Bactericides Based on Copper Nanoparticles Restrain Growth of Important Plant Pathogens

Abstract

Copper nanoparticles (CuNPs) can offer an alternative to conventional copper bactericides and possibly slow down the development of bacterial resistance. This will consequently lower the accumulation rate of copper to soil and water and lower the environmental and health burden imposed by copper application. Physical and chemical methods have been reported to synthesize CuNPs but their use as bactericides in plants has been understudied. In this study, two different CuNPs products have been developed, CuNP1 and CuNP2 in two respective concentrations (1500 ppm or 300 ppm). Both products were characterized using Dynamic Light Scattering, Transmission Electron Microscopy, Attenuated Total Reflection measurements, X-ray Photoelectron Spectroscopy, X-ray Diffraction and Scattering, and Laser Doppler Electrophoresis. They were evaluated for their antibacterial efficacy in vitro against the gram-negative species Agrobacterium tumefaciens, Dickeya dadantii, Erwinia amylovora, Pectobacterium carotovorum, Pseudomonas corrugata, Pseudomonas savastanoi pv. savastanoi, and Xanthomonas campestris pv. campestris. Evaluation was based on comparisons with two commercial bactericides: Kocide (copper hydroxide) and Nordox (copper oxide). CuNP1 inhibited the growth of five species, restrained the growth of P. corrugata, and had no effect in X. c. pv campestris. MICs were significantly lower than those of the commercial formulations. CuNP2 inhibited the growth of E. amylovora and restrained growth of P. s. pv. savastanoi. Again, its overall activity was higher compared to commercial formulations. An extensive in vitro evaluation of CuNPs that show higher potential compared to their conventional counterpart is reported for the first time and suggests that synthesis of stable CuNPs can lead to the development of low-cost sustainable commercial products.

Synthesis and Characterization of Novel Copper Nanoparticles for the Control of Leaf Spot and Anthracnose Diseases of Olive

“…The ATR method was utilized to detect the characteristic peaks of CuNPs. ATR spectra of CuNPs Types 1 and 2 presented similar stretching and bending frequencies to a previous study within our group [5], showing, in brief, the presence of four characteristic bands of stabilizer S1 as well as the symmetrical stretching and bending vibration of Cu-O bond (CuNP Type 1). In the same context, ATR spectrum of CuNP Type 2 indicated that copper oxide and copper hydroxide are the prevalent copper species and presented the six characteristic peaks of stabilizer S2.…”

“…The synthesized CuNPs presented a mean diameter range between 4.90 and 10.41 nm. The narrow size distribution and small size ensure a higher antimicrobial activity [ 5 ]. The resulted CuNPs were characterized among the lowest diameters reported in the literature [ 12 , 41 , 42 , 43 ].…”

“…Four types of Cu-based NPs were synthesized with a modified wet chemistry approach [ 5 ]. An overview of the process is being provided here, so as to ease the interpretation of the results and exhibit variations to the tested Cu types initially presented [ 5 ].…”

“…During the last two decades, engineered nanomaterials have attracted great experimental and research interest for applications in agriculture that include the delivery of genetic material, nutrients, and pesticides, the stabilization of biopesticides, and the development of nanobiosensors for pathogen detection or pesticide sensing [ 1 , 2 ]. Until now, several metal (silver, zinc, copper, magnesium, titanium) nanoparticles have been synthesized and evaluated for their antimicrobial activity against fungal and bacterial plant pathogens [ 3 , 4 , 5 ], while in other cases, nanoparticles have been utilized as carriers of conventional organic fungicides [ 6 ]. Most of the developed nanoproducts can be an excellent tool to reduce pesticide input into the environment by application at low dosages, since they ensured efficacy against the tested targets equal or higher to than that of commercially available conventional pesticides.…”

Direct Antibiotic Activity of Bacillibactin Broadens the Biocontrol Range of Bacillus amyloliquefaciens MBI600

“…The Pseudomonas syringae pv. tomato susceptibility test against B. amyloliquefaciens MBI600 was performed in 96-well microplates (Greiner CELLSTAR 96-well microplates, F-bottom) as previously described ( 73 , 74 ). In brief, P. syringae pv.…”