Preliminary results for genetic transformation of shoot tip of Eucalyptus saligna Sm. via Agrobacterium tumefaciens

Abstract

The regeneration of transgenic plants of Eucalypt is the largest difficulty for the genetic transformation of this genus; in addition a low rate of transformed plants is reached. The aim of this research was to evaluate acetosyringone (3',5'-Dimethoxy-4'-hydroxyacetophenone) on the co-culture medium during genetic transformation of shoot tips of Eucalyptus saligna via Agrobacterium tumefaciens and to promote the explants selection supposedly transformed. Shoot tip from multiple shoots was used as explants. These explants were pre-cultured during two days before the transformation. Strain EHA105 of A. tumefaciens harboring the plasmid pBI121 was used. The treatments were: 0 and 100 μM acetosyringone added to the co-culture, after co-culture the explants were cultured in multiplication medium supplemented with 250 mg.L-1 Cefotaxime® and each sub-culture the kanamycin levels were increased from 50 to 150 mg.L-1. The transient expression of the uidA gene in shoot tips was evaluated after the end of the co-culture (fifth day) and after seven days of culture on medium containing kanamycin. The presence of 100 μM acetosyringone at the co-culture of shoot tips of Eucalyptus saligna promoted higher transient expression of the uidA gene and retards toxic effects caused by kanamycin.