Chitosan nanoparticle encapsulation of celery seed essential oil: Antifungal activity and defense mechanisms against cucumber powdery mildew
Hajar Soleimani, Reza Mostowfizadeh‐Ghalamfarsa, Afsaneh Zarei
Abstract
The objective of the current study was to explore the antifungal potential of celery seed essential oil (CSEO) in a nano-carrier system against Podosphaera fusca, the causal agent of cucumber powdery mildew. We assessed the physicochemical characterization of CSEO-loaded chitosan nanoparticles (CSEO-LCNPs) using dynamic light scattering, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. The successful loading of various concentrations of CSEO into chitosan nanoparticles (1:0, 1:0.25, 1:0.5, 1:0.75, and 1:1) has been verified. The particles exhibited a spherical shape, with an average diameter of 113 nm, and a negatively charged surface with a zeta potential of -31.5 mV. The Korsmeyer-Peppas model well described the release behavior of CSEO from nanoparticles. Additionally, we examined the defense mechanism, as well as biochemical/molecular responses following foliar treatment with CSEO-LCNPs. In vivo, results revealed that CSEO-LCNPs foliar application on the cucumber seedlings inoculated with P. fusca significantly reduced the disease severity of powdery mildew. Treatment with CSEO-LCNPs led to an increase in phenolic and flavonoid compounds, chlorophyll concentration, enzyme activities, and gene transcriptions in inoculated cucumber seedlings. In our study, we observed a positive correlation between antioxidant compounds and the defense-associated enzymes as well as their corresponding gene expressions. Our study underscores the potential of CSEO-LCNPs as an eco-friendly and effective solution for managing cucumber powdery mildew.