Fig. 3

Schematic representation of the carotenoid biosynthesis pathway and duplication of key enzymes in karat. Geranylgeranyl pyrophosphate synthase small subunit (SSU-II) and carotenoid cleavage dioxygenase 4 (CCD4) are duplicated in the T genome compared to the A, B, and S genomes. Phytoene, α-carotene and β-carotene contents were highly enriched in karat pulp. a Schematic representation of the vitamin E and carotenoid biosynthesis pathways in karat. Interactions are represented by red dotted lines. IPP, isopentenyl diphosphate; DMAPP, dimethylallyl diphosphate; GGPP, geranylgeranyl pyrophosphate; GGPPS, geranylgeranyl pyrophosphate synthase; PSY, phytoene synthase; PDS, phytoene desaturase; ZDS, ζ-carotene desaturase; LCYB, lycopene β-cyclase; LCYE, lycopene ε-cyclase; β-OH, carotene β-hydroxylase; ε-OH, ε-hydroxylase; ZEP, zeaxanthin epoxidase; and NCED, 9-cis-epoxycarotenoid dioxygenase. b Distribution of SSUll and CCD4 genes and the distribution and synteny between the T genome and A genome. c Heatmap of carotenoid biosynthesis pathway genes in different tissues