HrpZ harpins from different Pseudomonas syringae pathovars differ in molecular interactions and in induction of anion channel responses in Arabidopsis thaliana suspension cells

► Responses of Arabidopsis suspension cells to different variants of HrpZ harpin. ► HrpZ from compatible (Pto) and incompatible (Pph) strains of Pseudomonas syringae. ► HrpZ(Pto) induced an anion current increase while HrpZ(Pph) did not. ► A mutation in HrpZ(Pto) peptide-binding region changed the anion channel response. ► HrpZ(Pto) and HrpZ(Pph) have different sequence preferences for peptide-binding.