Exigent carbon nanodots for trapping 6-thioguanine to resist fire blight caused by Erwinia amylovora in an orchard

Abstract

Fire blight, an extremely disastrous plant disease caused by the bacterium Erwinia amylovora, has the capacity to wipe out entire orchards in just one growing season when ideal conditions are present. A recent discovery has revealed that 6-thioguanine (6TG) plays a significant role in the development of fire blight caused by the plant pathogen. Therefore, it is of utmost importance to effectively prevent and manage fire blight in order to ensure the health and productivity of these fruit trees. In this research, we have developed a novel and significant approach focusing on trapping 6TG to disrupt the spreading of fire blight among trees. We have developed carbon quantum dots (N-CQDs) that efficiently bind 6TG through a fluorescence quenching process resulting in the alleviation of the disease. The quenching mechanism and related phenomena have been extensively elucidated through the implementation of analytical tools including the Stern–Volmer plot, UV-vis spectroscopy, fluorescence titration, and fluorescence lifetime decay analysis. Furthermore, the structural attributes and size of the nitrogen-doped carbon quantum dots (N-CQDs) have been definitively established through a comprehensive array of techniques, including Fourier-transform infrared (FT-IR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX, EM), and X-ray Photoelectron Spectroscopy (XPS). The nanodot has been successfully applied in guava saplings (Psidium guajava) to investigate the trapping of 6TG by treating them with N-CQDs. This process has been validated through the use of confocal microscopic imaging, providing visual confirmation of the 6TG trapping mechanism.