TRANSFER AND EXPRESSION OF CUCUMBER MOSAIC-VIRUS COAT PROTEIN GENE IN THE GENOME OF CUCUMIS-SATIVUS

Cotyledon explants of cucumber (Cucumis sativus L. cv. Poinsett 76) seedlings were cocultivated with disarmed Agrobacterium strain C58Z707 that contained the binary vector plasmid pGA482GG/cpCMV19. The T-DNA region of this binary vector contains plant-expressible genes for neomycin phosphotransferase II (NPT II), beta-glucuronidase (GUS), and the coat protein of cucumber mosaic virus strain C (CMV-C). After infection, the cotyledons were placed on Murashige and Skoog medium containing 100 mg kanamycin/liter. Putative transformed embryogenic calli were obtained, followed by the development of mature embryos and their germination to plants. All transformed R0 cucumber plants appeared morphologically normal and tested positive for NPT II. Southern blot analysis of selected cucumber DNAs indicated that NPT II, GUS, and CMV-C coat protein genes were integrated into the genomes. Enzyme-linked immunosorbent assay and Western blot analysis indicated that the CMV-C coat protein is present in the protein extracts of progeny plants. These results show that the Agrobacterium-mediated gene transfer system and regeneration via somatic embryogenesis is an effective method for producing transgenic plants in Cucurbitaceae.