This study describes an efficient method for Agrobacterium tumefaciens-mediated transformation of Arabidopsis thaliana root explants using kanamycin selection. The authors developed culture conditions that enable rapid shoot regeneration from Arabidopsis root cuttings, with an efficiency of 100%. They established a transformation procedure based on kanamycin selection, which allowed the production of viable seeds in vitro or after soil rooting. Using this method, transformed seed-producing plants were obtained with an efficiency ranging from 20% to 80% within 3 months. The F1 seedlings of these transformants showed Mendelian segregation of the kanamycin-resistance trait. The transformation method was applicable to three different Arabidopsis ecotypes. Additionally, the authors introduced a chimeric bar gene conferring resistance to the herbicide Basta into Arabidopsis, demonstrating its expression through enzymatic assays. The study highlights the potential of the root transformation system for studying early Agrobacterium transformation events and its utility in Arabidopsis molecular biology research.This study describes an efficient method for Agrobacterium tumefaciens-mediated transformation of Arabidopsis thaliana root explants using kanamycin selection. The authors developed culture conditions that enable rapid shoot regeneration from Arabidopsis root cuttings, with an efficiency of 100%. They established a transformation procedure based on kanamycin selection, which allowed the production of viable seeds in vitro or after soil rooting. Using this method, transformed seed-producing plants were obtained with an efficiency ranging from 20% to 80% within 3 months. The F1 seedlings of these transformants showed Mendelian segregation of the kanamycin-resistance trait. The transformation method was applicable to three different Arabidopsis ecotypes. Additionally, the authors introduced a chimeric bar gene conferring resistance to the herbicide Basta into Arabidopsis, demonstrating its expression through enzymatic assays. The study highlights the potential of the root transformation system for studying early Agrobacterium transformation events and its utility in Arabidopsis molecular biology research.