Résumé
Phosphoinositides are signaling lipids that regulate cellular responses by acting as gatekeepers of organelle identity or modulating protein localization and activity. 1 They are well established core elements of classical receptor kinase signaling in animals. 2 However, in plants, rapid phosphoinositide remodeling has not yet been recognized as a key regulation of receptor-like kinase signaling. 3,4 Here, we show that the receptor-like kinase FERONIA (FER) triggers acute phosphoinositide remodeling in response to Rapid ALkalinisation Factors23 (RALF23) and RALF1 peptides. Using high-resolution confocal microscopy, combined with microfluidics and advanced image analysis, we reveal that RALF peptides induce a rapid and FER-dependent recruitment of phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) sensors at the plasma membrane and a concomitant decrease of phosphatidylinositol-4-phosphate (PI4P) sensors from the cell surface. This PI4P-to-PI(4,5)P2 conversion is regulated by PI4P 5-Kinase7 (PIP5K7), PIP5K8 and PIP5K9 and is required for RALF-induced endocytosis, a response known to safeguard growth upon recovery from stress episodes. 5-7 These findings highlight a mechanism where FER regulates the PI4P/PI(4,5)P2 balance through PIP5Ks to control stress-induced endocytosis, linking phosphoinositide dynamics, vesicular trafficking and plant growth adaptation. In addition, it uncovers that peptide/receptor modules have coopted acute phosphoinositide conversion to act as lipid second messengers in both plant and animal systems.