Characterising a novel pathway in abiotic stress tolerance

• Applicant: Dr. Daniel McKay
• Subject Area: Plant Cell and Developmental Biology ; Plant Physiology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 513826948

The Trans-Golgi network/Early Endosome (TGN/EE) is an intracellular compartment vital for the flow of cargo within cells, particularly to and from the plasma membrane. Previous work has found that maintaining the acidic pH of the TGN/EE is crucial for enabling the continued flow of cargo and several proteins involved in regulating the pH in the TGN/EE have been identified. Such proteins are also involved in the regulation of osmolyte movement across the TGN/EE membrane. It was also found that mutants that lack the function of particular proteins involved in TGN/EE pH regulation also exhibit altered sensitivity to abiotic stresses such as salt or osmotic stress. Furthermore, challenging plants with salt or osmotic stress induces changes in the pH of the TGN/EE. This indicates that the role of these proteins in regulating TGN/EE pH or ion flux is likely important in the tolerance to salt or osmotic stress, however, we currently do not know how conditions in the TGN/EE impact stress tolerance. This project therefore aims to elucidate the role of the TGN/EE in abiotic stress tolerance. The project is separated into three key objectives. The first objective is to comprehensively characterise how changes in TGN/EE pH and ion conditions, impact salt and osmotic stress tolerance. Doing so will allow us to identify if particular changes in pH or ion transport are linked to increased or decreased stress tolerance and if the TGN/EE plays an important role in stress tolerance of particular plant organs or is important for specific salt tolerance mechanisms such as exclusion of salt from shoots. The second objective is to investigate the role the TGN/EE pH regulating proteins have in mediating the change in TGN/EE pH when challenged with salt or osmotic stress. This will enable us to determine the importance of this pH change in stress tolerance. The final objective is to identify how TGN/EE conditions impact stress tolerance. Three potential mechanisms have been identified and will be assessed to achieve this objective while the results of the first two objective will be used to inform which mechanisms are most likely, and therefore require the most attention. Achieving these three objectives will result in the identification of a new pathway of stress tolerance. This can be targeted for improving salt and water stress tolerance. Such tolerance is important for growing crops in saline soils and will also be important for understanding the way plants adapt to rapid osmotic changes, a response that is important in hydroponic and vertical agriculture systems.

• DFG Programme: WBP Position