Expression of an abscisic acid responsive promoter in Picea abies (L.) Karst. following bombardment from an electric discharge particle accelerator.

The 1.5 kilobase promoter sequence upstream of Dc8, a late embryo abundant gene of Daucus, fused to the reporter β-glucuronidase gene was introduced into several tissues of Picea abies via a custom-made electric-discharge particle accelerator. Transient expression was measured histochemically as spot number 2 d after bombardment. Embryogenic suspensions gave higher levels of expression depending upon cell line than embryogenic callus or zygotic embryos. Expression was enhanced when cultures were treated with abscisic acid for 3 d before bombardment. A mean and maximum of 17 and 34 spots/disk, respectively, were observed with the best cell line, which was comparable with the level of expression driven by an enhanced 35S promoter.