Molecular Characterization of Plant-Bacterial Interactions

Host-bacterial interaction has been a keen interest of my research for a long term. I previously identified a protease secreted by pathogenic bacteria, protease IV, which strongly activates a plant immune response. The defense response pathway in plant hosts that are involved in the perception of protease IV has not been previously characterized. In addition, I found that similar proteases in other plant pathogens could affect defense response in crop plants, indicating that the study of this protease could unveil agriculturally important defense pathways. The overall goal of the proposed program is to try to understand how plant hosts and pathogens operate as an integrated system during the process of infection and to use the knowledge from these studies to develop novel strategies to defend plants against pathogen attack. *** The projects in Aim 1 will focus on the identification of unknown components in the plant pathway for protease IV perception. The subsequent functional studies of these identified components will help place them into a comprehensive signaling network of the plant innate immune system. Interestingly, my data also suggest that protease functions as a virulence factor that has the opposite effect on the plant immune response. Additional experiments proposed in aim 1 will investigate the roles of protease IV in causing disease symptoms in plant hosts. The experiments proposed in Aim 2 of this research program will try to identify other proteins that are synthesized and secreted by bacteria and understand how they can affect immune responses in plant hosts. An additional goal of the projects in Aim 2 is to understand how both plant hosts and bacterial pathogens, as a whole system, operate during the process of infection. The initial step will be the investigation of the changes in their gene expression patterns. Then, the knowledge from this study will be used to develop new approaches to defend against pathogen attack.*** The overall goal of this research program is to utilize a collection of different approaches to figure out the precise mechanism by which bacterially secreted proteins affect the host immune response and to help plant researchers understand how plant innate immune signaling pathways are interconnected. Through various projects proposed in this research program, I will address several important questions in the field of plant-pathogen interactions. Moreover, the examination of both the virulence-related proteins and the activators of defense responses in plant hosts will provide a more thorough understanding of the evolutionary arms race model between host immunity and bacterial pathogenicity. *** In summary, this work will contribute to our understanding of the molecular basis of immune signaling pathways in plants and contribute in the long run to enhanced agricultural production while maintaining environmentally friendly, sustainable agricultural practices in Canada. **