Controlling hormonal balance in mutualistic interactions between trees and fungi
PI : Claire Veneault-Fourrey (Tree/Microorganism Interactions — IAM)
Collaboration :
- DOE Oak Ridge National Laboratory, Oak Ridge, Tennessee, US
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Context — Ectomycorrhizal mutualistic symbiosis between tree roots and fungal hyphae, are essential for tree health and thus forest sustainability. In exchange for carbohydrates, ECM fungi improve mineral supply of the trees. To facilitate nutrient exchanges, root morphology is strikingly altered and a mixt symbiotic organ (ectomycorrhiza : ECM) is formed. The signals from the two partners that promote and mediate the ECM symbiosis have remained mainly uncharacterized. Recent studies highlight the importance of fungal small-secreted proteins/peptides (SSP)-based communication (dialogue) between plants and their symbionts. These SSPs are called effectors as a reference towards effectors produced by plant pathogenic microbes to suppress or inactivate plant immunity thereby allowing access to plant nutrient stores. A previous study showed that one fungal effector Mycorrhizal induced Small Secreted Protein MiSSP7 is able to interact the co-receptor of jasmonic acid PtJAZ6, leading to an inhibition of JA-signalling pathway.
Objectives — The fundamental aim of this project is to decipher the hormone signalling pathways targeted by fungal effectors in order to restructure the plant host cell to promote mutualism.
Approaches — We propose to elucidate how MiSSP7 is regulating the protein complex involved in JA-mediated signalling pathway. We will also identify fungal effectors able to target hormone-receptor or hormone-mediated signalling such as Salicylic Acid (SA) and Giberrelic Acid (GA).
Expected results and impacts — Characterizing interactions between plants and microbes is critical to achieving long-term ecosystem productivity. Demonstrating that receptors for major hormones involved in symbiosis development are targeted by a diverse set of fungal MiSSPs would revolutionize the current models of symbiosis development and plant-microbe interactions.
