Abstract text: When plants die, so do we – eventually. As climate change leads to more extreme weather, including droughts and floodings, it is crucial to understand how plants sense water and cope with cell wall damage to ensure resilient agriculture and ecosystems. At the cell wall-plasma membrane-continuum, environmental cues and information about cell wall integrity (CWI) are communicated to the plant, resulting in adaptive responses. The receptor kinase THESEUS1 (THE1) is a central component of this cell wall integrity maintenance system. Interestingly, THE1 reacts to cell wall damage as well as hyperosmotic conditions (mimicking drought stress) and plays a dual role in plant hormone regulation: THE1 acts as positive regulator of jasmonic acid and negative regulator of abscisic acid.

To elucidate the role of THE1 in CWI maintenance, we expressed different GFP-tagged versions of THE1 and performed pulldown assays under cell wall damage and hyperosmotic stress conditions. We identified various proteins interacting with wildtype, truncated or mutated versions of THE1, providing insight into the molecular mechanism of THE1. Moreover, the two treatments revealed two distinct sets of interactors.  Hereby, we revealed specific stress responses and identified novel direct interactors in THE1-dependent signalling cascades allowing plants to dynamically adapt to an ever-changing environment.