The present invention relates to a method for excising a nucleic acid sequence from the genome of a plant or a plant cell. This method is based on the steps of transforming a plant cell with a construct encoding a DNA double strand break inducingenzyme (DSBI), generating a transgenic plant line, performing a transient assay to analyze the functionality of the transgenic enzyme, crossing the plant line with a line containing a nucleic acid sequence to be excised and performing an immature embryo conversion or a tissue culture regeneration through callus formation. The method can also be reversed, which means that a plant cell is transformed with a construct encoding a nucleic acid sequence to be excised, and the crossing is performed witha plant line containing a DSBI. As an alternative to the crossing step, a re-transformation of a transgenic plant line with a second construct can also be performed. The invention is also directed to a plant obtained by this method, or progeny, propagation material, part, tissue, cell or cell culture, derived from such a plant. Finally, the invention relates to the use of a plant or progeny, propagation material, part, tissue, cell or cell culture, derived from this method, as aliment, fodder or seeds or for the production of pharmaceuticals or chemicals.Linvention concerne un procédé dexcision dune séquence dacide nucléique provenant du génome dun végétal ou dune cellule végétale. Le procédé comporte les étapes consistant à: transformer une cellule végétale à laide dun gène hybride codant pour une enzyme induisant une cassure bicaténaire dADN (DSBI), produire une lignée de plante transgénique, mettre en œuvre un dosage transitoire pour analyser la fonctionnalité de lenzyme transgénique, croiser la lignée de plante avec une lignée contenant une séquence dacide nucléique à exciser et mettre en œuvre une conversion dembryon immature ou une régénération de culture tissulaire par formation de callus. Le procédé peut aussi être inversé, c
