title: Identification of three elicitins and a galactan-based complex polysaccharide from a concentrated culture filtrate of Phytophthora infestans efficient against Pectobacterium atrosepticum.
abstract: The induction of plant immunity by Pathogen Associated Molecular Patterns (PAMPs) constitutes a powerful strategy for crop protection. PAMPs indeed induce general defense responses in plants and thus increase plant resistance to pathogens. Phytophthora infestans culture filtrates (CCFs) are known to induce defense responses and decrease the severity of soft rot due to Pectobacterium atrosepticum in potato tubers. The aim of this study was to identify and characterize the active compounds from P. infestans filtrate. The filtrate was fractionated by gel filtration, and the protection effects against P. atrosepticum and the ability to induce PAL activity were tested for each fraction. The fraction active in protection (F1) also induced PAL activity, as did the whole filtrate. Three elicitins (INF1, INF4 and INF5) were identified in F1b, subfraction of F1, by MALDI-TOF-MS and MS/MS analyses. However, deproteinized F1b still showed biological activity against the bacterium, revealing the presence of an additional active compound. GC-MS analyses of the deproteinized fraction highlighted the presence of a galactan-based complex polysaccharide. These experiments demonstrate that the biological activity of the CCF against P. atrosepticum results from a combined action of three elicitins and a complex polysaccharide, probably through the activation of general defense responses.
authors.affiliation: INRA, UMR1349 IGEPP, Le Rheu-Cedex F-35653, France. guillaume.saubeau@agrocampus-ouest.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Saubeau
authors.affiliation: CNRS-Université Pierre et Marie Curie, FR2424, Station Biologique de Roscoff, Roscoff-Cedex 29682, France. gaillard@sb-roscoff.fr.
authors.forename: Fanny
authors.initials: F
authors.lastname: Gaillard
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, Rennes Cedex 7 35708, France. laurent.legentil@ensc-rennes.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Legentil
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, Rennes Cedex 7 35708, France. florence.val@agrocampus-ouest.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Nugier-Chauvin
authors.affiliation: Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, Rennes Cedex 7 35708, France. vincent.ferrieres@ensc-rennes.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Ferrières
authors.affiliation: INRA, UMR1349 IGEPP, Le Rheu-Cedex F-35653, France. didier.andrivon@rennes.inra.fr.
authors.forename: Didier
authors.initials: D
authors.lastname: Andrivon
authors.affiliation: Agrocampus Ouest, UMR1349 IGEPP, Rennes F-35000, France. florence.val@agrocampus-ouest.fr.
authors.forename: Florence
authors.initials: F
authors.lastname: Val
mesh_terms: D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D005591:Chemical Fractionation; D004789:Enzyme Activation / Q000187:drug effects; D008969:Molecular Sequence Data; D044043:Pectobacterium / Q000187:drug effects*; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D055750:Phytophthora infestans / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology*; D011506:Proteins / Q000737:chemistry / Q000494:pharmacology*; D016415:Sequence Alignment; D011198:Solanum tuberosum / Q000187:drug effects / Q000201:enzymology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D011134:Polysaccharides; D011506:Proteins; C085101:elicitin, Phytophthora; D010650:Phenylalanine Ammonia-Lyase