title: Transcriptional control of vitamin C defective 2 and tocopherol cyclase genes by light and plastid-derived signals: the partial involvement of GENOMES UNCOUPLED 1.
abstract: Previous findings have suggested that light and plastid-derived signals are involved in the regulation of biosynthetic pathways for l-ascorbic acid (AsA) and tocopherols (Toc). Photosynthetic electron transport (PET) activity, plastid gene expression (PGE), and the tetrapyrrole metabolism have been identified as signals that regulate nuclear gene expression through the GENOMES UNCOUPLED 1 (GUN1) protein. Here, we examined the effects of disrupting GUN1 on these pathways. The expression of vitamin C defective 2 (VTC2) and tocopherol cyclase (TC) genes, which encode key enzymes in the AsA and Toc biosynthetic pathways, respectively, was affected by illumination and darkness in parallel with the levels of both these antioxidants. However, the GUN1 disruption had no effect on these biosynthetic pathways under light-dark conditions. All treatments that inhibited PET, PGE, and the tetrapyrrole metabolism interrupted both biosynthetic pathways; however, this was partially mitigated by the GUN1 disruption. The expression patterns of VTC2 and TC reflected the levels of both antioxidants under most of the conditions examined. Our results suggest that the transcriptional control of VTC2 and TC by light and plastid-derived signals is important for the regulation of the biosynthetic pathways, and that GUN1 is at least partially involved in the plastid-derived signals-dependent regulation.
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane 690-8504, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Maruta
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tamoi
authors.affiliation: School of Agricultural, Biological, and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-minami, Tottori 680-8550, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Yabuta
authors.affiliation: Department of Food and Nutritional Science, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yoshimura
authors.affiliation: Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane 690-8504, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan. Electronic address: shigeoka@nara.kindai.ac.jp.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
mesh_terms: D017360:Arabidopsis / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism*; D008027:Light; D018087:Plastids / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D019751:Intramolecular Transferases; C103397:tocopherol cyclase
keywords: Arabidopsis; Ascorbate; Chloroplast; GENOMES UNCOUPLED 1; Plastid signaling; Tocopherol