In the face of population growth, the primary goal of breeding is high yield. The first green revolution of rice dwarf breeding was promoted so that it can be used in large quantities of fertilizers. The plant will not be too high to cause lodging, so that a higher yield can be obtained under high fertilizer. However, long-term breeding under high fertilizers has resulted in the loss of some important genetic resources, so that the fertilizer use efficiency of the main rice varieties is generally low.
The Chu Chengcai research group of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences collected 110 early rice samples collected in 52 countries (regions) in different geographic regions of the world over the past 100 years. A comprehensive identification of agronomic traits was conducted on farm species, and it was found that under different nitrogen fertilizer conditions, among many agronomic traits, there is a high correlation between the nitrogen response ability of rice tiller (branch) and the variation of nitrogen use efficiency. The research team used genome-wide association analysis technology to identify a rice nitrogen efficient gene OsTCP19, which acts as a transcription factor to regulate rice tillering.
Further research found that the absence of a small nucleic acid fragment (29-bp) in the upstream regulatory region of OsTCP19 is the main reason for the difference in the tiller nitrogen response of different rice varieties. Nitrogen-efficient variety OsTCP19 lacks the 29-bp nucleic acid sequence in the regulatory region, and the nitrogen-responsive negative regulatory factor LBD protein can efficiently bind to this site and inhibit the transcriptional expression of OsTCP19. Through multiple transcriptomics analysis, OsTCP19 was used as a transcription factor to inhibit the expression of the tiller promoting gene DLT, thereby realizing the regulation of rice tiller development. This study revealed the molecular basis of nitrogen regulation of rice tiller development.
The identification of , a key nitrogen-efficient gene, relies on a diverse”farm-grown” rice population. These farm varieties are local varieties grown by farmers around the world before the popularization of modern high-yield rice varieties, that is, before the massive application of nitrogen fertilizer. The differences in climate and soil quality around the world have created a rich genetic diversity of farm varieties. The research conducted genetic analysis of these”old” rice varieties in the rice seed bank, and finally located this key variation in the genome. Through the analysis of soil nitrogen content data in the world’s rice planting areas, the study found that the more barren the soil, the more common the variation of OsTCP19 nitrogen efficiency, and as the soil nitrogen content increases, the nitrogen efficient type varieties gradually decrease, while the modern rice varieties Almost all of this nitrogen efficient variation is lost. Re-introducing this nitrogen-efficient variation into modern rice varieties, under the conditions of reduced nitrogen, rice nitrogen use efficiency can be increased by 20-30%, that is to say, in rice production, using less chemical fertilizers can achieve the same The output.
In addition to the environmental impact of nitrogen fertilizer application, nitrogen fertilizer production itself is also an industry with high energy consumption and high pollution. Statistics show that producing 1 ton of nitrogen fertilizer requires 2.8 tons of high-quality coal and 1,600 kWh of electricity, resulting in 2.5 tons of carbon emissions. my country is striving to achieve carbon neutrality by 2060, and energy conservation and emission reduction in the agricultural sector, especially reducing the use of chemical fertilizers, are crucial. The research results provide a brand new idea for achieving this goal.
On January 6, 2021, Nature reported the results of this research in an article. Doctors Liu Yongqiang and Wang Hongru of the Institute of Genetics and Development are the co-first authors of the paper, and young researcher Hu Bin and researcher Chu Chengcai are the co-corresponding authors of the paper. The research work has been funded by the Chinese Academy of Sciences Strategic Leading Science and Technology Project, the National Natural Science Foundation of China, the G2P basic research project of the Ministry of Science and Technology, and the major basic research project of Guangdong Province.
OsTCP19-H can be used under low and medium nitrogen Significantly increase rice yield