Regulation of plant cell-to-cell communication

Plasmodesmata are membrane-lined cytoplasmic channels which are of fundamental importance to plant development, stress responses and defence against pathogens. They also serve as conduits for infection by plant viruses, major crop pathogens with a global agro-economic impact. Building on recent advances in understanding plasmodesmata architecture and virus transport by the Tilsner lab, and a novel method for identifying protein-protein interactions developed by the Hemsley lab, this project will characterize a contractile machinery at plasmodesmata putatively required for the regulation of intercellular communication in plants, and likely co-opted for virus transport.
Several actin-associated proteins have been localized to plasmodesmata and in some cases shown to be involved in regulation of plant cell-cell connectivity and virus transport. The aims of the project are:
Analyse interactions between actin-related proteins at plasmodesmata
Identify additional components of the putative contractile structure
Test effects of individual and combined knock-out mutations on plant development, cell-cell connectivity, virus transport and plasmodesmata ultrastructure.
The PhD candidate will use a novel system for detection of protein-protein interactions in vivo to identify new components of a putative actin-related contractile system at plasmodesmata. The plasmodesmal localization of new candidates will be confirmed by fluorescence and electron microscopy. Co-immunoprecipitation and yeast-two-hybrid assays will be used to analyse reciprocal interactions between all previously known and newly identified components. Functional relations between these proteins will be probed using crosses of Arabidopsis knock out lines, which will be analysed for developmental phenotypes, virus susceptibility and intercellular molecular transport. The student will travel to a collaborating lab for ultrastructural (electron tomography) analysis of plasmodesmata morphology in mutant lines.