OsNAR2.1 induced endogenous nitrogen concentration variation affects transcriptional expression of miRNAs in rice

Yong Zhang; Xiaoru Fan; Yulong Wang; Pulin Kong; Ling Zhao; Xiaorong Fan; Yadong Zhang

doi:10.3389/fpls.2023.1093676

OsNAR2.1 induced endogenous nitrogen concentration variation affects transcriptional expression of miRNAs in rice

Front Plant Sci. 2023 Feb 24:14:1093676. doi: 10.3389/fpls.2023.1093676. eCollection 2023.

Authors

Yong Zhang¹, Xiaoru Fan², Yulong Wang³, Pulin Kong³, Ling Zhao¹, Xiaorong Fan^{3

4}, Yadong Zhang^{1

4}

Affiliations

¹ Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Jiangsu High Quality Rice Research and Development Center, Nanjing Branch of China National Center for Rice Improvement, Nanjing, China.
² School of Chemistry and Life Science, Anshan Normal University, Anshan, China.
³ State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China.
⁴ Zhongshan Biological Breeding Laboratory, Nanjing, China.

Abstract

The studies of rice nitrogen concentration on the expression of miRNA so far are mostly limited to the exogenous nitrogen, leaving the effect of endogenous nitrogen largely unexplored. OsNAR2.1 is a high-affinity nitrate transporter partner protein which plays a central role in nitrate absorption and translocation in rice. The expression of OsNAR2.1 could influence the concentration of the endogenous nitrogen in rice. We showed that the expression and production of miRNA in rice can be influenced by manipulating the endogenous nitrogen concentration via OsNAR2.1 transgenic lines. The small RNA content, particularly 24 nucleotides small RNA, expressed differently in two transgenic rice lines (nitrogen efficient line with overexpression of OsNAR2.1 (Ov199), nitrogen-inefficient line with knockdown OsNAR2.1 by RNAi (RNAi)) compared to the wild-type (NP). Comparative hierarchical clustering expression pattern analysis revealed that the expression profiles of mature miRNA in both transgenic lines were different from NP. Several previously unidentified miRNAs were identified to be differentially expressed under different nitrogen concentrations, namely miR1874, miR5150, chr3-36147, chr4-27017 and chr5-21745. In conclusion, our findings suggest that the level of endogenous nitrogen concentration variation by overexpression or knockdown OsNAR2.1 could mediate the expression pattern and intensity of miRNA in rice, which is of high potential to be used in molecular breeding to improve the rice responses towards nitrogen utilization.

Keywords: OsNAR2.1; miRNA; nitrogen concentration; previously unidentified miRNA; rice.

Grants and funding

We would like to thank all funding sources, namely, the National Natural Science Foundation of China (32172665), Jiangsu Science and Technology Development Program (BE2021301-3), the Introduction Project of High-level Talents in Xinjiang Uygur Autonomous Region, the Jiangsu Funding program for Excellent Postdoctoral Talent (2022ZB774).