Abstract: Disclosed are a nucleic acid molecule, a polypeptide having epoxy group-removing catalytic activity and use thereof. According to the invention, by means of genetic engineering, the nucleic acid molecule encoding a de-epoxidation protein is expressed in a plant, so that an epoxy group of a trichothecene mycotoxin is removed, and the toxin amount in the plant is reduced. The polypeptide of the invention is capable of catalyzing a reaction between vomitoxin and glutathione under mild conditions to remove epoxy groups to produce a glutathionylated derivative.