Expression of thegus Agene in embryogenic cell lines of Sitka spruce followingAgrobacterium-mediated transformation

Transformation of Picea sitchensis (Bong) Carr. was investigated by incubating embryogenic cell lines, initiated from immature and mature zygotic embryos, with a supervirulent strain of Agrobacterium tumefaciens. The latter carried a gus A-intron gene. Transient gene expression was determined histochemically by recording the number of distinct areas of β-glucuronidase (GUS) activity. Maximum expression of the gus gene was achieved with a bacterial suspension with an OD600 of 0.8–1.1 diluted with an equal volume of MPM medium, Inoculation of cells with bacteria for 30 mm, 72 h co-cultivation period and exposure of Agrobacterium and plant cells to 50 μM acetosyrmngone. These results are discussed in relation to Agrobacterium-mediated gene delivery for the stable transformation of Sitka spruce and other conifers.