Performing Department
(N/A)
Non Technical Summary
Over 72% of flowering plant species are capable of mutualistic symbioses with arbuscular mycorrhizal (AM) fungi. In this nutritionally-based mutualism, the fungi live within and around the root and transfer phosphate and nitrogen from the soil to the root. In return, the plant cell provides the fungi with carbon, in the form of lipid and sugars. The symbiosis has a huge impact on plant mineral nutrition and on the level of carbon directed underground, both of which influence many aspects of ecosystem functioning. Phosphate transport proteins move phosphate across the fungal and plant membranes. Previous work has identified phosphate transport proteins active during symbiosis and has revealed that phosphate transport is a key regulator of the association. This project seeks a mechanistic understanding of the regulatory process and aims to identify how the plant root cells sense phosphate and regulate their cell biology to maintain the symbiosis. The function of a fungal phosphate transporter will also be assessed. A mechanistic understanding of Pi transport and its role in regulating the symbiosis could provide key targets for breeding crops that are optimized for Pi acquisition through AM symbiosis. This couldimprove phosphate capture by crops and ultimately reduce high fertilizer inputs in agriculture and associated environmental damage arising from excess fertilizer run-off. The project will provide training opportunities for scientists at all levels of their careers, from high school students to postdocs. Lectures andengagement activities with the public will increase awareness of AM symbiosis.
Animal Health Component
0%
Research Effort Categories
Basic
100%
Applied
0%
Developmental
0%
Goals / Objectives
Through analyses of PT4 interacting proteins, we aim to advance an understanding of PT4 function and the mechanisms by which it regulates maintenance of the symbiosis. We will test the hypothesis that PT4 functions as a sensor and through protein:protein interactions ultimately influences lipid provisioning. Second, we will investigate the functions of two PAM-resident kinases and their regulation of PT4. It is possible that phosphorylation of PT4 relates to its function as a potential sensor, thus objectives 1 and 2 are connected but independent; these objectives form the major focus of the proposal. Third, we will use HIGS to assess the role of DePT2, in Pi export from the arbuscule.Objectives Objective 1: Evaluate the interactions of PT4 and PT4 mutant proteins with candidate interacting proteinsObjective 2: Characterize M. truncatula kinc mutants and the roles of KINCs in AM symbiosis Objective 3. Evaluate the role of DePT2 in Pi export from the arbuscule though Host Induced Gene Silencing of DePT2
Project Methods
Under the experiments outlined in Objective 1, Protein:protein interactions will be evaluated through Biflluorescence Complementation Assays in Medicago truncatula root cells.Evaluation of the interaction is conducted via confocal microscopy.For objective 2, the colonization levels and arbuscule content ofM. truncatula kinc mutants will be evaluated by confocal microscopy to define the pheotype and a molecular assessment of the phenotype will be conducted through quantitative real time RT-PCR and possibly RNA-seq analyses. Additional protein interactors of the KINCs will be identified via Turbo-ID. In vitro phosphorylation assays will be used to assess whether the interacting proteins are KINC substrates.In objective 3, transgenic plants expressing HIGS constructs targetting DePT2 will be generated. Transgenics showing high levels of DePT2 HIGS hairpins will be inoculated with DePT2 and the mycorrhizal phenotype assessed. Phosphate transfer from the fungus to the plant will be assess through tracing studies.