Disarmed Agrobacterium strains, Ri plasmids and transformation procedures based on them

A method for producing a transgenic plant cell comprising the steps of: a) providing bacteria of a variant of non-pathogenic strain of Agrobacterium strain K599 (NCPPB 2659) which is a soil-borne plant-pathogenic bacterium characterized by an intergenic sequence of 16S-23S rRNA comprising at least one sequence motif selected from the group consisting of the sequence motifs described by SEQ ID NO: 5, 6, 7, 8, 9, 10, 11, 12, 13 and 14, wherein said strain variant is capable of infecting plant cells, but lacks inductive properties of the hair root phenotype and in which said strain variant further comprises a non-pathogenic plasmid variant of the plasmid Ri pRi2659 and a DNA -T transgenic, and b) co-cultivate a plant cell with said bacteria, and c) isolate or select plant cells that stably integrate said transgenic T-DNA into its genome, in which said non-pathogenic strain variant is capable of infecting plant cells, to mediate the transfer of T-DNA into plant cells, and to mediate the insertion of T-DNA into the plant genome, but lacks phenotype inducing properties. of hair roots and in which the non-pathogenic plasmid variant comprises at least one sequence having a sequence identity of at least 90% with a sequence as described by SEQ ID NO: 24.