title: Induction of PR-1 accumulation accompanied by runaway cell death in the lsd1 mutant of Arabidopsis is dependent on glutathione levels but independent of the redox state of glutathione.
abstract: The lesions simulating disease (lsd) mutants of Arabidopsis spontaneously develop hypersensitive-response-like lesions in the absence of pathogens. To address the function of the redox regulator glutathione in disease resistance, we examined the relationship between endogenous glutathione and PR-1 accumulation using one of these mutants, lsd1, as a disease resistance model. Lesion formation on lsd1 was suppressed by weak light and initiated by the subsequent transition to normal light. The application of buthionine sulfoximine, a specific inhibitor of glutathione biosynthesis, suppressed conditionally induced runaway cell death and expression of the PR-1 gene, suggesting that glutathione regulates the conditional cell death and PR-1 gene expression. The application of reduced (GSH) or oxidized (GSSG) glutathione to lsd1 upregulated the level of total glutathione ([GSH]+[GSSG]) accompanied by hastened accumulation of PR-1, and the basal level of total glutathione in lsd1 was higher than that in wild-type plants. The glutathione redox state defined as [GSH]/([GSH]+[GSSG]) decreased following the conditional transition, but the suppression of this decrease by the application of GSH did not inhibit the accumulation of PR-1. Taken together, conditional PR-1 accumulation in lsd1 is regulated not by the redox state but by the endogenous level of glutathione.
authors.affiliation: Research Institute for Biological Sciences, Okayama (RIBS Okayama), 7549-1 Yoshikawa, Kayou-cho, Okayama, 716-1241 Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Senda
authors.forename: Ken'ichi
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D016923:Cell Death; D004268:DNA-Binding Proteins / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D005978:Glutathione / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000494:pharmacology; D010084:Oxidation-Reduction; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C104920:LSD1 protein, Arabidopsis; D014157:Transcription Factors; C077262:PR-1 protein, Arabidopsis; D019328:Buthionine Sulfoximine; D005978:Glutathione; D019803:Glutathione Disulfide