Identification of glutathione degradation pathway and study on its physiological functions in plants
Research members： Naoko Ohkama-Ohtsu PhD.
Research fields： Agricultural chemistry
Departments： Institute of Agriculture
Keywords： glutathione, plant ,sulfur metabolism,plant nutrition
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Summary
Plants take up sulfur in the form of sulfate and assimilate it into organic sulfur. Glutathione, a tripeptide of Glu-Cys-Gly, is one of the major forms of organic sulfur and exists in all organisms. In plants, high concentration of glutathione is found in phloem sup, suggesting that organic sulfur is stored and transported as glutathione. After transportation, glutathione is degraded and metabolized into various sulfur containing molecules such as proteins, coenzymes, secondary metabolites, which have important functions in plant growth and stress responses. Other than storage and transport of organic sulfur, glutathione have functions in detoxification of oxidative stress as an antioxidant or regulation of redox status in cells. Our study is to identify all enzymes for glutathione degradation and to analyze their roles in distribution of sulfur and nitrogen in plants. And our goal is to find ways to improve plant growth and functions by regulating them.
Reference articles and patents
1) Ohkama-Ohtsu, N., Sasaki-Sekimoto, Y., Oikawa, A., Jikumaru, Y. Shinoda, S., Inoue, E., Kamide, Y., Yokoyama, T., Hirai, M.Y., Shirasu, K., Kamiya, Y., Oliver, D.J. and Saito, K.(2011) 12-Oxo-phytodienoic acid - glutathione conjugate is transported into the vacuole in Arabidopsis. Plant and Cell Physiology, 52, 205-209
2) Ohkama-Ohtsu, N., Fukuyama, K. and Oliver, D.J.(2009) Roles of γ-glutamyl transpeptidase and γ-glutamyl cyclotransferase in glutathione and glutathione-conjugate metabolism in plants. Advance in Botanical Research, 52, 87-113
3) Ohkama-Ohtsu, N., Oikawa, A., Zhao, P., Xiang, C., Saito, K. and Oliver, D.J. (2008) A γ-glutamyl transpeptidase-independent pathway of glutathione catabolism to glutamate via 5-oxoproline in Arabidopsis. Plant Physiology, 148, 1603-1613
4) Ohkama-Ohtsu, N., Zhao, P., Xiang, C. and Oliver, D.J. (2007) Glutathione conjugates in the vacuole are degraded by γ-glutamyl transpeptidase GGT3 in Arabidopsis. The Plant Journal, 49, 878-888
Contact
University Research Administration Center(URAC),
Tokyo University of Agriculture andTechnology
urac[at]ml.tuat.ac.jp
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