Webb Group: Mechanism controlling the propagation of Ca2+ signals in plants
Supervisor
Professor Alex Webb (Department of Plant Sciences) and Professor Paul Dupree (Department of Biochemistry).
Brief Summary
We have discovered that modifications to proteins on the surface of plants affects the propagation of waves of calcium signalling through the plant. This project aims to find out how that happens.
Importance of Research
Plant co-ordinate their activity across the multicellular organism by long distance signalling using hormones and waves of calcium propagated from cell to cell. We have discovered that proteins which are modified by the addition sugars present on the surface of plant cells are vey important in the propagation of these signals, and therefore are required for responses to the environment.
Project Summary
In collaboration with Professor Paul Dupree, we have discovered that extracellular arabinogalactan proteins are required for the generation of cell-cell Ca2+ waves in the roots of Arabidopsis. We hypothesise that these AGP proteins acts as capacitors which release Ca2+ when the extracellular pH is acidified to cause a flux of Ca2+ into the cytosol, which propagates a cell-to-cell Ca2+ wave. We now wish to perform detailed experiments testing this hypothesis using a range of Ca2+ reporters that will allow whole plant and single cell imaging of cytosolic and apoplastic free Ca2+. We have generated AGP loss-of-function mutants providing the first opportunity to determine the purpose of cell-cell Ca2+ waves in the biology of the plant and the mechanisms by which they occur. The student will determine which signalling pathways the AGPs contribute to, the mechanisms by which this occurs and how interfering with Ca waves using the AGP mutants affects the biology of the plant.
What will the successful application do?
This project will include single cell Ca2+ imaging, physiological analysis and RNAseq. The student will image waves of calcium signalling through plants in a range of mutants in response to different stimuli to understand the extent to which AGPs regulate signalling in plants. The student will then investigate how AGPs modulate calcium signalling by testing hypotheses about the role of pH and calcium binding in the generation of calcium signals
Training Provided
Single cell calcium imaging, cell wall biochemistry, molecular genetics.