The global environmental challenges of solid waste accumulation and aquatic eutrophication demand innovative and sustainable strategies. This study introduces a circular “waste-treats-waste” approach by converting dolomite-rich phosphate tailings (PT), a widespread industrial by-product, into a high-value adsorbent for phosphorus (P) removal. Thermal modification at 950 °C for 1 h dramatically enhanced the adsorption capacity by approximately 45 times, from 2.52 mg/g (raw PT) to 112.41 mg/g. This performance is highly competitive with, and often superior to, many engineered adsorbents. The calcination process was pivotal, decomposing carbonates into highly active CaO and MgO while developing a porous structure. Using a multi-technique characterization approach (X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), TESCAN VEGA3 tungsten filament scanning electron microscope (SEM), the Brunauer–Emmett–Teller method (BET)), the key immobilization mechanism was identified as hydroxyapatite formation, driven by Ca²⁺/Mg²⁺-phosphate precipitation and surface complexation. Nonlinear regression analysis revealed that the adsorption kinetics obeyed the pseudo-second-order model, and the equilibrium data were best described by the Freundlich isotherm. This indicates a chemisorption process occurring on a heterogeneous surface, consistent with the complex structure created by thermal modification. Notably, post-adsorption pore structure expansion suggested synergistic pore-filling and surface reorganization. This work not only demonstrates a circular economy paradigm for repurposing industrial solid waste on a global scale but also offers a cost-effective and high-performance pathway for controlling phosphorus pollution in aquatic systems, contributing directly to resource efficiency and sustainable environmental remediation.

Aconitum vilmorinianum (A. vilmorinianum) is an important medicinal plant in the Aconitum genus that is known for its diterpenoid alkaloids, which exhibit significant pharmacological activity and toxicity, thus making it valuable for both medicinal use and as a biopesticide. Although the biosynthesis of terpenoids is well characterized, the potential gene regulatory role of microRNAs (miRNAs) in terpenoid biosynthesis in A. vilmorinianum remains unclear, and further research is needed to explore this aspect in this species. In this study, miRNA sequencing was conducted to analyze the miRNA population and its targets in A. vilmorinianum. A total of 22,435 small RNAs were identified across the nine samples. Through miRNA target gene association analysis, 356 target genes from 54 known miRNAs and 977 target genes from 151 novel miRNAs were identified. Target identification revealed that miR6300 targets the hydroxymethylglutaryl-CoA reductase (HMGR) gene, which is involved in the formation of the terpenoid backbone and regulates the synthesis of diterpenoid alkaloids. Additionally, preliminary findings suggest that miR4995 and miR5021 may be involved in the regulation of terpenoid biosynthesis, although further biochemical analysis is needed to confirm these potential roles. This study provides a foundational understanding of the molecular mechanisms by which miRNAs regulate terpenoid biosynthesis in A. vilmorinianum and offers scientific evidence for further research on the biosynthesis of diterpenoid alkaloids in this medicinal plant.

Background: Fungal symbionts are critical for host plant survival but are vulnerable to abiotic stresses such as low temperature, which limits their agricultural utility. Armillaria mellea is an essential fungal partner for the cultivation of the valuable medicinal orchid Gastrodia elata (G. elata). Enhancing its cold tolerance is a key step toward stabilizing G. elata production. Methods: Based on G. elata transcriptome data, a manganese superoxide dismutase gene (GeSOD7) was identified and heterologously expressed in Escherichia coli for enzymatic characterization. The gene was then overexpressed in A. mellea via Agrobacterium tumefaciens-mediated transformation. Transgenic and wild-type strains were subjected to cold stress (13 °C for 45 days), after which physiological, biochemical, and molecular responses were analyzed. Results: Recombinant GeSOD7 showed optimal activity at pH 6.0 and 60 °C, with inhibition under high concentrations of metal ions, especially Mn2+ and Cu2+. Overexpression of GeSOD7 in A. mellea significantly improved hyphal growth and fresh weight under cold stress. Transgenic strains exhibited higher activities of catalase and glutathione peroxidase, increased accumulation of glutathione and proline, and reduced levels of hydrogen peroxide and malondialdehyde. Expression of genes involved in glutathione synthesis and peroxide detoxification was coordinately upregulated. Conclusions: This study demonstrates that heterologous expression of a plant-derived Mn-SOD can effectively enhance the cold stress tolerance of a symbiotic fungus by boosting its enzymatic and non-enzymatic antioxidant systems. These findings provide a novel genetic strategy for improving stress resilience in agriculturally important fungi and contribute to the sustainable cultivation of G. elata.

Aluminum (Al) toxicity in acidic soils severely inhibits root growth. While enhanced antioxidant defense and organic acid exudation are both known Al tolerance mechanisms, how these processes are coordinated remains unclear. This study investigates whether and how the soybean (Glycine max) superoxide dismutase gene GmSOD (GenBank accession no. M64267.1) orchestrates these responses via modulation of hydrogen peroxide (H₂O₂) signaling. Wild-type (WT) and GmSOD-overexpressing transgenic tobacco (Nicotiana benthamiana) lines ST7 were exposed to Al stress (0-400 μM). A combination of physiological assays, biochemical activity measurements, gene expression analysis (quantitative RT-PCR), protein-protein interaction studies (co-immunoprecipitation), and multivariate factor analysis was employed to dissect the response pathways. GmSOD overexpression conferred superior Al tolerance, as evidenced by better-maintained root growth in ST7 under moderate stress (≤200 μM). The transgenic line ST7 exhibited a stronger antioxidant system, resulting in lower H₂O₂ and malondialdehyde (MDA) accumulation. Crucially, under moderate Al stress, ST7 maintained root tips H₂O₂ within a narrow signaling range (0.35-0.6 μmol g^-1 FW). This specific H₂O₂ level promoted the phosphorylation of plasma membrane (PM) H⁺-ATPase (Gene: NtAHA2, GenBank Accession no: M80490) and enhanced its interaction with 14-3-3 proteins, leading to increased H⁺-pump activity and a significant boost in citrate exudation. In contrast, under severe stress (400 μM), H₂O₂ accumulated to toxic levels (>1.0 μmol g^-1 FW), inhibiting this pathway. Factor analysis distilled ten stress-response variables into two principal components-"Antioxidant Capacity" and "Al Toxicity Index"-quantitatively demonstrating that ST7 maintains a favorable balance at higher Al concentrations than WT. We propose a novel model in which GmSOD-mediated fine-tuning of H₂O₂ homeostasis plays a dual role: it directly alleviates oxidative damage and, at a specific low concentration, acts as a signal to activate the PM H⁺-ATPase-dependent citrate exudation pathway. This coupling of internal redox control with external detoxification constitutes a key integrative mechanism for Al tolerance, offering strategic insights for crop improvement.