FACTORS INFLUENCING TRANSIENT GENE-EXPRESSION IN BEAN (PHASEOLUS-VULGARIS L) USING AN ELECTRICAL PARTICLE-ACCELERATION DEVICE

The parameters influencing transient expression of the beta-glucuronid ase gene in bean embryonic axes, cotyledons, apical meristems and leav es were evaluated after gene delivery with an electrical particle acce leration device. A calcium-spermidine procedure for coating gold parti cles with DNA resulted in higher levels of GUS expression with lower c oncentrations of gold particles compared with a calcium phosphate proc edure. The DNA concentration, distance between the discharge chamber a nd the retaining screen and the vacuum in the apparatus also influence d gene delivery. Sections prepared for light and electron microscopy s howed the localisation, within target cells, of gold particles used to deliver the DNA. Immunolocalization of foreign gene expression within cells confirmed an even distribution of gene product throughout the c ell cytoplasm.