title: GABA shunt deficiencies and accumulation of reactive oxygen intermediates: insight from Arabidopsis mutants.
abstract: In plants, succinic semialdehyde dehydrogenase (SSADH)-deficiency results in the accumulation of reactive oxygen intermediates (ROI), necrotic lesions, dwarfism, and hypersensitivity to environmental stresses. We report that Arabidopsis ssadh knockout mutants contain five times the normal level of gamma-hydroxybutyrate (GHB), which in SSADH-deficient mammals accounts for phenotypic abnormalities. Moreover, the level of GHB in Arabidopsis is light dependent. Treatment with gamma-vinyl-gamma-aminobutyrate, a specific gamma-aminobutyrate (GABA)-transaminase inhibitor, prevents the accumulation of ROI and GHB in ssadh mutants, inhibits cell death, and improves growth. These results provide novel evidence for the relationship between the GABA shunt and ROI, which may, in part, explain the phenotype of SSADH-deficient plants and animals.
authors.affiliation: Department of Plant Sciences, Weizmann Institute of Science, 76100 Rehovot, Israel.
authors.forename: Aaron
authors.initials: A
authors.lastname: Fait
authors.forename: Ayelet
authors.initials: A
authors.lastname: Yellin
authors.forename: Hillel
authors.initials: H
authors.lastname: Fromm
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors; D000445:Aldehyde Oxidoreductases / Q000235:genetics*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008027:Light; D009154:Mutation / Q000235:genetics; D011392:Proline / Q000032:analysis / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012978:Sodium Oxybate / Q000032:analysis / Q000378:metabolism; D050644:Succinate-Semialdehyde Dehydrogenase; D020888:Vigabatrin / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D005680:gamma-Aminobutyric Acid; D012978:Sodium Oxybate; D011392:Proline; D006861:Hydrogen Peroxide; D000445:Aldehyde Oxidoreductases; D050644:Succinate-Semialdehyde Dehydrogenase; D000612:4-Aminobutyrate Transaminase; D020888:Vigabatrin