Detection of the reporter and selection genes in transformed hop (Humulus lupulus L.)

Abstract

Agrobacterium-mediated transformation of hop nodal explants with meristems was used for the introduction of a gus reporter gene and nptII plant selection gene into Slovenian hop cv. Aurora. Emerging hop regenerants were previously tested for the gus gene expression by histochemical analysis of β-glucoronidase (GUS) activity. Approximately six months after the transformation procedure, PCR molecular analysis of shoots originating from previously GUS positive regenerants was performed to check integration of the reporter and selection genes into the hop genome. We also compared whether there were any differences in transgene integration in relation to the intensity of gus gene expression (intensive blue coloration on a larger proportion of the leaf surface or just a few blue spots) revealed by GUS-assay. In both cases, the majority of shoots had both transgenes integrated (47.7 or 55.3%) and in smaller number of shoots both transgenes were missing (38.6 or 18.8%). The fewest shoots analyzed showed just gus (2.3 or 8.9%) and slightly more nptII (11.4 or 17.0%) gene presence.