Comparison of procedures for DNA coating of micro-carriers in the transient and stable biolistic transformation of sugarcane

Biolistic gene transfer is one of the preferred methods for both transient gene expression studies and stable genetic transformation for improvement of crops including sugarcane. In preparation for bombardment, DNA is precipitated onto micro-particles in the presence of a cationic polyamine and buffer. Three different DNA coating procedures were compared for biolistic transformation of sugarcane using linear expression cassettes: spermidine (free base), protamine sulfate, and the Seashell DNAdel? Gold Carrier with proprietary precipitation buffer from Seashell Technology. All three DNA coating procedures produced transient and stable sugarcane transformation events in multiple experiments. Spermidine resulted in three-fold and 2.65-fold higher transient GUS expression than protamine and Seashell DNAdel?, respectively when averaged over 10 coating reactions per treatment. However, no significant difference in stable genetic transformation was found between the three DNA coating procedures. This study determined that spermidine-, protamine-, and Seashell DNAdel? Gold Carrier-mediated DNA coating can be equally effective for biolistic transformation of sugarcane.