title: The HrpN(ea) harpin from Erwinia amylovora triggers differential responses on the nonhost Arabidopsis thaliana cells and on the host apple cells.
abstract: Erwinia amylovora is a gram-negative necrogenic bacterium causing fire blight of the Maloideae subfamily of Rosaceae such as apple and pear. It provokes progressive necrosis in aerial parts of susceptible host plants (compatible interaction) and a hypersensitive reaction (HR) when infiltrated in nonhost plants (incompatible interaction). The HrpN(ea) harpin is a type three secretion system effector secreted by E. amylovora. This protein is involved in pathogenicity and HR-eliciting capacity of E. amylovora. In the present study, we showed that, in nonhost Arabidopsis thaliana cells, purified HrpN(ea) induces cell death and H2O2 production, two nonhost resistance responses, but failed to induce such responses in host MM106 apple cells. Moreover, HrpN(ea) induced an increase in anion current in host MM106 apple cells, at the opposite of the decrease of anion current previously shown to be necessary to induce cell death in nonhost A. thaliana cells. These results suggest that HrpN(ea) induced different signaling pathways, which could account for early induced compatible or incompatible interaction development.
authors.affiliation: LEM, EA 3514, Université Paris 7, Case 7069, 2 place Jussieu, 75251 Paris 5, France.
authors.forename: David
authors.initials: D
authors.lastname: Reboutier
authors.forename: Cécile
authors.initials: C
authors.lastname: Frankart
authors.forename: Joël
authors.initials: J
authors.lastname: Briand
authors.forename: Bernadette
authors.initials: B
authors.lastname: Biligui
authors.forename: Sandrine
authors.initials: S
authors.lastname: Laroche
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Rona
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Barny
authors.forename: François
authors.initials: F
authors.lastname: Bouteau
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects* / Q000382:microbiology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D044084:Erwinia amylovora / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D027845:Malus / Q000166:cytology / Q000187:drug effects* / Q000382:microbiology; D010575:Pesticides / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D010575:Pesticides; D015221:Potassium Channels; C075462:harpin protein, Erwinia amylovora