Relationship between transembrane ion movements, production of reactive oxygen species and the hypersensitive response during the challenge of tobacco suspension cells by zoospores of Phytophthora nicotianae

Able, Amanda J. and Guest, David I. and Sutherland, Mark W. (2001) Relationship between transembrane ion movements, production of reactive oxygen species and the hypersensitive response during the challenge of tobacco suspension cells by zoospores of Phytophthora nicotianae. Physiological and Molecular Plant Pathology, 58 (5). pp. 189-198. ISSN 0885-5765

Abstract

We have examined the responses of suspension cultured tobacco cells after inoculation with zoospores from compatible or incompatible races of the Oomycete pathogen Phytophthora nicotianae. The incompatible interaction, characterized by the production of reactive oxygen species (ROS) (speci®cally superoxide (HO�2=Oÿ2 ) and hydrogen peroxide (H2O2)), and by a hypersensitive response (HR), was not dependent upon the presence of exogenous calcium. However, perturbation of calcium ion movements by EGTA or LaCl3 suppressed both ROS production and the extent of cell death. The Ca2�-speci®c ionophore, A23187, slightly enhanced ROS production during the incompatible interaction but had no e�ect on the responses of susceptible or unchallenged cells. These results con®rm that both ROS production and the HR are potentiated by movement of endogenous calcium across the plasmalemma. While there was no evidence of a transmembrane K�/H� exchange immediately following incompatible zoospore challenge, a later potassium e�ux from cells coincided with the onset of the HR. Unexpectedly, medium pH drifted downwards during all host cell responses suggesting that alkaline peroxidases are not the major source of ROS generation during an incompatible tobacco cell/zoospore interaction.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Author's version unavailable in electronic format.
Depositing User: Prof Mark Sutherland
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 17 Jul 2008 23:58
Last Modified: 28 Oct 2013 04:30
Uncontrolled Keywords: calcium, hydrogen peroxide, HR, Nicotiana tabacum, Phytophthora nicotianae, plant-, pathogen interactions, ROS, superoxide, XTT, potassium, pH
Fields of Research (FOR2008): 06 Biological Sciences > 0607 Plant Biology > 060704 Plant Pathology
Identification Number or DOI: doi: 10.1006/pmpp.2001.0328
URI: http://eprints.usq.edu.au/id/eprint/3150

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