Title: “Reprogramming roots cells for arbuscular mycorrhizal symbiosis”
Host: David Nelson & Dawn Nagel
Abstract: In natural ecosystems, most vascular flowering plants live in symbiosis with arbuscular mycorrhizal (AM) fungi. These mutually beneficial associations develop in the roots, where the fungus colonizes the cortex to obtain carbon from the plant while providing mineral nutrients to the root. Our research focuses on the molecular events that underlie development of this endosymbiosis with a particular emphasis on the colonized cortical cells where extensive signaling, cellular remodeling and metabolic alterations occur to enable accommodation of the fungal endosymbiont. Recently, phylogenomics analysis of 52 plant genomes enabled us to identify 138 plant genes that we predict have been conserved for AM symbiosis (1). Initial evidence suggests that some of these genes function together in small modules to modify aspects of root cell biology or metabolism to enable symbiosis. Examples include new subunits of the exocyst predicted to direct deposition of the periarbuscular membrane, and the redirection of lipid metabolism to provide fatty acids for the fungus. Current electron microscopy and tomography studies contribute new views of the plant-fungal interface and continue to challenge our thinking about AM symbiosis. Recent progress in these areas will be discussed.
(1) Bravo A, York T, Pumplin N, Mueller LA, & Harrison MJ (2016) Genes conserved for arbuscular mycorrhizal symbiosis identified through phylogenomics. Nature Plants 2:1-6.