The invention provides isolated and at least partially-purified dicamba-degrading enzymes, isolated DNA molecules coding for dicamba-degrading enzymes, DNA constructs coding for dicamba-degrading enzymes, transgenic host cells comprising DNA coding for dicamba-degrading enzymes, and transgenic plants and plant parts comprising one or more cells comprising DNA coding for dicamba-degrading enzymes. The invention further provides a transit peptide for use in a DNA construct comprising such dicamba-degrading enzymes that targets said dicamba-degrading oxygenase to organelles of a plant cell. Expression of the dicamba-degrading enzymes results in the production of dicamba-degrading organisms, including dicamba-tolerant plants. The invention further provides a method of controlling weeds in a field containing the transgenic dicamba-tolerant plants of the invention and a method of decontaminating a material containing dicamba comprising applying an effective amount of a transgenic microorganism or dicamba-degrading enzyme(s) of the invention to the material. Finally, the invention provides a method of selecting transformed plants and plant cells based on dicamba tolerance and a method of selecting or screening transformed host cells, intact organisms and parts of organisms based on the fluorescence of 3,6-dichlorosalicylic acid produced as a result of dicamba degradation.La presente invención se refiere a enzimas que degradan el dicamba, aisladas, y por lo menos purificadas parcialmente, moléculas de ADN aisladas que codifican las enzimas que degradan el dicamba, constructos de ADN que codifican las enzimas que degradan el dicamba, células huésped transgénicas que comprenden el ADN que codifican las enzimas que degradan el dicamba, plantas o partes de plantas transgénicas que comprenden una ó más células que comprenden el ADN que codifica las enzimas que degradan el dicamba. La invención además proporciona un péptido de tránsito para usarlo en una construcción de ADN que c
