Figure 1.

Schematic biosynthetic pathway of carotenoids and apocarotenoids. Uppercase abbreviations are enzymes. Carotenoid metabolites are in lowercase boldface. Dashed arrows represent series of enzymatic reactions. Bar-headed lines represent enzyme inhibitors [norflurazon (NF) and 2-(4-chlorophenylthio) triethylamine hydrochloride (CPTA)] or mutant name (yofi). ABA, Abscisic acid; CCDs, carotenoid cleavage dioxygenases; DXR, 1-deoxy-d-xylulose-5-phosphate reductoisomerase; DXS, 1-deoxy-d-xylulose-5-phosphate synthase; GGPP, geranylgeranyl diphosphate; GGPPS, geranylgeranyl pyrophosphate synthase; NCED, 9-cis-epoxycarotenoid dioxygenase; β-OHase, β-carotene hydroxylase; VDE, violaxanthin deepoxidase; ZEP, zeaxanthin epoxidase.