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

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