Studies on carotenoids in watermelon flesh

Abstract

Carotenoids are\rresponsible for the different flesh colors in watermelon fruit, such as white,\rsalmon yellow, orange, pale yellow, canary yellow, crimson red, and scarlet\rred. In red-fleshed watermelons lycopene\rconstitutes the major pigment and b-carotene\rthe secondary. The predominant carotenoid in yellow-fleshed watermelon is\rneoxanthin. Lycopene content in watermelon is related to genotype and ploidy\rlevel, harvest maturity, and growth and development conditions. Watermelon\rflesh colors are controlled by several gene loci. There are two or three\ralleles identified at each gene locus. Up to now several full-length cDNAs or\rgene fragments encoding enzymes in the carotenoid metabolic pathway have been\risolated and characterized from mature watermelon fruits. Differential\rexpression of carotenogenic genes was examined in flesh, ovary, leaf, and\rroot tissues across different colored fleshes (white, canary yellow, salmon\ryellow, orange, and red). Carotenogenic gene expression was also analyzed at\rthree fruit developmental stages (10, 20, and 30 days postanthesis) in five flesh colors of watermelon cultivars\r(red, pink, orange, yellow, and white).