Genetic transformation of grapevine cells using the minimal cassette technology: the need of 3'-end protection.

The use of minimal cassettes (linear DNA comprising promoter+open reading frame+terminator) for genetic transformation offers a means of transforming plant cells by biolistics without introducing unwanted sequences. However, a species-specific approach of the factors involved in successful transformation with this technology is advisable. Protection of the minimal cassette upstream promoter and downstream terminator may be necessary due to the nuclease activity of target plant material. Genetic transformation by biolistics followed by expression analysis was used to evaluate different DNA constructs in 110 Richter (Vitis sp.) cell suspensions. Our results suggest the importance of 3'-end cassette protection for successful protein expression using the minimal cassette technology.