Cell-cell communication:  Initial work began by characterizing the various functions of PVX proteins that relate to intercellular movement.  PVX encodes 3 proteins that contribute to transport.  TGBp1 is a suppressor of silencing and gates open plasmodesmata. TGBp2 protein induces novel vesicles to bud from the ER which are essential for intercellular transport.  TGBp3 is ER associated. We are currently employing proteomic tools to characterize vesicle contents and confocal microscopy to study vesicle transport dynamics.  Research goals also include understanding the role of the ER in virus intra and intercellular transport.

ER stress and ER associated cell death (ERAD):  We have discovered the significant relationship of plant viruses and ERAD.  The Potato virus X (PVX) TGBp2 and TGBp3 proteins are ER associated proteins involved in plasmodesmata transport.  TGBp2 and TGBp3 are degraded by the 26S proteasome in PVX infected cells.  The PVX TGBp3 protein is a movement protein that is expressed at low levels from the PVX genome and does not induce death during PVX infection. However, prolonged expression of TGBp3 from Tobacco mosaic virus (TMV) genome or from a plasmid delivered by agroinfiltration leads to programmed cell death (PCD).  The unfolded protein response (UPR) is central to TGBp3 induced PCD. Our current research focuses on mapping the ER stress signalling pathways induced by TGBp3 which lead to oxidative stress and programmed cell death. 

Nanotechnology:  We are currently attempting to engineer the cell-to-cell transport machinery for delivery of proteins and nucleic acids for antiviral therapeutics or for altering cell programming will provide valuable new opportunities for gene therapy and synthetic biology.  This research employs flow cytometry, MRI technology, and confocal microscopy.  We are characterizing the utility and cytotoxicity of this nanoparticle for plant biology research, delivery of nucleic acids, and analysis of trafficking signals.  We also have teamed up with researchers for proof of concept research testing the utility of plant virion nanoparticles for plant vascular biology research.  This research will assess vascular flow dynamics and determine if antibodies and virus nanoparticles can be delivered into the plant vasculature for transport to target tissues.  This research will provide a platform for engineering antibodies for in situ diagnosis of plant diseases and further engineering of virus nanoparticles for delivery of antimicrobial or pesticidal compounds to plants, using virion scaffolds (rather than synthetic polymers).  This technology will provide an alternative to transgenic applications or chemical spraying for disease control.