Efficient transformation of potato stems segments from cultivar Désirée, using phosphinothricin as selection marker

This work describes the development of a fast and efficient methodology for Agrobacterium tumefaciens-mediated genetic transformation of internodal stem segments from potato (Solanum tuberosum L.), cultivar Désirée, using phosphinothricin (PPT, glufosinate ammonium) as a selection agent. This methodology has a transformation efficiency of 68%, inducing shoots after 4 to 5 weeks in the presence of 2 mg/L of phosphinothricin. The expression of the bar gene in leaf segments from resistant, transformed plants was demonstrated by the chlorophenol red assay, as was its presence in the genome of explants by Polymerase Chain Reaction. An additional observation was the presence of high levels of resistance to phosphinothricin (up to 500 mg/L) in the transgenic clones, with an otherwise normal phenotype. These transgenic plants were transplanted to greenhouses and after aspersion with the herbicide Finale (Bayer CropScience) at 2.5 L/ha remained healthy and green, in contrast with the non-transgenic controls which died after 7 days.