Generation of thymidine auxotrophicAgrobacterium tumefaciensstrains for plant transformation

Agrobacterium -mediated transformation is a widely used gene delivery method for fundamental researches and crop trait improvement projects. Auxotrophic Agrobacterium tumefaciens strains are highly desirable for plant transformation because they can be easily removed from the explants after co-cultivation due to their dependence on essential nutrient supplementation. The thymidine auxotrophic A. tumefaciens strain LBA4404Thy- has been successfully used for plant transformation, however, auxotrophic version of other commonly used strains are not available yet to public laboratories. Here we report the generation of EHA101, EHA105 and EHA105D thymidine auxotrophic strains. These strains exhibited thymidine-dependent growth in the bacterial medium, and the transient GUS expression assay using Arabidopsis seedling showed that they retain the equivalent T-DNA transfer capability as the original strains thus are suitable for plant transformation.