CHEMICAL INDUCTION OF POLY-CIS CAROTENOID BIOSYNTHESIS

Article abstract of DOI:10.1016/S0031-9422(00)83793-0

Key Word Index - Citrus paradisi; Rutaceae; Marsh white seedless grapefruit; carotenoid biosynthesis; bioregulators; poly-cis carotenoids; carotenoids; prolycopene.A new class of synthetic bioregulators is reported which cause the accumulation of poly-cis carotenoids in the flavedo of Marsh white seedless grapefruit.The compounds tested were all secondary amines: dibenzylamine, substituted dibenzylamines (4-F; 4-Cl; 4-Br; 2-, 3- and 4-Me; 4-NO2; 4-CN; 4-Cl; 4'-Me; 4-Me, 4'-NO2), N-benzyl phenethylamine and N-benzyl 2-naphthalenemethylamine.The most effective, 4-chlorodibenzylamine, caused the accumulation of 74 μg/g dry wt of poly-cis carotenoids.Prolycopene was the predominant pigment but substantial amounts of proneurosporene, poly-cis-γ-carotenes and other cis carotenes were also present.The mode of action of these new bioregulators is probably gene derepression, the same as that of the lycopene inducers.However, the secondary amines probably derepress a recessive gene governing the biosynthesis of poly-cis carotenoids; whereas, the lycopene inducers derepress the dominant gene that gives rise to the normall all-trans carotenoids.The new compounds did not seem to inhibit the cyclase(s), as the lycopene inducers do.