Globally indigenous nitrogen in soil cannot meet the crop requirement at contemporary production levels. Synthetic nitrogenous fertilisers along with other nutrients have to be applied to sustain existing production and, in many countries, further increase crop production commensurate with their population growth. Nitrogen use efficiency of crops is abysmally low (25–50 %) under uncontrolled field conditions. This not only is an economic loss, but the unutilised nitrogen also causes environmental pollution.
Nitrogen is taken up by plants as NO3 − and NH4 +. It has been recently found that uptake of both the forms is strictly under genetic control. There are high-affinity transporters, which carry the ions across the plasma membrane of root cells when their concentrations in the growth medium are low as well as low-affinity transporters when the concentrations are high. Many of these transporters have been characterised and mechanism of their action is known.
Biotechnological approach to improve nitrogen use efficiency includes overexpression of transporters, manipulation of genes involved in N-uptake, N-assimilation and N-translocation. Transgenic GDH-rice plants have been found to have larger number of tillers, spikelet numbers per panicle, higher biomass production, higher grain yield as well as higher NUE than the control plants. AlaAT transgenic rice shows improved NUE at medium and high N-supply.
KeywordsGlutamine Synthetase Nitrate Uptake Glutamine Synthetase Activity Nitrate Transporter Ammonium Transporter
- Anthony DM, Glass D, Britto TD, Kaiser BN, James R, Kinghorn JR, Kronzucker HJ, Anshuman A, Okamoto M, Rawat S, Siddiqi MY, Unkles SF, Vidmar JJ (2002) The regulation of nitrate and ammonium transport systems in plants. J Exp Bot 53(370):855–864, Inorganic Nitrogen Assimilation Special IssueCrossRefGoogle Scholar
- Chichkova SJ, Arellano CP, Vance CP, Herna’ndez G (2001) Transgenic tobacco plants that over express alfalfa NADH-glutamate synthase have higher carbon and nitrogen content. J Exp Biol 52:2079–2087Google Scholar
- Kurai T, Wakayama M, Aoki N, Ohsugi R (2009) Over expression of ZmDof1 in rice alters carbohydrate and nitrogen partitioning. Plant Biol, Abs # P51014Google Scholar
- Lansing AJ, Franceschi VR (2000) The para-veinal mesophyll: a specialised path for intermediary transfer of assimilates in legume leaves. Aust J Plant Physiol 27:757–767Google Scholar
- Mae T, Makino A, Ohira K (1983) Changes in the amounts of ribulose bisphosphate carboxylase synthesized and degraded during the life span of a rice leaf (Oryza sativa L.). Plant Cell Physiol 24:1079–1086Google Scholar
- Martin A, Lee J, Kichey T, Gerentes D, Zivy M, Tatout C, Dubois F, Balliau T, Valot B, Davanture M, Terce-Laforgue T, Quillere I, Coque M, Gallais A, Gonzalez-Moro M, Bethencourt L, Habash D, Lea P, Charcosset A, Perez P, Murigneux A, Sakakibara H, Edwards K, Hirel B (2006) Two cytosolic glutamine synthetase isoforms of maize are specifically involved in the control of grain production. Plant Cell 18:3252–3274CrossRefPubMedCentralPubMedGoogle Scholar
- Naohiro A, Tomohito E, Akira K, Tomomi A, Masataka W, Haruto S, Ryu O (2009) Genetic modification of nitrogen use efficiency in potato and rice by introducing fungal glutamate dehydrogenase, American Society of Plant Biologists. Plant Biol, 2009, Honolulu, Hawaii, Abs # P39004Google Scholar
- Quaggiotti S, Ruperti B, Borsa P, Destro T, Malagoli M (2003) Expression of a putative high‐affinity NO3– transporter and of an H+−ATPase in relation to whole plant nitrate transport physiology in two maize genotypes differently responsive to low nitrogen availability. J Exp Bot 54(384):1023–1031CrossRefPubMedGoogle Scholar
- Rolletschek H, Hosein F, Miranda M, Heim U, Götz KP, Schlereth A, Borisjuk L, Saalbach I, Wobus U, Weber H (2005) Ectopic expression of an amino acid transporter (VfAAP1) in seeds of Vicia narbonensis and pea increases storage proteins. Plant Physiol 137:1236–1249CrossRefPubMedCentralPubMedGoogle Scholar
- Shaw L (2009) The Dof transcription factor family in Triticum aestivum. PhD thesis, School of Biological Sciences, The University of QueenslandGoogle Scholar
- Sperandio MVL, Santos LA, de Araujo OJL, Braga RP, Coelho CP, Nogueira EM, Fernandes MS, de Souza SR (2014) Response of nitrate transporters and PM H+−ATPase expression to nitrogen flush on two upland rice varieties contrasting in nitrate uptake kinetics. Aust J Crop Sci 8(4):568–576Google Scholar
- Walch-Liu P, Forde BG (2008) Nitrate signaling mediated by the NRT1.1 nitrate transporter antagonizes L-glutamate-induced changes in root architecture. Plant J 54(5):820–828. Epub 2008 Feb 7Google Scholar