The invention relates to a method for producing a transgenic plant in
which the capability for incorporating undesired nitrogen compounds,
especially amino acids, in the storage organs is reduced compared with
the wild type, comprising the steps:
introducing at least one DNA sequence and/or at least one RNA sequence
corresponding to the DNA sequence and/or a mixed sequence composed of DNA
and RNA nucleotides corresponding to the DNA sequence with the coding
region for an amino acid transporter or parts thereof into a plant cell,
wherein the DNA and/or RNA sequence and/or mixed sequence is used in
sense or antisense orientation and the expression of an endogenous amino
acid transporter gene is prevented or reduced,
and regenerating a plant from this plant cell, wherein the DNA and/or RNA
sequence is a sequence from Beta vulgaris.