Biosynthesis and regulation of carotenoids in plants-micronutrients, vitamins and health benefits

Carotenoids are a major class of natural, coloured pigments, ranging from the yellow, orange and red of many fruits, vegetables, flowers and autumn leaves, through to the colours of butterflies and crayfish. The bright colours of carotenoid pigments attract insects for pollination and dispersal of seeds, which are essential for reproduction. Carotenoids are essential components of the photosynthetic machinery, involved in the assembly of the photosystems, light-harvesting and photoprotection. They are the second most abundant pigment in nature and provide substrate derivatives for the production of phytohormones, such as abscisic acid and strigolactones. Fruits and vegetables are an essential dietary requirement for humans and provide carotenoid-derived micronutrients which promote health benefits including antioxidant activity, precursors for vitamin A biosynthesis, and prevention of macular degeneration. The main focus of this chapter is directed towards the biosynthesis, regulation, function and manipulation of carotenoid-derived micronutrients in plants and their benefits in human health.