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Pyrroles and its fused forms possess antimicrobial activities, they can easily interact with biomolecules of living systems. A series of substituted pyrroles, and its fused pyrimidines and triazines forms have been synthesised, all newly synthesised compound structures were confirmed by spectroscopic analysis. Generally, the compounds inhibited growth of some important human pathogens, the best effect was given by: 2a, 3c, 4d on Gram-positive bacteria and was higher on yeast ( C. albican s), by 5c on Gram-negative bacteria and by 5a then 3c on filamentous fungi (A. fumigatus and F. oxysporum ). Such results present good antibacterial and antifungal potential candidates to help overcome the global problem of antibiotic resistance and opportunistic infections outbreak. Compound 3c gave the best anti-phytopathogenic effect at a 50-fold lower concentration than Kocide 2000, introducing a safe commercial candidate for agricultural use. The effect of the compounds on DNA was monitored to detect the mode of action.

Owing to the remarkable antimicrobial potential of these materials, research into the possible use of nanomaterials as alternatives to fungicides in sustainable agriculture is increasingly progressing. Here, we investigated the potential antifungal properties of chitosan-decorated copper oxide nanocomposite (CH@CuO NPs) to control gray mold diseases of tomato caused by Botrytis cinerea throughout in vitro and in vivo trials. The nanocomposite CH@CuO NPs were chemically prepared, and size and shape were determined using Transmission Electron Microscope (TEM). The chemical functional groups responsible for the interaction of the CH NPs with the CuO NPs were detected using the Fourier Transform Infrared (FTIR) spectrophotometry. The TEM images confirmed that CH NPs have a thin and semitransparent network shape, while CuO NPs were spherically shaped. Furthermore, the nanocomposite CH@CuO NPs ex-habited an irregular shape. The size of CH NPs, CuO NPs and CH@CuO NPs as measured through TEM, were approximately 18.28 ± 2.4 nm, 19.34 ± 2.1 nm, and 32.74 ± 2.3 nm, respectively. The antifungal activity of CH@CuO NPs was tested at three concentrations of 50, 100 and 250 mg/L and the fungicide Teldor 50% SC was applied at recommended dose 1.5 mL/L. In vitro experiments revealed that CH@CuO NPs at different concentrations significantly inhibited the reproductive growth process of B. cinerea by suppressing the development of hyphae, spore germination and formation of sclerotia. Interestingly, a significant control efficacy of CH@CuO NPs against tomato gray mold was observed particularly at concentrations 100 and 250 mg/L on both detached leaves (100%) as well as the whole tomato plants (100%) when compared to the conventional chemical fungicide Teldor 50% SC (97%). In addition, the tested concentration 100 mg/L improved to be sufficient to guarantee a complete reduction in the disease's severity (100%) to tomato fruits from gray mold without any morphological toxicity. In comparison, tomato plants treated with the recommended dose 1.5 mL/L of Teldor 50% SC ensured disease reduction up to 80%. Conclusively, this research enhances the concept of agro-nanotechnology by presenting how a nano materials-based fungicide could be used to protect tomato plants from gray mold under greenhouse conditions and during the postharvest stage. [ABSTRACT FROM AUTHOR]

RNAi technique was used to regulate Fusarium crown and root rot in tomatoes caused by F. oxysporum f. sp. radicis-lycopersici (FORL), by targeting three essential genes namely FoCYP51, FoChs1, and FoEF2, considering the fungicide site of action. The designed naked dsRNA was delivered on a hexagonal mono-dispersed and biodegradable layered double hydroxide (LDH) nanosheets with 30–90 nm diameter, providing high protection and stability for dsRNA with long term sustained release manner inside plant cells. The laboratory findings revealed the functional role of the three selected genes in reducing FORL's invasive growth on tomato fruits, indicating their involvement in FORL pathogenesis on tomatoes, and could be good targets for disease control using RNAi. Three different practical methods were applied for topical delivery of dsRNA into the plant cells: i) leaves spray; ii) petiole adsorption; and iii) root dipping, demonstrating three significant levels of spray-induced gene silencing (SIGS) efficacy in controlling FORL virulence infecting tomato plants. Significantly, topical spray of dsRNA delivered on LDH nanosheets provided Fusarium crown and root rot protection for at least 60 days. Obtained findings introduce critical information data on the potential to exploit spray-induced gene silencing (SIGS) as an effective alternative sustainable strategy for plant disease management. Given the ease design and production of biodegradable nano-delivery systems with high specificity and sustainability, and ease of applicability against many disease caused fungi. The use of target-specific dsRNA as an anti-fungal agent has a lot of promise and provide exceptional potential as a unique disease control and plant protection strategy. • Fusarium crown and root rot disease is affecting most of the tomato-growing areas worldwide. • Potential use of LDH nanosheets to deliver dsRNA molecules was investigated. • SIGS, as an eco-friendly and sustainable solution to synthetic fungicides was confirm. • FoCYP51, FoChs1, and FoEF2 genes were silenced through RNAi constructs. • LDH nanosheets were functionalized as a carrier system to deliver dsRNA molecules into plants. [ABSTRACT FROM AUTHOR]