1997 Fiscal Year Final Research Report Summary
Localization of nitrogen-related enzymes in higher plants
| Project/Area Number |
08044187
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | Tohoku University |
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Principal Investigator |
YAMAYA Tomoyuki Tohoku University, Faculty of Agriculture, Professor, 農学部, 教授 (30144778)
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| Co-Investigator(Kenkyū-buntansha) |
HAYAKAWA Toshihiko Tohoku University, Faculty of Agriculture, Assistant Professor, 農学部, 助手 (60261492)
ALYSON K Tob St. Andrews大学, 生物学科, 準教授
TOBIN Alyson K. Univ.of St.Andrews, School of Biol.Sci., Associate Professor
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| Project Period (FY) |
1996 – 1997
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| Keywords | rice / barley / glutamate synthase / immuno-gold / intracellular localizatio / nitrogen utilization / gene structure / gene expression |
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| Research Abstract |
NADH-dependent glutamate synthase (GOGAT) is a key enzyme in nitrogen assimilation and utilization in higher plants. However, little is known on the intracellular localization and molecular properties of this enzyme.
In this joint research, intracellular localization of this enzyme protein has been demonstrated by the methods of immuno-gold electron microscopy in rice roots. As the first instance, we determine that the NADH-GOGAT protein locates in plastids of epidermis, exodermis, and central cylinder of the roots. We also succeeded to purify the enzyme from barley roots.
Further, genomic clones, as well as cDNA clones, for rice NADH-GOGAT have been isolated and sequenced and the gene structure was thoroughly analyzed. The nucleotide sequences were registered into a Gene-Bank. Expression of this gene has been studied in response to the nitrogen supply in the roots of rice seedlings. The NADH-GOGAT gene is specifically induced within 3 hr after the supply of NH_4^+ among another GOGAT gene and glutamine synthetase genes. When the content of NADH-GOGAT protein in developing leaves were compared among various types of rice, i.e.japonica, indica, and javanica, the leaves in indica-type rice contained less amounts of the protein than those in japonica-type.
From those studies, molecular and physiological properties of NADH-GOGAT are getting clear, at least in rice plants.
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