Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Developing And Mapping ESTs For Watermelon

Amnon Levi¹ , Angela Davis² , Alvaro Hernandez³ , Pat Wechter¹ , Tova Trebitsh⁴ , Kobi Tadmor⁵ , Nurit Katzir⁵ , Umesh Reddy⁶

¹  USDA, ARS, U.S. Vegetable Laboratory, 2700 Savannah Highway, Charleston, South Carolina 29414, USA

²  USDA, ARS, P.O. Box 159, Lane, Oklahoma 74555, USA

³  University of Illinois at Urbana-Champaign, Biotechnology Center, W.M. Keck Center for Comparative and Functional Genomics, 1201 W. Gregory Drive, Urbana, IL 61801, USA

⁴  Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel

⁵  Agricultural Research Organization, P.O. Box 1021, Ramat Yishay 30095, Israel

⁶  Department of Biology, West Virginia State University, Institute, WV 25112-1000, USA

A cDNA library was constructed using watermelon fruit mRNA. The cDNA library was normalized and subtracted by hybridization with leaf cDNA of the same watermelon cultivar (Illini Red). Randomly selected cDNA clones of the 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 other plant 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 are being used for development of EST-SSR markers and mapping on a genetic linkage map for watermelon. This study provides useful information with respect to expression and mapping of genes controlling fruit development and quality in watermelon and in other cucrbit crops.