Paper-Based Analytical Devices for the Rapid and Direct Electrochemical Detection of Hydrogen Peroxide in Tomato Leaves Inoculated with Botrytis cinerea

Hydrogen peroxide (H2O2) is an important signaling molecule and plays key roles in multiple plant physiological processes. The rapid and direct monitoring of H2O2 could improve our understanding of its regulatory mechanisms in plants. In this study, we developed a paper-based analytical device consisting of a disposable nano-gold modified indium tin oxide working electrode to provide a platform for the rapid and direct detection of H2O2. The total analytical time was dramatically shortened to be approximate 3 min due to the avoidance of the time-consuming and complex treatment of plant samples. In addition, the amount of plant samples required was less than 3 mg in our approach. We used this system to monitor the concentrations of H2O2 in tomato leaves infected by Botrytis cinerea within 24 h. Our results showed that the concentration of H2O2 in tomato leaves was increased in the initial phase, peaked at 1.5 mu mol gFW(-1) at 6 h, and then decreased. The production trend of H2O2 in tomato leaves inoculated with Botrytis cinerea detected with our approach is similar to the 3,3-diaminobenzidine staining method. Taken together, our study offers a rapid and direct approach for the detection of H2O2, which will not only pave the way for the further investigation of the regulation mechanisms of H2O2 in plants, but also promote the development of precision agriculture technology.