title: Over-expression of cinnamate 4-hydroxylase leads to increased accumulation of acetosyringone in elicited tobacco cell-suspension cultures.
abstract: Cell-suspension cultures were produced from transgenic tobacco (Nicotiana tabacum L.) plants harboring a constitutively expressed alfalfa cinnamate 4-hydroxylase (C4H) transgene. Increased levels of C4H enzyme activity in the transgenic cultures were observed only following exposure of the cells to yeast elicitor, although alfalfa C4H transcripts were expressed at a high level from the cauliflower mosaic virus 35S promoter in the absence of elicitation. Increased expression of C4H in elicited cell-suspension cultures had no appreciable effect on the HPLC profiles of soluble phenolic compounds. However, levels of one compound, subsequently identified as 3,5-dimethoxy-4-hydroxy acetophenone (acetosyringone), were strongly elevated in the wall-bound phenolic fraction. The results are discussed in relation to the correlation between C4H activity and the synthesis of 3,5-dimethylated hydroxycinnamic acid derivatives in tobacco.
authors.affiliation: Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA.
authors.forename: Jack W
authors.initials: JW
authors.lastname: Blount
authors.forename: Sameer
authors.initials: S
authors.lastname: Masoud
authors.forename: Lloyd W
authors.initials: LW
authors.lastname: Sumner
authors.forename: David
authors.initials: D
authors.lastname: Huhman
authors.forename: Richard A
authors.initials: RA
authors.lastname: Dixon
mesh_terms: D000098:Acetophenones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002473:Cell Wall / Q000378:metabolism; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D009682:Magnetic Resonance Spectroscopy; D000455:Medicago sativa / Q000235:genetics; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D010649:Phenylalanine / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D050564:Trans-Cinnamate 4-Monooxygenase
chemical_list: D000098:Acetophenones; D002250:Carbon Radioisotopes; D010636:Phenols; D010649:Phenylalanine; C051667:acetosyringone; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D050564:Trans-Cinnamate 4-Monooxygenase