Fig. 6. Gene expression patterns among the interactions between carotenoids, the ABA and ethylene biosynthesis pathways, and regulatory mechanisms in D. chrysotoxum (adapted from Watkins and Pogson53, Yin et al.55, Nisar et al.101, Sun et al.102, and Finkelstein96).
Increased gene expression during the four developmental stages of flowers is shown by thick green arrows, while decreased gene expression is shown by thick red arrows. The enzymes or genes are indicated alongside the arrows. The dashed lines suggest that there are multiple steps. Carotenes are shown in orange, and light gold indicates xanthophylls. ABA-related genes are shown in yellow, and ethylene-related genes are shown in light green. CCDs (orange arrows) regulate carotenoid accumulation. Plastoglobule-localized metallopeptidase 48 (PGM48) is hypothesized to regulate CCD4. The orange protein regulates PSY activity, acting as a chaperone. ClpB3 (red arrow) regulates the activity of DXS, acting as an enzyme in the MEP pathway