Effects of tabtoxin on nitrogen metabolism

Turner, JG, Taha, RR and Debbage, J (1986) Effects of tabtoxin on nitrogen metabolism. Physiologia Plantarum, 67 (4). pp. 649-653. ISSN 0031-9317

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Abstract

Tabtoxin is a chlorosis-inducing toxin produced by the plant pathogenic bacterium Pseudomonas syringae pv. tabaci. Previous studies have indicated that tabtoxin inhibits glutamine synthetase (EC 6.3.1.2) in vitro. We report here that tabtoxin also inhibits glutamine synthetase in vivo. The main evidence was that assimilation of exogenous 15NH3 into Asparagus sprengeri protein was rapidly inhibited in isolated cells exposed to tabtoxin. This was associated with an equivalent decline in glutamine synthetase activity in extracts of these cells and the accumulation of extracellular ammonia. Glutamine synthetase was also inhibited in leaves of Nicotiana tabacum L. cv. White Burley treated with tabtoxin and the affected tissue accumulated ammonia and became chlorotic. However, the development of symptoms and accumulation of ammonia was suppressed when the leaves were held in air containing 1% CO2 to reduce photorespiration. This indicates that the chlorotic symptom did not result from the inhibition of nitrogen assimilation but was a consequence of the interruption of the photorespiratory nitrogen cycle.

Item Type: Article
Faculty \ School: Faculty of Science > School of Biological Sciences
Related URLs:
Depositing User: Deborah Clemitshaw
Date Deposited: 13 Sep 2011 09:31
Last Modified: 16 Jan 2019 14:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/34738
DOI: 10.1111/j.1399-3054.1986.tb05072.x

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