The present invention provides a method for changing nitrogen utilization efficiency in a plant comprises regulating the expression of Arabidopsis NRT 1.7 or an ortholog thereof so that the nitrate remobilization from older leaves to young leaves in the plant is regulated, thereby the nitrogen utilization efficiency is changed. The present invention also provides a transgenic plant obtainable by transforming a plant with an expression construct with a high or low level of expression of NRT 1.7. On the other hand, the present invention yet provides a chimera nitrate transporter, a DNA molecule coding for this chimera transporter and an expression vector thereof.