Petunias Engineered. Petunia--the common one is Petunia x atkinsiana--are easy to grow. Petunias are fast-growing, hardy, diploid plants and so several plant research labs tried studying them. They soon became a model organism, widely used for research on plants, including plant genetics. (See previous blog on petunias generally). They were cutting edge for inserting and turning on genes from other species.
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| petunias in many colors |
For this blog, I shopped a large garden store and came home with two transgenic petunias--orange and bioluminescent--and possibly the blackest flower in the world. Researchers inserted genes from corn into petunias to see how the biochemical pathways work; the successful insertion created an orange-flowered petunia. The orange petunia was a desirable garden plant which caused a scandal, a story I find fascinating.
The Rise of Genetic Engineering. I was working in ecology and genetics in the 1980s when inserting genes from other organisms and turning them on first became possible. The geneticists were promising all kinds of wonderful applications; environmentalists were predicting destruction of the natural world. At the time, the technology was crude and worked in petunia and its close relative tobacco, but did not work in wheat or rice or other important crops. Thus many promised applications were simply wishful thinking. (And, yet, many have been achieved today).
Genetic engineering is a tool. As it was developed, researchers everywhere considered whether it would help them solve whatever problem they were trying to solve, and in many cases, it did help. The concern was that there would be unintended consequences, a problem that is not limited to high-tech genetic problem solving. I spent six months in 1986 with the Audubon Society researching the environmental risks posed by transgenic organisms. We concluded that the most serious risk was of success: transgenic plants that could grow in marginal situations would allow plowing of currently wild areas; transgenic microorganisms might allow mining of fragile ecosystems that are uneconomical today. Tools can be used for both good and bad outcomes.
The scientific community took the risks seriously and pooled its wisdom to limit the potential of undesirable consequences. One real success of the early efforts was putting up regulatory barriers to using transgenic microorganisms and encouraging the use of plants, which are much easier to control and contain. [Note: if you succeed at preventing something, no one finds out how bad it could be.]
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| One of petunia's natural colors |
Engineering Petunias to Understand Plant Biology. Petunias were one of the plants researchers used to push the limits of knowledge. P. Meyer and coworkers made a breakthrough in 1987 by creating a brick-red petunia. Wild petunias are lavender or white but by the 1980s breeders had crossed and recrossed them, selecting for naturally-occurring mutant pigments, until they had every color (blue, purple, yellow, red, brown) except orange. Brick red is an orangy red and requires a molecule normal petunias are unable to synthesize.
By 1987 the chemical pathways responsible for creating color were pretty well understood; how different atoms were added to a molecule and which changed the color from lavender to blue or red or yellow. But there was no orange. Orange in flowers is normally from a molecule called pelargonidin and petunias lacked the enzyme necessary to make pelargonidin. They had the precursor molecules, so Meyer and coworkers gave a white-flowered petunia the gene from corn (Zea mays) that replaced a double-bonded oxygen atom with an oxygen atom and a hydrogen atom, and from that, petunias easily synthesized pelargonidin. As proof of their success, the transformed plants had orange pigmentation in their flowers (and pelargonidin in their tissues, but the colorful photo is more dramatic than the test results chart.) This was a much-heralded paper, because it confirmed our understanding of how the pigments that cause flower color are produced in the plant. So genetic engineering of petunias extended our understanding of the chemical pathways within plants.
It also made a pretty flower. Plant breeders thought it would be popular. But the regulations to bring transgenic plants to stores (commercialization) were long and arduous. At least two companies considered it, but each ultimately decided that there wasn't enough of a demand for an orange petunia to justify the cost of getting release approved.
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| petunia "Sunset Orange" |
The GMO Orange Petunia Escapes. Fast forward to 2017. Finnish plant pigment researcher T. Teeri spotted a bright orange petunia growing in a flower box in the Helsinki railroad station. He knew there were no orange petunias because in 1993 his lab had also transformed a petunia to produce pelargonidin using a gene from the gerbera daisy (Gerbera hybrida); it produced a bright orange flower. If orange petunias had been deregulated, he would have known. Intrigued, he purchased orange petunias such as 'Bonnie Orange' and 'African Sunset' and tested for pelargonidin and also for genes that would have accompanied the transgenic back in 1987. (Transforming plants today is much cleaner, often without accompanying genes inserted). He found both. So transgenic orange petunias were in stores all over the world. (orange petunia flowers link).
This was a scandal. They were illegal. To be sold, transgenic plants required pages and pages of safety documentation and government approval. Nobody--not Finland, not the European Union, not the United States...--had approved petunias modified with a corn gene for commercial production.
The result was a massacre of petunias in 2017 and 2018, as growers everywhere destroyed their orange petunias.
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| orange petunias |
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| Firefly petunia in daylight |
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| Firefly petunia in the dark |
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| 'Black Velvet' petunia |
Kathy Keeler
A Wandering Botanist
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