Carotenoids in Carrot
The mature roots of most commercial varieties of Daucus carota (commonly known as carrots) accumulate massive amounts of carotenoids, a class of plastidial isoprenoid pigments that represent an essential source of retinoids (including vitamin A) and provide additional health benefits in the human diet. In plants, carotenoids participate in light harvesting and are essential for photoprotection in photosynthetic tissues, whereas their properties as natural pigments in the yellow to red range are exploited by the flowers and fruits of many plant species to attract animals for pollination and dispersal of seeds. The production of high carotenoid levels in the carrot root is a unique feature since this is an organ almost devoid of carotenoids in the vast majority of plants. In fact, carrot root was likely white before domestication and breeding generated the currently known carotenoid-rich varieties. Orange carrots are one of the richest dietary sources of provitamin A carotenoids (β-carotene and, to a lower extent, α-carotene), whereas red carrots provide a substantial amount of lycopene and yellow carrots accumulate lutein. Our knowledge of the mechanisms involved in carotenoid biosynthesis and accumulation in this vegetable has remained scarce until recently. Here, we review recent advances in this field.
KeywordsBiosynthesis Carotenoid Carrot Development Gene expression Isoforms Light Root
We acknowledge the financial support from the Catalan AGAUR (2009SGR-26, 2014SGR-1434 and XRB), Spanish DGI (BIO2011-23680 and PIM2010IPO-00660), and European Union FP7 (TiMet, contract 245143) to MRC, and Chilean Fondef (D10I1022) and Fondecyt (1130245) to CS. Our collaborative work was funded by grants CSIC-2010CL0039 and CSIC/ESPAÑA 10/11-2, and it is currently ongoing in the frame of the IBERCAROT network funded by Programa Iberoamericano de Ciencia y Tecnologia para el Desarrollo (CYTED, code 112RT0445).
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