title: Accumulation of γ- rather than α-tocopherol alters ethylene signaling gene expression in the vte4 mutant of Arabidopsis thaliana.
abstract: Tocopherols are antioxidants found in chloroplasts of leaves, and it is a matter of current debate whether or not they can affect signaling and gene expression in plant cells. For insight into the possible effects of altered tocopherol composition in chloroplasts on gene expression in the nucleus, the expression of ethylene biosynthesis, perception and signaling genes was investigated in vte1 and vte4 Arabidopsis thaliana mutants, which are impaired in tocopherol (vitamin E) biosynthesis. Changes in gene expression were measured in plants exposed to either salt or water stress, and in young and mature leaves of vte1 and vte4 mutants, which lack tocopherol cyclase and γ-tocopherol methyltransferase, respectively. While transcript levels of ethylene signaling genes in the vte1 mutant and the wild type were similar in all tested conditions, major changes in gene expression occurred in the vte4 mutant, particularly in mature leaves (compared with young leaves) and under salt stress. Accumulation of γ- instead of α-tocopherol in this mutant led to elevated transcript levels of ethylene signaling pathway genes (particularly CTR1, EIN2, EIN3 and ERF1) in mature leaves of control plants. However, with salt treatment, transcript levels of most of these genes remained constant or dropped in the vte4 mutant, while they were dramatically induced in the wild type and the vte1 mutant. Furthermore, under salt stress, leaf age-induced jasmonic acid accumulated in both the vte1 mutant and the wild type, but not in the vte4 mutant. It is concluded that jasmonic acid and ethylene signaling pathways are down-regulated in mature leaves of salt-stressed vte4 plants.
authors: Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain.
authors: Jana
authors: J
authors: Cela
authors: Caren
authors: C
authors: Chang
authors: Sergi
authors: S
authors: Munné-Bosch
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D003681:Dehydration; D005030:Ethylenes / Q000096:biosynthesis / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D054883:Oxylipins / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013997:Time Factors; D024502:alpha-Tocopherol / Q000378:metabolism*; D024504:gamma-Tocopherol / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D012965:Sodium Chloride; C011006:jasmonic acid; D024504:gamma-Tocopherol; C036216:ethylene; D008780:Methyltransferases; C047259:gamma-tocopherol methyltransferase; D024502:alpha-Tocopherol