Cellular gatekeepers: which proteins stand guard at the connections between plant cells?

Plant cells are connected to their neighbours via 'tubes' called plasmodesmata, creating an interconnected cytoplasm that joins cells within and between tissues and organs. Many molecules use plasmodesmata to move freely between cells and it is critical for a plant to tightly control how open its plasmodesmata are to enable control over how far molecular information and resources can travel through tissues.

Indeed, this control is important to how a plant responds to many different environmental and developmental changes, including immune responses when it is being invaded by a pathogen.

We, and others, have discovered that specialised protein machinery sits at plasmodesmata and controls whether they are open or closed under different conditions. For example, when a plant cell perceives a pathogenic microbe it rapidly closes over its plasmodesmata and isolates itself from its neighbours. Curiously, the signal to close over plasmodesmata when a microbe is detected is transmitted independently from responses in the rest of the cell, leading us to ask how do plasmodesmata recruit specialised machinery and why are plasmodesmata a unique signalling domain?

This project will take advantage of recent advances in the Faulkner lab and investigate how a specific family of membrane proteins sort signalling machinery to plasmodesmata. The student will profile how plasmodesmal recruitment is dependent on these sorting proteins, and how they influence the execution of immune responses. The project will identify novel signaling components and determine how sorting proteins define the function a signalling protien executes.

The project will use biochemical, genetic and advanced imaging approaches to gain a high resoltuion of how different immune responses are executed in different regions of a cell.