After many years of field experiments, the researchers enhanced the expression of OsDREB 1C gene in "Japan Sunny" rice, which was 4 1.3%-68.3% higher than that in wild rice, and in "Xiushui 134" rice, it was 30./kloc-0 higher than that in wild rice. Qian Qian, director of Crop Research Institute of Chinese Academy of Agricultural Sciences and academician of Chinese Academy of Sciences, commented that the results of "Rice High Yield Gene" released this time provided important gene resources and more production and application possibilities for the next scientific research work.
Compared with the field phenotype of over-expressed materials (left), wild type (middle) and gene knockout materials (right), over-expressed rice materials grow faster than wild type under light. Photo courtesy of China Academy of Agricultural Sciences
A discovery made seven years ago.
20 14, an article in Nature Biotechnology caught the attention of zhou wenbin's team. By comparing maize and rice, 1 18 transcription factors were found to regulate maize photosynthesis.
Zhou wenbin introduced that these 1 18 transcription factors have one-to-one homologous genes in maize and rice. Corn and rice are both Gramineae plants, but their yields are quite different. The yield of corn is much higher than that of rice, almost twice that of rice. This is because they have different ways of photosynthesis. Maize is a C4 crop, which is characterized by higher photosynthetic efficiency, nitrogen use efficiency and water use efficiency than C3 crops (such as rice and wheat).
These functions are closely related to the output. Photosynthesis assimilates carbon dioxide in the air into organic matter, which is the basis of crop biomass and yield. Nitrogen is an important component of chlorophyll, protein, nucleic acid and metabolites, and it is also the main limiting factor of yield formation.
What attracts scientists' attention is, why do homologous genes, which also exist in corn and rice, produce huge differences?
Two research teams undertook the preliminary identification task, namely, Dr. Wei and Dr. Li Xia, Ph.D. students from the Institute of Crop Science, Chinese Academy of Agricultural Sciences, who are also the first authors of this paper.
This is a long journey of discovery. Wei told reporters that in the constant identification and analysis, they faced the situation of giving up several times, but they all persisted in the end. Fate blessed them, and they identified a transcription factor OsDREB 1C induced by light and low nitrogen in rice.
It is this small transcription factor that may be an opportunity to greatly increase rice yield.
High yield is still the most important pursuit.
China has a population of1400 million, accounting for about 19% of the world's population, but the cultivated land in China is only about 7% of the world's. It has been less than 40 years since this huge country really bid farewell to hunger. Especially in recent years, the number of people affected by hunger in the world is gradually increasing. The latest report "World Food Security and Nutrition in 2022" points out that in 20021year, the global population affected by hunger reached 828 million, and the world food security is facing great challenges.
Therefore, high yield is still one of the most important pursuits in agricultural breeding, especially in grain breeding.
Zhou wenbin introduced that in the 1960s, the "Green Revolution" began, and through the breeding of varieties such as semi-dwarf breeding and cross breeding, as well as the improvement of cultivation and management techniques, the crop yield was greatly improved.
However, in recent years, this growth is entering a platform period, and the growth of yield has become slow. "About 24%-39% of the world's corn, rice, wheat and soybean planting areas are stagnant or even declining."
At the same time, using a large amount of nitrogen fertilizer is still one of the important measures to improve crop yield. However, excessive use of nitrogen fertilizer is not only not conducive to increasing production, but also brings increasingly obvious negative effects, including environmental pollution and "greedy for green crops and late ripening". Among them, "greedy for green and late ripening" may affect multiple cropping, which in turn will affect the overall yield.
The difficulty of global grain production makes it increasingly urgent to greatly increase crop yield and efficiently use nitrogen fertilizer, which is also the difficulty and hot spot of agricultural scientific research at present.
The discovery of OsDREB 1C has brought light to solve these problems.
On-site long-term verification
After the appraisal is completed, it is a longer testing process.
Zhou wenbin told reporters that the research team selected two varieties for experiments. One is Japanese Haruki, which is a model crop in rice research. Because its whole genome sequence has been sequenced, it is an excellent experimental object. Another variety is "Xiushui 134", which is currently being used in production. This is a conventional japonica rice variety with an yield of 600 kg per mu.
At present, one of the experimental materials, Japan Sunny, is being planted in the research base in Shunyi, Beijing. Although it is still in the seedling stage, the growth of crops in rice fields can already be distinguished with the naked eye.
Zhou wenbin told reporters that through modern genetic engineering techniques, researchers have constructed knock-out materials and over-expression materials, and compared them with the wild type that has not been operated.
The results showed that rice materials with over-expression of the gene grew faster than wild type under light, and the photosynthesis rate was significantly improved, and the grain filling rate was faster. At the same time, in the field experiment, the researchers also found that the over-expressed materials significantly improved the efficiency of nitrogen utilization. In the three experimental fields of no nitrogen application, medium nitrogen application and high nitrogen application, the yield of overexpression materials can reach or even exceed that of wild type under the condition of medium nitrogen application without nitrogen application.
"We are expected to achieve the goal of nitrogen reduction and high yield." Zhou wenbin said.
In Beijing, Hangzhou, Sanya and other places, researchers have conducted many field experiments for many years. The results show that after the expression of OsDREB 1C in Japan, the yield in Beijing area can be significantly increased, with the plot yield increasing by 4 1.3%-68.3%. Xiushui 134 can increase production by 30. 1%-4 1.6% in Hangzhou. At the same time, both experimental materials have different degrees of premature effect.
A new method to increase rice yield?
Zhou wenbin said that this new research not only innovated the theory of crop high yield, but also confirmed the possibility that one gene can regulate multiple physiological functions. Overexpression of OsDREB 1C in rice has triple effects of high photosynthetic efficiency, high nitrogen efficiency and early maturity, which plays an important role in increasing rice yield, reducing the use of nitrogen fertilizer and solving practical agricultural production problems such as tight cropping. In addition, OsDREB 1C also has the conservative function of high yield and early maturity of wheat, which makes it have broad application potential and development prospects.
Three reviewers of this paper fully affirmed this discovery, and one of them thought that "this study has a remarkable effect on increasing production, which is exciting and has potential influence." If it is applied to actual agricultural production, it will further promote the continuous intensive production of rice. "
Wan Jianmin, former vice president of China Academy of Agricultural Sciences and academician of China Academy of Engineering, said, "The discovery of this gene provides us with a new research material and genetic resources, and also provides us with unlimited possibilities, but the next step is to scientifically organize and accelerate the application of breeding."
Yang, an academician of China Academy of Sciences, also said, "This is another major discovery in rice research in China, which provides an important genetic resource for cultivating more crop varieties with high yield, efficient use of nitrogen and early maturity."
However, there is still a long way to go from new discovery to real application. Qian Qian, director of the Crop Research Institute of Chinese Academy of Agricultural Sciences and academician of China Academy of Sciences, said that the discovery of this gene "is indeed a new dawn of breeding. In the future, it is even more necessary to put theory into practice as soon as possible and realize application at a faster speed. "