Use of a new tetrazolium-based assay to study the production of superoxide radicals by tobacco cell cultures challenged with avirulent zoospores of Phytopthora parasitica var nicotianae

Able, Amanda J. and Guest, David I. and Sutherland, Mark W. (1998) Use of a new tetrazolium-based assay to study the production of superoxide radicals by tobacco cell cultures challenged with avirulent zoospores of Phytopthora parasitica var nicotianae. Plant Physiology, 117 (2). pp. 491-499. ISSN 1532-2548

Abstract

The relationship between the production of reactive oxygen species and the hypersensitive response (HR) of tobacco (Nicotiana tabacum L.) toward an incompatible race of the Oomycete Phytophthora parasitica var nicotianae has been investigated. A new assay for superoxide radical (O2 2) production based on reduction of the tetrazolium dye sodium,3*-(1-[phenylamino-carbonyl]-3,4- tetrazolium)-bis(4-methoxy-6-nitro) benzene-sulfonic acid hydrate (XTT) has enabled the quantitative estimation of perhydroxyl/superoxide radical acid-base pair (HO2 z/O2 2) production during the resistant response. Tobacco suspension cells were inoculated with zoospores from compatible or incompatible races of the pathogen. Subsequent HO2 z/O2 2 production was monitored by following the formation of XTT formazan. In the incompatible interaction only, HO2 z/O2 2 was produced in a minor burst between 0 and 2 h and then in a major burst between 8 and 10 h postinoculation. During this second burst, rates of XTT reduction equivalent to a radical flux of 9.9 3 10215 mol min21 cell21 were observed. The HO2 z/O2 2 scavengers O2 2 dismutase and Mn(III)desferal each inhibited dye reduction. An HR was observed in challenged, resistant cells immediately following the second burst of radical production. Both scavengers inhibited the HR when added prior to the occurrence of either radical burst, indicating that O2 2 production is a necessary precursor to the HR.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Author's version unavilable in electronic format.
Depositing User: Prof Mark Sutherland
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 31 Jul 2008 01:11
Last Modified: 28 Oct 2013 04:26
Fields of Research (FOR2008): 06 Biological Sciences > 0607 Plant Biology > 060704 Plant Pathology
URI: http://eprints.usq.edu.au/id/eprint/3147

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