Open AccessThe Pto kinase mediates a signaling pathway leading to the oxidative burst in tomato
Author(s) -
Sreeganga S. Chandra,
Gregory B. Martin,
Philip S. Low
Publication year - 1996
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.93.23.13393
Subject(s) - pseudomonas syringae , respiratory burst , biology , transgene , kinase , pathogen , hypersensitive response , microbiology and biotechnology , plant disease resistance , gene , biochemistry , genetics
ThePto gene encodes a serine/threonine kinase that confers resistance in tomato toPseudomonas syringae pv.tomato strains that express the avirulence geneavrPto . Partial characterization of thePto signal transduction pathway and the availability of transgenic tomato lines (±Pto ) make this an ideal system for exploring the molecular basis of disease resistance. In this paper, we test two transgenic tomato cell suspension cultures (±Pto ) for production of H2 O2 following independent challenge with two strains ofP. syringae pv.tomato (±avrPto ). Only whenPto andavrPto are present in the corresponding organisms are two distinct phases of the oxidative burst seen, a rapid first burst followed by a slower and more prolonged second burst. In the remaining three plant–pathogen interactions, we observe either no burst or only a first burst, indicating that the second burst is correlated with disease resistance. Further support for this observation comes from the finding that both resistant and susceptible tomato lines produce the critical second oxidative burst when challenged withP. syringae pv.tabaci , a nonhost pathogen that elicits a hypersensitive response on both tomato lines. ThePto kinase is not required, however, for the oxidative burst initiated by non-specific elicitors such as oligogalacturonides or osmotic stress. A model describing a possible role for thePto kinase in the overall scheme of oxidative burst signaling is proposed.