Professor Li Yi, a biologist in China, and his "Exogenous Gene Removal" Technology

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Our correspondent to the United Nations Bian Chenguang.

Character file

Yi Lee, graduated from Beijing Forestry University in 1982, and went to study in the United States in 1983, and obtained a doctorate from new york State University. He is currently a professor at the University of Connecticut, director and chief scientist of the New England Invasive Plant Research Center, and director of the Transgenic Plant Center at the University of Connecticut. He created a "gene deletion" technology, which can make genetically modified crops safe and harmless and make genetically modified foods safe to eat.

Huge potential

Transgenic crops can increase crop yield, reduce the use of herbicides, pesticides and other pesticides, and save a lot of labor, thus bringing great economic and social benefits to mankind. According to the annual report issued by the International Agricultural Biotechnology Application Service Organization (ISAAA), in 2006, the global planting area of genetically modified crops soared by 654.38+0.2 billion hectares, breaking through the 654.38+0 billion hectares mark for the first time. From 1996 to 10 in 2006, the planting area of transgenic crops increased by 60 times. James, chairman of ISAAA, estimated that the planting scope of genetically modified crops will be further expanded in the commercialization process in the next 65,438+00 years. By 2025, more than 20 million farmers in more than 40 countries will plant 200 million hectares of genetically modified crops.

Be troubled

Although transgenic crops play an important role in solving the global hunger problem and ensuring the sustainable development of agriculture, and can make great contributions to alleviating the world energy crisis through transgenic energy plants, they can spread the foreign genes of transgenic plants among populations through pollen and seeds, which may produce "super weeds" or lead to unexpected changes in the characteristics of other plants, thus bringing harm to human ecological environment and biodiversity. At the same time, the effects of genetically modified crops and genetically modified foods made from this raw material on human body have been inconclusive. Around the world, especially in Europe and Japan, people's arguments and concerns about the safety of genetically modified plants have affected the commercialization and application of genetically modified plants.

In order to get rid of many troubles in the popularization and application of transgenic technology, scientists have made many efforts and made many attempts. For example, pollen sterility technology, seedless technology and chloroplast transgenic technology have been used to control the safety of transgenic plants, but these technologies can not fundamentally solve the problem of the spread of foreign genes, and still can not completely relieve the public's vigilance against transgenic plants and genetically modified foods.

Shaded willows and blooming flowers ―― beautiful scenery

At the beginning of February this year, after Professor Yi Lee gave an academic report on "Exogenous Gene Removal" technology at the international conference on transgenic plants held in Vienna, the scientists attending the conference suddenly brightened up and immediately realized that the safety problem of transgenic plants finally had an excellent solution, which made transgenic technology enter a new development stage. The first reaction of chilton, a famous plant molecular biologist, a pioneer in the field of transgenic plants and a member of the National Academy of Sciences of the United States, was, "Have you applied for the patent of' foreign gene removal' technology? Can we use it? " After the article was published in the Journal of Plant Biotechnology at the end of February, it immediately attracted worldwide attention. Newspapers and magazines in various languages and important internet sites have reported in succession. Dr. Cherfus of the International Institute of Plant Genetic Resources (Italy) wrote an article commenting that "foreign gene removal" technology has an inestimable impact on solving the environmental and food safety problems brought by transgenic plants. Belgian biotechnology expert gabriel pointed out that Professor Yi Lee's technology is of great significance in eliminating people's concerns about genetically modified plants. Professor Koch, a professor of cell and molecular biology at the University of Rhode Island in the United States, believes that the technology newly developed by Professor Yi Lee is an outstanding contribution to the field of genetically modified plants, especially for the commercialization of genetically modified energy and bioreactor plants. Dr. Li, chairman of the International Agricultural Research Center and a French scientist, believes that the technology of "removing foreign genes" is one of the most important events since the birth of genetically modified organisms for more than 20 years, and it is a real revolution in the field of biotechnology.

A key point of "foreign gene removal" technology is to add a special gene controlled by the promoter of DNA gap regulatory fragment to the target plant. Under the action of promoter, foreign genes and themselves can be cut off from transgenic plants at the required time and place according to the wishes of scientists, so that pollen, seeds and fruits of transgenic crops no longer contain foreign genes. Or completely remove foreign genes from the parts that people need to eat (such as stems, leaves and tubers of plants), so as to achieve the purpose of producing non-GM food with GM crops, and fundamentally solve the problem of gene diffusion of GM plants and the safety problem of GM food that has long troubled people.

The argument stopped.

As soon as the paper on "Exogenous Gene Removal" technology was published, Sowerch, an Austrian plant molecular biologist, wrote that Professor Li Yi's technology could end the debate about the famous terminator seed technology for many years. The so-called "terminator" seed technology is to introduce the lethal gene of seeds into plants, so that the seeds can not germinate and grow normally, thus solving the problem of exogenous gene drift. But in underdeveloped countries, farmers are usually used to sowing their own harvested seeds. If farmers plant terminator seeds, because the harvested seeds are indistinguishable from ordinary seeds, other farmers will continue to use these seeds by selling or exchanging, and the consequence is naturally no harvest. This is undoubtedly a disaster for farmers in developing countries. Therefore, the technology was criticized as soon as it was launched, and Monsanto, which owns the technology, was also severely criticized. Under strong pressure, Monsanto, which owns this technology, has to declare that it will never use terminator seed technology. As Dr. Chervis pointed out, "foreign gene removal" technology not only has the advantages of "terminator" seed technology, but also solves the safety problem of genetically modified food that "terminator" seed technology can't solve, and overcomes the major defects of "terminator" seed technology itself. Because even if farmers sow with their own harvested seeds, the seeds will grow normally, but such seeds have no characteristics of foreign genes, and farmers can still get the harvest of ordinary crops.

There are good reasons for this.

Speaking of it, Professor Yi Lee had a keen interest in the safety of genetically modified plants from the beginning, which was also related to a patent on genetically modified plants 10 years ago. From 65438 to 0996, Professor Li Yi, who worked in the Biology Department of Kansas State University at that time, led his laboratory to construct a broad-spectrum seedless melon gene with auxin synthesis gene and obtained a patent. Because seedless fruit technology can not only improve the quality of fruits and vegetables, but also overcome the yield reduction caused by poor pollination, thus achieving high and stable yield of fruits and vegetables, Professor Li Yi's patent right to use seedless genes in tomatoes, watermelons, cucumbers and green peppers was immediately bought out by a large European company. However, because many consumers in Europe and other places did not accept genetically modified foods, the company terminated its contract two years later. However, in the United States, the experimental cost for a transgenic plant to pass the safety review is as high as tens of millions of dollars. Usually, the output value of any single melon and fruit variety is not too high, so no company is willing to invest in any transgenic crop with low output value except corn, soybean, cotton, rape and other major crops. It is for these reasons that many advanced transgenic technologies, including seedless melon and fruit technology, have not been applied in production. Therefore, Professor Yi Lee began to conceive, hoping to find a way to make foreign genes (such as insect resistance, stress resistance, disease resistance, high yield, seedless genes, etc. ) play their role, and then completely remove, get the non-transgenic products. Therefore, the project of "Exogenous Gene Removal" was applied in 1999. The unique concept, novel design and broad application prospects make this project fully funded by the Connecticut Reform and Innovation Project.

China's contribution

To turn the idea into reality, we need to overcome many technical difficulties, the most important of which is to make the removal efficiency reach nearly 100%, otherwise it will not be used in the field. At that time, Duan Hui, a doctoral student of Professor Li Yi (graduated from Lanzhou University), made arduous exploration and a lot of experiments, which greatly improved the removal efficiency. Duan Hui's work not only laid a solid foundation for improving the removal efficiency, but also made an extremely important contribution to the successful development of "foreign gene removal". In 2002, just as the preliminary results of the experiment came out, the famous academic journal Nature Biotechnology published an article on how to control the foreign gene pollution of genetically modified crops. The molecular strategy mentioned in this paper coincides with the idea of Professor Yi Lee three years ago. Luo Keming, a doctoral student in Sino-American cooperative culture, and other scientists in the laboratory used tobacco plants to prove that the recognition site of the new recombinant enzyme can really greatly improve the removal efficiency. His experiments proved that the removal rate of foreign genes reached 100% in more than 30 thousand transgenic tobacco plants. The experimental results of Dr. Luo Keming and Dr. Zhao Degang (Guizhou University) provide the most basic and important data for the paper on "Exogenous Gene Removal" technology. Zheng Xuelian and Deng Wei, doctoral students jointly trained by China and the United States, participated in the later work of the project at the University of Connecticut, and also made important contributions to the smooth completion of the project. Among them, Deng Wei and Luo Keming also completed some auxiliary experiments in Southwest University. In addition, Dr. Chen Yongqin (Hubei University), Dr. Jiang Xiangning (Beijing Forestry University), Dr. Pei Yan (Southwest University professor, Luo Keming, Zheng Xuelian, Deng Wei China doctoral supervisor) also participated in the research and made great contributions. Therefore, although the technology of "removing foreign genes" was born in the United States, it is actually a masterpiece of scientists in China.

Talking about the future plan, Professor Li Yi expressed the hope to cooperate with scientists in China to further improve the technology of "foreign gene removal" and promote the application of this technology in many fields for the benefit of China and the people.