Genomic Technologies: Understanding the Foundations of the Debate

Genomic technologies (GT), particularly targeted genome modification ("editing" in English) through CRISPR, are now at the heart of scientific, regulatory, and societal debates. What do they really allow? How do they differ from GMOs that have crystallized certain oppositions? And why do they arrive at a time when plant improvement faces unprecedented challenges? An interview with Vincent Pétiard, geneticist and member of the editorial board of Bloom Agritech.

Genomic technologies are now presented as a turning point for agriculture. Why do these techniques generate so much interest?

Because plant improvement is not a luxury; it is a permanent necessity. Cultivated varieties must continuously be adapted: to evolving diseases, environmental changes, regulatory constraints, or consumer expectations regarding quality or sustainability. Until now, conventional breeding has partially addressed these needs, but with strong limitations that GMOs could have compensated for in some cases but failed to do so due to a lack of general acceptance.

" Plant improvement is not a luxury,

it is a permanent necessity."

GTs arrive in a context where there is sometimes a lack of available genetic diversity and where selection cycles are long. They offer a tool that is more targeted and sometimes faster and potentially more accessible to meet these challenges.

Before delving into the details of GTs, can you remind us what limits conventional breeding?

Conventional breeding is based on a simple principle: crossing sexually compatible plants to combine their characteristics. However, this compatibility greatly reduces the accessible genetic pool. It is thus impossible to mix plants that are too distantly related: a tomato can only reproduce with other tomatoes or with very closely related species. It cannot receive, through simple crossing, a trait that exists only in more distant plants, such as potatoes. This example is not naive: for decades, attempts at cell fusion have only led to abnormal plants that produced neither tomatoes nor potatoes. The second limitation is time. Each generation can take several years depending on the species. For tomatoes, about two to three cycles can be done per year, but what about certain trees like Ginkgo biloba or some pines or firs for which a single generation can take more than twenty years? This significantly slows down the integration of new traits, especially when one must retain all the existing qualities of the original variety and only add one or a few traits.

Have these limitations led to the development of other approaches, such as GMOs?

GMOs have indeed been a first way to overcome these constraints, allowing the introduction of a gene from the same or another species, whether plant, bacterial, or animal, and even human to produce certain specific medicines and to confer a trait of interest. GTs, on the other hand, mark a break: they do not add foreign DNA but precisely modify a sequence already present in the plant.

" Genomic technologies do not add foreign DNA: they precisely modify

a sequence already present in the plant. "

Why have these limitations led to the development of other technologies?

Faced with these constraints, geneticists have sought ways to broaden the accessible diversity and reduce timelines. Genetically modified organisms (GMOs) were a first response: they allow the introduction of a gene from the same or another species – plant, bacterial, or otherwise – which would be impossible through conventional crossing.

How are new genomic technologies, like CRISPR, different from GMOs?

GTs, particularly targeted genomic modification techniques like CRISPR, do not involve introducing foreign DNA. They allow for a targeted, precise modification in the plant's genome. This modification can correspond to a variation that already exists in nature or that could have appeared spontaneously, but which is obtained here more quickly and in a specific and controlled manner.

Did mutation not already exist before CRISPR?

Yes. Random mutation techniques have been used since the post-war period, notably through irradiation or chemical treatments. They caused numerous uncontrolled mutations, requiring the sorting of tens of thousands of plants to identify those that had acquired the desired trait without necessarily seeing other potentially undesirable mutations. CRISPR marks a break by allowing action at a precise location in the genome, without modifying the rest of the plant's genetic heritage.

Why is CRISPR at the heart of current debates on GTs?

The debate mainly concerns the regulatory qualification of these plants. The question is whether a plant obtained through genomic "editing," without the integration of foreign DNA and reproducing a mutation that could exist naturally, should be considered a GMO in the legal sense of the term. This question has been brought before the Court of Justice of the European Union and currently fuels discussions at the European level.

What are the concrete regulatory issues?

They concern not only the labeling of the plants themselves but also the products derived from them, authorization procedures, and control obligations. Some official laboratories currently responsible for controlling GMOs have indicated that it is technically impossible to distinguish a natural mutation from a mutation obtained by CRISPR, which poses a practical application problem for the regulation. And it deserves further developments (Note: which will be proposed in a future episode of this long format).

" The question is whether a plant obtained through genomic "editing," without the integration of foreign DNA and reproducing a mutation that could exist naturally, should be considered a GMO in the legal sense of the term."

Do GTs raise specific food safety questions?

Regardless of the tool used – conventional selection, mutagenesis, GMOs, or GTs – any new variety must undergo evaluations aimed at assessing its environmental and even food safety. Modifying a trait can lead to unintended and undesirable side effects, which must be identified and controlled. This requirement does not depend on the technology used and must be applied to the result obtained.

What objectives are pursued with GTs?

They are multiple: resistance to diseases, adaptation to climate change, yield improvement, nutritional quality, shelf life, or even the development of new industrial applications, for example for biofuels. GTs are one tool among others to meet these needs, and it is up to the breeder to choose what applies best to the problem at hand.

What economic and societal questions are raised?

A central issue concerns (or perhaps I should say concerned) the concentration of the seed sector and access to innovation for global agriculture and food. As was the case in pharmaceuticals, high regulatory constraints can favor large groups capable of bearing the costs, to the detriment of smaller companies. It remains to be seen whether the regulatory framework will allow for a wide dissemination of these technologies or whether it will reinforce a concentration already largely caused by the regulations put in place for GMOs.

" It remains to be seen whether the regulatory framework will allow for a wide dissemination of these technologies or whether it will reinforce a concentration already largely caused by the regulations put in place for GMOs.

Are GTs already being used elsewhere in the world?

Yes. Several countries, such as the United States, Japan, or the United Kingdom, have already authorized the marketing of plants resulting from genomic "editing" without specific labeling of the final products, under certain specific conditions. Products are already on the market, including vegetables or varieties improved for their nutritional quality or preservation. Numerous projects are underway for very diverse traits, including public health by blocking the pollen production of trees that cause severe allergies."