The genetic material in genetically modified organisms (GMOs) is altered in a way that cannot occur naturally through mating or recombination. Selected genes (referred to as transgenes) are transferred from one organism to another. This can occur between organisms from the same or different species.
Genes are often transferred using an agrobacterium which naturally incorporates sections of its genetic material into the host it is infecting. Scientists choose the exact genes that are transferred from the agrobacterium into the host when creating a GMO.
Cultivated sweet potato is an example of a naturally transgenic plant. During the evolution and domestication of the sweet potato thousands of years ago, it experienced an agrobacterium infection. One DNA sequence that was introduced to sweet potato during this infection is present in all cultivated sweet potatoes, suggesting it provided benefits that were selected during domestication by our ancestors.
GM plants can help achieve sustainability by decontaminating soil impacted by military activity and therefore containing toxic explosives such as RDX. Without action, the RDX could seep into groundwater, contaminating drinking water and negatively affecting human health. GM switchgrass offers a sustainable and cost-effective solution: the transgenes allow the plant to degrade RDX, removing it from the environment in a process known as phytoremediation.
GM plants can also help tackle soil salinisation. The increasing salt levels of soil are being exacerbated by climate change as prolonged droughts concentrate salt in soil and the thermal expansion of water leads to sea level rise. Salty soil reduces crop yields, compromising food security. GM sweet potatoes have been created to adapt to this challenge. These sweet potatoes are tolerant to salt stress, allowing yields to be maintained in areas particularly affected by soil salinisation.
Disease is another factor with a direct consequence on food security. For instance, cassava brown streak disease endangers the 800 million people who rely on cassava as a staple crop. To tackle this, GM cassava has been created, resistant to the responsible virus.
However, GM plants have their own challenges. This includes their safety as antibiotic resistance genes are often used to detect whether a transgene has been successfully introduced to a cell. There is a low risk that this resistance could transfer to other species, which would be problematic if the resistance transferred to a disease-causing bacteria. However, there are methods of creating GMOs that do not contain antibiotic resistance genes, meaning this is unlikely to be a major issue.
A second safety issue is that the new genes introduced to a GMO could unintentionally encode for allergenic compounds. However, GM foods currently available have not caused any allergic reactions and products are tested before being allowed on the market.
Some GM plants may only be beneficial in the short term and are not sustainable. For example, some GM crops are resistant to herbicides such as glyphosate. This allows glyphosate to be used without damaging the crop itself, however, there is the risk the transgenes could transfer to weeds, making the herbicide ineffective.
Furthermore, some GM crops may negatively impact the wider environment. For example Bt cotton is resistant to bollworms, an insect pest. This reduces insecticide use, therefore improving the health of farm workers. However, Bt cotton can harm non-target insects such as butterflies and lacewings.
The application of GM plants to achieve sustainability is limited by power imbalances as many GM crops and genetic engineering techniques are patented. This means a few large companies can gradually dominate global agriculture and the global food system. In the long-term, this could be unsustainable as desire for profit may hinder climate change adaptation and reinforce existing inequalities.
With legislation and regulation to tackle the above issues, GM plants have the potential to improve quality of life globally, whether by improving people’s health or access to food. Alongside other measures, GM plants could form a valuable part of a sustainable and more equal future.