An optimised bombardment protocol to introduce DNA into Coffea arabica suspension culture cells was developed. Osmotic preconditioning of cells and physical bombardment parameters including Helium pressure, gap and target distances affecting DNA delivery were evaluated by monitoring transient expression of the uidA gene driven by the CaMV35S promoter. The highest transient GUS expression was obtained when cells were subjected to a 0.5 M mannitol–sorbitol pre-treatment 4 h prior to bombardment and a Helium pressure of
