreased by 1.1-fold, p = 0.021) and malondialdehyde concentration (decreased by 1.4-fold, p = 0.0027) of rice shoots was significantly reduced after AT exposure, while no significant changes were observed following RT exposure. Antioxidant enzyme activities were significantly altered both in the AT and RT groups, indicating TiO2 NPs induced rice oxidative damage (with changes of 1.1 to 1.4-fold, p < 0.05). Additionally, compared to the control, AT exposure altered 3247 differentially expressed genes (DEGs) and 56 significantly differentially metabolites in rice (collectively involved in pyrimidine metabolism, TCA cycle, fatty acid metabolism, and amino acid metabolism). After RT exposure, 2814 DEGs and 55 significantly differentially metabolites were identified, which were collectively involved in fatty acid metabolism and amino acid metabolism. Our results indicated that AT exposure led to more pronounced changes in biological responses related to oxidative stress and had more negative effects on rice growth compared to RT exposure. These findings provide new insights into the phytotoxic mechanisms of TiO2 NPs with different crystalline forms. Based on the observed adverse effects, the study emphasizes that any form of TiO2 NPs should be used with caution in rice ecosystems. This study is the first to demonstrate that AT is more toxic than RT in paddy ecosystems, providing crucial insights into the differential impacts and toxic mechanisms of TiO2 NPs with different crystalline forms. These findings suggest prioritizing the use of RT when TiO2 NPs are necessary in agricultural development to minimize toxicity risks.