A new method for transformation of rapeseed microspore-derived embryos (MDEs), based on microwounding of MDEs by particle bombardment prior to inoculation with an Agrobacterium suspension was reported. In this study, effects of two transformation systems (integrated bombardment and Agrobacterium transformation system and the singular bombardment) on transient GUS expression in hypocotyls of rapeseed (Brassica napus L. cv. PF704) MDEs were studied. Bombardment parameters were: helium pressure, 1350 psi; distance between stopping screen and target tissue, 9 cm, gold particles size of 1.0 microm and chamber vacuum pressure, 24 in Hg. In integrated system A. tumefaciens strain AGL1 carrying the binary vector pCAMBIA3301 was used. Bombarded hypocotyls of MDEs were inoculated with Agrobacteria at OD600 = 1.0 for 10 min or OD600 = 0.25 for 24 h. Integrated transformation system increased the mean number of blue spots about 2-2.5 fold compared to singular bombardment and inoculated hypocotyls with OD600 = 1.0 for 10 min produced the highest number of blue spots per bombardment (743 +/- 23.67).
