Biocompatible antiviral Pickering emulsion-based formulation for plant root protection from tobamovirus-infected soil

The soil-borne virus known as tomato brown rugose fruit virus (ToBRFV) has a low rate of around 3% soil-mediated infection when the soil has root debris from a previous 30-50 day development cycle of tomato plants infected with ToBRFV. This study presents anti-viral coating formulations based on Pickering emulsion. The coating formulation is based on water-in-canola oil emulsions stabilized using commercial hydrophobic silica, with water-soluble polymer (sodium polyacrylic acid). The structure of the emulsions and their stability were characterized by confocal microscopy, centrifugal analysis using a LUMiSizer (R), used to confirm the emulsion stability. We tested a few different silica concentration-based formulations, which were prepared with or without the addition of various virus disinfectants. We found that under conditions of 100% soil-mediated ToBRFV infection of uncoated positive control plants, root-coating with formulations based on silica Pickering emulsion were prepared with the disinfectant chlorinated-trisodium phosphate (TSP-Cl) showed low percentages of soil-mediated ToBRFV infection. These formulations had no adverse effect on plant growth parameters when compared to negative control plants grown under non ToBRFV inoculation conditions.