Genetics

High-tech Tomatoes

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By Dr. Matthew Lisy, UConn Adjunct Faculty
UConn Home & Garden Education Center

Assorted slicing and cherry tomatoes
An assortment of tomato varieties of both the slicing and cherry types.  The colors include red, orange, pink, yellow, and now purple (photo by M. Lisy).

Tomatoes are one of the most popular food plants in the world, and as such, have undergone massive amounts of selective breeding. Native to western South America, the tomato can now be found all over the world. Originally grown for ornamental purposes due to fear of toxicity, modern gardeners grow many different colors including red, yellow, pink, orange, and white.

Tomatoes are prone to certain diseases which led to dependence on chemicals to control either the disease or the pest that transmits it. Disease resistant varieties of tomatoes were made by crossing certain parental tomatoes that had beneficial traits. For example, if a certain tomato tasted great but was prone to some type of wilt disease, it was crossed with a tomato that was resistant to wilt. Of course, this was VERY time consuming, and many times the final product is not perfect, but as close to ideal as possible. This does make people dependent on the seed producers, but at least you get the tomatoes you desire.

People were sad that they could never get the old heirloom varieties with superior taste to grow in the presence of modern-day diseases, so science came up with another solution – grafted tomatoes. Using young plants, the grower would take and graft the top of the desired tomato onto the roots of the undesirable but disease resistant rootstock. Certainly, these types of tomatoes have an important role in agriculture, but they are not feasible/economical in many situations.

One modern scientific solution is genetic engineering. This process takes a gene, or piece of DNA that codes for a specific trait, out of one species, and places it into another. The public generally does not like this type of technology partially due to a lack of understanding of the process, but also a fear of what could happen because of it. While science continues to make new GMOs, many companies will not use them due to consumer preference. In 1994, the “Flavr Savr” tomato became the first genetically engineered food to be granted a license for human consumption by the FDA. Although flavorful throughout its long shelf life, this tomato failed to meet commercial standards due to being easily damaged during harvest and shipping. Even though this tomato failed to become the success the company had hoped for, Calgene (now owned by Monsanto) made history.

Purple tomatoes with a blue pen cap to display size.
“The Purple Tomato,” the first GMO tomato available to home gardeners. Note the completely deep purple skin and flesh (photo by M. Lisy).

Thirty years later, the year 2024 saw another milestone in the world of GMO tomatoes. Norfolk Plant Sciences, and its seed-selling subsidiary, Norfolk Healthy Produce, produced the first tomato with completely purple skin and flesh. This is also the first time a GMO food crop has been approved for home gardeners. The color comes from the anthocyanin pigment, which is said to have heart-healthy and antioxidant benefits when consumed in the quantity found in this tomato. In addition, this pigment may increase the shelf life of the tomato. The gene for this pigment came from edible snapdragon flowers.

Many times, people fear GMOs saying that it is unnatural to have an extra “foreign” gene in an organism, and the potential risk of a “new combination of genes” created by this engineering process. The Food and Drug Administration deems this tomato as safe for human consumption as any other. In the end, each person should do their own research and make an informed decision for themselves and their family. For me, it is an exciting time to be alive as we are living through history. I felt really excited to grow the first-ever GMO tomato for home gardeners. One day, many of the tomatoes will be like this, but for right now, I will marvel at the original.

For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.homegarden.cahnr.uconn.edu or contact your local Cooperative Extension center.

Firefly Petunias Light Up the Night

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By Dr. Matthew Lisy, UConn Adjunct Faculty

A pot of white flowered firefly petunias
Firefly Petunias by Day. (Photo by M. Lissy)

The world of genetics has really had a tremendous impact on our lives. There is a lot of talk about GMOs, or genetically modified organisms, in the news. Labels even alert us to the presence of these crops in our foods. I wanted to share a new plant called the Firefly Petunia. It was not fireflies, but mushrooms that gave this plant its ability to glow. This is known as bioluminescence in the world of biology.

Through feats of genetic engineering, a gene is taken from one organism and placed into another.  This is where people become worried. Humans, however, have been doing this for hundreds of years. The best looking or most productive organisms were bred together for the next generation.  This is called selective breeding, and it essentially concentrates beneficial versions of genes in the offspring.

Now what is determined to be the most beautiful is truly in the eye of the beholder. Some people, for example, selected for white flowers in a normally purple flowered species, Echinacea purpurea. Some have even taken things a step farther and crossed different species of plants to obtain new colors of flowers. In nature, separate species have evolved isolation mechanisms to maintain their identity. When our plant breeders force a cross of the species boundary, much of the time it was done with closely related species of plants within the same genus.  A great example of this is the crossing of Echinacea purpurea, the purple cone flower, with Echinacea paradoxa, the yellow cone flower. This was done to obtain hybrid offspring that have red or orange flowers. These were back crossed with the parent varieties, so they have the same growth habit and form, but with new colored flowers.

Firefly petunia flowers glowing green in the dark.
Firefly petunias by night. This is no trick, the plants actually glow (photo by M. Lisy)

This hybridizing never really ruffled many feathers though, as the plants were very closely related anyway. More modern GMOs, like our Firefly Petunias, are obtained not through “natural” pollination processes, but through genetic manipulation. Scientists literally take one or more genes from one species and place them in another. These species are not closely related, so it may become an ethical conundrum. Here, one may ask if we should take a gene from a mushroom and place it into a plant. A similar circumstance was seen over twenty years ago in the aquarium industry, where genes from corals and jellyfish were placed into tropical fish to make them fluorescent Glofish.

On the question of ethics, I cannot tell you what to think, or what is right or wrong. We each will need to answer that question for ourselves. It does remind me of a quote from Jurassic Park, where Dr. Ian Malcolm states “…your scientists were so preoccupied with whether or not they could that they didn’t stop to think if they should.” The real question is where do we go from here. For the fish, it was species after species of Glofish, and for me, the novelty started wearing off. After all, how many species will be made fluorescent before it just gets boring? Now for our plants, will we have roads lined with glowing trees to eliminate the need for streetlights? Will we have glowing houseplants that function like night lights? Ultimately, it will be up to you, the consumer.

For me, this is just cool science. We ship and plant petunias all over the world. Are these glowing petunias going to cause any harm? Probably not, as none of the other ones have. When I go outside at night to take the dog out and see the bioluminescent petunias, it puts a smile on my face. It reminds me of the fact that we, as humans, are capable of many things. I can’t help but ponder if this will inspire a sense of awe and wonderment in our children. Maybe some may even study genetics because of these petunias. What if one of them ends up finding a cure for a debilitating human disease, all because of a glowing plant? And while some may say that this daydream of mine is just science fiction, need I remind you that so were glowing plants a few years ago?

For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.ladybug.uconn.edu or contact your local Cooperative Extension center.