Receptor-like kinases at the initiation and maintenance of AM symbiosis

We propose a synthetic biology approach to investigate the where and how receptor kinase signalling operates in arbuscular mycorrhizal (AM) symbiosis.

The Idea

A ubiquitous and ecologically-significant symbiosis develops between most clades of land plants and arbuscular mycorrhizal fungi (AMF). This intimate endosymbiosis developed early in the evolution of land plants and recent phylogenetic studies revealed the presence of a ‘symbiotic toolkit’ that can be traced further back to the charophytes. Components of this symbiotic toolkit have also been shown to be required for other biotic associations in the rhizosphere that have evolved subsequently. These range from beneficial nodulation symbiosis to pathogenic hemibiotrophs like Magnaporthe spp.

Amongst the key signalling components involved in arbuscular mycorrhizal symbiosis are receptor-like kinases that perceive hitherto unknown extracellular stimuli and transduce these signals into intracellular responses. Of particular interest are lysin-motif (LysM) receptor kinases and a new family of symbiosis-specific receptor kinases, both of which are found in land plants that develop symbiosis with AMF. In our model organism, rice, the LysM receptor kinase CERK1 is required for the perception and accommodation of both beneficial and pathogenic fungi; whereas the symbiotic-specific kinase ARK1 regulates the maintenance and longevity of the symbiosis. In addition, both receptor kinases appear to be key signalling nodes in their respective processes, each requiring the concerted action of unknown co-receptors that perceive their respective extracellular stimuli.

Following the identification of their symbiotic roles, further investigations into their biochemical mechanisms and cell biology at the early and late stages of symbiosis will reveal mechanistic insights of receptor kinase signalling in roots.

Aims: Here we propose to understand the mechanisms of receptor kinase signalling via two main approaches, both involving DNA synthesis of Golden Gate modules for subsequent cloning and transformations. Creating chimeric receptors and receptor variants is laborious using traditional cloning methods. The Golden Gate modules created would accelerate the assembly, transformation and biological characterisation of symbiotic signalling in roots significantly.