Rice nitrate reductase NIA3 protein gene OsNia3 and application thereof

The invention discloses a rice nitrate reductase NIA3 protein gene OsNia3. The rice nitrate reductase NIA3 protein gene OsNia3 has a cDNA sequence shown as SEQ ID NO. 1 which encodes a rice NIA3 protein having an amino acid sequence shown as SEQ ID NO. 2. Homozygous mutants with rice gene OsNia3 knocked-out and homozygous stains with OsNia3 overexpression are obtained by utilizing a transgenic technology. It has been discovered by analysis that the stains with the OsNia3 gene knocked-out have shortened plant height, shorted growth period and reduced yield per plant; however, the stains with OsNia3 overexpression have relatively high plant height, prolonged growth period and increased yield per plant. Thus, the rice nitrate reductase NIA3 protein gene OsNia3 can be introduced into plants asa target gene, thereby improving nitrogen use efficiency of the plants so as to be subjected to plant variety improvement. 水稻硝酸还原酶NIA3蛋白基因OsNia3，其cDNA序列如SEQ ID NO.1所示，其编码的水稻NIA3蛋白，氨基酸序列如SEQ ID NO.2所示；利用转基因技术获得水稻基因OsNia3的纯合敲除