Abstract

- Elevating the Vitamin E Content of Plants Through Metabolic Engineering

Elevating the Vitamin E Content of Plants Through Metabolic Engineering

David Shintani, Dean DellaPenna ^*

-Tocopherol (vitamin E) is a lipid-soluble antioxidant synthesized only by photosynthetic organisms. -Tocopherol is an essential component of mammalian diets, and intakes in excess of the U.S. recommended daily allowance are correlated with decreased incidence of a number of degenerative human diseases. Plant oils, the main dietary source of tocopherols, typically contain -tocopherol as a minor component and high levels of its biosynthetic precursor, -tocopherol. A genomics-based approach was used to clone the final enzyme in -tocopherol synthesis, -tocopherol methyltransferase. Overexpression of -tocopherol methyltransferase in Arabidopsis seeds shifted oil compositions in favor of -tocopherol. Similar increases in agricultural oil crops would increase vitamin E levels in the average U.S. diet.

Department of Biochemistry, Mail Stop 200, University of Nevada, Reno, NV 89557, USA. ^*   To whom correspondence should be addressed. E-mail: della_d@med.unr.edu

Source: Science 11 December 1998: Vol. 282. no. 5396, pp. 2098 - 2100.