title: Degeneration of hrpZ gene in Pseudomonas syringae pv. tabaci to evade tobacco defence: an arms race between tobacco and its bacterial pathogen.
abstract: The HrpZ harpin of Pseudomonas syringae is known to induce a hypersensitive response (HR) in some plants. In P. syringae pv. tabaci (Pta), the harpin gene hrpZ has been spontaneously disrupted by an internal deletion in its open reading frame and a frame shift. The loss of the ability of the recombinant harpin polypeptide of Pta to induce HR despite the high sensitivity of tobacco plants to harpin led us to investigate the meaning of the disrupted hrpZ gene in the virulence of Pta 6605. The hrpZ gene from P. syringae pv. pisi was introduced into wild-type (WT) Pta. The hrpZ-complemented Pta secreted harpin into the culture medium, but failed to cause disease symptoms by both infiltration and spray inoculation. Inoculation with the hrpZ-complemented Pta induced defence responses in tobacco plants, whereas the defence responses of tobacco plants were not prominent on inoculation with WT Pta. These results indicate that an ancestor of Pta might have disrupted hrpZ by an internal deletion to evade plant defences and confer the ability to cause disease in tobacco plants.
authors: Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Okayama 700-8530, Japan.
authors: Kazuhiko
authors: K
authors: Tsunemi
authors: Fumiko
authors: F
authors: Taguchi
authors: Mizuri
authors: M
authors: Marutani
authors: Megumi
authors: M
authors: Watanabe-Sugimoto
authors: Yoshishige
authors: Y
authors: Inagaki
authors: Kazuhiro
authors: K
authors: Toyoda
authors: Tomonori
authors: T
authors: Shiraishi
authors: Yuki
authors: Y
authors: Ichinose
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D014026:Nicotiana / Q000382:microbiology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; C087295:HrpZ protein, Pseudomonas syringae