Hormesis-Inducing Essential Oil Nanodelivery System Protects Plants against Broad Host-Range Necrotrophs.

Botrytis cinerea, a broad host-range necrotrophic (BHN) phytopathogen, establishes compatible interactions with hosts by deploying multigene infection strategies, rendering simply inherited resistance ineffective to fight off this pathogen. Since essential oils (EOs) serve as intermediators during phytobiome communication, we hypothesize that they have the potential to enhance the quantitative disease resistance against BHN by eliciting the adaptive stress response (hormesis) in plants. However, using EOs is challenging due to their poor solubility in water. Nanoemulsification of EOs enhances not only the solubility of EOs but also their potency and stability. Here, we demonstrate the potential use of essential oil nanoemulsions (EONEs) to control infections caused by BHN. Using basic engineering principles of nanocarrier design, we demonstrate the efficacy of a robust EONEs design for controlling B. cinerea infection in a model plant, Arabidopsis thaliana. Our nanoemulsion delivery system significantly enhanced the disease resistance of the host by reducing the necrotic area by up to 50% compared to untreated plants. RNA-seq analysis indicated that successful treatments upregulated autophagy, ROS scavenging, and activation of the jasmonic acid signaling pathway.