Pedosphere 20(5): 623--632, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Characterization of nitrogen metabolism in the low-nitrogen tolerant lnt1 mutant of Arabidopsis thaliana under nitrogen stress
TENG Yi-Bo1, LI Ya-Juan2, FANG Ping1,2 and LA Gui-Xiao1
1 Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029 (China)
2 Zhejiang Provincial Key Laboratory of Subtropical Soil Science and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029 (China)
ABSTRACT
      A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen (N) metabolism of a low-N tolerant mutant (lnt1) of Arabidopsis thaliana under different N levels as compared with the wildtype (WT) Arabidopsis. On the agar medium, no apparent growth differences were observed between the lnt1 and WT plants under a normal N level of 9 mmol L-1 NO3-. However, under a low N level of 0. 18 mmol L-1 NO3-, the growth of the WT plants was greatly retarded, while the lnt1 plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lnt1 mutant had higher activities of glutamine synthetase (GS) and NADH-dependent glutamate synthase (NADH-GOGAT) in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium (NH4+) but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.
Key Words:  ammonium, free amino acids, glutamate synthase, glutamine synthetase, nitrogen assimilation
Citation: Teng, Y. B., Li, Y. J., Fang, P. and La, G. X. 2010. Characterization of nitrogen metabolism in the low-nitrogen tolerant lnt1 mutant of Arabidopsis thaliana under nitrogen stress. Pedosphere. 20(5): 623-632.
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