Seminarios IHSM La Mayora - Elwira Smakowska-Luzan (University of Wageningen)

Redox-mediated receptor kinase signalling in plants Cellular processes in plants are tightly regulated by extracellular Receptor Kinases (RKs), which play a crucial role in perceiving and relaying signals for stress responses and developmental processes. An intriguing aspect of RK activation is the generation of extracellular Reactive Oxygen Species (ROS), which function as signalling molecules to amplify and relay stress or developmental signals. The presented work explores the modulatory role of ROS on the interaction networks of the Cysteine-Rich Receptor-Like Kinases (CRKs) by generating a large redox-dependent interactome assay (RIACRK) between ectodomains of CRKs. Parallelly, a map of oxidative modifications of the CRK extracellular domains (ECDs) was generated. These findings suggest that ROS modulate CRK interactions through direct chemical modifications on the cysteine residues of CRK ECDs.  Multilayer filtering of the RIACRK networks by CRK expression pattern, oxidative modification signature and ROS modulation of interactions facilitates candidate selection. Using this approach and the available literature, CRK28 was selected for further in planta validation studies. Combining physiological measurements, proteomics and phosphoproteomics studies revealed a strong association between CRK28 and processes with elevated ROS production, such as senescence and defence responses. This study sheds light on the intricate interplay between RKs, ROS signalling, and CRK-mediated cellular responses, offering new insights into the regulatory mechanisms governing plant stress responses and developmental processes.