|Wechter, William - Pat|
Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 2/27/2008
Publication Date: 5/19/2008
Citation: Levi, A., Wechter, W.P., Harris, K.R., Davis, A.R., Zhangiun, F., Giovannoni, J.J., Trebitsh, T., Salman, A., Hernandez, A., Thimmapuram, J., Tadmor, Y., Portnoy, V., Katzir, N. 2008. Expression and Polymorphism of Watermelon Fruit ESTs. Acta Horticulturae. P257-262. In: M. Pitrat (ed.). Proceedings of the IX EUCARPIA Meetings on Genetics and Breeding of Cucurbitaceae. INRA.
Technical Abstract: Over 8,000 ESTs were generated for watermelon and were assembled into 4,700 EST-unigenes (http://www.icugi.org). Microarray and Real-Time PCR analyses were used to examine differential expression of 832 of these EST-unigenes in developing and ripening watermelon fruit. RNA was isolated from watermelon fruits (in three sequential stages of development and ripening) and from young leaves of field grown plants (during three consecutive years). The microarray analysis identified 335 EST-unigenes differentially expressed (by at least two-fold when compared to leaf) in watermelon fruit during the early, ripening, or mature stage. A considerable number of these watermelon ESTs are associated with vascular system differentiation and development, ethylene biosynthesis, fruit softening, carotenoid and flavonoid biosynthesis, transcriptional regulation, and pathogen and stress response. Quantitative Real-Time PCR experiments with 127 ESTs validated their expression in the microarray analysis. This study highlights the critical phase of vascular system formation and ethylene involvement in the developing and ripening watermelon fruit. Primers were constructed for 110 of the watermelon fruit-ESTs and were used in PCR amplification experiments with genomic DNA of 25 heirloom cultivars to amplify EST-PCR markers. About 14% of these EST-PCR markers were polymorphic among the heirloom cultivars, indicating that polymorphism may be detected without great difficulty in coding regions of genes associated with watermelon fruit quality. The polymorphic EST-PCR markers can be useful in the construction of a genetic linkage map for watermelon and identifying genes associated with watermelon fruit quality.