Understanding how plant pathogens cause disease - who does what to whom and where?

Plant pathogens are one of the major global causes of crop loss and food spoilage. Understanding how plants perceive and respond to pathogens is therefore vital in understanding how to breed plants with improved pathogen resistance. The interactions between plants and pathogens is very complex but perception of pathogens is achieved by 2 major groups of proteins; receptor-like kinases perceive extracellular stimuli such as bacterial proteins and cell wall fragments, while R-proteins perceive intracellular changes to protein function and activity caused by pathogen proteins (termed "effectors") that have been secreted into the pant cell. Understanding these protein-protein interactions is critical to our understanding of the processes underlying plant resistance or susceptibility to pathogens. As an agronomically-relevant model system we use the Oomycete pathogen Phytophthora infestans, the causative agent of potato late blight, and the model plant Nicotiana benthamiana to study plant-pathogen interactions.
Traditional methods to study protein-protein interactions in plants (and all other organisms) are limited for a variety of reasons, but largely because all of these methods are invasive, destructive or do not reflect the native environment of the cell where interactions are taking place. This means that our ability to define the composition of protein complexes, and particularly how these complexes change after a stimulus such as pathogen challenge, is very poor. The field is therefore in critical need of new approaches to drive future research.
We have recently developed a new enzyme mediated method to map protein-protein interactions in-vivo that is non-invasive and maintains the native plant cellular environment intact. This allows us to identify and analyse changing protein-protein interactions in a meaningful cellular context and extract hitherto unavailable information.
The aim of this project is to develop this system further using synthetic biology methods and use it to identify new interacting partners of plant R-proteins and Phytophthora infestans effectors. Identified proteins will be assessed for their roles in defending against pathogen attack or promoting pathogen virulence with the ultimate aim of improving crop protection strategies and aiding food security.