Metabolic engineering of beta-carotene and lycopene content in tomato fruit.
Ripe tomato fruits accumulate large amounts of the red linear carotene, lycopene (a dietary antioxidant) and small amounts of its orange cyclisation product, beta-carotene (pro-vitamin A). Lycopene is transformed into beta-carotene by the action of lycopene beta-cyclase (beta-Lcy). We introduced, via Agrobacterium-mediated transformation, DNA constructs aimed at up-regulating (OE construct) or down-regulating (AS construct) the expression of the beta-Lcy gene in a fruit-specific fashion. Three transformants containing the OE construct show a significant increase in fruit beta-carotene content. The fruits from these plants display different colour phenotypes, from orange to orange-red, depending on the lycopene/beta-carotene ratio. Fruits from AS transformants show up to 50% inhibition of beta-Lcy expression, accompanied by a slight increase in lycopene content. Leaf carotenoid composition is unaltered in all transformants. In most transformants, an increase in total carotenoid content is observed with respect to the parental line. This increase occurs in the absence of major variations in the expression of endogenous carotenoid genes.
Rosati
C
C
Ente per le Nuove tecnologie, l'Energia e l'Ambiente (ENEA), Casaccia Res. Ctr., Biotechnology and Agriculture Division, Via Anguillarese 301, 00060 S. Maria di Galeria (Roma), Italy.
Aquilani
R
R
Dharmapuri
S
S
Pallara
P
P
Marusic
C
C
Tavazza
R
R
Bouvier
F
F
Camara
B
B
Giuliano
G
G
D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D001483:Base Sequence; D002338:Carotenoids / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D016373:DNA, Antisense / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D005818:Genetic Engineering; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D030821:Plants, Genetically Modified; D014170:Transformation, Genetic; D019207:beta Carotene / Q000378:metabolism*
D017931:DNA Primers; D016373:DNA, Antisense; D019207:beta Carotene; D002338:Carotenoids; D019753:Intramolecular Lyases; C070925:lycopene cyclase-isomerase; D000077276:Lycopene