@Article{IPB-1960, author = {Li, C.-M. and Haapalainen, M. and Lee, J. and Nürnberger, T. and Romantschuk, M. and Taira, S.}, title = {{Harpin of Pseudomonas syringae pv. phaseolicola Harbors a Protein Binding Site}}, year = {2005}, pages = {60-66}, journal = {Mol. Plant Microbe Interact.}, doi = {10.1094/MPMI-18-0060}, volume = {18}, abstract = {Harpin HrpZ of plant-pathogenic bacterium Pseudomonas syringae elicits a hypersensitive response (HR) in some nonhost plants, but its function in the pathogenesis process is still obscure. HrpZ-interacting proteins were identified by screening a phage-display library of random peptides. HrpZ of the bean pathogen P. syringae pv. Phaseolicola (HrpZPph) shows affinity to peptides with a consensus amino acid motif W(L)ARWLL(G/L). To localize the peptide-binding site, the hrpZPph gene was mutagenized with randomly placed 15-bp insertions, and the mutant proteins were screened for the peptide-binding ability. Mutations that inhibited peptide-binding localized to the central region of hrpZPph, which is separate from the previously determined HR-inducing region. Antiserum raised against one of the hrpZPph-binding peptides recognized small proteins in bean, tomato, parsley, and Arabidopsis thaliana but none in tobacco. On native protein blots, hrpZPph bound to a bean protein with similar pI as the protein recognized by the peptide antiserum. The result suggests a protein-protein interaction between the harpin and a host plant protein, possibly involved in the bacterial pathogenesis.} }