02095naa a2200229 a 450000100080000000500110000800800410001910000160006024500970007626000090017352014600018265000270164265000300166965000130169965300260171265300150173870000150175370000150176870000150178370000150179877300520181310753111995-11-01       1994    bl ---       0--  u    #d1 aCHOI, P. S.  aGenetic transformation and plant regeneration of watermelon using Agrobacterium tumefaciens.  c1994  aAdventitious shoots formed on the proximal cut edges of different cotyledonary explants of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai; cvs. Sweet Gem and Gold Medal] cultured on Murashige and Skoog's (MS) medium with 1 mgl-1 6-benzyladenine (BA). Light (16-h photoperiod, about 7 Wm-2 cool-white fluorescent lamps) was essential for shoot formation. To obtain transformed plants, cotyledonary explants of "Sweet Gem" were cocultured with Agrobacterium tumefaciens LBA4404, a disarmed strain harboring a binary vector pBI121 carrying the CaMV 35S promoter-belta-glucuronidase (GUS) gene fusion used as a reporter gene and NOS promoter-neomycin phosphotransferase gene as a positive selection marker, for 48h on MS medium with 1 mgl-1 BA and 200 uM beta-hydroxyacetosyringone. After 48h of culture, explants were transferred to medium with 1 mgl-1 BA, 250 mgl-1 carbenicillin, and 100 mgl-1 kanamycin and cultured in the light. Adventitious shoots formed on the explants after 4 weeks of culture. When subjected to GUS histochemical assay, young leaves obtained from the shoots showed a positive response at a frequency of up to 16%. Preculturing cotyledonary explants on MS medium with 1 mgl-1 BA for 5d enhanced the competence of the cells to be transformed by Agrobacterium Southern blot analysis confirmed that the GUS gene was incorporated into the genomic DNA of the GUS-positive regenerants. The transformed plants were grown to maturity.  agenetic transformation  aAgrobacterium Tumefaciens  aMelancia  aMelhoramento genetico  aWatermelon1 aSOH, W. Y.1 aKIM, Y. S.1 aYOO, O. J.1 aLIU, J. R.  tPlant Cell Reportsgv.13, n.6, p.344-348, 1994.