title: Peptidoglycan and muropeptides from pathogens Agrobacterium and Xanthomonas elicit plant innate immunity: structure and activity.
abstract: Peptidoglycan (PGN) is a unique and essential structural part of the bacterial cell wall. PGNs from two contrasting Gram-negative plant pathogenic bacteria elicited components characteristic of the innate immune system in Arabidopsis thaliana, such as transcription of the defense gene PR1, oxidative burst, medium alkalinization, and formation of callose. Highly purified muropeptides from PGNs were more effective elicitors of early defense responses than native PGN. Therefore, PGN and its constituents represent a Microbe-Associated Molecular Pattern (MAMP) in plant-bacterial interactions. PGN and muropeptides from aggressive Xanthomonas campestris pv. campestris were significantly more active than those from Agrobacterium tumefaciens, which must maintain host cell viability during infection. The structure of muropeptide components and the distinctive differences are described. Differing defense-eliciting abilities appear to depend on subtle structural differences in either carbohydrate or peptide groups.
authors.affiliation: Faculty of Life Sciences, Department of Plant Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Gitte
authors.initials: G
authors.lastname: Erbs
authors.forename: Alba
authors.initials: A
authors.lastname: Silipo
authors.forename: Shazia
authors.initials: S
authors.lastname: Aslam
authors.forename: Cristina
authors.initials: C
authors.lastname: De Castro
authors.forename: Valeria
authors.initials: V
authors.lastname: Liparoti
authors.forename: Angela
authors.initials: A
authors.lastname: Flagiello
authors.forename: Pietro
authors.initials: P
authors.lastname: Pucci
authors.forename: Rosa
authors.initials: R
authors.lastname: Lanzetta
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
authors.forename: Mari-Anne
authors.initials: MA
authors.lastname: Newman
authors.forename: Richard M
authors.initials: RM
authors.lastname: Cooper
mesh_terms: D002118:Calcium / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D017343:Genes, Plant; D007113:Immunity, Innate / Q000187:drug effects*; D013058:Mass Spectrometry / Q000379:methods; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010457:Peptidoglycan / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D010944:Plants / Q000235:genetics / Q000276:immunology*; D012231:Rhizobium / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014974:Xanthomonas / Q000737:chemistry*
chemical_list: D010455:Peptides; D010457:Peptidoglycan; D002118:Calcium