Genomic and Proteomic Approaches To Understanding Phytonutrient Accumulation In Fruits and Vegetables

Fruits and vegetables are rich sources for phytonutrients, which are associated with reducing the risk of some chronic diseases and improving human nutrition. Carotenoids serve as the primary dietary sources of pro-vitamin A and offer protection against cancer, cardiovascular diseases and age-related macular degeneration. Glucosinolates and Se-methylselenocysteine are known to be anti-cancer agents. To investigate the factors that control these phytonutrient accumulations in fruits and vegetables, proteomic and genomic approaches have been employed. Proteomic analysis of carotenoid-containing plastids from six crop species, i.e. watermelon, tomato, carrot, orange cauliflower, red papaya, and red bell pepper, identified a total between 953 and 2262 proteins. The early carotenoid pathway enzymes were found in almost all crops, suggesting a general relative abundance of them among carotenoid pathway enzymes. The repeatedly detection of high abundance of proteins involved in ATP production and transport implies their important role to energize various metabolic processes for high levels of carotenoid accumulation. Transcriptome analysis of melon and cauliflower revealed the changed pathways and processes associated with high levels of carotenoid accumulation. Interestingly, a large number of WRKY transcription factors are differentially expressed in carotenoid-rich tissue in comparison with carotenoid-free one. Analysis of glucosinolates and Se-methylselenocysteine from various selenium biofortified Brassica crops and germplasms showed that sprouts contained high abundance of these phytonutrients and it is possible to simultaneously accumulate both of these health beneficial compounds. These studies provide basis to understand phytonutrient accumulation and identify genetic resources for developing more nutritious and healthy food crops.