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Nitrate reductase regulation in tomato roots by exogenous nitrate: a possible role in tolerance to long-term root anoxia

Allègre, Adeline and Silvestre, Jérôme and Morard, Philippe and Kallerhoff, Jean and Pinelli, Eric Nitrate reductase regulation in tomato roots by exogenous nitrate: a possible role in tolerance to long-term root anoxia. (2004) Journal of Experimental Botany, Vol. 55 (n° 408). pp. 2625-2634. ISSN 2473-2482

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Official URL: http://dx.doi.org/10.1093/jxb/erh258

Abstract

The mechanism of nitrate reductase (NR) regulation under long-term anoxia in roots of whole plants and the putative role of nitrate in anoxia tolerance have been addressed. NR activity in tomato roots increased significantly after 24 h of anaerobiosis and increased further by 48 h, with a concomitant release of nitrite into the culture medium. Anoxia promoted NR activation through dissociation of the 14-3-3 protein inhibitor and NR dephosphorylation. After 24 h of anoxia, the total amount of NR increased slightly up to 48 h. However, NR-mRNA levels remained constant between 0 h and 24 h of root anoxia and decreased after 48 h. This is probably due to the inhibition of NR degradation and the accumulation of its native form. NR was slightly dephosphorylated in the absence of oxygen and nitrate. Under anoxia, NR dephosphorylation was modulated by nitrate-controlled NR activity. In addition, the presence of nitrate prevents anoxic symptoms on leaves and delays wilting by 48 h during root anoxia. In the absence of nitrate, plants withered within 24 h, as they did with tungstate treatment, an inhibitor of NR activity. Thus, anoxia tolerance of tomato roots could be enhanced by nitrate reduction.

Item Type:Article
Additional Information:Thanks to Oxford University Press editor. This article is available on the Journal of Experimental Botany website http://jxb.oxfordjournals.org/content/55/408/2625
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution: Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
French research institutions > Centre National de la Recherche Scientifique - CNRS
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Deposited By: Florence Amor

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