Simple Phenotypic Sensor for Visibly Tracking H₂O₂ Fluctuation to Detect Plant Health Status

Abstract

Hydrogen peroxide (H2O2), as a main component of reactive oxygen species (ROS), serves as a key signaling molecule relevant to plant stress response and health status. Many strategies have been developed for detecting or quantifying H2O2 concentration. However, reports on simply, visibly tracking H2O2 fluctuation in vivo are limited. Here, for visibly tracking the plant H2O2 wave, a green fluorescent phenotypic probe was designed by merging a H2O2-sensitive tertiary amine moiety with the core fluorophore tetraphenylethene skeleton. The green fluorescence emission is quenched up to 52% by H2O2 with good sensitivity, selectivity, and reversibility within the plant physiological range of 10–100 μM H2O2. In response to various abiotic stresses, including mechanical damage, high salt, strong light and drought, fluorescence fluctuations, response to H2O2 concentration alterations in vivo was visible to the naked eye under irradiation of commercially available UV light (365 nm) after simple injection of this H2O2 probe solution into seedling leaves. This phenotypic fluorescent H2O2 probe illustrates great potential as early sensors of plant health under stress without the aid of skillful operation and specialized equipment.