Fluorinated Plant Activators Induced Dual-Pathway Signal Transduction and Long-Lasting ROS Burst in Chloroplast

Abstract

Synthetic plant activators represent a promising novel class of green pesticides capable of triggering endogenous plant immunity against pathogen invasion. In our previous study, a series of fluorinated compounds that can elicit disease resistance in plants has been developed; however, the underlying regulatory mechanisms remained elusive. In this study, we conducted a systematic investigation into the mechanism of plant immune activation using four synthetic plant activators in Arabidopsis thaliana (A. thaliana), including two fluorine-substituted molecules and two non-fluorine-substituted molecules. Our findings revealed that the fluorinated compounds exhibited superior disease resistance activity compared to the other two molecules. Analysis of gene expression levels in systemic acquired resistance (SAR)- and induced systemic resistance (ISR)-related pathways demonstrated that fluorine substitution could effectively regulate both SAR- and ISR-pathway activation, highlighting the distinct roles of fluorine substitution in modulating the plant immune system. Notably, prolonged ROS burst was observed at chloroplasts following treatment with all four plant activators, contrasting with the transient ROS burst induced by natural elicitors treatment. These results provide insights into the unique mechanisms underlying synthetic plant activator-induced plant immunity. Furthermore, the induced immune activation of A. thaliana was analyzed through comprehensive proteomic analysis, revealing a robust immune response mediated by fluorine-substituted plant activators. These findings offer novel insights into the role of fluorinated substitution in SAR- and ISR-associated immune signaling pathways and their distinct impact on ROS production within chloroplasts.

Keywords: plant activator, systemic acquired resistance, induced systemic resistance, plant immune system