Herein, we synthesized 34 novel tryptanthrin derivatives, among which T7NHCO-series compounds showed great antibacterial activity againstXanthomonas axonopodis pv. citri,Pseudomonas syringae pv. actinidiae, andRalstonia solanacearum with EC50 values ranging from 0.26 to 0.56 mu g/mL. Meanwhile, these compounds exhibited low cytotoxicity against HEK-293. Additionally, compound T7NHCO can inhibit biofilm formation, damage bacterial morphology, downregulate the expression of bacterial chemotaxis-related proteins, cause bacterial necrosis, and effectively control citrus and kiwifruit canker (the curative and protective efficiency is 79.35 and 88.31%, respectively) diseases. However, compound T7NHCO exhibited a significant phytotoxicity to tobacco. Subsequently, based on the characteristic of tobacco wilt disease being prone to outbreak in weakly acidic soil conditions, we introduced the pH-responsive ZIF-8 drug delivery system. Fortunately, T7NHCO@ZIF-8 nanoparticles exhibited low phytotoxicity and noticeable activity against tobacco wilt disease. Above all, T7NHCO@ZIF-8 nanoparticles may be a promising green lead agent against plant bacterial diseases.

In recent years, lead (Pb) contaminated soil has caused irreversible damage to human beings. It is urgent to develop a novel technology for accurate detection of Pb in the soil solution. Herein, a new electrochemical sensor was fabricated. Fe/ZIF-8 was used as the modification material, gold nanoparticles (AuNPs) were electrodeposited, and DNAzyme was applied on the surface as the probe. Under the optimum conditions (DNAzyme concentration of 1 mu mol, fixation time of 4 min, incubation time of 17 h and reaction time of 30 min), the detection range was 5x10(-12) similar to 5x10(-5) M, and the minimum detection limit was 10(-13) M (3 delta). Furthermore, the electrochemical sensor demonstrated outstanding anti-interference ability to common cations, anions, organic compounds and other interference factors. After four consecutive tests, the relative standard deviation (RSD) was only 0.39%, and it still displayed excellent reproducibility with 0.69% of RSD. After 20 days, the sensor's response to Pb2+ remained at 93.58%. In addition, the sensor could accurately detect Pb2+ in the actual soil solutions, and the recoveries of the samples ranged from 92% to 109.4%. In conclusion, this electrochemical sensor can specifically detect Pb2+ in the soil solution with enhanced sensitivity, anti-interference capability and stability, which is of great significance for Pb2+ detection in the field.

Film mulching is one of the most important methods to control soil-borne diseases. However, the traditional mulch may cause microplastic pollution and soil ecological damage. Herein, a biodegradable film was developed using oxidized starch and carboxymethyl chitosan and incorporated ZIF-8 carrying fludioxonil to sustainably control soil-borne disease. The microstructure, mechanical properties, optical properties, and water barrier properties of the composite films (Flu@ZIF-8-OS/CMCS) were investigated. The results show that Flu@ZIF-8-OS/ CMCS had a smooth and uniform surface and excellent light transmittance. The excellent mechanical properties of the films were verified by tensile strength, elongation at break and Young's modulus. Higher contact angle and lower water vapor permeability indicate water retention capacity of the soil was improved through using Flu@ZIF-8-OS/CMCS. Furthermore, the release properties, biological activity, degradability and safety to soil organisms of Flu@ZIF-8-OS/CMCS was determined. The addition of ZIF-8 significantly improved the film's ability to retard the release of Flu, while the Flu@ZIF-8-OS/CMCS has good soil degradability. In vitro antifungal assays and pot experiments demonstrated excellent inhibitory activity against Rusarium oxysporum f. sp. Lycopersici. Flu@ZIF-8-OS/CMCS caused only 13.33 % mortality of earthworms within 7 d. This research provides a new approach to reducing microplastic pollution and effectively managing soil-borne diseases.