Inducible depletion of PI(4,5)P 2 by the synthetic iDePP system in Arabidopsis.

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P ₂ ) is a low-abundance membrane lipid essential for plasma membrane function ^1,2 . In plants, mutations in phosphatidylinositol 4-phosphate (PI4P) 5-kinases (PIP5K) suggest that PI(4,5)P ₂ production is involved in development, immunity and reproduction ^3-5 . However, phospholipid synthesis is highly intricate ⁶ . It is thus likely that steady-state depletion of PI(4,5)P ₂ triggers confounding indirect effects. Furthermore, inducible tools available in plants allow PI(4,5)P ₂ to increase ^7-9 but not decrease, and no PIP5K inhibitors are available. Here, we introduce iDePP (inducible depletion of PI(4,5)P ₂ in plants), a system for the inducible and tunable depletion of PI(4,5)P ₂ in plants in less than three hours. Using this strategy, we confirm that PI(4,5)P ₂ is critical for various aspects of plant development, including root growth, root-hair elongation and organ initiation. We show that PI(4,5)P ₂ is required to recruit various endocytic proteins, including AP2-µ, to the plasma membrane, and thus to regulate clathrin-mediated endocytosis. Finally, we find that inducible PI(4,5)P ₂ perturbation impacts the dynamics of the actin cytoskeleton as well as microtubule anisotropy. Together, we propose that iDePP is a simple and efficient genetic tool to test the importance of PI(4,5)P ₂ in given cellular or developmental responses, and also to evaluate the importance of this lipid in protein localization.