EXPRESSION OF THE GUS-A GENE IN EMBRYOGENIC-CELL LINES OF SITKA SPRUCE FOLLOWING AGROBACTERIUM-MEDIATED TRANSFORMATION

Transformation of Picea sitchensis (Bong) Carr. was investigated by in cubating embryogenic cell lines, initiated from immature and mature zy gotic embryos, with a supervirulent strain of Agrobacterium tumefacien s. The latter carried a gus A-intron gene. Transient gene expression w as determined histochemically by recording the number of distinct area s of beta-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 min, 72 h co-cultivation period and exposure of Agrob acterium and plant cells to 50 mu M acetosyringone. These results are discussed in relation to Agrobacterium-mediated gene delivery for the stable transformation of Sitka spruce and other conifers.