Developing a quantum dot nanotracker for endophytic bacteria translocation in plants

Abstract

Endophytes are bacteria that have been shown in previous studies to promote plant growth without eliciting any sign of infection or plant disease, as well as promote bio-fortification and has thus gained much attention in agriculture. However, due to the limited confirmatory visual evidence of the in planta presence of bacteria, the significance of this plant-endophyte interaction has not been comprehensively understood. The aim of this study was to synthesise quantum dots to track the translocation of endophytes in a plant. Conventional methods track endophytes by transformation of green fluorescent protein which has the problem of fluorophore bleaching and blinking reducing detectability. Quantum dots (QDs) offer distinct advantages over organic dyes and fluorescent proteins for biological imaging applications because of their brightness, photostability, tunability and their extremely small size ensures little to no interference with the normal functions of the bacterium. This project required the synthesis of cadmium telluride QDs to be capped with mercaptopropionic acid thus making them biocompatible and the subsequent characterization techniques were performed. CdTe and Carbon QDs were transformed into the endophytic bacteria and were thereafter used to treat Brassica napus L plants. Physiological and biochemical assays were done to detect the effect of QDs on the plant and bacteria, respectively.