Herbicide-detoxifying enzymes, compositions containing one or more of the enzymes, and plant seeds treated with the enzymes are provided. The enzymes can be used in methods for detoxifying auxin herbicides or degrading auxin plant regulators, including in methods for decontaminating surface of an apparatus used in agriculture or pesticide manufacturing, methods for decontaminating water, soil, soilless media, or sludge, and methods for protecting a plant from an auxin herbicide, improving a plant's tolerance to an auxin herbicide, or removing an auxin herbicide from the surface of a plant.