The application of nanotechnology in agriculture has not yet been as thoroughly explored as its application in other fields such as medicine. However, nanoparticles have the potential to be used as smart delivery vehicles for a controlled and targeted delivery of biocides to treat and control the spread of diseases affecting plants.
Mesoporous silica nanoparticles (MSNPs) are biocompatible, biodegradable, stable, safe and cheap to produce. Additionally, MSNPs can be functionalised for targeted delivery and can be customised to encapsulate particular biocides. Furthermore, MSNPs have been previously reported to have mainly beneficial effects on plants such as improving tolerance to abiotic stress, enhancing plant growth and development, and increasing yields.
This study evaluated the use of MSNPs loaded with essential oils as a potential seed treatment against Pseudomonas syringae pv pisi, a phytopathogenic bacteria that causes pea bacterial blight. Essential oils can be highly antimicrobial and environmentally-safe but their volatility, easy degradability and poor miscibility hinders their use in agriculture. Hence, the encapsulation of these volatile compounds into MSNPs would facilitate their delivery and would enable a controlled release of the biocide.
The effect of essential oil-loaded MSNPs on P. syringae pv. pisi was studied in vitro and in planta. A decrease in live bacterial cells demonstrated the efficacy of the oil as an antimicrobial and the correct encapsulation of the oil into the nanoparticle. In addition, pea seeds coated with a seed treatment containing loaded-MSNPs showed a short-term increased plant resistance against the pathogenic bacteria. The capping of the MSNPs to achieve a targeted and long-term effect is currently being evaluated. This biocide-delivery system can be further applied to encapsulate other antimicrobials to treat a wide variety of agriculturally important bacterial and fungal diseases.