title: Overexpression of Arabidopsis homogentisate phytyltransferase or tocopherol cyclase elevates vitamin E content by increasing gamma-tocopherol level in lettuce (Lactuca sativa L.).
abstract: Tocopherols, essential components of the human diet, are synthesized exclusively by photosynthetic organisms. To increase tocopherol content by increasing total flux to the tocopherol biosynthetic pathway, genes encoding Arabidopsis homogentisate phytyltransferase (HPT/V-TE2) and tocopherol cyclase (TC/VTE1) were constitutively overexpressed in lettuce (Lactuca sativa L.). Total tocopherol content of the transgenic plants overexpressing either of the genes was increased by more than 2-fold mainly due to an increase in gamma-tocopherol. However, chlorophyll content in the HPT/VTE2 and TC/VTE1 transgenic lines decreased by up to 20% and increased by up to 35%, respectively (P < 0.01). These results demonstrate that manipulation of the tocopherol biosynthetic pathway can increase or decrease chlorophyll content depending on the gene introduced.
authors.affiliation: School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Korea.
authors.forename: Koeun
authors.initials: K
authors.lastname: Lee
authors.forename: Sa Mi
authors.initials: SM
authors.lastname: Lee
authors.forename: Sang-Ryoung
authors.initials: SR
authors.lastname: Park
authors.forename: Jinwook
authors.initials: J
authors.lastname: Jung
authors.forename: Joon-Kwan
authors.initials: JK
authors.lastname: Moon
authors.forename: Jong-Joo
authors.initials: JJ
authors.lastname: Cheong
authors.forename: Minkyun
authors.initials: M
authors.lastname: Kim
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D018744:DNA, Plant; D030841:Food, Genetically Modified; D015870:Gene Expression; D018745:Genome, Plant; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism*; D018545:Lactuca / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012231:Rhizobium; D024505:Tocopherols / Q000378:metabolism*; D014170:Transformation, Genetic; D019076:Transgenes; D024504:gamma-Tocopherol / Q000737:chemistry / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D002734:Chlorophyll; D024504:gamma-Tocopherol; D019883:Alkyl and Aryl Transferases; C446531:HPT1 protein, Arabidopsis; D019751:Intramolecular Transferases; C103397:tocopherol cyclase; D024505:Tocopherols