title: Expression analysis of the VTC2 and VTC5 genes encoding GDP-L-galactose phosphorylase, an enzyme involved in ascorbate biosynthesis, in Arabidopsis thaliana.
abstract: Arabidopsis thaliana contains two GDP-L-galactose phosphorylase genes, VTC2 and VTC5, which are critical for ascorbate (AsA) biosynthesis. We investigated the expression levels of both VTC2 and VTC5 genes in wild-type A. thaliana and the AsA deficient mutants during early seedling growth. Ascorbate accumulated to an equal extent in all genotypes up to 5 d post-germination (DPG). The transcript level of VTC2 was dominant, and increased in parallel with AsA accumulation in the wild type. On the other hand, the expression of VTC5 compensated for the reduced VTC2 transcription levels in the AsA deficient mutant vtc2-1 in young seedlings. A luciferase activity assay indicated that the VTC5 promoter was more active in young (2 DPG) cotyledons and that the VTC2 and VTC5 promoters drove a day-to-night variation in expression. The present work provides clues to the precise roles of VTC2 and VTC5 in AsA biosynthesis in A. thaliana at the young seedling stage.
authors: Department of Applied Bioscience and Biotechnology, Faculty of Life and Environmental Science, Shimane University.
authors: Yongshun
authors: Y
authors: Gao
authors: Adebanjo Ayobamidele
authors: AA
authors: Badejo
authors: Hitoshi
authors: H
authors: Shibata
authors: Yoshihiro
authors: Y
authors: Sawa
authors: Takanori
authors: T
authors: Maruta
authors: Shigeru
authors: S
authors: Shigeoka
authors: Mike
authors: M
authors: Page
authors: Nicholas
authors: N
authors: Smirnoff
authors: Takahiro
authors: T
authors: Ishikawa
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001205:Ascorbic Acid / Q000096:biosynthesis* / Q000235:genetics; D018548:Cotyledon / Q000201:enzymology / Q000235:genetics; D005690:Galactose / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D018525:Germination; D006153:Guanosine Diphosphate / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008027:Light; D008156:Luciferases / Q000032:analysis; D009154:Mutation; D006005:Phosphorylases / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000235:genetics; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D036226:Seedlings / Q000201:enzymology / Q000235:genetics; D013997:Time Factors; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; D006153:Guanosine Diphosphate; D008156:Luciferases; D006005:Phosphorylases; D001205:Ascorbic Acid; D005690:Galactose