Carotenoid biosynthesis and regulation in plants

Carotenoids are important in photosynthesis, photo protection, and the production of a range of hormones and signaling molecules. This chapter focuses on regulatory aspects of carotenogenesis relating to: cross-talk between and within the carotenoid and MEP pathways, environmental and developmental control, epigenetic and posttranscriptional regulatory mechanisms, plastid differentiation and communication, enzyme localization and metabolon compartmentalization, and carotenoid degradation and apocarotenoid signaling metabolites. Non-enzymatic photooxidation and enzymatic cleavage of carotenoids are two well-studied processes that can degrade carotenoids to apocarotenoid signaling molecules. Carotenoid biosynthetic pathway in plants is complex and tightly regulated. The carotenoid biosynthetic pathway bifurcates after lycopene to produce lutein or ß-carotenes, and their derivatives. By enhancing our knowledge of the regulation of biosynthetic processes and flux through the pathway, undoubtedly new possibilities will emerge to enhance plant biofortification as a convenient resource to produce valuable micronutrient compounds.