The present invention specifies a glutathione-S-transferase that exhibits metabolic/detoxification activity on an isoxazoline derivative such as pyroxasulfone or the like. Provided is a transformed plant cultivation method that is characterized in that a plant that is transformed by introducing thereinto a nucleic acid coding for a protein (a) or (b) is cultivated in the presence of an isoxazoline derivative, wherein the protein (a) is a protein that contains an amino acid sequence of SEQ ID NO: 2, and the protein (b) is a protein that contains an amino acid sequence that is at least 80% identical to the amino acid sequence of SEQ ID NO: 2 and that exhibits glutathione-S-transferase activity.
