Genetically modified tomato facts for kids
A genetically modified tomato, also called a transgenic tomato, is a tomato whose genes have been changed using genetic engineering. The very first genetically modified food ever sold was a tomato. It was designed to stay fresh longer and was called the Flavr Savr. It appeared in stores on May 21, 1994, but only for a short time. In 2021, the first GM tomato approved for people to eat directly was allowed in Japan.
Scientists are mostly working to create tomatoes with new features. These include being stronger against pests or tough weather like frost or drought. Other projects aim to make tomatoes healthier by adding good substances or more nutrients. Besides making new crops, scientists also use GM tomatoes to learn how genes naturally work in regular tomatoes.
Wild tomatoes used to be small, green, and not very tasty. But after hundreds of years of breeding, there are now thousands of different kinds grown all over the world. In the late 1980s, new ways were found to move genes into tomato cells. This can be done using a special bacteria called Agrobacterium. Genes can also be put into other parts of the tomato cell, like the chloroplasts. Tomatoes were the first fruit crop where this was possible.
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Cool Examples of GM Tomatoes
Tomatoes That Ripen Slower
Tomatoes are often used to study how fruits ripen. This is because they are a "climacteric" fruit, meaning they continue to ripen after being picked. Scientists have changed tomato genes to understand this process better.
In 1994, the Flavr Savr tomato was the first genetically engineered food sold for people to eat. Scientists added an extra copy of a tomato gene called polygalacturonase. This gene usually makes an enzyme that breaks down the tomato's cell walls, making it soft. By adding the gene in a special "antisense" way, it stopped the enzyme from being made. This made the tomato ripen slower. However, the Flavr Savr tomato was not very successful and was taken off the market in 1997. A similar idea was used to make a tomato paste that stayed fresh longer.
Other companies also made tomatoes that ripened slowly by stopping the production of ethylene. Ethylene is a plant hormone that tells fruits to ripen. These tomatoes lowered ethylene by changing how a substance called ACC was made or broken down. One tomato, called Endless Summer, was briefly sold but had to be removed due to legal issues.
Scientists in India have also made tomatoes ripen slower. They stopped two genes that affect how the fruit softens. These special tomatoes stayed good for 45 days at room temperature, while regular tomatoes spoiled. In India, a lot of fruit goes bad before it reaches stores because there isn't enough refrigeration. Researchers hope these GM tomatoes can help reduce this waste.
Tomatoes That Handle Stress Better
Things like frost, drought, and too much salt in the soil can stop tomatoes from growing well. While no GM tomatoes that resist these stresses are sold yet, scientists are researching them.
An early GM tomato was made with a gene from a fish called the winter flounder. This fish has an antifreeze protein that helps it live in cold water. The idea was to make the tomato more resistant to frost. This "fish tomato" became famous in early discussions about GM foods. People wondered if it was right to mix genes from different species. However, the antifreeze protein didn't work well in the tomato, and it was never sold.
Other genes from different plants have been put into tomatoes to help them resist tough conditions. A gene from rice was added, which made tomatoes more tolerant to drought. Another gene from a plant called Arabidopsis helped tomatoes grow better in salty soil. It made the salt build up in the leaves, not the fruit. Also, genes from tobacco plants helped tomatoes hold more water, making them better at handling drought and salty conditions.
Tomatoes That Resist Pests
Scientists have put a gene from a bacteria called Bacillus thuringiensis (Bt) into tomato plants. This gene makes a natural bug-killing substance. When tested in fields, these Bt tomatoes were resistant to common pests like the tobacco hornworm and tomato fruitworm. A study showed they were safe for rats to eat, but these Bt tomatoes have never been sold.
Tomatoes have also been made resistant to tiny worms called nematodes. This was done by adding a gene from a plant called taro. Another gene, from a giant silk moth, was put into tomatoes. This made them much more resistant to diseases caused by bacteria. When certain proteins in the tomato's cell walls are stopped, the fruits are also less likely to get mold. Making pest-resistant tomatoes can help farmers use fewer pesticides and earn more money.
Tomatoes with Better Nutrition
Scientists have tried to make tomatoes more nutritious. In 2000, they increased the amount of pro-vitamin A in tomatoes by adding a bacterial gene. However, this tomato was not expected to be sold because of concerns about GM foods at the time.
More recently, scientists created blue tomatoes. These tomatoes have more anthocyanin, which is a healthy antioxidant. One group added genes from a plant called Arabidopsis. Another group used genes from snapdragon flowers. When the snapdragon genes were used, the blue tomatoes had as much anthocyanin as blackberries and blueberries. The scientists who made these blue tomatoes started a company to sell them. They are working on getting approval to sell the tomatoes and their juice.
Another group tried to increase healthy substances called isoflavones in tomatoes. These are known for possibly helping prevent cancer. They did this by adding a gene from soybeans. In 2021, a Japanese company released a tomato called Sicilian Rouge High GABA. It has higher levels of GABA, which is a substance that can help lower blood pressure.
Tomatoes That Taste Better
Scientists added a gene from lemon basil to tomatoes. This gene makes a substance called geraniol, which gives a nice smell and taste. When people tasted these GM tomatoes, 60% of them liked the taste and smell better than regular tomatoes.
Tomatoes for Making Vaccines
Tomatoes, along with other plants like potatoes and bananas, are being studied as a way to deliver vaccines that people can eat. Studies have been done on mice using tomatoes that make substances that can fight viruses like norovirus and hepatitis B. Korean scientists are even looking at using tomatoes to make a vaccine for Alzheimer's disease. One scientist, Hilary Koprowski, who helped create the polio vaccine, led a group that developed a tomato that could make a vaccine for SARS.
Tomatoes for Basic Science
Tomatoes are very useful for scientific research. Scientists often change their genes to learn more about how plants work. For example, tomatoes have been used to find specific genes. They have also helped scientists understand how a plant hormone called systemin works. This is done by either turning off the natural gene or adding extra copies of it.
Images for kids
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Plant scientist Athanasios Theologis with tomatoes that have a special gene added
