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Abstract Bacterial canker disease caused by Clavibacter michiganensis is a substantial threat to the cultivation of tomatoes, leading to considerable economic losses and global food insecurity. Infection is characterized by white raised lesions on leaves, stem, and fruits with yellow to tan patches between veins, and marginal necrosis. Several agrochemical substances have been reported in previous studies to manage this disease but these were not ecofriendly. Thus present study was designed to control the bacterial canker disease in tomato using green fabricated silver nanoparticles (AgNps). Nanosilver particles (AgNPs) were synthesized utilizing Moringa oleifera leaf extract as a reducing and stabilizing agent. Synthesized AgNPs were characterized using UV–visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and Fourier transform infrared spectrometry (FTIR). FTIR showed presence of bioactive compounds in green fabricated AgNPs and UV-visible spectroscopy confirmed the surface plasmon resonance (SPR) band in the range of 350 nm to 355 nm. SEM showed the rectangular segments fused together, and XRD confirmed the crystalline nature of the synthesized AgNPs. The presence of metallic silver ions was confirmed by an EDX detector. Different concentrations (10, 20, 30, and 40 ppm) of the green fabricated AgNPs were exogenously applied on tomato before applying an inoculum of Clavibacter michigensis to record the bacterial canker disease incidence at different day intervals. The optimal concentration of AgNPs was found to be 30 µg/mg that exhibited the most favorable impact on morphological (shoot length, root length, plant fresh and dry weights, root fresh and dry weights) and physiological parameters (chlorophyll contents, membrane stability index, and relative water content) as well as biochemical parameters (proline, total soluble sugar and catalase activity). These findings indicated a noteworthy reduction in biotic stress through the increase of both enzymatic and non-enzymatic activities by the green fabricated AgNPs. This study marks a first biocompatible approach in assessing the potential of green fabricated AgNPs in enhancing the well-being of tomato plants that affected with bacterial canker and establishing an effective management strategy against Clavibacter michiganensis. This is the first study suggests that low concentration of green fabricated nanosilvers (AgNPs) from leaf extract of Moringa oleifera against Clavibacter michiganensis is a promisingly efficient and eco-friendly alternative approach for management of bacterial canker disease in tomato crop.

Bacterial canker disease caused by Clavibacter michiganensis is a substantial threat to the cultivation of tomatoes, leading to considerable economic losses and global food insecurity. Infection is characterized by white raised lesions on leaves, stem, and fruits with yellow to tan patches between veins, and marginal necrosis. Several agrochemical substances have been reported in previous studies to manage this disease but these were not ecofriendly. Thus present study was designed to control the bacterial canker disease in tomato using green fabricated silver nanoparticles (AgNps). Nanosilver particles (AgNPs) were synthesized utilizing Moringa oleifera leaf extract as a reducing and stabilizing agent. Synthesized AgNPs were characterized using UV–visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and Fourier transform infrared spectrometry (FTIR). FTIR showed presence of bioactive compounds in green fabricated AgNPs and UV-visible spectroscopy confirmed the surface plasmon resonance (SPR) band in the range of 350 nm to 355 nm. SEM showed the rectangular segments fused together, and XRD confirmed the crystalline nature of the synthesized AgNPs. The presence of metallic silver ions was confirmed by an EDX detector. Different concentrations (10, 20, 30, and 40 ppm) of the green fabricated AgNPs were exogenously applied on tomato before applying an inoculum of Clavibacter michigensis to record the bacterial canker disease incidence at different day intervals. The optimal concentration of AgNPs was found to be 30 µg/mg that exhibited the most favorable impact on morphological (shoot length, root length, plant fresh and dry weights, root fresh and dry weights) and physiological parameters (chlorophyll contents, membrane stability index, and relative water content) as well as biochemical parameters (proline, total soluble sugar and catalase activity). These findings indicated a noteworthy reduction in biotic stress through the increase of both enzymatic and non-enzymatic activities by the green fabricated AgNPs. This study marks a first biocompatible approach in assessing the potential of green fabricated AgNPs in enhancing the well-being of tomato plants that affected with bacterial canker and establishing an effective management strategy against Clavibacter michiganensis. This is the first study suggests that low concentration of green fabricated nanosilvers (AgNPs) from leaf extract of Moringa oleifera against Clavibacter michiganensis is a promisingly efficient and eco-friendly alternative approach for management of bacterial canker disease in tomato crop. [ABSTRACT FROM AUTHOR]

AbstractRecent years have witnessed a growing embrace of green chemistry for nanoparticle manufacturing due to its time and energy efficiency compared to conventional methods. This research aimed to biosynthesize zinc oxide nanoparticles (ZnO NPs) using environmentally friendly aqueous extracts from Malva neglecta leaves and seeds as reducing and stabilizing agents. Various analytical methods, including UV–Vis spectrophotometry, FTIR, XRD, TGA, EDX, and TEM, confirmed the synthesis and characterization of ZnO NPs. Their antioxidant activity was assessed using the DPPH assay, while antibacterial properties were examined against S. aureus and E. coli, along with determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. FTIR spectra indicated ZnO bonding and surfactant molecule adsorption on ZnO NPs’ surface. TEM revealed spherical and hexagonal ZnO NPs with an average size of 40–50 nm. This green synthesis method with Malva neglecta extracts is eco-friendly, cost-effective, and safe, producing antibacterial nanoparticles without adverse effects. [ABSTRACT FROM AUTHOR]

A versatile economically viable method for green fabricated gold nanoparticles (AuNPs) using almond hull has been developed. The bioactive components such as catechins, vanillic acid and other polyphenols in almond hull extract (AHE) act as reducing as well as stabilizing agents for the synthesis of AuNPs. The resulting AHE–AuNPs were examined by several confirmation tools such as nanodrop spectrophotometer (NDS), Fourier transform infrared spectroscopy, scanning electron microscopy (SEM)-energy dispersive X-ray and high-resolution transmission electron microscopy. Moreover, the futuristic application of AuNPs was described for selective and ultrasensitive assay of Pb(II) ions by using NDS. In the presence of Pb(II) (0.2–1.0 ppm), the absorbance of AuNPs drop linearly and might be prompted to aggregate with colour changes instantaneously. The absorption ratio (A664/A522) of AuNPs displayed a linear correlation coefficient (r2) of 0.9887 with 1.1% relative standard deviation and the limit of detection was 0.163 ppm. The co-existing ions do not interfere even in the absence of masking agents. Hence, the synthesized AuNPs were also used as an efficient probe for the quick and facile determination of Pb(II) in the real water samples via NDS. [ABSTRACT FROM AUTHOR]