Stefanie Ranf-Zipproth
Ordentliche_r Professor_in
Departement für Biologie
PER 04 bu. 0.113
Rue A.-Gockel 3
1700 Fribourg
Rue A.-Gockel 3
1700 Fribourg
PER 04, 0.113
Forschung und Publikationen
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Ranf lab publications
35 Publikationen
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Forschungsprojekte
Molecular mechanisms of early LORE immune signalling
Status: LaufendBeginn 01.06.2022 Ende 31.05.2026 Finanzierung SNF Projektblatt öffnen Plants have a largely extended repertoire of cell-surface receptor-like kinases (RLKs) to sense a multitude of external and internal signals and to translate them into adaptive cellular and physiological responses. In order to sense a wide variety of signals, the extracellular domains of RLKs are highly diverse in composition, resulting in many different subclasses. Despite their fundamental role in virtually all aspects of plant life, only a few RLKs from a few classes have been studied mechanistically in detail. While they have become important models for their RLK classes, models of other RLK classes are needed to understand plant RLK signalling in its entirety. Many RLKs serve as pattern recognition receptors (PRRs) that sense microbe-associated molecular patterns (MAMPs) and activate broad-spectrum pattern-triggered immunity (PTI). Due to the conserved nature of PTI, PRRs are prime candidates for genetic plant protection. The engineering of plant immune sensing capacity through cross-family transfer of PRRs and PRR signal transduction are important tools for sustainable and environmentally friendly disease management. To successfully develop PRR-based disease resistance strategies in crops in the future, we need a comprehensive mechanistic understanding of PRR signalling and regulation. We have identified the Arabidopsis thaliana S-domain-RLK LORE as a PRR that senses medium-chain 3-hydroxy fatty acid (3-OH-FA) metabolites in antibacterial immunity. As one of only very few SD-RLKs with a known ligand and thus a controllable means of activation, LORE is an excellent and important prototype model for the large class of SD-RLKs that is widely distributed in plants. To date, we have gained a basic understanding of LORE signalling and its role in plant immunity, but the molecular details remain largely unresolved. Here, we will use LORE and its small synthetic ligand 3-OH-FA as a model to gain new insights into SD-RLK signalling mechanisms. We aim to characterize the early signalling dynamics of the LORE receptor complex in unprecedented molecular detail. The proposed work builds on a set of molecular tools we have developed recently and that are specifically tailored to study SD-type RLKs. In scope of the proposed project, we will employ a combination of state-of-the-art analytics, biochemical and genetic approaches, and in silico modelling to investigate: (1) activation and regulation of the LORE receptor complex by phosphorylation, (2) a proposed regulatory crosstalk of LORE phosphorylation and Ca2+ signalling through phospho- and Ca2+-sensors, (3) the role of heteromerization of LORE and related SD-RLKs in immune signalling, and (4) their regulation by FERONIA. We will examine in depth how these components work together to fine-tune LORE activation and immune responses. Phosphorylation and the second messenger Ca2+ are universal signalling components in eukaryotes and also central to RLK signalling in plants. Yet, our understanding of how these network components cooperate in translating extracellular stimuli into cellular responses and in fine-tuning these responses in the face of the multitude of stimuli perceived by a single plant cell is limited. The regulatory principles obtained from this project will improve our understanding of biological signalling processes in general. As they are broadly applicable to other RLK signalling pathways involved in development, growth, reproduction, and adaptation to abiotic and biotic stresses, they will help in the development of future strategies to improve stress resistance and other yield-related traits in crops, which is of utmost importance to society.