Metabolic Engineering of Apocarotenoids in Plants

Apocarotenoids are valuable natural compounds with diverse food, pharmaceutical, and cosmetic applications. Metabolic engineering in plant systems offers a sustainable approach to enhance their production by optimizing carotenoid biosynthesis and cleavage pathways. Several strategies have been employed, including selecting suitable plant platforms, using tissue-specific promoters, and introducing carotenoid cleavage dioxygenases (CCDs) with broader substrate specificity. Tomato has become an optimal chassis due to its natural carotenoid accumulation, fruit-specific promoters, and well-established processing methods. Additionally, maize endosperm, potato tubers, and carrot roots present promising alternatives due to their high carotenoid content and tissue-specific gene regulation. Plant cell suspension cultures also provide controlled environments for production and scalability. Further improvements involve engineering the carotenoid biosynthetic pathway to enhance precursor availability and suppressing competing CCDs to redirect flux toward the desired apocarotenoids. These approaches collectively advance the feasibility of heterologous plant systems for the sustainable biosynthesis of saffron-derived apocarotenoids and other high-value metabolites.