Biosynthesis of β‐Carotene (Provitamin a) in Rice Endosperm Achieved by Genetic Engineering

摘要: To obtain a functioning provitamin A (beta-carotene) biosynthetic pathway in rice endosperm, we introduced single, combined transformation effort the cDNAs coding for (1) phytoene synthase (psy) and (2) lycopene beta-cyclase (beta-lcy; both from Narcissus pseudonarcissus under control of endosperm-specific glutelin promoter), with (3) bacterial desaturase (crtI, Erwinia uredovora constitutive 35S promoter control). This combination covers requirements beta-carotene synthesis, yellow, beta-carotene-bearing endosperm was obtained T0 generation. However, further experiments revealed that presence beta-lcy not necessary, since psy crtI alone were able to drive synthesis as well formation downstream xanthophylls. finding could be explained if these enzymes are either constitutively expressed or induced by transformation, e.g. products derived therefrom. Based on results N. model system, likely hypothesis can developed trans derivative acts an inductor kind feedback mechanism stimulating endogenous carotenogenic genes.