2020年,诺贝尔化学奖花落两位杰出女性科学家—美国的Jennifer Doudna与法国的Emmanuelle Charpentier,她们因共同发明CRISPR/Cas9基因编辑技术而享誉全球。
CRISPR/Cas9 technology is derived from the CRISPR-Cas immune system naturally occurring in bacteria and archaea. This system allows microorganisms to defend themselves by retaining memories of fragments of invading viruses (or other foreign DNA) and then using those memories to instruct Cas enzymes to precisely recognize and cleave the same viral DNA that invades again. Scientists have discovered and unraveled this mechanism and creatively transformed it into a gene-editing tool. This innovative technology, derived from the microbial immune system, is like a "molecular scissors", which can accurately locate and modify any target sequence in the biological genome, ushering in a new era of gene manipulation.
Genetic technology opens a new era of breeding
We have been using traditional breeding methods to improve crops for thousands of years, and we have accumulated a wealth of experience and practical foundation. Traditional breeding methods mainly rely on naturally occurring genetic variation and artificial selection processes to achieve genetic recombination through inter-breed crossing. These processes are generally safe and have a high level of public acceptance. But its biggest feature is the long breeding cycle and heavy workload. From hybridization and selection to the stabilization and promotion of new varieties, it often takes years or even decades. The breeding cycle is long, the accuracy is poor, and the genetic resources are limited.
In 1974, Cohen transferred the penicillin-resistant gene on the Staphylococcus aureus plasmid into Escherichia coli, which opened the prelude to the application of transgenic technology. Based on the principle of genetic engineering, transgenic breeding transfers artificially isolated and modified high-quality genes into target organisms through modern scientific and technological means to obtain individuals with stable performance of specific genetic traits. This technology can add new characteristics to living organisms, obtain new varieties and produce new products. Compared with traditional breeding, transgenic breeding can create new varieties with specific excellent traits in a short period of time with its precision, efficiency, cross-species and other characteristics, and the research on transgenic cotton in mainland China has made great progress with the strong support of the Ministry of Science and Technology. At the end of 1992, the transgenic Bt insect-resistant cotton was successfully developed, and the cry gene from Bacillus thuringiensis (Bt) was implanted into cotton cells, so that cotton plants can produce Bt protein, which is highly toxic to lepidopteran pests such as cotton bollworm and greatly reduces the use of pesticides. In addition, genetically modified herbicide-resistant soybean and genetically modified insect-resistant corn have also appeared. However, due to its technical complexity, it is strictly regulated by the government, and there are also some controversial issues in terms of safety, and some members of the public have reservations about it.
The advent of CRISPR/Cas9 technology quickly sparked a boom in the global scientific community. Its ease of operation, low cost and high degree of flexibility have quickly made it a standard tool in the laboratory, and the cycle of traditional breeding, which can often take several years or even more than a decade, has been greatly reduced in the face of CRISPR/Cas9. In a laboratory environment, gene editing can be completed in just a few weeks, and the time cost of moving a new variety from concept to field is greatly reduced. Gene editing breeding has brought unprecedented opportunities for biological breeding, and "gene scissors" are affecting traditional agriculture, gene editing has reduced the time cost of breeding and made it possible to commercialize biological breeding.
From transgenic breeding to gene editing breeding, it marks that the breeding technology has shifted from extensive gene integration to fine gene sequence adjustment, which improves the accuracy and efficiency of breeding, reduces the ecological and ethical concerns brought by transgenesis from the outside world, and brings new development opportunities for modern agriculture and biotechnology industry.
Gene editing breeding technology is in full bloom around the world
In May 2023, Pairwise of the United States made an important achievement in gene-edited vegetables, launching the first gene-edited vegetable, mustard greens. With the approval of the U.S. Department of Agriculture, the gene-edited mustard was officially launched in the U.S. foodservice industry, becoming the first vegetable product on the U.S. market to use CRISPR technology for gene editing.
Source: Pairwise
Gene editing breeding is also widely used in Japan. At the beginning of 2021, GABA-rich tomatoes (γ-aminobutyric acid) began to be officially sold in the Japanese market. Due to the use of gene editing technologies such as CRISPR, the GABA content of this tomato is significantly higher than that of ordinary tomatoes, reaching 5 to 6 times, which is one of the first gene-edited foods to be publicly sold on the Japanese market, marking an important breakthrough in the application of gene editing technology in the agricultural field.
In July 2023, researchers at the University of Tsukuba in Japan used gene editing technology to knock out CmACO1, a gene associated with the ripening and aging process of melons, and successfully extended the storage time of melons. The edited melon retains its original taste and quality while remaining fresh for a longer time. This is very beneficial for the transportation, sale, and consumption of melons.
The Chinese Academy of Agricultural Sciences and other research institutions have invested heavily in gene editing technology, and have made a number of breakthroughs in recent years, and the research team led by Professor Zhu Jianxing has successfully cultivated new soybean varieties with high oleic acid content and high-quality lettuce varieties rich in vitamin C with gene editing technology. In April 2023, Shandong Shunfeng Biotechnology Co., Ltd. independently developed high-oleic soybeans obtained the country's first plant gene editing safety certificate. These innovations have not only enriched the mainland's agricultural biological resources, but also strongly promoted agricultural modernization and green and sustainable development.
Source: Science and Technology Daily
In recent years, the Chinese government has clearly proposed to strengthen the research and development and supervision of agricultural biotechnology in its strategic layout for agricultural modernization and food security. The No. 1 document of the Central Committee has repeatedly emphasized the importance of agricultural science and technology innovation, encouraged and supported scientific research institutions and enterprises to carry out gene technology research, and strived to occupy a leading position in the international agricultural science and technology competition.
Digital Empowerment: Towards a New Era of Intelligent Breeding
In March 2024, the Chinese Academy of Agricultural Sciences and Alibaba DAMO Academy jointly released a smart breeding platform for the whole process of breeding data processing. Through the integration of artificial intelligence, big data and cloud computing technology, it serves breeding experts around the world to achieve efficient management and intelligent prediction of breeding data. At present, breeders from 23 units around the world have used the platform. Leading enterprises such as Longping Hi-Tech and Dabeinong have also promoted the modernization of agricultural production and management through the research and development of digital agricultural products and services, such as seed gene editing, precision planting, agricultural Internet of Things technology, and big data analysis.
As a key force leading the agricultural science and technology revolution, gene editing is reshaping the global seed industry landscape at an unprecedented speed. In the context of the continuous increase in policy support and scientific research investment in the mainland, the strategy of "seed industry revitalization" has become increasingly significant in its significance. At the same time, international cutting-edge concepts, such as the "Breeding 4.0" concept proposed by authoritative experts in maize breeding from the United States Department of Agriculture, deeply integrate gene editing, synthetic biology, genomics, bioinformatics, big data and AI technologies, aiming to create a new era of intelligent breeding.
Gene editing is not only a core tool in this new breeding model, but also a decisive factor in driving the development of agriculture in a precise, efficient and sustainable direction. In the future, through precision editing of crop genes, we will be able to target improved varieties to solve many challenges such as food security and environmental adaptability, laying a solid foundation for ensuring food supply for 10 billion people around the world.