title: Gene expression of ascorbic acid-related enzymes in tobacco.
abstract: GDP-D-mannose pyrophosphorylase (GMPase) and L-galactono-1, 4-lactone dehydrogenase (GalLDH) are key enzymes in L-ascorbic acid (AsA) biosynthesis of plants, and a full-length cDNA for GMPase was isolated from tobacco using PCR. Additionally, expression of GMPase, GalLDH and other AsA-related enzymes was examined in tobacco tissues and cultured BY-2 cells, and the relationship between their expression patterns and AsA content is discussed. It was found that the expression of GalLDH and GMPase mRNAs was markedly suppressed by loading AsA, suggesting that AsA concentration in the cells may regulate AsA biosynthesis. Moreover, the expression of GMPase and GalLDH mRNAs in tobacco leaf also suggested that AsA biosynthesis may be induced by light.
authors.affiliation: Faculty of Applied Biological Science, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, 739-8528, Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Tabata
authors.forename: Takahiko
authors.initials: T
authors.lastname: Takaoka
authors.forename: Muneharu
authors.initials: M
authors.lastname: Esaka
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D001483:Base Sequence; D015152:Blotting, Northern; D017931:DNA Primers; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D009713:Nucleotidyltransferases / Q000235:genetics*; D010088:Oxidoreductases / Q000235:genetics*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D012333:RNA, Messenger / Q000235:genetics; D014026:Nicotiana / Q000235:genetics*
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C093910:galactonolactone dehydrogenase; D009713:Nucleotidyltransferases; C026917:mannose 1-phosphate guanylyltransferase; D001205:Ascorbic Acid