Science demonstrates the concrete benefits of new breeding methods
The Swiss Academy of Sciences (SCNAT) recognizes the significant opportunities offered by new breeding methods. In a new dossier, the Academy presents five examples of crops cultivated using genome editing, which have high potential for Swiss agriculture. This publication emphasizes the scientific consensus on the use of genetic scissors. The new breeding methods offer numerous advantages for the environment and agriculture.
Thursday, June 29, 2023
Currently, nearly 700 research projects are underway worldwide, aiming to optimize crops through genome editing. In the publication titled "New breeding technologies: Examples of plant research applications" (available only in German and French), the Swiss Academy of Sciences presents five examples of particularly interesting and useful crops for Swiss farmers and consumers. According to the Academy, this publication aims to stimulate the discussion on new breeding methods. It invites the Federal Council to present a draft law containing risk-based rules for the use of crops obtained through these new breeding technologies by mid-2024. These crops, created using genetic scissors, are indistinguishable from traditional crops and could occur naturally. They do not contain foreign genetic material and should provide added value to agriculture, consumers, and the environment. According to SCNAT, the following five examples meet these criteria.
1. Reducing the use of plant protection products through targeted improvements
In the case of grapes, powdery mildew and downy mildew regularly cause significant crop losses. These fungal diseases spread rapidly and can affect entire vineyards. In the worst cases, the losses can be total, as seen in the cool and humid summer of 2021. The quantities of fungicides needed in case of an attack are, therefore, very high. According to SCNAT, researchers have succeeded in making a grape variety more resistant to powdery mildew using CRISPR/Cas genetic scissors, without introducing foreign genes to the species. Cultivating new varieties using genome editing requires much less time than traditional breeding methods. Genome editing also offers the possibility of providing established and appreciated varieties such as "Chasselas" or "Pinot Noir" with powdery mildew resistance without losing their positive characteristics. Genome editing could thus help reduce crop losses and the use of fungicides.
2. More resistant potatoes - less food waste
Late blight is one of the greatest enemies of potatoes. This fungal disease thrives in warm and humid conditions and spreads rapidly. It first attacks the plant's foliage before spreading to the tubers, making them unfit for consumption. In the 19th century, late blight caused a famine in Ireland, resulting in the deaths of approximately one million people. Today, although infected potato fields can be treated with fungicides, these treatments are often ineffective during persistent rains, as experienced in the summer of 2021 when the soils were saturated, and agricultural machinery could no longer access the fields. Organic potatoes are particularly affected by late blight. According to SCNAT, researchers have succeeded in making the "Desiree" variety much more resistant to late blight by precisely disabling two genes using CRISPR/Cas genetic scissors. In this case as well, genome editing helps reduce crop losses and the use of fungicides, thus reducing food loss in the fields.
3. Combating fire blight with genetic scissors
Fire blight is a bacterial disease that poses a significant threat to indigenous fruit cultivation. Previously, treatments involved the use of antibiotics, which are now banned due to the risk of resistance. Removing infected trees is often the only solution to prevent the disease from spreading. Between 2000 and 2014, it is estimated that around 300,000 fruit trees, including 100,000 tall-stem trees, had to be felled. Popular apple varieties in Switzerland, such as "Braeburn," "Gala," or "Golden Delicious," are particularly susceptible to fire blight. Although there are older varieties that are more resistant to the disease, they have not managed to establish themselves in the market. Genome editing offers the possibility of making these apple varieties resistant to fire blight. Researchers have successfully disabled a gene involved in fire blight susceptibility in the "Golden Delicious" and "Gala" varieties using CRISPR/Cas genetic scissors. The resulting plants showed 50% fewer symptoms during a fire blight infection, thereby preserving numerous trees.
4. Effectively protecting tomato crops
The Tomato brown rugose fruit virus is also a bacterial disease that primarily affects tomatoes. This plant disease was first discovered in Israel in 2014 and spread rapidly. A case has also been reported in Switzerland. Infected plants exhibit colorful mosaic leaves, wilt, and die. Infected tomatoes do not ripen properly and develop yellow spots, making them unappealing for sale. So far, the only measures to save healthy plants were to quarantine and destroy the infected plants and their surroundings. A team of researchers has succeeded in disabling certain genes necessary for the multiplication of the Tomato brown rugose fruit virus in the commercial variety "Craigella" using CRISPR/Cas genetic scissors. During trials, no viral particles were detected in the genome-edited tomatoes, even several days after viral infection. Thus, in the future, it may no longer be necessary to uproot and destroy infected plants.
5. Wheat for allergic individuals
Approximately one percent of the population suffers from celiac disease, a chronic disease of the small intestine caused by gluten, a protein present in many grains such as wheat, rye, and barley. Individuals with gluten intolerance must avoid consuming many foods. Certain gluten proteins, called gliadins and glutenins, are responsible for the intolerance. Using CRISPR/Cas genetic scissors, researchers have managed to reduce gliadin content by up to 82% in a bread-making wheat line and a durum wheat line by precisely disabling certain genes. Although this appears promising, further research is needed to create a wheat variety that is compatible with allergic individuals while retaining its baking properties.
Targeted breeding allows for a drastic reduction in the use of plant protection products. However, it will not be possible to completely eliminate the use of these products in the future. New pests and diseases will always threaten farmers' crops. In addition to researching new resilient plant varieties, research on new, targeted, and environmentally friendly plant protection products remains essential.
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