Project Details
Projekt
Role of vacuole in amplification of long-distance Ca2+ signals
Subject Area
Plant Biochemistry and Biophysics
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 563126265
Most of the volume of a plant cells is occupied by a central large vacuole, of which the free Ca2+ concentration is 10^4 times higher, as that of the cytosol. It is likely that the vacuolar Ca2+ store plays an important role in the generation of short transient rises of the cytosolic Ca2+ concentration, which act as Ca2+ signals. However, little is known about the mechanisms by which the vacuole fulfills this function. In the Vamplicas project, we will study the interaction of several ion transport proteins in the vacuolar membrane and test if these proteins can amplify small initial Ca2+ signals that are initiated at the plasma membrane. A previous study (Dindas et al., New Phytologist 2021) has shown that depolarization of the vacuolar membrane increases the cytosolic free Ca2+ concentration. Our project will test, if depolarization of the vacuolar membrane is initiated by Tandem Pore K+ channels (TPKs) and boosted by the Two-Pore Channel 1 (TPC1). Such a mechanism would explain why the TPC1 channel is required for long distance Ca2+ signals, which are propagating along the vascular system of leaves and roots. In the Vamplicas proposal, we describe three work packages (WPs) in which we test the function of the TPK and TPC1 ion channels, as well as the CAtion/proton eXchangers (CAX). In the first WP we will study the properties and activation mechanism of CAX-transporters and focus on their sensitivity to changes in the vacuolar membrane potential. In WP2, we will study the ability of TPK and TPC1 channels to depolarize the vacuolar membrane, as well as their potency to amplify Ca2+. Finally, in the 3rd WP we will study long distance Ca2+ signals that propagate along vascular strands and how they are affected by CAX-transporters, TPK- and TPC1 channels. Overall, our Vamplicas project has to goal to unravel the molecular machinery that enables vacuolar Ca2+-signal initiation and amplification and thus short- and long-distance calcium-dependent communication within plants. The outcome of the project will help to understand how plants tissues can coordinate their responses to environmental stress such as heat, drought, and pathogen attack. These responses are of central importance for the survival of plants at harsh conditions, which are expected to occur more often in the near future, because of global climate change.
DFG Programme
Research Grants
