Michael J. Striem(1), and B.I. Reisch, and J.R. Kikkert. 1997. Differences in GUS expression among grapevine transformants. Proc. 5th Intern. Symp. Grapevine Physiology. 25-30 May 1997. Jerusalem, Israel. Acta Horticulturae (in press)

Department of Horticultural Sciences, Cornell University, Geneva NY 14456, USA

(1) Present address: Department Fruit Tree Breeding, Volcani Center, Bet Dagan 50250, Israel

Keywords: Biolistic transformation, histochemical staining, transgene expression,Vitis

Transgenic grape plantlets (Vitis vinifera L. cv. Chancellor) produced by biolistic transformation, were characterized for gene integration and expression. Nine plantlines (and a non-transformed control) were propagated in vitro, rooted in peat pellets, and then grown in a greenhouse. Presence of the GUS and Npt-II genes in leaves and roots was tested by PCR amplification and Southern blot analysis. GUS expression was also tested by histochemical staining of various tissues. Three plant-lines which carried the GUS-gene construct did not express the GUS gene. The other lines expressed GUS, but the strength of expression differed between individuals and in different tissues. GUS expression in one plantline was detected in the shoots but not in the roots. In Southern blot analysis, between 1 and 11 bands per plantlet were observed when the Npt-II gene was used as a probe. Differential expression of the GUS gene should be expected due to chimerism, position effects, and transgene inactivation.