Abstract The oxidation of molten silicon powder in a high‐temperature suspension phase represents a promising technique for the continuous production of spherical silica. However, the agglomeration of silicon powder at high temperatures increases particle size and reduces reactant surface area, ultimately slowing the oxidation rate and disrupting the suspension state, leading to failed silica preparation. To address these issues, a pre‐oxidation step was implemented, whereby an oxide layer was created on the silicon powder. This was done to prevent molten silicon from agglomerating. This paper investigates the effect of pre‐oxidation time and melting temperature on the generation of spherical silica using a static suspension method. The 5 µm average‐sized silicon powder underwent pre‐oxidation at 1300°C for 30 min, followed by oxidation at the silicon's melting point. This resulted in amorphous spherical silica, ranging from 200 to 400 nm. Pre‐oxidation results in a Si@SiO 2 core–shell structure, which effectively prevents molten silicon agglomeration and significantly enhances particle oxidation rates. These findings lay the foundation for scaled‐up production of spherical silica using the airflow suspension method.
Abstract Background Viral diseases continue to pose a major threat to the world’s commercial crops. The in-depth exploration and efficient utilization of resistance proteins have become crucial strategies for their control. However, current delivery methods for introducing foreign DNA suffer from host range limitations, low transformation efficiencies, tissue damage, or unavoidable DNA integration into the host genome. The nanocarriers provides a convenient channel for the DNA delivery and functional utilization of disease-resistant proteins. Results In this research, we identified a cysteine-rich venom protein (NbCRVP) in Nicotiana benthamiana for the first time. Virus-induced gene silencing and transient overexpression clarified that NbCRVP could inhibit the infection of tobacco mosaic virus, potato virus Y, and cucumber mosaic virus, making it a broad-spectrum antiviral protein. Yeast two-hybrid assay, co-immunoprecipitation, and bimolecular fluorescence complementation revealed that calcium-dependent lipid-binding (CaLB domain) family protein (NbCalB) interacted with NbCRVP to assist NbCRVP playing a stronger antiviral effect. Here, we demonstrated for the first time the efficient co-delivery of DNA expressing NbCRVP and NbCalB into plants using poly(amidoamine) (PAMAM) nanocarriers, achieving stronger broad-spectrum antiviral effects. Conclusions Our work presents a tool for species-independent transfer of two interacting protein DNA into plant cells in a specific ratio for enhanced antiviral effect without transgenic integration, which further demonstrated new strategies for nanocarrier-mediated DNA delivery of disease-resistant proteins. Graphical abstract
Nanoparticles (NPs) derived from RNA interference (RNAi) are considered a potentially revolutionary technique in the field of plant protection in the future. However, the application of NPs in RNAi is hindered by the conflict between the high cost of RNA production and the large quantity of materials required for field application. This study aimed to evaluate the antiviral efficacy of commercially available nanomaterials, such as chitosan quaternary ammonium salt (CQAS), amine functionalized silica nano powder (ASNP), and carbon quantum dots (CQD), that carried double-stranded RNA (dsRNA) via various delivery methods, including infiltration, spraying, and root soaking. ASNP-dsRNA NPs are recommended for root soaking, which is considered the most effective method of antiviral compound application. The most effective antiviral compound tested was CQAS-dsRNA NPs delivered by root soaking. Using fluorescence, FITC-CQAS-dsCP-Cy3, and CQD-dsCP-Cy3 NPs demonstrated the uptake and transport pathways of dsRNA NPs in plants when applied to plants in different modes. The duration of protection with NPs applied in various modes was then compared, providing references for evaluating the retention period of various types of NPs. All three types of NPs effectively silenced genes in plants and afforded at least 14 days of protection against viral infection. Particularly, CQD-dsRNA NPs could protect systemic leaves for 21 days following spraying.
Crops can greatly benefit from the use of nanoparticles to suppress phytopathogens and promote plant growth. This work looks into the physiochemical changes that occur in wheat under biotic stress caused by Bipolaris sorokiniana, using myco-synthesized zinc oxide nanoparticles (ZnO-NPs) synthesized from Chlorophyllum molybdites mushroom. The myco-synthesized ZnO-NPs were characterized prior to its application. The average size of the nanoparticles produced was calculated to be 45 nm and the element content was determined by Energy dispersive X‑Ray (EDX) to be 52.7% Zn and 26.4% oxygen. ZnO-NPs were applied as a foliar spray on wheat plants (Pakistan-2013 variety) at concentrations of 20 mg/L, 30 mg/L, 40 mg/L, and 50 mg/L to reduce the impacts of B. sorokiniana. Among these, the 50 mg/L concentration of ZnO-NPs was most efficient in controlling the spot blotch severity and improving morphological, physiological, and biochemical parameters, as well as antioxidant activity in wheat plants. The 50 mg/L significantly increased plant height (75.6 cm), shoot length (68.5 cm), leaf surface area (34.6 cm), shoot dry weight (0.2 g), and root dry weight (0.25 g) while the chlorophyll a (26.542), chlorophyll b (35.768 mg/g), total chlorophyll content (70.23), carotenoid content (5.21) and relative water content (80.55) in treated plant. The results also indicated that ZnO-NPs applied at a concentration of 50 mg/L significantly increased the proline content (415.2 mg/g), soluble sugar content (120.54) and protein content (350.76). The addition of 50 mg/L ZnO-NPs considerably improved the overall health and resistance of the wheat cultivar. This study reveals the significance of myco-mediated ZnO-NPs in increasing wheat resistance to B. sorokiniana, providing important insights for disease management in wheat and also promoting the growth parameters and metabolic aspects.
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