Antimicrobial Magnesium Hydroxide Nanoparticles As an Alternative to Cu Biocide for Crop Protection

Abstract

In agriculture, prolonged use of copper biocides increases the risk of development of Cu resistance and its accumulation in soil, demanding an alternative. In this paper, we report antimicrobial magnesium hydroxide nanoparticles (NPs) as an alternative to Cu biocides with low cytotoxicity. To improved bioavailability, Mg hydroxide NPs were synthesized followed by coating with water-soluble capping agents, trisodium citrate (zeta potential, ξ = -22 mV) or betaine (ξ = +35 mV). Electron microscopy study confirmed the formation of ∼10-nm-sized cubical NPs with citrate and ∼100-nm-sized lamellar NPs with betaine. As-synthesized Mg hydroxide NPs inhibited bacterial growth of X. alfalfae, P. syringae, and E. coli within 4 h. Significant bacterial growth inhibition and killing were observed at 24 h post-treatment. Phytotoxicity studies on tomato plants showed no significant tissue injury. Therefore, Mg hydroxide NPs have the potential to serve as a Cu alternative.

Copper-fixed quat: a hybrid nanoparticle for application as a locally systemic pesticide (LSP) to manage bacterial spot disease of tomato

“…Engineered nanomaterials (ENMs) are expected to offer some benets in food safety and production, 16 however a lot of unknowns remain. Metals and metalloids of Ag, 17,18 Ti, 19,20 Mg, 21,22 Zn, [23][24][25][26] Mn 27,28 have been studied as potential substitutes for Cu but the registration process of a new active is very cumbersome. In an effort to identify a short-term solution using the same Cu active ingredient, Strayer-Scherer et al demonstrated that ultra-small size Cu nanoparticles (NPs) can provide comparable protection against Cu-tolerant strains of X. perforans at Cu concentrations ve times lower than commercial formulations.…”

A Review of Metal and Metal-Oxide Nanoparticle Coating Technologies to Inhibit Agglomeration and Increase Bioactivity for Agricultural Applications

“…This paper reviews specialized coatings on metal and metal-oxide NP formulations for the purpose of inhibiting agglomeration and promoting targeted application. Metal and metal-oxide NPs are widely explored in agricultural applications because they may supply essential elements as fertilizers, and at higher doses, as pesticides [1][2][3][4][5][6][7]. Nanoscale silicon dioxide, copper oxide, and zinc oxide can support crops against drought and alleviate heavy metal contamination [8,9].…”

Effects of Magnesium Oxide and Magnesium Hydroxide Microparticle Foliar Treatment on Tomato PR Gene Expression and Leaf Microbiome

“…Recently, metal oxides (TiO 2 , ZnO, CuO, MgO, etc.) and magnesium hydroxide (MgOH) 2 nanoparticles (NPs) with high surface-to-volume ratios were shown to possess antibacterial properties, and these materials are finding applications in biomedicine and agriculture [4][5][6][7][8][9]. In the case of (Cu)-based antimicrobials, which are currently widely used by the agricultural sector for disease control, the trend is to minimize their usage due to potential toxicity and reduced effectiveness in several cases (EPA-HQOPP-2010-0212).…”