"Our country has a lot of people and little land. In the context of industrialization and urbanization, there is great pressure to ensure the red line of 1.8 billion mu of arable land. Food safety production is under great pressure. How to solve the problem?"
"Using the role of marginal land, especially saline-alkali land, can greatly alleviate this problem." Academician Li Jiayang of the Chinese Academy of Sciences held a meeting at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Genetic Development) on March 22. said in the results release.
After seven years of joint research, Xie Qi's team from the Institute of Genetics and Development, Yu Feifei's team from China Agricultural University, and Ouyang Yidan's team from Huazhong Agricultural University have cooperated with ten units to open the "Tibetan Grain Code" of the main alkali-resistant gene AT1 using sorghum as a material ", the study also showed that the gene can significantly increase the yield of sorghum, rice, corn, wheat, corn and millet in moderate to severe saline-alkaline land. On March 24, 2023, related research was published in Science .
"This research has great application prospects in improving the comprehensive utilization of saline-alkali land." Wan Jianmin, academician of the Chinese Academy of Engineering and chairman of the Chinese Crop Society, commented.
An international reviewer for "Science" also commented that this work is "a major breakthrough in agricultural production."
"Make up for shortcomings" in the study of saline-alkali land
In early March, the Food and Agriculture Organization of the United Nations (FAO) released a report stating that 45 countries around the world are in urgent need of food aid, and millions of people are suffering from severe hunger.
Also according to FAO data, as of 2015, the world's existing arable land area is 4.2 billion hectares, and there are more than 1 billion hectares of salinized soil that has not been effectively utilized, which provide space for global food production.
How to release the production potential of saline-alkali land? This has always been a frontier and key scientific issue in the world.
Up to now, there have been a large number of innovative researches on germplasm resources suitable for saline-alkali land in the world. However, there are still great "short boards" in this research.
"What people usually call 'saline-alkaline land' can actually be divided into two main types: salinized soil and alkalized soil." Xie Qi, the corresponding author of the paper and a researcher at the Institute of Genetic Development , told the "Chinese Journal of Science". 40% of the waterlogged land, and the latter accounts for about 60%.
Figure: Aerial photos of saline-alkali land
However, in contrast to this, the global plant salt tolerance research has achieved rich results, but the mechanism of plant alkali tolerance is still poorly understood. A typical data is that there have been more than 22,600 papers on crop salt tolerance so far, while there are only more than 400 papers on alkali tolerance.
Why is there such a big gap between the research on "salt tolerance" and "alkali tolerance"? One of the difficulties is that laboratory model plants, such as Arabidopsis, usually do not originate in saline soils, leaving them with a lack of genetic adaptation for alkali tolerance. This makes it impossible for researchers to deeply explore the alkali resistance mechanism of crops, and it is even more difficult to match the research results to production.
What are the key alkali-tolerant crop materials? Xie Qi focused his research on sorghum.
This grain originated in the high-saline Sahel region of central Africa, and has formed rich genetic resources of alkali resistance during long-term evolution. Over the past two decades, Xie Qi and his team have cultivated 6 nationally registered varieties of sweet sorghum, and promoted the planting of more than 500,000 mu of saline-alkali and other barren land in my country, providing scientific and technological support for poverty alleviation and rural revitalization.
Since 2015, he has cooperated with Yu Feifei and others to conduct whole-genome sequencing of more than 350 sorghum germplasm resources collected from all over the world, compare them repeatedly with relevant information in public gene banks, and select potential resistant ones from them. base gene. They also used CRISPR-Cas9 and other gene editing technologies to edit wild sorghum, and combined with field growth conditions, they found a main alkali resistance gene AT1 that was negatively correlated with crop yield.
"These strains are wild-type strains, and these strains are mutant strains." Xie Qi pointed to the control picture on the computer monitor and told the "Chinese Journal of Science". Comparing the two pictures, it can be clearly seen that the sorghum plant height is higher and the leaves are greener after knocking out AT1.
According to reports, saline-alkali soil is mainly caused by sodium oxide or sodium hydroxide. These two compounds are usually used to adjust the alkali strength of the system in the laboratory, which easily leads to large and unstable pH changes, making the experiment impossible to repeat. To overcome this problem, Xie Qi's team even dug 2 tons of saline-alkali soil from Ningxia and transported it to Beijing for experiments to ensure the reliability of the research results.
To know why, Xie Qi cooperated with Chen Chang, a researcher at the Institute of Biophysics, Chinese Academy of Sciences, in order to understand the mechanism of the alkali resistance of the gene, and successively used mammalian cells and crop systems to discover that under high-salt-alkaline stress, AT1 can regulate the activity of aquaporin in stress by regulating the phosphorylation of aquaporin, and pump the reactive oxygen species (ROS) produced in stress to the extracellular area to reduce peroxidative stress.
"Simply put, alkali mainly causes redox stress in cells, which denatures DNA and proteins in cells. For example, excessive ROS leads to cell damage or death. Knocking out AT1 can reduce ROS in cells." Chen Chang explained to the "Chinese Journal of Science" that this allowed the research team to reveal the molecular mechanism of crop salt-alkali tolerance for the first time.
Figure: AT1 gene knockout increases sorghum yield on saline-alkali soil
From an encounter to a joint research
In 2019, during a business trip, Xie Qi and Li Jiayang met by chance at the airport. During the conversation, Xie Qi mentioned that the ongoing research on salt-alkali resistance has entered the stage of functional verification, which may be an important discovery. He also found that AT1 is a homolog of the rice grain shape regulator gene GS3 (a gene inherited from a common ancestor in different species).
Li Jiayang has been studying molecular design and breeding of rice. The "Zhongkefa" 804 and other rice series created by him and his team all contain the GS3 gene. The two hit it off right away.
The research team further cooperated with academician Zhang Qifa, professor of Huazhong Agricultural University, and confirmed that the AT1/GS3 gene can also regulate the tolerance to alkali in rice and corn, and the related metabolic pathways are conserved in different crops.
They moved the laboratory to Da'an, Jilin, where the pH of the saline-alkali soil can reach 9.17. They found that rice can achieve an annual increase of 22.4% to 27.8%, which is extremely excellent.
Field experiments were conducted on crops such as sorghum, millet, and corn in Pingluo saline-alkali land (pH 9.10, salt 6‰) in Ningxia. They found that "cutting off" the AT1 gene with gene scissors can increase the biomass of sorghum whole plant (for silage) by nearly 30.5%, increase the grain yield by 20.1%; increase the yield of millet by 19.5%; survival rate.
The international reviewers of "Science" commented that this work reveals an important conserved biological mechanism of grass crops, which is a major discovery.
"To consolidate the foundation of food security, it is necessary to strengthen the research on the innovative utilization of germplasm resources from the source. This research is a typical case of solving practical problems starting from basic research." Zhong Kang, an academician of the Chinese Academy of Sciences, commented.
Promote "a gene changes an industry"
From excavating molecular mechanisms to joint research on multiple locations and multiple crops, the new research proves that the regulatory mechanism of the AT1 gene is conserved in major food crops, and also shows its "universal applicability" to increase production of related crops.
Several experts who attended the press conference said that this study is of great significance to food security in my country and the world.
According to the National Bureau of Statistics, in 2021, my country's per capita grain possession has reached 483 kilograms, which is higher than the internationally recognized safety line of 400 kilograms. But in the same year, my country's cumulative grain imports hit a record high, reaching 160 million tons, accounting for 24% of the grain output that year. This shows that my country's large-caliber grain foreign dependence has increased, which is worrying.
The participating experts said that my country has 1.17 billion mu of marginal land, including about 500 million mu of saline-alkali land, which provides room for my country's grain production increase.
At the global level, Xie Qi has also calculated an account: If the gene is used in 20% of the world's saline-alkali lands, the annual production of at least 250 million tons of grain can be increased.
At present, the research team has cooperated with Syngenta Group and applied for an international patent on the gene.
At present, there are still many debates in the scientific and technological circles about the importance of basic and applied research. In Li Jiayang's view, basic and applied research are two fundamental aspects of a unity. "Basic research needs to provide a source for application, and applied research must provide an outlet for basic research. The two complement each other." He said that a basic research is an innovation chain from the discovery of an important principle or mechanism to its application. Continue to promote solutions to relevant social issues and major national needs.
It is reported that this research is an important breakthrough made under the support of the Chinese Academy of Sciences' forward-looking layout of science and technology pilot project (category A) "Precise Design and Creation of Seeds" project "Molecular basis for the formation of environmental intelligent response traits". The special project aims to lead the molecular precision design breeding technology in response to major strategic needs such as food security in the new era of our country, and accelerate the new green revolution.
"This research involves a variety of crops, and the workload is huge. The research team worked together and took seven years to find this important alkali-resistant site. This kind of persistent research practice in the face of difficulties is the spirit of scientists." Genetics Chen Shouyi, senior director and researcher of the Development Institute, said.
"My friends talk about a lot of things when they meet, sometimes it's not about science, but every time I meet Xie Qi, he always talks about his sorghum, and he is very excited every time." Academician of the American Academy of Sciences, Southern University of Science and Technology Professor Zhu Jianjian said, "Scientists should have this kind of spirit and a strong interest in science, so they can persist for so many years and make such good results."
Zhu Jiankang said that this research has made important breakthroughs in basic theory, and he looks forward to seeing "changing an industry through a gene" in the future, so that relevant research can be applied on millions of acres, or even tens of millions of acres of saline-alkali land.
Related paper information:
science.org/doi/10.1126/science.ade8416
Editor | Yu He
Typesetting | Wang Daxue
Past products (click on the picture to go directly to the text corresponding tutorial)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Reply in the background with "The first wave of benefits in the Life Letter Collection" or click to read the original text to get a collection of tutorials
