This Article Full Text Full Text (PDF) All Versions of this Article: 142/3/901    most recent pp.106.085514v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Related articles in Plant Physiol. Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Igarashi, D. Articles by Ohsumi, C. Search for Related Content PubMed PubMed Citation Articles by Igarashi, D. Articles by Ohsumi, C. Agricola Articles by Igarashi, D. Articles by Ohsumi, C.

BIOENERGETICS AND PHOTOSYNTHESIS

Glutamate:Glyoxylate Aminotransferase Modulates Amino Acid Content during Photorespiration¹

Institute of Life Sciences, Ajinomoto Company, Inc., Kawasaki 210–8681, Japan (D.I., C.O.); and National Institute of Agrobiological Sciences, Tsukuba 305–8602, Japan (H.T., M.M.)

In photorespiration, peroxisomal glutamate:glyoxylate aminotransferase (GGAT) catalyzes the reaction of glutamate and glyoxylate to produce 2-oxoglutarate and glycine. Previous studies demonstrated that alanine aminotransferase-like protein functions as a photorespiratory GGAT. Photorespiratory transamination to glyoxylate, which is mediated by GGAT and serine glyoxylate aminotransferase (SGAT), is believed to play an important role in the biosynthesis and metabolism of major amino acids. To better understand its role in the regulation of amino acid levels, we produced 42 GGAT1 overexpression lines that express different levels of GGAT1 mRNA. The levels of free serine, glycine, and citrulline increased markedly in GGAT1 overexpression lines compared with levels in the wild type, and levels of these amino acids were strongly correlated with levels of GGAT1 mRNA and GGAT activity in the leaves. This accumulation began soon after exposure to light and was repressed under high levels of CO₂. Light and nutrient conditions both affected the amino acid profiles; supplementation with NH₄NO₃ increased the levels of some amino acids compared with the controls. The results suggest that the photorespiratory aminotransferase reactions catalyzed by GGAT and SGAT are both important regulators of amino acid content.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Daisuke Igarashi (daisuke_igarashi{at}ajinomoto.com).

www.plantphysiol.org/cgi/doi/10.1104/pp.106.085514

^* Corresponding author; e-mail daisuke_igarashi{at}ajinomoto.com; fax 81–44–244–9617.

Received June 21, 2006; accepted August 17, 2006; published September 1, 2006.

Related articles in Plant Physiol.:

On the Inside

Peter V. Minorsky
Plant Physiol. 2006 142: 807-808. [Full Text]  

This article has been cited by other articles:

				V. Tavernier, S. Cadiou, K. Pageau, R. Lauge, M. Reisdorf-Cren, T. Langin, and C. Masclaux-Daubresse The plant nitrogen mobilization promoted by Colletotrichum lindemuthianum in Phaseolus leaves depends on fungus pathogenicity J. Exp. Bot., September 1, 2007; 58(12): 3351 - 3360. [Abstract] [Full Text] [PDF]

				B. G. Forde and P. J. Lea Glutamate in plants: metabolism, regulation, and signalling J. Exp. Bot., July 1, 2007; 58(9): 2339 - 2358. [Abstract] [Full Text] [PDF]