Submitted to: Proceedings of the Workshop on Cucurbit Genomics
Publication Type: Proceedings
Publication Acceptance Date: July 24, 2005
Publication Date: N/A
Technical Abstract: A cDNA library was constructed using ‘Illini Red’ watermelon fruit mRNA. The cDNA library was normalized and subtracted by hybridization with leaf cDNA of the same watermelon cultivar. Randomly selected cDNA clones of the subtraction library were sequenced to identify genes associated with fruit development and quality. Of 1,046 cDNA clones sequenced, 832 were unique sequences and designated as expressed sequenced tags (ESTs). Of the 832 ESTs, 205 (24.6%) have not been reported in any other plant species and might be unique to watermelon and other cucurbit species. Additionally, 186 ESTs (22.4%) correspond to genes with unknown function, while 441 ESTs (53.0%) correspond to genes with known function in other plant species. These ESTs are mainly associated with primary metabolism, membrane transport, cytoskeleton synthesis and structure, cell wall and cell division, signal transduction, nucleic acid binding and transcription factors, and defense and stress response. The ESTs were screened for simple sequence repeat (SSR) motifs. Of 832 ESTs screened, 177 contain SSR motifs. Primer pairs are being designed for these ESTs, and will be used for high quality (EST-SSR) marker development and mapping on a genetic linkage map constructed for watermelon genome. This preliminary study provides useful information with respect to genes controlling watermelon fruit quality.