title: Improvement of vitamin E quality and quantity in tobacco and lettuce by chloroplast genetic engineering.
abstract: Vitamin E (tocopherol: Toc) is an important lipid-soluble antioxidant synthesized in chloroplasts. Among the 8 isoforms of vitamin E, α-Toc has the highest activity in humans. To generate transgenic plants with enhanced vitamin E activity, we applied a chloroplast transformation technique. Three types of the transplastomic tobacco plants (pTTC, pTTMT and pTTC-TMT) carrying the Toc cyclase (TC) or γ-Toc methyltransferase (γ-TMT) gene and the TC plus γ-TMT genes as an operon in the plastid genome, respectively, were generated. There was a significant increase in total levels of Toc due to an increase in γ-Toc in the pTTC plants. Compared to the wild-type plants, Toc composition was altered in the pTTMT plants. In the pTTC-TMT plants, total Toc levels increased and α-Toc was a major Toc isoform. Furthermore, to use chloroplast transformation to produce α-Toc-rich vegetable, TC-overexpressing transplastomic lettuce plants (pLTC) were generated. Total Toc levels and vitamin E activity increased in the pLTC plants compared with the wild-type lettuce plants. These findings indicated that chloroplast genetic engineering is useful to improve vitamin E quality and quantity in plants.
authors.affiliation: School of Agricultural, Biological, and Environmental Sciences, Faculty of Agriculture, Tottori University, 4-101 Koyama-minami, Tottori, 680-8550, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Yabuta
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Sahoko
authors.initials: S
authors.lastname: Yoshimura
authors.forename: Akiko
authors.initials: A
authors.lastname: Suzuki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tamoi
authors.forename: Takanori
authors.initials: T
authors.lastname: Maruta
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
mesh_terms: D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D005818:Genetic Engineering; D006801:Humans; D018545:Lactuca / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism; D014810:Vitamin E / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014810:Vitamin E