Pedosphere 18(5): 664--673, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Effect of nitrate on activities and transcript levels of nitrate reductase and glutamine synthetase in rice
CAO Yun, FAN Xiao-Rong, SUN Shu-Bin, XU Guo-Hua, HU Jiang and SHEN Qi-Rong
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China). E-mail: youngtsao66@yahoo.com.cn
ABSTRACT
      Real-time polymerase chain reaction analysis was used to compare the effect of NO3- on the activities of nitrate reductase (NR)and glutamine synthetase (GS), and the transcript levels of two NR genes, OsNia1 and OsNia2, two cytosolic GS1 genes, OsGln1;1 and OsGln1;2, and one plastid GS2 gene OsGln2, in two rice (Oryza sativa L.)cultivars Nanguang (NG)and Yunjing (YJ).Both cultivars achieved greater biomass and higher total N concentration when grown in a mixed N supply than in sole NH4+ nutrition.Supply of NO3- increased NR activity in both leaves and roots.Expression of both NR genes was also substantially enhanced and transcript levels of OsNia2 were significantly higher than those of OsNia1.NO3- also caused an increase in GS activity, but had a complex effect on the expression of the three GS genes.In roots, the OsGln1;1 transcript increased, but OsGln1;2 decreased.In leaves OsGln1;2 had no effect on the GS1 expression, but the transcript for OsGln2 increased both in the leaves and roots of rice with a mixed supply of N.These results suggested that the increase in GS activity might be a result of the complicated regulation of the various GS genes. In addition, the NO3- induced increase of biomass, NR activity, GS activity, and the transcript levels of NR and GS genes were proportionally higher in NG than in YJ, indicating a stronger response of NG to NO3- nutrition than YJ.
Key Words:  ammonium, glutamine synthetase, nitrate, nitrate reductase, Oryza sativa L.
Citation: Cao, Y., Fan, X. R., Sun, S. B., Xu, G. H., Hu, J. and Shen, Q. R. 2008. Effect of nitrate on activities and transcript levels of nitrate reductase and glutamine synthetase in rice. Pedosphere. 18(5): 664-673.
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