Nature Biotechnology
18, 666 - 669 (2000)
doi:10.1038/76523
Elevation of the provitamin A content of transgenic tomato plantsSusanne Römer1, 2, Paul D. Fraser1, Joy W. Kiano1, Cathie A. Shipton3, Norihiko Misawa4, Wolfgang Schuch3
& Peter M. Bramley11
School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 OEX, UK
2
Present address: Fakultät fur Biologie, Universität Konstanz, D-78434, Konstanz, Germany
3
Zeneca Plant Science, Jealott's Hill Research Station, Bracknell, Berks, RG42 6EY, UK
4
Kirin Brewery, Central Laboratories for Key Technology, 1-13-5, Fukuura, Kanazawa-ku, Yokohama -shi 236, Japan
Correspondence should be addressed to Peter M. Bramley p.bramley@rhbnc.ac.ukagricultural biotechnologynutriceuticalsmetabolic engineeringTomato products are the principal dietary sources of lycopene and major source of  -carotene, both of which have been shown to benefit human health. To enhance the carotenoid content and profile of tomato fruit, we have produced transgenic lines containing a bacterial carotenoid gene (crtI) encoding the enzyme phytoene desaturase, which converts phytoene into lycopene. Expression of this gene in transgenic tomatoes did not elevate total carotenoid levels. However, the -carotene content increased about threefold, up to 45% of the total carotenoid content. Endogenous carotenoid genes were concurrently upregulated, except for phytoene synthase, which was repressed. The alteration in carotenoid content of these plants did not affect growth and development. Levels of noncarotenoid isoprenoids were unchanged in the transformants. The phenotype has been found to be stable and reproducible over at least four generations.
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