Genetically Engineered Plants in Times of Climate Change – a Contribution to Global Food Security?

Summary

The potential contribution of genetically engineered plants to global food security has been debated for years. At least in the case of the first generation of transgenic plants, which have been cultivated since the 1990s, hopes have not really been fulfilled.

The field of genetic engineering applications in plants has expanded significantly in recent years. This is due to new tools such as the CRISPR/Cas ‚gene scissors.’ Using this ‘new genetic engineering’ (or genome editing) technology, characteristics of plants can be drastically altered beyond the known traits of a species without having to insert additional genes. Apart from applications and characteristics, the number of species affected has also increased significantly. Furthermore, artificial intelligence programs specifically suited to applications of ‘new genetic engineering’ in plants have been developed recently. The consequences of this convergence of advanced technologies are difficult to assess.

In general, expectations for ‘new genetic engineering’ are high in terms of climate change and global food security, including improved resistance to heat and drought. However, there are currently no varieties available for cultivation that enable higher yields under changed environmental conditions. If genetically engineered plants are to be used, care must be taken not to introduce them too quickly and without sufficient controls. Although the plants could deliver good results in terms of certain characteristics under specific environmental conditions, they could also pose a potential threat to food security and the environment.

1. Experience with transgenic plants to date

Transgenic plants have been around for about 40 years. In practice, individual genes from bacteria are usually transferred into the genetic material of plants to make them resistant to herbicides or toxic to certain insects. These two characteristics are highly controversial in terms of sustainability and food security. Within this first generation of genetically engineered plants, there are three examples of plants that have been cultivated and have specific characteristics that are considered potentially useful for global food security: so-called “golden rice” as well as corn and wheat that are said to be better adapted to drought.

1.1 Golden Rice

The best-known example of transgenic plants that are said to offer benefits for global food security is ‘golden rice.’ This rice has a higher content of β-carotene (a precursor of vitamin A) in the rice grains and is intended to be used to combat vitamin A deficiency, which is a major problem in many developing countries. The rice was harvested for the first time in the Philippines in 2022, but cultivation was halted by court order. Further studies on its actual benefits are to be carried out using the 2022 harvest. Despite a long development period spanning several decades, questions  still remain: the available data from approval applications show rather low levels of β-carotene, and high losses are to be expected as a result of storage and cooking. Published studies also confirm a significant variation in carotene contents, which depend, among other things, on the respective varieties (or their genetic background). Cross-pollination of genetically engineered rice into regional varieties, whether through seed contamination or pollen drift in the fields, would be a particular problem in the Philippines, as it is one of the most important centers of biological diversity in rice.

1.2 Drought-tolerant corn from Monsanto

Corn plants from Monsanto/Bayer, with a supposedly increased tolerance to drought, have been approved for cultivation in the US, among other places (MON87460). To achieve drought tolerance, the gene of a bacterial “stress protein” (cold-shock protein) was transferred to the plants. How exactly this gene works in plants is not fully understood. However, higher yields have been reported when growing the plants under drought conditions. According to current estimates, genetically engineered corn is currently being cultivated on a relatively small area. As recent publications show, there still appears to be great potential for drought tolerance in conventional breeding (Manigben et al., 2024; Menkir et al., 2024; Worku et al., 2024). The question arises as to whether the yield of genetically engineered corn is actually superior to that of varieties resulting from conventional breeding. It also might be that a patent-protected innovation, the use of which can be exclusively controlled by Bayer, has been introduced to substitute  traditionally bred varieties.

1.3 HB4 wheat

In 2020, HB4 wheat was approved for cultivation in Argentina. The wheat with supposedly  higher yields under conditions of water scarcity (González et al., 2020). To achieve this, a gene from a so-called transcription factor from sunflowers was transferred into the wheat. In essence, transcription factors regulate the production of other genes. This can increase or decrease the expression of the affected genes (and consequently also the production of the corresponding proteins). These complex functions are important for plants to adapt to changing environmental conditions and are therefore  of interest for genetic engineering applications.

Results from cultivation trials initially showed positive results: the plants achieve a 16 percent higher yield under drought stress. However, official figures from the Argentine authorities showed a rather reduced yield in 2021 and 2022. In 2024, updated results from field trials with HB4 wheat were published (Ayala et al., 2024). Here they also report higher yields. However, HB4 wheat showed lower yields in fields without water deficits. Another problem seems to be that HB4 plants sometimes produced lower yields than conventional varieties at very high temperatures .

According to these findings, the genetically engineered variant is more productive than conventional varieties only under very specific conditions – a combination of drought and mild heat stress. The reason for the sensitivity to extreme heat could be increased evaporation in the genetically engineered plants, because the stomata on their leaves close later than in conventional varieties when exposed to heat and drought. In fact, higher evaporation rates were observed in the genetically engineered plants compared to the original variety, which also measurably increased water consumption. This could cause the soil to dry out even more. These results not only demonstrate a further need for research, but also the necessity for comprehensive risk assessment that also considers  extreme environmental conditions.

2. Options for ‘new genetic engineering’

The field of genetic engineering applications in plants has expanded significantly in recent years. This is due to new tools that have made it possible to specifically modify plant genes. The best known of these is the CRISPR/Cas ‘gene scissors’. Whereas in the past, scientists tended to work with ‘gene building blocks’ that were introduced into plants, now they often intervene in the regulation of the plants' own genes. With ‘new genetic engineering’, plants can be drastically altered in their characteristics, even beyond the known traits of a species, without having to insert additional genes.

In addition, artificial intelligence (AI) algorithms are being developed that are specifically suited to the applications of ‘new genetic engineering’ in plants. They increase the speed of development and the range of possible applications. AI-targets include the identification of regulatory DNA sequences and genetic designs for possible changes in the expression of the plant‘s own genes. As a result, the applications, the desired characteristics, and the number of species affected have increased strongly. In general, expectations for ‘new genetic engineering’ are high.  However, there are no concrete successes in the form of varieties ready for cultivation to date. The most important reason for this is the genetic complexity of the desired traits.

2.1 Possibilities for intervention

Climate change causes stress for plants on several levels. Under stress, various signaling pathways are activated in plants, which activate a whole series of processes within the cells, often involving transcription factors. Thereby, it is intended to adapt the gene activity of plants to changing environmental conditions. Signal molecules (often phytohormones) play an important role here, serving as information carriers between plant tissues and participating in the regulation of the stress response. This leads to changes in plant growth and architecture, the timing of flowering, fruit and seed formation, aging processes, and photosynthesis. It also regulates the closure of the stomata on the undersides of the leaves.

The various signaling substances often have overlapping functions and frequently influence each other's effects. They are therefore in constant interaction, among other things to be able to react quickly to changing environmental conditions. Small RNA segments (known as micro RNA/miRNA) play a decisive role in their regulation, for example, as they can intervene in the regulation of several gene functions simultaneously. The miRNA MiR529a in rice, for example, is involved in the regulation of five transcription factors that influence plant height, architecture, and the number and size of grains (Yan, et al., 2021). Genetic changes to alter this miRNA, whose function can hardly be influenced by previous breeding methods, therefore appears promising.

However, because these small molecules are involved in so many processes that are vital for plants, serious side effects are frequently observed as a result of genetic engineering. As recent reviews show, development is mostly still at the level of basic research (Chakraborty et al., 2024; Chakraborty & Wylie, 2025; Waites et al., 2025). Chakraborty et al (2024), for example, list 15 publications on experiments in which the response of plants to heat was altered and 13 publications on the response to cold. However, nothing has actually made it into cultivation yet.

2.2 Risks

The results of ‘new genetic engineering’ to date may not be suitable for cultivation, but they show that new gene combinations and changes in plant physiology can be achieved that go far beyond the results of conventional breeding. One reason for this is, for example, the further development of gene scissors, which can be used to achieve very specific changes in regulatory sequences (Zhou et al., 2023). This gives rise to risks: the underlying genetic networks and cellular mechanisms have developed alongside each other and in concert over a long period of time, i.e., they have co-evolved. Interactions in ecosystems, are also based on co-evolution. These networks are crucial for plants' response to environmental factors such as pathogens, climate, soil, and their interaction with other species such as pollinators and soil organisms.

If large numbers of ‘reprogrammed’ organisms are released into the environment within a short period of time, these networks can be severely disrupted, interrupted, and damaged. This affects plant health as well as ecosystems, food networks, and biodiversity. In addition, if genetically engineered plants crossbreed with related wild species, this can have long-term ecological effects far beyond agriculture. Spontaneous crossbreeding can also lead to new combinations of the genetic changes that have never been tested for interactions before.

It is important to understand that this is not ‘just’ about protecting biodiversity, but also about the health of cultivated varieties and food safety. When genetically engineered plants are exposed to pathogens and/or extreme climatic conditions, for example, they can perform significantly worse than conventionally bred plants because their natural adaptability may be impaired by genetic “optimization.”

2.3 Do not overestimate genetic engineering

Recent publications not only show that the cultivation of genetically engineered plants achieves poorer results than conventional varieties under certain environmental conditions. Rather, they warn that overly simplistic approaches can lead to false expectations regarding the suitability of genetically engineered plants for cultivation in hot and dry conditions (Yeaman, 2025; Evans et al., 2025). One reason for this is that the strategies plants have developed to cope with heat and drought are much more complex than previously thought. Strengthening a single protective mechanism can often be to the detriment of other adaptation mechanisms (Evans et al., 2025). This makes it extremely difficult to draw conclusions from greenhouse or field experiments about the actual suitability of plants under practical conditions. Given the rather disappointing or ambivalent results to date, possible positive effects from the use of genetic engineering cannot be ruled out. However, conventional breeding and climate-resilient cultivation systems should be given much greater weight in agriculture. If genetically engineered plants are to be used, one should warn against introducing them too quickly and without sufficient controls. Under certain environmental conditions, these plants may produce good results, such as stabilizing yields, but under other conditions they may pose a threat to food security and the environment. The greater the apparent success of genetic engineering, the greater the likelihood may be of unwanted side effects and the occurrence of corresponding risks.

Christoph Then, a doctor of veterinary sciences, is director of Testbiotech. He has been working on regulatory science in the area of biotechnology for more than 30 years. The work of Testbiotech is strictly based on scientific approaches and assesses available information in terms of the protection of health, environment and nature. Then is also coordinator of the international alliance “No Patents on Seeds”.

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