Poster: Oxidative stress
Abs #
71: The GABA shunt and oxidative stress
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Presenter: |
Fromm, Hillel |
Authors | Fait, Aaron (A) Yellin, Ayelet (B) Fromm, Hillel (B) | | Affiliations: |
(A): Department of Plant Sciences, Weizmann Institute of Science, Israel
(B): Department of Plant Sciences, Tel Aviv University, Israel
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| Web Site: | http://www.tau.ac.il/~hillelf/ | |
The activity of the GABA shunt in plants is rapidly enhanced in response to various biotic and abiotic stresses. Recently we analyzed Arabidopsis T-DNA knockout mutants of the gene encoding succinic semialdehyde dehydrogenase (SSADH), the ultimate enzyme of the pathway. We found that ssadh mutants are hypersensitive to UV light and heat, compared to wt plants, as the mutants develop necrosis when submitted to such stress (Ref. 1). Moreover, UV and heat cause a rapid increase in the levels of hydrogen peroxide in ssadh mutants, which is associated with enhanced cell death (Ref 1). Preliminary results have shown severe impairment of metabolic profiles of the mutants compared to wt plants. Subsequently, we have taken biochemical and genetic approaches to elucidate the mechanisms underlying the role of the GABA shunt in oxidative stress. We are analyzing the phenotype (e.g. ROS accumulation) of ssadh mutants subjected to GABA-shunt inhibitors, and to known agonists and antagonists of mammalian GABA receptors. In addition, we are screening EMS-induced mutants for suppressors of the ssadh phenotype. The combination of biochemical and genetic approaches should facilitate the dissection of the metabolic and signaling roles of the GABA shunt in plants (reviews Refs. 2, 3).
Refs: (1) N. Bouche, A. Fait, D. Bouchez, S.G. Moller and H. Fromm (2003) Proc. Natl. Acad. Sci. USA 100: 6843-6848; (2) N. Bouche B. Lacombe and H. Fromm (2003) GABA signalling, a conserved and ubiquitous mechanism. Trends in Cell Biol. 13: 607-610. (3) N. Bouche and H. Fromm (2004) GABA in plants: just a metabolite? Trends in Plant Science (in press). Supported by Research Award 2743-96 from the United States–Israel Binational Agricultural Research and Development Fund (BARD).
