University of Cambridge
Cambridge CB2 3EA
The ancient microbe-host symbiotic association between plants and arbuscular mycorrhiza (AM) fungi presents an excellent model system to elucidate molecular processes that underpin complex invader-mediated reprogramming of eukaryotic organisms. Within the roots of most land plants beneficial arbuscular mycorrhiza fungi (AMF) form complex tree-shaped feeding structures called arbuscules. Monumental cellular re-differentiation and reprogramming in the inner root cortex result in the de novo synthesis of a host-derived membrane that surrounds the arbuscule, the peri-arbuscular membrane (PAM). This functional symbiosome interface facilitates bi-directional nutrient exchange between fungus and plant and is a likely site of fungal effector delivery. Membrane biogenesis, PAM-specific protein delivery and turnover and dynamics of the PAM during arbuscule development remain poorly understood partly due to a lack of deep-tissue in vivo imaging in plants. Live-cell imaging of arbuscule development using confocal laser scanning microscopy (CLSM) in inner cortical root cell layers has been hampered by low resolution and photo-bleaching that impairs cell viability.
This project aims to pioneer the application of deep-tissue live-cell imaging in rice roots with the objective to provide a structural framework for 4-D modelling of membrane dynamics during the establishment of endosymbioses. State-of-the-art multi-photon confocal microscopy (MPCM) has enabled live-cell time-lapse imaging at high resolution with minimal tissue damage. In addition, SBFSEM imaging with 3-D reconstruction at a resolution of 5nm will provide a first structural atlas of 'naïve' and colonized cells at unprecedented resolution. MPCM and SBFSEM phenotyping of rice mutants compromised in arbuscule development will provide a novel insight into the complex molecular mechanisms that underpin cellular morphogenesis during plant endosymbiosis.
Project Funded by Marie Curie-FP7-PEOPLE-2013_IEF fellowship