Seed Infiltration with Polymer-Functionalized Carbon Dots Induces a Biotic Stress Response in Tomato (<i>Solanum lycopersicum</i> L.)

Global food security is a pressing issue in our society. Maintaining food security in coming years will require improving crop yield, as well as increased resiliency to abiotic and biotic stress. Nanoscale materials have increasingly been proposed as a tool which could be used to meet these challenges. However, much research is needed to optimize nanoparticle design and crop application for this to become a reality. In this study, we investigated the impact of polymer-functionalized carbon dots on tomatoes (Solanum lycopersicum L.). Tomato seeds were vacuum infiltrated with carbon dots and then grown for 3 weeks before collection of phenotypic and transcriptomic data. No changes to fresh biomass or chlorophyll content were observed, indicating that these particles can be applied without overt harm to the plant at early growth stages. In addition, changes in gene expression suggest that polymer-functionalized carbon dots can initiate the expression of biochemical pathways associated with a pathogen resistance response in tomato plants. Specifically, genes involved in ethylene signaling, ethylene production, and camalexin synthesis were upregulated. These findings suggest that seed priming with carbon dots may improve plant tolerance to biotic stress by modulating ethylene signaling pathways. Carbon dots could also be loaded with nutrients or other agrochemicals to create a multifunctional platform. Future work should focus on understanding the mechanisms by which nanoparticles can modulate ethylene signaling, enabling use of this knowledge to develop sustainable and effective nanoparticles for agricultural applications.