In the Mingxi Botanical Garden on Fudan's Jiangwan Campus, there is a small closed experimental area where genetically modified rice is grown. Careful people will find that although no pesticides are used here, the plants are exceptionally strong;

Devil or hero? Uncovering the fog of genetically modified technology

Biological breeding technology helps agricultural self-improvement series of reports (1)

Author Wu Yiting first published in Shanghai Science and Technology News

In the Mingxi Botanical Garden on the Jiangwan Campus of Fudan, there is a small closed experimental area where planting transgenic rice . Careful people will find that although no pesticides are used here, the plants are exceptionally strong; during the harvest season, the rice ears are particularly plump. 65-year-old Professor Lu Baorong of the School of Life Sciences of Fudan University often leads his students to take classes here.

html The GMO debate that took place 27 years ago has gradually faded out of public view, but misunderstandings about GMOs have not been eliminated to this day. Professor from the University of California, Davis, once conducted a survey on "How do you view anti-GMOs" among Chinese residents. More than half of the respondents believe that genetically modified food safety problems are more serious than known food safety problems; only 11.7% of the respondents said they understood the basic principles of genetically modified technology, and 38.8% said they had "no idea at all" about it.

On the one hand, there is disapproval at the social level, and on the other hand, there is ignorance at the scientific level. Embarrassment and contradictions still permeate the daily lives of Chinese people.

Over the years, Lu Baorong and his colleagues, in addition to sticking to their own professional research fields, also have another important task, which is to carry out relevant science popularization work. They visit government agencies, major universities, primary and secondary schools, and even communities and enterprises to convey scientific principles to the public, hoping to answer their questions.

Cross-breeding Why can't solve all problems?

In China's agricultural field, hybrid breeding technology is particularly famous. Through decades of efforts, scientists such as Yuan Longping, Zhu Yingying have continuously set new highs in staple grain yields per mu, and also created many new varieties, achieving self-sufficiency in staple grains. GMO technology may not seem necessary.

Biological breeding is the process of using modern biotechnology and other methods to create genetic variations and cultivate new biological varieties. Lu Baorong said that traditional cross-breeding essentially belongs to the category of "transgenic". It mainly transfers genes from donor plants with excellent traits to target plants through sexual hybridization. Donor plants are often accidentally found by scientists with special characteristics. Traditional farm varieties and wild relatives, which are insect-resistant, cold-tolerant, or rich in certain nutrients. However, sexual hybridization is more time-consuming and less efficient. The biggest difficulty is that it is difficult to overcome the reproductive isolation between species to transfer high-quality genes.

Lu Baorong explained that sexual hybrid objects are often the same species or closely related wild species. Scientists once had a dream, hoping to cross tomatoes and potatoes so that the plants could grow big, red tomatoes, and especially large potatoes could grow underground, but this could not be realized. In order to overcome the reproductive isolation between species and obtain high-quality genes from distantly related species, transgenic technology must be used. It can provide a broad space for selection, allowing crops to obtain a large number of high-quality genes from other species.

Researcher Wang Feng, chief expert of the Rice Molecular Design Innovation Team of the Fujian Academy of Agricultural Sciences, has worked in the field of genetically modified rice for 30 years. Over the years, he has been developing genetically modified rice varieties that are resistant to Spodoptera Frugiperda.

"Spodoptera frugiperda is an invasive species that causes serious harm to corn and rice and has strong resistance to pesticides. In the rice germplasm resources, there are no insect-resistant gene resources for lepidopteran pests, and it cannot be through cross-breeding. The final defense method for cultivating varieties that are resistant to stem borer and Spodoptera Frugiperda is genetically modified technology," Wang Feng said.

As early as 1992, genetically modified technology was in danger. At that time, the cotton bollworm was raging, and wild cotton varieties that could not be killed by pesticides and had no insect resistance could be used for hybridization, causing direct economic losses of more than 6 billion yuan."When we were helpless, genetically modified insect-resistant cotton varieties were put on the market, which played a key role in saving the industry." recalled Professor Lu Daru of the School of Life Sciences at Fudan University.

Unimaginably complicated operation procedures

In the 1980s, the University of Washington and the American biotechnology company Monsanto developed the world's first batch of genetically modified plants. In 1996, genetically modified crops entered commercial use. Today, there are 70 countries growing genetically modified crops.

Discussions on genetically modified technology have continued for many years, but the actual implementation is rarely known. A technical director of a world-renowned agricultural breeding company disclosed to reporters the process of operating genetically modified crops.

"Each transgene is an arduous road of scientific exploration and will cost huge costs. The transgenic process usually starts with the construction of a vector, which includes the target gene , promoter, terminator , and marker genes. Scientists will use specialized transformation technology to insert it into the genome of crops, but this insertion is random. It is impossible to know in advance which ones will succeed and which ones will fail, nor where the 'target gene' will be transferred. It can be screened through phenotypic results, and the elimination rate is very high.” The technical director said that for example, in corn transgenic experiments, usually only 2-3 satisfactory transformants can be selected from tens of thousands of plants before proceeding. Gene sequencing to find the specific location of the "target gene". The function of "marker genes" is to facilitate the precise finding of "target genes" in gene sequences. This is not the end yet. Next, these "lucky ones" will undergo backcrossing and transbreeding, that is, backcrossing the genetically modified corn plants with the parent plants, observing their stability, and determining the stable plant offspring and then breeding them with other corn plants. Parental plants are sexually crossed to form multiple varieties with new traits.

What are the potential harms of genetically modified technology?

Will eating genetically modified foods cause various diseases? In the past few years, the safety issues of genetically modified foods have been constantly raised. But in the eyes of scientists, this seems to lack scientific basis.

Professor Wang Jiucun from the School of Life Sciences of Fudan University has some doubts about this understanding. She said: "There is no difference in chemical composition between genetically modified foods and natural foods. After passing through the digestive system, the nutrients will be converted into adenosine triphosphate (ATP) to provide necessary energy for the human body. The genetic information carriers of both are nucleic acids and will It is broken down into small molecules in the digestive tract and cannot reach the nucleus of human cells. is integrated with human genes.”

As a member of the National Biosafety Committee, Lu Baorong has been working on the front line of safety evaluation of genetically modified crops for many years. He said that any genetically modified products must undergo safety evaluation before entering commercial application. The first is to identify molecular characteristics and confirm which gene has been inserted into which position in the genome of the target organism; the second is to detect food safety and evaluate the acute and chronic toxicity, allergenicity, etc. of genetically modified crops; the third is to assess environmental safety and detect whether the genetic modification will cause harmful effects on the organism. The ecological environment and biodiversity have an impact. Lu Baorong believes that environmental safety should be taken more seriously than the first two.

"Rice with herbicide-tolerant genes may naturally hybridize with surrounding non-GMO rice varieties, ancestral species wild rice or related weedy rice through natural pollination, resulting in gene drift , and The introduced genes 'ran' into their genetic sequences, causing genetic confusion. This herbicide will no longer be able to kill them in the future, affecting their yields," said Lu Baorong.

Potential risks are not impossible to prevent. Spatial isolation is the best way to reduce genetic drift. Lu Baorong said that for wind-pollinated and self-pollinated rice, if the spatial isolation distance is more than 10 meters, the drift frequency will drop to 0.01%. The EU standard, the world’s most stringent, has a tolerance of 0.9% for genetically modified products.

"For crops with insect-resistant genes, we must not only consider whether they can kill pests, but also whether they will affect the survival of beneficial insects and other organisms in the ecological environment." Lu Baorong said.

How difficult is it to get security certificate ?

Longping Biotechnology (Hainan) Co., Ltd. (hereinafter referred to as Longping Biotechnology) located in Hainan Yazhou Bay Science and Technology City is intensively conducting scientific research on transgenic corn and soybeans. The relevant person in charge of the company said that research and development is only the first step. If you want to enter industrialization, you must first obtain a safety certificate. The process is similar to the clinical trial of new drugs, with a long cycle and high requirements.

As early as 2000, the Conference of the Parties to the Convention on Biological Diversity adopted the Cartagena Protocol on Biosafety, whose goal is to protect biological diversity from potential threats posed by genetically modified living organisms; More than 100 countries, including China, have signed the agreement, and each country has established relevant laws and regulations. In May 2001, my country promulgated the Regulations on the Management of Agricultural Genetically Modified Organisms. In October 2020, the "Biosafety Law of the People's Republic of China " was promulgated, which is the highest legal basis for biosafety management in China.

The relevant person in charge of Longping Bio said that the safety evaluation of the production and application of genetically modified crops needs to go through five stages: experimental research, intermediate testing, environmental release, productive testing and application for safety certificates; currently, the company’s genetically modified corn LP007 product has reached the third stage. Four phases, the complete process is expected to take 4 to 5 years. It took five years for the genetically modified corn Ruifeng 125 product of Hangzhou Ruifeng Biotechnology Co., Ltd. to obtain a safety certificate for production and application.

The Crop Ecological Environment Safety Supervision, Inspection and Testing Center (Shanghai) of the Ministry of Agriculture and Rural Affairs is a ministerial-level quality inspection center engaged in genetically modified testing and environmental safety assessment. The center has completed the environmental safety of a variety of genetically modified plants (soybeans, flowers and medicinal plants ) Evaluate work. Lu Baorong said that there are more than 40 similar institutions across the country, and genetically modified crop products that need to declare a safety certificate will be sent to a third-party qualified biosafety testing center for safety testing and evaluation.

In 2009, the insect-resistant genetically modified rice products "Huahui No. 1" and "Bt Shanyou 63" and the genetically modified phytase corn product "BVLA430101" obtained the production and application safety certificate issued by the Ministry of Agriculture at that time. After 2019, 10 more corn products and 3 soybean products have obtained production and application safety certificates.