A variety-independent protocol was developed for genetic transformation and regeneration of Egyptian cotton (Gossypium barbadense) plants from meristematic tissue of excised embryonic axes and from the shoot apical meristem of seedlings using the Bio-Rad PDS/1000/He gene gun. Tungsten beads coated with plasmid DNA (pBI221) carrying the coding sequence for the GUS protein were used to deliver the gene directly into the meristematic tissue. Transgenic cotton plants were obtained using techniques of shoot meristem transformation and direct regeneration of shoots and roots. Plants derived from this process were screened for integration of the GUS gene into the plant genome using dot blotting, genomic Southern analysis, immunoblot hybridization and histochemical assay. This work represents the first report of shoot meristem genetic transformation and regeneration of commercial varieties (Giza 45, Giza 87 and Giza 88 as extra-long staple varieties and Giza 85, Giza 89 and Giza 86 as long staple varieties) using biolistic gun transformation. Molecular and genetic characterization of primary transformants and their progeny proved that GUS gene was successfully integrated into the genome.
