title: Involvement of putative glutamate receptors in plant defence signaling and NO production.
abstract: Ionotropic glutamate receptors (iGluRs) are non-selective cation channels permeable to calcium, present in animals and plants. In mammals, glutamate is a well-known neurotransmitter and recently has been recognized as an immunomodulator. As animals and plants share common mechanisms that govern innate immunity with calcium playing a key role in plant defence activation, we have checked the involvement of putative iGluRs in plant defence signaling. Using tobacco cells, we first provide evidence supporting the activity of iGluRs as calcium channels and their involvement in NO production as reported in animals. Thereafter, iGluRs were shown to be activated in response to cryptogein, a well studied elicitor of defence response, and partly responsible for cryptogein-induced NO production. However, other cryptogein-induced calcium-dependent events including anion efflux, H(2)O(2) production, MAPK activation and hypersensitive response (HR) did not depend on iGluRs indicating that different calcium channels regulate different processes at the cell level. We have also demonstrated that cryptogein induces efflux of glutamate in the apoplast by exocytosis. Taken together, our results demonstrate for the first time, an involvement of a putative iGluR in plant defence signaling and NO production, by mechanisms that show homology with glutamate mode of action in mammals.
authors.affiliation: UMR INRA 1088, CNRS 5184, Université de Bourgogne, Plante-Microbe-Environnement, 17 Rue Sully, Dijon, France.
authors.forename: Parul
authors.initials: P
authors.lastname: Vatsa
authors.forename: Annick
authors.initials: A
authors.lastname: Chiltz
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bourque
authors.forename: David
authors.initials: D
authors.lastname: Wendehenne
authors.forename: Angela
authors.initials: A
authors.lastname: Garcia-Brugger
authors.forename: Alain
authors.initials: A
authors.lastname: Pugin
mesh_terms: D020418:Algal Proteins / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D018929:Cell Culture Techniques; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005656:Fungal Proteins; D018698:Glutamic Acid / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D007113:Immunity, Innate; D009569:Nitric Oxide / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D017470:Receptors, Glutamate / Q000378:metabolism*; D014026:Nicotiana / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D020418:Algal Proteins; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D005656:Fungal Proteins; D010940:Plant Proteins; D017470:Receptors, Glutamate; C061032:cryptogein protein, Phytophthora cryptogea; D009569:Nitric Oxide; D018698:Glutamic Acid; D002118:Calcium