CarboTag: a modular approach for live and functional imaging of plant cell walls

Plant cells are contained inside a rigid network of cell walls. Cell walls are highly dynamic structures that act both as a structural material and as a hub for a wide range of signaling processes. Despite its crucial role in all aspects of the plant life cycle, live dynamical imaging of the cell wall and its functional properties has remained challenging. Here, we introduce CarboTag, a modular toolbox for live functional imaging of plant walls. CarboTag relies on a small molecular motif, a pyridine boronic acid, that targets its cargo to the cell wall, is non-toxic and ensures rapid tissue permeation. We designed a suite of cell wall imaging probes based on CarboTag in any desired color for multiplexing. Moreover, we created new functional reporters for live quantitative imaging of key cell wall features: network porosity, cell wall pH and the presence of reactive oxygen species. CarboTag opens the way to dynamical and quantitative mapping of cell wall responses at subcellular resolution.