Systematic understanding of the impact of nanomaterials (NMs) on the health and activity of plant-associated microorganisms is required for sustainable development of efficient nano-enabled agrochemicals. Zinc (Zn) is an essential micronutrient for plant growth and development. It plays a vital role in various physiological processes, including enzyme activation, protein synthesis, cell division, etc. The present study investigated the effects of foliar exposure to different sizes of ZnO particles, including ZnO quantum dots (ZnO QDs, 4.06 nm), ZnO nanoparticles (ZnO NPs, 60.0 nm), bulk-scale ZnO particles (ZnO BPs, 464.5 nm), and Zn ions at an equivalent Zn molar concentration (0.61 mM) on the endophytic and rhizosphere microbial communities of pumpkin seedlings. ZnO QDs increased the total plant biomass by 24.6% as compared to the control. ZnO QDs also increased the contents of total chlorophyll and carotenoids, elevated micronutrient (Zn, Fe, and B) uptake, and triggered the activities of antioxidant enzymes, such as peroxidase (POD), polyphenol oxidase (PPO), and catalase (CAT), as compared to controls. The composition and diversity of the endophytic and rhizosphere bacterial or fungal communities were significantly altered as a function of ZnO NM size, and a significant difference between the control and ZnO treatments was also evident. Linear discriminant effect size analysis (LEfSe) shows that the putative beneficial host microbes Steroidobacter (relative abundance, RA: 1.05%) and Paenibacillus (RA: 0.59%) were enriched in pumpkin seedlings treated with ZnO QDs, which may lead to greater plant growth, nutrient acquisition, and stress resistance. Cooccurrence networks indicate that ZnO QDs increased both node and link numbers of the bacterial networks by 46.94 and 123.38% in the roots, which could further stabilize the microbial community and confer resistance to environmental disturbance. Our overall findings demonstrate that ZnO QDs could enhance plant growth both directly by improving physiological performances and indirectly by modulating beneficial endophytic and rhizosphere microorganisms. Thus, nano-enabled strategies can be a promising and sustainable approach to increase crop growth and resistance to stress.

In recent years, with the development of the nanomaterials discipline, many new pesticide drug-carrying systems—such as pesticide nano-metal particles, nano-metal oxides, and other drug-carrying materials—had been developed and applied to pesticide formulations. Although these new drug-loading systems are relatively friendly to the environment, the direct exposure of many metal nanoparticles to the environment will inevitably lead to potential effects. In response to these problems, organic nanomaterials have been rapidly developed due to their high-quality biodegradation and biocompatibility. Most of these organic nanomaterials were mainly polysaccharide materials, such as chitosan, carboxymethyl chitosan, sodium alginate, β-cyclodextrin, cellulose, starch, guar gum, etc. Some of these materials could be used to carry inorganic materials to develop a temperature- or pH-sensitive pesticide drug delivery system. Herein, the pesticide drug-carrying system developed based on polysaccharide materials, such as chitosan, was referred to as the pesticide polymer drug-carrying system based on polysaccharide materials. This kind of drug-loading system could be used to protect the pesticide molecules from harsh environments, such as pH, light, temperature, etc., and was used to develop the function of a sustained release, targeted release of pesticides in the intestine of insects, and achieve the goal of precise application, reduction, and efficiency of pesticides. In this review, the recent progress in the field of polysaccharide-based polymer drug delivery systems for pesticides has been discussed, and suggestions for future development were proposed based on the current situation.

Background: ω-hexatoxin-Hvn1b is an insecticidal toxin produced by the Tasmanian funnel-web spider (Hadronyche venenata), that can be exploited for development of novel bioinsecticides. Due to its larger size and low membrane permeability, this toxin usually has a slower mode of action compared to conventional small molecule insecticides. Nanoscale materials have unique optical, electrical, mechanical and biological properties, and show great application prospects for pesticide delivery.Results: The physical and chemical properties of nanocapsules were characterized using transmission electron microscopy, laser particle size analysis, Fourier transform infrared spectroscopy, contact angle testing and with a fluorescence spectrophotometer. The results indicated that the nanocapsules were spherical, with an average particle size of 197.70 nm, the encapsulation efficiency rate was 75.82% and the Zeta potential was −32.90 mV. Penetration experiments showed that the nanocapsules could promote protein passage through the intestinal tract of Spodoptera litura and reach the body fluid. Then we expressed ω-hexatoxin-Hvn1b by prokaryotic expression. Bioassay results showed that the oral toxicity of ω-hexatoxin-Hvn1b nanocapsules to S. litura was higher than that of the ω-hexatoxin-Hvn1b. Conclusion:In this paper, we reported a construction method of spider venom peptide nanocapsules based on polylactic-coglycolic acid by multiple emulsion for delivery of protein to improve the insecticidal effect and oral activity of ω-hexatoxin-Hv1a.

The overuse of copper-based fertilizers and pesticides over the last few decades has resulted in detrimental risks to our environment. Nano-enabled agrichemicals with a high effective utilization ratio have shown great potential for maintaining or minimizing environmental issues in agriculture. Copper-based nanomaterials (Cu-based NMs) serve as a promising alternative to fungicides. Three types of Cu-based NMs with different morphologies were analyzed for their different antifungal effects on Alternaria alternata in this current study. Compared to commercial copper hydroxide water power (Cu(OH)2 WP), all tested Cu-based NMs, including cuprous oxide nanoparticles (Cu2O NPs), copper nanorods (Cu NRs) and copper nanowires (Cu NWs), especially Cu2O NPs and Cu NWs, showed higher antifungal activity against Alternaria alternata. Its EC50 were 104.24 and 89.40 mg L−1, respectively, achieving comparable activity using a dose approximately 1.6 and 1.9-fold lower. Cu-based NMs could introduce the downregulation of melanin production and soluble protein content. In contrast to trends in antifungal activity, Cu2O NPs showed the strongest power in regulating melanin production and protein content and similarly exhibited the highest acute toxicity to adult zebrafish compared to other Cu-based NMs. These results demonstrate that Cu-based NMs could offer great potential in plant disease management strategies.

Based on high surface areas, adjustable porosity and microbicide activity, metal-organic frameworks (MOFs) HKUST-1 are widely used as drug release carriers for their slow degradation characteristics under slightly acidic conditions. In this work, porous HKUST-1 was reacted rapidly by cholinium salt (as the deprotonation agent and template) in an aqueous solution at room temperature. A novel antimicrobial system based on an imazalil encapsulated metal organic framework (imazalil IL-3@HKUST-1) was established. Imazalil IL-3@HKUST-1 could achieve synergism in inhibiting pathogenic fungi and bacteria. Moreover, six days after treatment, the slow and constant release of imazalil from imazalil IL@HKUST-1 exhibited better sustainability and microbicidal activity than imazalil. We believe that the method may provide a new strategy for related plant diseases caused by bacteria or fungi.