Submitted to: Plant Cell Reports
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/25/2006
Publication Date: 11/1/2006
Citation: Levi, A., Davis, A.R., Hernandez, A., Wechter, W.P., Thimmapuram, J. 2006. Genes Expressed during the Development and Ripening of Watermelon Fruit. Plant Cell Reports 25:1233-1245. Interpretive Summary: Watermelon is a major vegetable crop in the U.S. In recent years, there has been an increased demand for seedless watermelon. Over 60% of the watermelons produced in the U.S. in 2004 were seedless. There is a great interest in the watermelon industry to improve watermelon fruit quality and nutritional values. Also, consumers have a great interest in the naturally occurred carotenoid pigment called lycopen in watermelon. Lycopen is known to be a main dietary source of vitamin A in humans, and is associated with reduced risk of cancer, heart disease and eye degeneration. Developing watermelon cultivars with increased lycopen levels will benefit consumer health. However, there is insufficient information about the genes that control fruit quality, particularly the genes controlling lycopen production in watermelon. In this study we developed a library of genes that control watermelon fruit quality and identified genes that control watermelon fruit development and ripening. Among them are a few genes that involved in lycopen production in watermelon. The results in this study are useful for gene discovery and for further improvement of cultivars with increased watermelon fruit quality and nutritional values
Technical Abstract: A normalized cDNA library was constructed from watermelon flesh mRNA representing three sequential stages of watermelon fruit. The normalized library was subtracted by hybridization with leaf cDNA to enrich it with cDNA clones unique to watermelon fruit. Randomly selected cDNA clones of the watermelon flesh subtraction library were sequenced in order to identify potentially informative genes associated with fruit setting, development and ripening. The 1,046 sequenced cDNA clones produced 832 unique expressed sequenced tags (ESTs). Of these 832 ESTs, 205 (24.6%) have not been reported in any other species, and are likely to be unique to watermelon fruit. Additionally, 186 ESTs (22.4%) correspond to genes with unknown function in other species. Four-hundred and forty-one ESTs (53.0%) correspond to genes with known function in other plant species. These ESTs are associated with metabolism, membrane transport, cytoskeleton synthesis and structure, cell wall formation and cell division, signal transduction, nucleic acid binding and transcription factors, defense and stress response and secondary metabolism. This study provides useful information with respect to fruit-related genes in watermelon.