Recently, the Plant Hormone and Gene Editing Team of the Agricultural College of Nanjing Agricultural University published the title”Natural Allelic Variation in a Modulator” in The Plant Cell, an international authoritative journal in the field of botany. of Auxin Homeostasis Improves Grain Yield and Nitrogen Use Efficiency in Rice” research paper, the proven N-DNR1-Auxin-OsARF molecular module enriches the understanding of nitrogen-auxin-nitrogen fertilizer utilization efficiency, revealing growth at the molecular level The mechanism of nutrient homeostasis regulating nitrogen use efficiency.
Nitrogen fertilizer is one of the factors that promote the increase of crop yield. However, the increase in the use of nitrogen fertilizers in recent years has not led to a substantial increase in crop yields, and economic and ecological benefits have shown a downward trend. How to improve the efficiency of nitrogen fertilizer utilization has become an urgent problem in agricultural production. Cultivating new crop varieties that use nitrogen fertilizer efficiently is an effective way to reduce production costs, reduce environmental pollution, and greatly increase ecological benefits. In this study, using the rice single-segment substitution line material with Huajingxian 74 as the background, combined with contig mapping and map-based cloning techniques, the nitrogen-efficient gene DNR1 was isolated from indica rice, which encodes the pyridoxal phosphate-dependent amino group. Transferase, negatively regulates the synthesis of auxin. It has been reported that auxin can regulate the nitrogen fertilizer use efficiency of plants, but the specific molecular mechanism is not clear. The study found that external nitrogen sources can change the auxin content in rice by regulating the expression level of the DNR1 gene, thereby affecting the ability of the auxin signal pathway response gene OsARFs to activate downstream nitrogen metabolism-related genes, and ultimately achieve the efficiency of rice nitrogen utilization. Regulation.
Figure 1. Model of How Rice NUE and Yield are Regulated by the DNR1-Auxin-OsARFs Module in indica and japonica Rice Varieties.
The promoter sequence of DNR1 differs by 520 bp between indica and japonica rice subspecies, which leads to a significant difference in nitrogen absorption rate between indica and japonica; in indica The low expression of DNR1indica allele leads to the increase of auxin content in indica rice, which makes it have higher nitrogen utilization capacity. Planting japonica rice varieties and DNR1 knockout lines in fields with different amounts of nitrogen fertilizer, DNR1 knockout lines can increase yield by 8%-25%, which shows that DNR1 has great potential and value in improving the nitrogen use efficiency of japonica rice.
The first unit of this research work is the State Key Laboratory of Crop Genetics and Germplasm Innovation, College of Agriculture, Nanjing Agricultural University. Doctoral students Zhang Siyu from the School of Agriculture of Nanjing Agricultural University, Master students Zhu Limei, Shen Chengbo, and Dr. Ji Zhe from the University of Oxford are the co-authors; Professor Li Shan from the School of Agriculture of Nanjing Agricultural University and Professor Wang Shaokui from South China Agricultural University are the co-corresponding authors of this article; Chinese Academy of Sciences Genetics and Development Researcher Fu Xiangdong from the Institute of Biology, Professor Nicholas Harberd from Oxford University, and Professor Wu Juyou from Nanjing Agricultural University participated in part of the research. This research was funded by the Fifth Young Talents Promotion Project of the Chinese Association for Science and Technology, the start-up funding for the introduction of high-level talents from Nanjing Agricultural University, the basic operating expenses of central universities and BBSRC.