Romain Castilleux1, Barbara Plancot1, Bruno Gügi1, Agnès Attard2, Corinne Loutelier-Bourhis3, Benjamin Lefranc4, Eric Nguema-Ona5, Mustapha Arkoun5, Jean-Claude Yvin5, Azeddine Driouich1, Maïté Vicré1. 1. Normandie Université, UNIROUEN, Laboratoire Glyco-MEV EA 4358, Fédération de Recherche 'Normandie Végétal' FED, Rouen, France. 2. INRA, CNRS, Université Côte d'Azur, ISA, France. 3. IRCOF COBRA, UMR6014 and FR3038, CNRS, Université de Rouen Normandie, Mont-Saint-Aignan Cedex, France. 4. INSERM U1239, Différenciation et Communication Neuronale et Neuroendocrine, Normandie Université, Rouen, France. 5. Centre Mondial de l'Innovation, Groupe Roullier, Saint Malo Cédex, France.
Abstract
BACKGROUND AND AIMS: Extensins are hydroxyproline-rich glycoproteins thought to strengthen the plant cell wall, one of the first barriers against pathogens, through intra- and intermolecular cross-links. The glycan moiety of extensins is believed to confer the correct structural conformation to the glycoprotein, leading to self-assembly within the cell wall that helps limit microbial adherence and invasion. However, this role is not clearly established. METHODS: We used Arabidopsis thaliana mutants impaired in extensin arabinosylation to investigate the role of extensin arabinosylation in root-microbe interactions. Mutant and wild-type roots were stimulated to elicit an immune response with flagellin 22 and immunolabelled with a set of anti-extensin antibodies. Roots were also inoculated with a soilborne oomycete, Phytophthora parasitica, to assess the effect of extensin arabinosylation on root colonization. KEY RESULTS: A differential distribution of extensin epitopes was observed in wild-type plants in response to elicitation. Elicitation also triggers altered epitope expression in mutant roots compared with wild-type and non-elicited roots. Inoculation with the pathogen P. parasitica resulted in enhanced root colonization for two mutants, specifically xeg113 and rra2. CONCLUSIONS: We provide evidence for a link between extensin arabinosylation and root defence, and propose a model to explain the importance of glycosylation in limiting invasion of root cells by pathogenic oomycetes.
BACKGROUND AND AIMS: Extensins are hydroxyproline-rich glycoproteins thought to strengthen the plant cell wall, one of the first barriers against pathogens, through intra- and intermolecular cross-links. The glycan moiety of extensins is believed to confer the correct structural conformation to the glycoprotein, leading to self-assembly within the cell wall that helps limit microbial adherence and invasion. However, this role is not clearly established. METHODS: We used Arabidopsis thaliana mutants impaired in extensin arabinosylation to investigate the role of extensin arabinosylation in root-microbe interactions. Mutant and wild-type roots were stimulated to elicit an immune response with flagellin 22 and immunolabelled with a set of anti-extensin antibodies. Roots were also inoculated with a soilborne oomycete, Phytophthora parasitica, to assess the effect of extensin arabinosylation on root colonization. KEY RESULTS: A differential distribution of extensin epitopes was observed in wild-type plants in response to elicitation. Elicitation also triggers altered epitope expression in mutant roots compared with wild-type and non-elicited roots. Inoculation with the pathogen P. parasitica resulted in enhanced root colonization for two mutants, specifically xeg113 and rra2. CONCLUSIONS: We provide evidence for a link between extensin arabinosylation and root defence, and propose a model to explain the importance of glycosylation in limiting invasion of root cells by pathogenic oomycetes.
Authors: Alberto Nuñez; Marshall L Fishman; Laurie L Fortis; Peter H Cooke; Arland T Hotchkiss Journal: J Agric Food Chem Date: 2009-11-25 Impact factor: 5.279