Rimao Hua

Indoxacarb is considered a substitute for some highly toxic carbamate insecticides after their prohibition. However, it is easily hydrolyzed into the highly toxic N-decarbomethoxylated metabolite (DCJW) in the environment and nontarget organisms. In this study, an indoxacarb-degrading strain, Agrobacterium sp. DPX-5, was screened. It could degrade 57.8% of 10 mg/L indoxacarb within 24 h in LB medium with urea. Three degradation products M513, M469, and M455 were identified. The structures of the degradation products revealed a new low-risk hydrolysis metabolic pathway, which does not produce DCJW. Two novel functional indoxacarb-hydrolyzing enzymes InhA and InhB were found and characterized, with purified InhA showing higher degradation activity than InhB. Their key binding sites were further verified by molecular docking and point mutation. The research not only provides strain and enzyme resources but also discovers a lower-risk indoxacarb metabolic pathway to providing technical support for the bioremediation of carbamate insecticides.

Fenpyrazone is a hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide registered in China in 2020, while its aquatic environmental fate remains unclear. This study provides the first investigation of its degradation characteristics, products, and ecological risks in water. Results indicate that the degradation of fenpyrazone in aquatic environments is influenced by temperature, pH, and ionic conditions. Photolysis under neutral conditions was 193 times faster than hydrolysis, indicating photosensitivity. Five new metabolites, M440, M156, M140, M96 and M82 were identified, primarily formed via hydrolysis, decarboxylation, demethylation, and hydroxylation. In the photolysis process, ·OH, ·O₂^-, and ¹O₂ play key roles. Two key reactive sites are identified, the carboxylic ester bond for hydrolysis and the 1,3-dimethylpyrazole ring for photooxidation. Toxicity assessment revealed that metabolite M440 exhibited higher toxicity than the parent compound. Furthermore, most products were predicted to pose significantly higher chronic toxicity risks, highlighting long-term environmental hazards and providing critical data for ecological risk assessment.

Dichlorvos (DDVP) has been used in the management of agricultural pests for a long time. DDVP can cause DNA damage in mammals, and its residues in the environment and food have attracted attention. In this study, we reported a DDVP-degrading strain, Stenotrophomonas acidaminiphila G1, which could degrade DDVP to 20 mg/L with a DT₅₀ of 3.81 min at 37 °C, a pH of 7.0, and a concentration of 1.18 × 10¹⁰ colony-forming units (CFUs)/mL. Strain G1’s DDVP degradation products were determined by comparison with standard substances and UPLC-MS/MS analysis. The results showed that dimethyl phosphate (DMPP) was the main metabolite of DDVP, and its toxicity to non-target organisms was significantly lower than that of the parent compound. Furthermore, the key genes for the degradation of DDVP by strain G1 were analyzed using whole-genome sequencing. A methyl parathion hydrolase gene, mpd, was identified, and its activity was verified through prokaryotic expression and enzyme kinetics. The purified enzyme MPD could entirely degrade 20 mg/L DDVP within 1 min. These results not only provide biological resources for the rapid degradation of organophosphorus pesticides but also offer a theoretical basis for the efficient remediation of pesticide residues.

BACKGROUND: Phytohormones regulate plant growth, development, and stress responses. Strigolactones are a class of phytohormones that have attracted significant scientific interest because of their multifunctional roles in plant biology and ecological interactions. RESULTS: In this study, 34 strigolactone mimics were efficiently synthesized by substituting pre‐synthesized 5‐chloro‐3‐methylfuran‐2(5 H )‐one with phenolics and benzenethiols. Most of the chemicals showed seed germination‐promoting activities on corn, sorghum, soybean, and sunflower seeds. At a concentration of 100 mg/L, 3 s and 4 h showed a promotion rate of 56% and 63% on corn bud growth and 50% and 62% on sorghum root growth, respectively. The promotion rates of 3 s and 4 h on corn, sorghum, soybean, and sunflower root growth ranged between 35–48% and 46–71%, respectively. The effect on germination of the target compound exhibited a dose‐dependent trend, increasing within the range of 0.01–10 mg/L and decreasing within the range of 10–100 mg/L. Optimal promotion rates for corn root and shoot growth at 3 s and 4 h were achieved at a concentration of 10 mg/L. 3 s and 4 h regulated the content of the abscisic acid, auxin, cytokinin, and gibberellin to promote plant germination. The binding energy of GR24 docking with strigolactone receptor proteins derived from Arabidopsis (AtD14) was −7.30 kcal/mol, while 3 s and 4 h were −7.96 and −8.05 kcal/mol, respectively. CONCLUSIONS: The structure–activity relationships of 34 novel strigolactone mimics and docking simulations provided structural optimization strategies for designing new strigolactone mimics as plant growth regulators. © 2025 Society of Chemical Industry.

Chlorothalonil (CTL) is a well-known water contaminant and has high toxicity to aquatic species and amphibians. Sodium lignosulfonate (SL) as an inexpensive surfactant is renewable, biodegradable, and environmentally benign. Effects of SL on photodegradation of CTL were studied under different light. SL enhanced the photodegradation rate of CTL by 14, 18, 7.4, and 18.5 fold under a high-pressure mercury lamp (HPML), an UV lamp, a xenon lamp, and sunlight, respectively, compared to the SL-free control. The mechanism of SL-enhanced CTL degradation was revealed as a reductive dechlorination reaction by radical scavenging activity and electron donation of SL. Further experiments evidenced that the photoreductive capacity of SL generated electrons to reduce generation of hydroxyl radicals (•OH) and singlet oxygen (¹O₂) under irradiation and promoted dechlorination of CTL̇. The results are helpful to understand the effects of SL on phototransformation and the high potential of using SL as a catalyst to abate chloroarenes pollution.

Background/Objectives: Grapes (Vitis vinifera), particularly ‘Shine Muscat’, are prone to postharvest quality loss mainly due to poor storage tolerance. Actinomycetes are microbial resources that produce secondary metabolites that exhibit notable functional properties. Methods: This study explored the use of Streptomyces albulus Ah11601 fermentation broth (SFB) as a postharvest treatment to preserve ‘Shine Muscat’ grape quality during 6 days of room temperature storage using physiological, transcriptomic, and bioinformatics analyses to elucidate the underlying regulatory mechanism. Results: The results demonstrated that, compared to the control group stored at room temperature (25 °C) for 6 days (6D), the SFB-treated group (T6D) presented a significant delay in the decrease in fruit hardness and vitamin C content. Further investigations revealed that the 6D treatment significantly elevated lipoxygenase activity, MDA content, O₂⁻ generation rate, and H₂O₂ levels. In addition, both the 6D and T6D treatments significantly increased the activities of SOD and APX. Functional enrichment analysis revealed that the upregulated DEGs in the 6D group were predominantly enriched in pathways such as phenylpropanoid biosynthesis; flavonoid biosynthesis; phenylalanine metabolism; and stilbenoid, diarylheptanoid, and gingerol biosynthesis. The downregulated DEGs were enriched primarily in the endoplasmic reticulum protein processing pathway. In the T6D group, the upregulated DEGs were predominantly enriched in the zeatin biosynthesis pathway. In addition, significant alterations in the expression of genes associated with the ethylene and abscisic acid signaling pathways were detected. Conclusions: In conclusion, SFB treatment effectively mitigated the deterioration of the postharvest quality of ‘Shine Muscat’ grapes by preserving the cellular redox balance, regulating cytokinin and ethylene biosynthesis, and optimizing the regulation of ethylene and abscisic acid signaling.

This study investigated the photocatalytic degradation of chlorothalonil under a range of ultraviolet lamp configurations, and studied the improvement in the photocatalytic degradation efficiency of a reflective material (silver-white aluminium foil). Increasing the number of UV lamps significantly enhanced degradation efficiency, reducing the half-life from 29.95 min with one lamp to 8.15 min with four in a 20 cm enamel bucket. The use of silvery-white aluminium foil further decreased the half-life to 3.86 min, improving degradation rates by up to 262.9%. In larger containers, degradation efficiency increased by up to 414.7% with aluminium foil. Comparisons with black aluminium foil confirmed that silver-white aluminium foil enhanced degradation by reflecting and redistributing UV light, increasing intensity by 252% and reducing the CTL half-life from 150.36 min to 22.9 min in a controlled light box. Further tests confirmed that silver-white aluminium foil amplified UV irradiation, increasing degradation efficiency by up to 555.1%. These improvements might suggest that aluminium foil enhances UV utilisation through direct reflection, refraction, and diffuse reflection, effectively redirecting photons that would otherwise escape the system. Experiments with natural water sources showed similar trends, with half-lives of 55.23 min in ultrapure water, 12.63 min in pond water, and 16.36 min in paddy field water. The addition of silver-white aluminium foil further reduced these times to 23.92 min, 7.13 min, and 12.34 min, respectively. These findings demonstrate that silvery-white aluminium foil significantly enhances CTL photodegradation without increasing energy consumption. While effective, the method faces challenges in acidic or alkaline wastewater due to potential corrosion of system components. Future research should focus on identifying stable, high-reflectivity materials for long-term applications. This study offers practical insights into the optimisation of photodegradation processes, which contributes to improved water treatment strategies and environmental pollution mitigation.

Profenofos insecticide poses risks to nontarget organisms including mammals and hydrobionts, and its effects on crops are not known. This study examined the invisible toxicity of profenofos on pakchoi (Brassica rapa L.), using transcriptome and metabolome analyses. Profenofos inhibited the photosynthetic efficiency and light energy absorption by leaves and severely damaged the chloroplasts, causing the accumulation of reactive oxygen species (ROS). Metabolomic analysis confirmed that profenofos promoted the conversion of β-carotene into abscisic acid (ABA), as evidenced by the upregulation of the carotenoid biosynthesis pathway genes: zeaxanthin epoxidase (ZEP), 9-cis-epoxycarotenoid dioxygenase (NCED3), and xanthoxin dehydrogenase (XanDH). The inhibitory effects on carotenoid accumulation, photosynthesis, and increased ABA and ROS contents of the leaves led to invisible injury and stunted growth of the pakchoi plants. The findings of this study revealed the toxicological risk of profenofos to nontarget crops and provide guidance for the safe use of insecticides.