TRANSGENIC PLANTLETS OF CHANCELLOR GRAPEVINE (VITIS SP) FROM BIOLISTIC TRANSFORMATION OF EMBRYOGENIC-CELL SUSPENSIONS

Transgenic plantlets of 'Chancellor' grapevine (Vitis L. complex inter specific hybrid) were produced via biolistic transformation. Embryogen ic cell suspensions were bombarded with 1 mu m tungsten particles coat ed with pBI426 which encodes a fusion peptide between beta-glucuronida se (GUS) and neomycin phosphotransferase II (NPTII). The fusion peptid e is under the control of a double 35S Cauliflower Mosaic Virus promot er and a leader sequence from Alfalfa Mosaic Virus. The cells were pla ced on kanamycin-containing media (10, 25 or 50 mg/l) 2 d after bombar dment. Activated charcoal reduced cell browning. Embryos were first ob served on selective media 14-29 weeks after bombardment. More than 160 0 clusters of embryos were germinated and/or assayed for GUS. Of 621 e mbryos assayed for GUS expression, 182 (29.3%) were positive. PCR conf irmed the presence of the NPTII gene in all 5 GUS-positive and 2 GUS-n egative (bombarded) embryos tested. In germination experiments, 15% of the embryo clusters produced at least one plant with normal shoot gro wth. Of 164 normal plants assayed for GUS expression, 37 (22.6%) were positive. The NPTII gene was amplified by PCR in 1 (of 1) GUS-positive and 4 (of 5) GUS-negative bombarded plants, but not in non-bombarded control plants. Southern blotting confirmed integration of the NPTII g ene in all 3 of the GUS and PCR-NPTII positive plants tested. Biolisti cs is an efficient method for transformation of 'Chancellor' and shoul d be applicable to other important grape cultivars.