Abstract text: The plant cell wall is a dynamic and structurally complex interface that orchestrates key biological processes including growth, morphogenesis, stress adaptation, immunity and symbiosis. To gain deeper insights into these processes we need tools to observe cell wall structure and physicochemical properties, especially in vivo. Here we will present a palette of advanced fluorescence bioimaging tools to achieve these goals. 
We will discuss the application of single particle tracking using photoconvertible fluorescence proteins to follow the dynamics of cell wall modification and assembly in vivo. We will also present development of genetically-expressed FLIM-based (Fluorescence Life time Imaging Microscopy) sensors and markers to follow in vivo physicochemical properties of the cell wall. Finally, we will discuss the perspective of cell wall-localized optogenetic actuators.
All these techniques require fluorescence markers that resist the extreme physico-chemical environment of the cell wall while having a minimal impact on cell wall function. This imposes important constraints on the applicability of fluorescent proteins in this context. The limitations and perspectives for cell wall localized fluorescence markers will be presented. Finally, we will compare fixed sample to in vivo super-resolution imaging.