Is nitrate reductase a major player in the plant NO (nitric oxide) game?
Nitric oxide (NO) is a diffusible, very reactive gas that is involved in the regulation of many processes in plants. Several enzymatic sources of NO production have been identified in recent years. Nitrate reductase (NR) is one of them and it has been shown that this well-known plant protein, apart from its role in nitrate reduction and assimilation, can also catalyse the reduction of nitrite to NO. This reaction can produce large amounts of NO, or at least more than is needed for signalling, as some escape of NO to the outside medium can be detected after NR activation. A role for NO and NR in stomata functioning in response to abscisic acid has also been proposed. The question that remains is whether this NR-derived NO is a signalling molecule or the mere product of an enzymatic side reaction like the products generated by the oxygenase activity of RuBisCO.
Meyer
Christian
C
Unité de Nutrition Azotée des Plantes, Institut Jean-Pierre Bourgin, INRA, F-78026 Versailles Cedex, France. meyer@versailles.inra.fr
Lea
Unni S
US
Provan
Fiona
F
Kaiser
Werner M
WM
Lillo
Cathrine
C
D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D018515:Plant Leaves / Q000502:physiology; D010944:Plants / Q000201:enzymology*; D015398:Signal Transduction
D009569:Nitric Oxide; D009565:Nitrate Reductases; D050901:Nitrate Reductase