There is provided an expression method of a target foreign gene in a plant induced by a chemical substance, which comprises a step of activating with copper ions a transcription factor encoded by a foreign gene different from the target foreign gene to induce activation of transcription of the target foreign gene by a region having a promoter function contained in the target foreign gene, wherein a nucleotide sequence encoding said transcription factor is contained in a gene construct which is constructed so as to comprise a nucleotide sequence of a 5'-untranslated region of an arbitrary foreign gene downstream from the region having a promoter function contained in the target foreign gene.本發明係提供在植物中表現由化學物質所誘導之標的外源基因的方法，其包括以銅離子活化由不同於標的外源基因之外源基因所編碼之轉錄因子，以藉由該標的外源基因所包含的具有啟動子功能之區域來誘導標的外源基因轉錄之活化，其中，編碼該轉錄因子之核苷酸序列係包含於基因構築體(construct)，該基因構築體係經建構成包括位於標的外源基因所包含的具有啟動子功能之區域下游之任意外源基因之5'-非轉譯區的核苷酸序列。
