Responses of two rice cultivars differing in seedling-stage nitrogen use efficiency to growth under low-nitrogen conditions
Demand for low-input nitrogen sustainable rice is increasing to meet the need for environmentally friendly agriculture and thus development of rice with high nitrogen use efficiency (NUE) is a major objective. Hence, understanding how rice responds to growth under low-nitrogen conditions is essential to devise new ways of manipulating genes to improve rice NUE. In this study, using two rice varieties with different seedling-stage NUE obtained from previous field experiments, we investigated the physiological and molecular responses of young rice to low-nitrogen conditions. Our results suggest that glutamine synthetase (GS) and NADH-dependent glutamate synthase (NADH-GOGAT) play important roles in N assimilation of seedling rice roots under low-nitrogen conditions; the regulatory mechanisms of GS and NADH-GOGAT in seedling rice roots do not occur at the transcription level, and may be posttranscriptional; OsAMT1;1 play important roles in rice N acquisition by partially regulating N uptake under low-nitrogen conditions; and OsAMT1;1 and OsNRT2;1 also play important roles in rice N acquisition by partially regulating root growth and development under low-nitrogen conditions. The challenge for future studies is to characterize the functional roles of GS, NADH-GOGAT, OsAMT1;1, and OsNRT2;1 in young rice NUE using RNAi and mutant techniques.
KeywordsGlutamine synthetase NADH-dependent glutamate synthase Nitrogen use efficiency OsAMT1;1 OsNRT2;1 Seedling-stage rice
We sincerely thank Professor Andre Jagendorf (Cornell University) for a critical review of the manuscript. The present investigation was financially supported by grants from the National 973 Project (No. 2007CB109303), CAS Knowledge Innovation Project (No. KSCX2-YW-N-002), and the National Natural Science Foundation of China (No. 30390083).
- Britto DT, Kronzucker HJ (2004) Biotechnology of nitrogen acquisition in rice — Implication for food security. In: Amancio S, Stulen I (eds) Plant ecophysiology, Nitrogen acquisition and assimilation in higher plants. Kluwer Academic Publishers, 261–281Google Scholar
- Gansel X, Munos S, Tillard P, Gojon A (2001) Differential regulation of the NO3- and NH4 + transporter genes AtNrt2.1 and AtAmt1.1 in Arabidopsis: relation with long-distance and local controls by N status of the plant. Plant J 26:143–155. doi: 10.1046/j.1365-313x.2001.01016.x CrossRefPubMedGoogle Scholar
- Hirel B, Bertin P, Quillere I, Bourdoncle W, Attagnant C, Dellay C, Gouy A, Cadiou S, Retailliau C, Falque M, Gallais A (2001) Towards a better understanding of the genetic and physiological basis for nitrogen use efficiency in Maize. Plant Physiol 125:1258–1270. doi: 10.1104/pp.125.3.1258 CrossRefPubMedGoogle Scholar
- Kumar A, Silim S, Okamoto M, Siddiqi MY, Glass ADM (2003) Differential expression of three members of the AMT1 gene family encoding putative high-affinity NH4+ transporters in roots of Oryza sativa subspecies indica. Plant Cell Environ 26:907–914. doi: 10.1046/j.1365-3040.2003.01023.x CrossRefPubMedGoogle Scholar
- Lejay L, Tillard P, Lepetit M, Domingo OF, Filleur S, Daniel VF, Gojon A (1999) Molecular and functional regulation of two NO3- uptake systems by N- and C-status of Arabidopsis plants. Plant J 26:143–155Google Scholar
- Loqué D, Yuan LX, Kojima S, Gojon A, Wirth J, Gazzarrini S, Ishiyama K, Takahashi H, von Wirén N (2006) Additive contribution of AMT1;1 and AMT1;3 to high-affinity ammonium uptake across the plasma membrane of nitrogen-deficient Arabidopsis roots. Plant J 48:522–534. doi: 10.1111/j.1365-313X.2006.02887.x CrossRefPubMedGoogle Scholar
- Ni PS (1985) Water and mineral nutrition. In: Xue YL, Xia ZA (eds) Laboratory manual for plant physiology study. Shanghai Society of Plant Physiologists, Shanghai, pp 57–66Google Scholar
- Remans T, Nacry P, Pervent M, Girin T, Tillard P, Lepetit M, Gojon A (2006) A central role for the nitrate transporter NRT2.1 in the integrated morphological and physiological responses of the root system to nitrogen limitation in Arabiopsis. Plant Physiol 140:909–921. doi: 10.1104/pp.105.075721 CrossRefPubMedGoogle Scholar
- Tony R, Nacry P, Pervent M, Girin T, Tillard P, Lepetit M, Gojon A (2006) A central role for the nitrate transporter NRT2.1 in the integrated morphological and physiological responses of the root system to nitrogen limitation in Arabidopsis. Plant Physiol 140:909–921. doi: 10.1104/pp.105.075721 CrossRefGoogle Scholar
- UNEP (1999) Global environment outlook 2000. United Nations Environment Programme and London Earthscan, NairobiGoogle Scholar
- Zhao SP, Zhao XQ, Shi WM (2006) Differentiation of nitrogen uptake of rice seedlings (Oryza Sativa L.) of cultivars different in nitrogen use efficiency and its mechanism. Soil 38:400–409 in ChineseGoogle Scholar