University of Tasmania, Australia

Understanding apoptosis and Programmed Cell Death in plants

Programmed Cell Death (PCD) is a fundamental cellular process observed in eukaryotic cells of different origin. Being an ordered series of events, PCD facilitates the removal of redundant, misplaced, or damaged cells and is essential for cellular differentiation and tissue homeostasis. PCD also plays an important role in mediating plant adaptive responses to the environment. The most characterised type of PCD in plants is a hypersensitive response (HR) observed in plants in response to pathogen attack; recently, PCD has also been proved to occur in response to various abiotic stresses such as salinity, cold stress, waterlogging and hypoxia. In contrast to the relatively well-described cell death pathway in animals, often referred to as apoptosis, mechanisms and regulation of plant PCD are still ill-defined. Recent studies in our laboratory have suggested that cell’s ability to maintain K⁺ homeostasis is central to this process and highlighted the crucial role of several plasma membrane transporters in controlling PCD in plants. Several hypothesis has been put forward:

1. NaCl-induced PCD should be substantially attenuated (or absent) in plants lacking KOR channels;
2. PCD in salt-treated cells may also be prevented by more efficient scavenging of ROS by endogenous or exogenous means;
3. plants capable of better maintaining negative membrane potential under saline conditions (e.g. ones with intrinsically higher H+-ATPase activity) must be more prone to NaCl-induced PCD.

This project will test the above hypotheses by applying a range of cutting edge electrophysiological and molecular techniques. The project will be undertaken in a close collaboration with Univ. Copenhagen (Denmark) and Univ. Michigan (USA) and will require the PhD candidate to spend up to 6 months in one of participating overseas laboratories.