Development of a rapid multiplex detection method for analysing plant stress hormones ACC and ABA using a fiber-optic SPR biosensor

Plant hormones play a crucial role in steering developmental processes and controlling responses towards (a)biotic stressors. For example, drought, salinity, and flooding stress evoke ethylene (by its precursor ACC) and abscisic acid (ABA) root-to-shoot signalling via the xylem to activate survival responses of the shoot. Especially with the advent of climate change, early stress detection is critical to prevent agricultural losses and breed stress-resistant cultivars. Therefore, a rapid and cost-effective method to simultaneously detect ACC and ABA in plant extracts or xylem sap exudates would revolutionize the field of plant stress diagnostics. In this project, we will develop an immuno-based multiplex biosensor based on state-of-the-art fiber optic surface plasmon resonance (FO-SPR). This technology, proven in medical diagnostics, will be retrofitted for plant applications. We will develop a competitive inhibition bioassay using antibodies against ACC and ABA. This multiplex biosensor will be optimized in buffer conditions and validated in plant extracts. Furthermore, we will develop a noninvasive xylem sap sampling technique to enable picomolar ACC and ABA detection in the transpiration stream of plants facing abiotic stress. This novel FO-SPR hormone biosensor will become a true alternative for cumbersome and expensive analytical techniques (e.g. HPLC-MS/MS) and revolutionize the field of plant hormone biology.