Trafficking of proteins to the tonoplast and the effects of abiotic stress

Plants feed the world, both directly in the food that we eat and indirectly in providing feed for livestock. The world's population is predicted to increase to approximately 8 billion by 2024, and this increase, in combination with the effects of climate change, will greatly affect global agricultural production. Since a major proportion of the developing world's crops are grown in areas affected by drought and poor soil conditions research into this area is paramount in order to develop crops able to withstand such adverse conditions. Alongside being resilient, the challenge is to ensure there are no detrimental effects on crop yield or quality. Plants as sessile organisms have to constantly adapt to the changing conditions of their immediate environment.

Most plant proteins essential for human and/or livestock nutrition are synthesised and stored in the plant secretory pathway. This is a system of dynamic, membrane-bound organelles comprising of the endoplasmic reticulum (ER), Golgi complex, endosomes and vacuoles. Vacuoles are the intracellular endpoint of the secretory pathway. In many seed crops, proteins are stored in special vacuoles called protein storage vacuoles (PSVs). The vacuolar membrane, the tonoplast, contains proteins such as aquaporins that act as channels for the transport of water and small molecules.

To date, no definitive mechanism by which tonoplast associated proteins are trafficked to this vacuolar membrane has been described. This project aims to elucidate the sorting of membrane proteins along the secretory pathway to the tonoplast, and how this trafficking is altered under abiotic stress conditions. Results generated from this fundamental research in the model plant Arabidopsis thaliana could subsequently be translated into sustainable crop species in order to enable the development of abiotic stress tolerant crops.