title: Nitrate reductase, nitrite reductase, glutamine synthetase, and glutamate synthase expression and activity in response to different nitrogen sources in nitrogen-starved wheat seedlings.
abstract: The objective of this study was to examine the expression and activity of nitrate reductase (NR, EC 1.7.1.1), nitrite reductase (NiR, EC 1.7.2.2), glutamine synthetase (GS, EC 6.3.1.2), and glutamate synthase (GOGAT, EC 1.4.7.1) in response to potassium nitrate, ammonium chloride, and ammonium nitrate in nitrogen-starved wheat seedlings. Plants were grown in standard nutrient solution for 17 days and then subjected to nitrogen starvation for 7 days. The starved plants were supplied with potassium nitrate ammonium nitrate and ammonium chloride (50 mM) for 4 days and the leaves were harvested. The relative expression of NR, NiR, GS, and GOGAT as well as the enzyme activities were investigated. Nitrogen starvation caused a significant decrease both in transcript levels and in NR, NiR, GS, and GOGAT activities. Potassium nitrate and ammonium nitrate treatments restored NR, NiR, GS, and GOGAT expressions and activities. Ammonium chloride increased only the expressions and activities of GS and GOGAT in a dose-dependent manner. The results of our study highlight the differential effects between the type and the amount of nitrogen salts on NR, NiR, GS, and GOGAT activities in wheat seedlings while potassium nitrate being more effective.
authors: Institute of Biotechnology, Shiraz University, Shiraz, Iran.
authors: Sadegh
authors: S
authors: Balotf
authors: Institute of Biotechnology, Shiraz University, Shiraz, Iran.
authors: Gholamreza
authors: G
authors: Kavoosi
authors: Department of Biology, Faculty of Sciences, Shiraz University, Shiraz, Iran.
authors: Bahman
authors: B
authors: Kholdebarin
mesh_terms: D004789:Enzyme Activation; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D005970:Glutamate Synthase / Q000235:genetics / Q000378:metabolism*; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism*; D050901:Nitrate Reductase / Q000235:genetics / Q000378:metabolism*; D009572:Nitrite Reductases / Q000235:genetics / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D012313:RNA / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D036226:Seedlings / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D014908:Triticum / Q000737:chemistry / Q000378:metabolism*
chemical_list: D012313:RNA; D005970:Glutamate Synthase; D009572:Nitrite Reductases; D050901:Nitrate Reductase; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen
keywords: glutamate synthase; glutamine synthetase; nitrate reductase; nitrite reductase; wheat seedlings