Overexpression of Arabidopsis homogentisate phytyltransferase or tocopherol cyclase elevates vitamin E content by increasing gamma-tocopherol level in lettuce (Lactuca sativa L.).
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.
Lee
Koeun
K
School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Korea.
Lee
Sa Mi
SM
Park
Sang-Ryoung
SR
Jung
Jinwook
J
Moon
Joon-Kwan
JK
Cheong
Jong-Joo
JJ
Kim
Minkyun
M
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*
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