An improved selection strategy and the use of acetosyringone in shoot induction medium increase almond transformation efficiency by 100-fold

An improved almond transformation system was developed with a 100x increase in efficiency (12.3%) as compared to the existing transformation method (0.1%) in spite of the lower regeneration ability of the explants used. Leaf transformation was performed with Agrobacterium EHA105/p35 SGUSINT. Main modifications introduced in the transformation protocol were the use of 150 mu M acetosyringone (AS) during the 21-days induction period, and a different selection strategy. Transformed shoots were assayed using PCR, GUS analyses and Southern blotting. The improved methodology is being applied for transformation of in vitro propagated cultivars and opens the possibility of using almond as model for functional studies in Prunoideae.