Context is everything - how do plants organise receptor complexes to regulate growth, fight pathogens and mitigate environmental stress?

Climate change is one of the biggest threats to global food production, leading to unpredictable weather patterns and geographical migration of pathogens. As sessile organisms, plants must respond to a changing environment in situ and have developed complex systems of perception and response to mitigate against environmental stress. Plants perceive physical environmental stimuli, such as pathogens, cell wall changes or hormones governing plant development, through receptor kinases in the plasma membrane. We have found that the correct assembly of activated receptor complexes is governed not only by protein-protein interactions but also by protein-lipid and lipid-lipid interactions. It is therefore necessary to understand the receptor protein complex in the context of its membrane environment. Using novel detergent-free techniques to isolate protein complexes and their attendant membrane lipids we have found that naïve receptor kinases form ~300 kDa complexes, but upon ligand binding rapidly form complexes greater than 1 MDa. This is larger than any hypothesised receptor complex, suggesting that previous work has missed many crucial aspects of how these receptor complexes form and function. Taking the plant immune receptor FLS2 as a model, we will define the proteome and lipidome of active and inactive complexes. Using genetic and molecular techniques we will validate findings by investigating novel protein components found in the complex for a role in immunity. This knowledge will provide substantial understanding of how plants perceive and respond to their external environment and mitigate against environmental change.