Plant Viral Nanocarrier Soil Mobility as a Function of Soil Type and Nanoparticle Properties

The use of nanoparticles for agrochemical delivery is an important step toward achieving global food security. Specifically, the ability to target the delivery of pesticides and other useful chemicals into the soil will greatly improve the efficiency and efficacy of these molecules, mitigating crop losses associated with pests and parasitic organisms. While synthetic nanoparticles can be a good delivery vehicle and demonstrate high mobility in the soil, their fate and persistence have some implications for human and environmental health. Therefore, using proteinaceous materials such as plant virus nanoparticles, which have already been adapted for the soil, provides a fruitful avenue of exploration. Previously, tobacco mild green mosaic virus (TMGMV) and red clover necrotic mosaic virus (RCNMV) have shown high soil mobility and nematicide delivery for the treatment of plant parasitic nematodes. To further the use of these plant virus nanoparticles in soil delivery applications, understanding the properties of the soil and the nanoparticles is essential. In this work, we assessed the mobility of TMGMV, potato virus X, and tobacco mosaic virus with a genetically encoded lysine on its surface (TMV-Lys) and virus-like particles of physalis mottle virus (PhMV) in four types of soil. The particles were loaded in a cylindrical column of soil, eluted, and analyzed for the protein signal. A mathematical model was used to compare their relative mobility. Data indicate that TMGMV has higher soil mobility compared to the other plant virus-based nanoparticles analyzed, and this appeared to be independent of the soil environment. Data indicate that the presence of a high-density lysine corona may not be favorable for soil applications. While this work provides insights into nanoparticle design rules for soil applications, data also highlight that more systemic studies are needed to delineate the design rules for soil delivery of nanocarriers.