Römer S, Fraser P D, Kiano J W, Shipton C A, Misawa N, Schuch W, Bramley P M
School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 OEX, UK.
Nat Biotechnol. 2000 Jun;18(6):666-9. doi: 10.1038/76523.
Tomato products are the principal dietary sources of lycopene and major source of beta-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 beta-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.
番茄制品是番茄红素的主要膳食来源和β-胡萝卜素的主要来源，这两种物质均已被证明对人体健康有益。为了提高番茄果实中类胡萝卜素的含量和种类，我们培育了含有细菌类胡萝卜素基因（crtI）的转基因品系，该基因编码八氢番茄红素去饱和酶，可将八氢番茄红素转化为番茄红素。该基因在转基因番茄中的表达并未提高总类胡萝卜素水平。然而，β-胡萝卜素含量增加了约三倍，占总类胡萝卜素含量的45%。除了被抑制的八氢番茄红素合酶外，内源性类胡萝卜素基因同时被上调。这些植物类胡萝卜素含量的改变并未影响其生长和发育。转基因植株中非类胡萝卜素类异戊二烯的水平未发生变化。已发现该表型在至少四代中是稳定且可重复的。
