Genetic modification of tomato with the tobacco lycopene β-cyclase gene produces high β-carotene and lycopene fruit.

Transgenic Solanum lycopersicum plants expressing an additional copy of the lycopene β-cyclase gene (LCYB) from Nicotiana tabacum, under the control of the Arabidopsis polyubiquitin promoter (UBQ3), have been generated. Expression of LCYB was increased some 10-fold in ripening fruit compared to vegetative tissues. The ripe fruit showed an orange pigmentation, due to increased levels (up to 5-fold) of β-carotene, with negligible changes to other carotenoids, including lycopene. Phenotypic changes in carotenoids were found in vegetative tissues, but levels of biosynthetically related isoprenoids such as tocopherols, ubiquinone and plastoquinone were barely altered. Transformants showed tolerance to the bleaching herbicide β-cyclase inhibitor, 2-(4-chlorophenylthio) triethylamine. The phenotype was inherited for at least three generations.