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The dynamics of LRX-RALF-FER module in the regulation of cell wall development

English title The dynamics of LRX-RALF-FER module in the regulation of cell wall development
Applicant Ringli Christoph
Number 192495
Funding scheme Project funding (Div. I-III)
Research institution Institut für Pflanzen- und Mikrobiologie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Botany
Start/End 01.04.2020 - 31.03.2024
Approved amount 634'768.00
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All Disciplines (2)

Discipline
Botany
Cellular Biology, Cytology

Keywords (9)

cell wall; cell wall-plasma membrane signaling; LRX1; cell wall integrity sensing; Rapid alkalinization factors; LRR-extensins; Arabidopsis; FERONIA; development

Lay Summary (German)

Lead
Wachstum und Vermehrung verlangt von Pflanzen den Austausch von Informationen zwischen Geweben und Zellen, um ihre Entwicklung an die vorherrschenden Bedingungen wie zum Beispiel Salzstress, Krankheitserreger, Nährstoffe, u.s.w. anzupassen. Dieses Projekt untersucht auf der molekularen Ebene, wie Signale innerhalb der Pflanze ausgetaucht und weitergegeben werden.
Lay summary

Inhalt und Ziel des Forschungsprojektes

Pflanzenzellen sind von einer Zellwand umgeben, welche die Zellform definieren und die Zellen vor verschiedensten Stresseinflüssen schützt. Entsprechend beinhaltet das Wachstum die koordinierte Ausdehnung der Zelle und der sie umgebenden Zellwand, was wiederum einen Austausch an Information zwischen dem Zellinnern und Zelläussern voraussetzt.

Dieses Projekt untersucht die Funktion von LRR-extensinen (LRX), Proteine, welche in der Zellwand verankert sind. Sie stellen eine Verbindung zum Zellinnern her, indem sie mit einem Protein der Zellmembran in Kontakt treten. Die Dynamik und Feinregulation dieser Protein-Protein Interaktion wird im Detail uintersucht. Darüber hinaus analysieren wir die zellulären Abläufe, welche durch diesen Informationsaustausch kontrolliert werden und damit das Wachstum der Zelle und der Zellwand beeinflussen.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

In der Fragestellung und experimentellen Herangehensweise an der „Modellpflanze“ Arabidopsis thaliana handelt es sich um ein Grundlagenprojekt, welches einen fundamentalen Kontrollprozess untersucht. Im Licht der sich verändernden Umgebunsbedingungen (Krankheiten, Trockenstress, Temperaturschwankungen, Nährstoffangebot, Übersalzung der Böden u.s.w.) ist es wichtig zu verstehen, wie Pflanzen ihre Umgebung wahrnehmen und die entsprechenden Informationen austauschen. Daher wird dieses Wissen auch dazu beitragen, agronomische Fragestellungen beantworten zu helfen, und damit einen Beitrag zur gesellschaftlichen Frage der Ernährung leisten.
Direct link to Lay Summary Last update: 27.03.2020

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
103891 LRX in root hair cell wall development and suppressors of the lrx1 root hair mutant: genetic and biochemical approaches to elucidate the function of the LRX gene familiy in Arabidopsis 01.06.2004 Project funding (Div. I-III)
166577 Analysis of LRX proteins as potential regulators of Ca2+ fluxes 01.04.2016 Project funding (Div. I-III)
166577 Analysis of LRX proteins as potential regulators of Ca2+ fluxes 01.04.2016 Project funding (Div. I-III)

Abstract

Plant cell growth requires monitoring and coordination of processes in the cell wall and the cytoplasm. To this end, plants have developed a system for cell wall integrity (CWI) sensing that perceives the status of the cell wall and can induce alterations in cell wall structures by intracellular signaling. Transmembrane receptors involved in CWI sensing can also bind hormones that are involved in modifying growth processes. The Catharanthus roseus receptor-like kinase 1-like proteins (CrRLK1Ls) such as the Arabidopsis thaliana FERONIA (FER) are transmembrane proteins with a malectin-like extracellular domain and a cytoplasmic kinase domain. Several of them have functions in CWI sensing, influence cell growth, and are receptors for RALF (RAPID ALKALINIZATION FACTOR) peptides that modulate cell growth and other processes. My group has been studying the function of extracellular LRR-extensin (LRX) proteins and their function in regulating cell growth and cell wall development. In recent years -in collaboration with different groups - my group was involved in identifying LRXs as binding sites for RALF peptides and in establishing a link between the cell wall and the plasma membrane by interacting with the CrRLK1L protein FER. Based on these published and own unpublished data presented here, we suggest a LRX-RALF-FER module that links the cell wall with the cytoplasm. At this point, it is not clear how these proteins interact, whether some of them are excluding other interactions, and which interactions are relevant for the different cellular processes influenced by this module.I propose to investigate these questions using root hair formation in Arabidopsis as the model system. We have been studying the function of LRX1 in root hair development over a long time and have produced a large array of mutants and transgenic lines that put us in an excellent position to investigate the function of LRX1 in RALF/FER binding and CWI sensing. Specifically, the extensin-less LRX1?E expressed in the wild type induces a dominant negative effect. Analysis of the LRX1?E -induced defect revealed that this protein interferes with the LRX1-RALF-FER network. Thus, this line is an excellent tool for characterizing the process that integrates hormone signaling and CWI sensing, and we have started forward- and reverse-genetic approaches to investigate the LRX1?E-induced effect. The initial analyses presented here suggest that this line indeed allows to get a much better insight into LRX1-RALF-FER interaction dynamics and the processes that are influenced by these proteins. Together, the proposed research activities should provide novel insights into LRX protein function and the effects of LRX-related activities during cell growth and the maintenance of cell wall integrity.
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