在蕃茄、馬鈴薯、葡萄、松樹及水稻的研究中，Asr基因的功能被推測與醣分代謝、逆境調控及果
實成熟有關。 然而，在已完成解碼的阿拉伯芥基因組中，卻不存有Asr與其相似基因。 為進一步探討Asr基因的生理功能，本研究選殖馬鈴薯Asr基因家族中ci21A基因的啟動子序列，並將其與報導基因(β-glucuronidase；GUS)連結，再將此重組基因分別轉殖於阿拉伯芥與蕃茄植株中，藉著追蹤報導基因的表現，可瞭解ci21A啟動子控制基因表現的情形。 本研究的實驗結果顯示，報導基因在阿拉伯芥與蕃茄轉殖株內的表現情形相似，最顯著表現於積儲器官部位。本研究的結果不僅有助於釐清ASR蛋白質在植物發育過程所扮演的角色，也證明ci21A啟動子具有在其他植物基因工程方面被應用的潛力。

The Asr gene is related to a number of functions, such as sugar regulation, stress induction, and fruit ripening in many plants, including tomato, potato, grape, pine, and rice. We used the promoter of the ci21A
gene of potato, which belongs to the Asr family, to characterize the genetic expression of this gene in tomato and Arabidopsis. Particularly, there is known to be no Asr gene in Arabidopsis. In order to identify the spatial and temporal expression of the ci21A promoter, we used β-glucuronidase (GUS) as the reporter gene. The ci21A-GUS fusion gene was found to exhibit a very similar expression pattern in transgenic tomato and Arabidopsis. The distribution of GUS revealed that most of the expression appears in the sink organs of tomato and Arabidopsis. The expression pattern controlled by ci21A promoter helped us to clarify the role of the ASR protein in the developmental processes of plants. It also provided the possibility of applying this promoter in the expression of foreign genes in plants. The ci21A promoter could be suitable for various applications in different species.