AUTHOR=Chen Jingguang , Qi Tiantian , Hu Zhi , Fan Xiaoru , Zhu Longlong , Iqbal Muhammad Faseeh , Yin Xiaoming , Xu Guohua , Fan Xiaorong 

TITLE=OsNAR2.1 Positively Regulates Drought Tolerance and Grain Yield Under Drought Stress Conditions in Rice

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00197

DOI=10.3389/fpls.2019.00197

ISSN=1664-462X

ABSTRACT=<p>Drought is an important environmental factor that severely restricts crop production. The high-affinity nitrate transporter partner protein <italic>OsNAR2.1</italic> plays an essential role in nitrate absorption and translocation in rice. Our results suggest that <italic>OsNAR2.1</italic> expression is markedly induced by water deficit. After drought stress conditions and irrigation, compared with wild-type (WT), the survival rate was significantly improved in <italic>OsNAR2.1</italic> over-expression lines and decreased in <italic>OsNAR2.1</italic> RNAi lines. The survival rate of Wuyunjing7 (WYJ), <italic>OsNRT2.1</italic> over-expression lines and <italic>OsNRT2.3a</italic> over-expression lines was not significantly different. Compared with WT, overexpression of <italic>OsNAR2.1</italic> could significantly increase nitrogen uptake in rice, and <italic>OsNAR2.1</italic> RNAi could significantly reduce nitrogen uptake. Under drought conditions, the expression of <italic>OsNAC10, OsSNAC1, OsDREB2a</italic>, and <italic>OsAP37</italic> was significantly reduced in <italic>OsNAR2.1</italic> RNAi lines and increased substantially in <italic>OsNAR2.1</italic> over-expression lines. Also, the chlorophyll content, relative water content, photosynthetic rate and water use efficiency were decreased considerably in <italic>OsNAR2.1</italic> RNAi lines and increased significantly in <italic>OsNAR2.1</italic> over-expression lines under drought conditions. Finally, compared to WT, grain yield increased by about 9.1 and 26.6%, in <italic>OsNAR2.1</italic> over-expression lines under full and limited irrigation conditions, respectively. These results indicate that <italic>OsNAR2.1</italic> regulates the response to drought stress in rice and increases drought tolerance.</p>