An Everyday DNA blog article
Written by: Sarah Sharman, PhD
Illustrated by: Rita Clare, Scivetica
When I hear the word “transformation,” my mind immediately jumps to caterpillars turning into butterflies. They crawl around as little worm-like creatures, eating leaves, and preparing for their next stage of life. Then they build their cocoon and emerge weeks later as a totally different creature altogether. It’s quite fascinating.
In the world of genomics, “transformation” means something slightly different, but still equally fascinating. Over the past few decades, scientists have learned how to change plants at the genetic level to impart better traits to their offspring.
In nature, transformation takes time and patience, and the same is true in the lab. Scientists working with plants are guiding their own kind of metamorphosis, one written not in silk cocoons, but in strands of DNA.
What is plant transformation?
Plant transformation is a process that scientists use to introduce new DNA into a plant’s genome. Think of it as leaving the plant’s instruction manual mostly the same, but adding a new paragraph or tweaking a sentence to give it new abilities, like resisting disease, surviving drought, or producing more seeds.
Sometimes this new DNA comes from another species (for example, a bacterial gene that protects a plant from pests). Other times, it’s rearranged or edited versions of the plant’s own genes. Either way, the result is the same: a living organism with a slightly updated set of biological instructions.
Why go to all that trouble? Farmers and researchers alike are looking for crops that can thrive in new climates, resist pests, and make farming more sustainable.
How does plant transformation actually work?
The first step sounds simple, but is actually quite challenging: researchers must slip DNA past the plant cell’s rigid wall and into its nucleus. Researchers have developed several clever methods for delivering DNA into plant cells.
The most common and elegant method uses a naturally occurring soil bacterium called Agrobacterium tumefaciens. In nature, this microbe has a pretty sneaky trick: it transfers part of its DNA into plants, causing tumor-like growths known as crown galls. Scientists have learned how to disarm Agrobacterium by removing the tumor-inducing genes and replacing them with genes that confer the beneficial trait they aim to impart to the plant. The bacterium does the hard work of delivering the new gene package into the plant cell. It’s like hijacking a delivery service that already knows the plant’s address; scientists just swap out the package inside.
For plants that Agrobacterium doesn’t easily infect, researchers take a more physical approach. They coat microscopic gold or tungsten particles with DNA and use a device nicknamed the “gene gun” to shoot these particles into plant cells at high speed. This technique is especially handy for crops that resist bacterial infection, like certain grains or grasses.
Once a cell successfully takes up the new DNA, scientists help it grow into a whole plant through a process called tissue culture. It’s a bit like nurturing a cutting from a houseplant, but instead of a leaf or stem, researchers start with a single transformed cell. With the right mix of plant hormones and nutrients, that lone cell can regrow roots and shoots, eventually becoming a full, fertile plant.
Not all plants cooperate easily. Many important crops are what scientists call recalcitrant, meaning they’re tough to transform and regrow in the lab. Researchers are tackling this challenge in a number of ways. One way is that they’re using special “morphogenic regulators,” genes that act like growth boosters, encouraging cells to become full plants more readily. Because many staple crops, including wheat, sorghum, and peanuts, are recalcitrant, improving their transformation efficiency is a major goal for plant biologists.
Why is plant transformation important?
All this lab work might seem abstract, but transformation has had a huge, real-world impact. Transformation lets researchers do more than just improve crops. It helps them understand how plants work at a fundamental level. By adding, removing, or tweaking specific genes, researchers can test how those genes influence plant growth, yield, and stress resistance.
These insights turn into real-world benefits. For example:
- Bt corn: Corn that has been transformed with a gene from the Bacillus thuringiensis (Bt) bacterium, giving it natural resistance to certain insect pests. This reduces pesticide use and boosts yields.
- Golden rice: By adding a few genes related to vitamin A production, researchers created rice varieties that can help reduce preventable childhood blindness and malnutrition.
- Rainbow papaya: Researchers inserted a fragment of the papaya ringspot virus coat protein gene into the papaya genome, providing a form of immunity to the devastating papaya ringspot virus. This saved the Hawaiian papaya industry from destruction.
The same principles that underpin Bt corn and Golden Rice are now helping researchers at HudsonAlpha improve regional crops like peanuts and bioenergy grasses.
Plant transformation at HudsonAlpha
At HudsonAlpha Institute for Biotechnology, our researchers are using plant transformation to address real agricultural problems. Members of the Swaminathan lab are experts at plant transformation techniques in these “recalcitrant” plants. Together, they were among the first to successfully edit the genome of Miscanthus, a tall grass that looks ordinary but is a very valuable plant for bioproducts.
Through the BRIDGES Engine project, the lab is fine-tuning Miscanthus to grow right here in the Southeast. The goal of the project is to turn these grasses into sustainable raw material for everything from eco-friendly packaging to car parts. For example, instead of using petroleum-based plastics for car dashboards, we can use the fiber from these transformed grasses.
While Miscanthus research focuses on renewable materials, another HudsonAlpha team has its sights set on food safety. The Clevenger lab is leveraging the Swaminathan lab’s expertise in difficult transformations to tackle another stubborn plant: the peanut. They are currently pioneering new protocols to overcome peanut recalcitrance. Once they’ve mastered the “delivery service” for peanut cells, they can introduce genes that help peanuts mitigate the production of aflatoxin, a dangerous toxin that costs the industry millions and threatens food safety.
Looking Ahead
Plant transformation raises thoughtful questions about how and why we alter living organisms, but it also holds immense potential to feed a growing global population and create more sustainable agricultural systems. From staple food security to renewable bio-based materials, breakthroughs in plant genomics are already shaping a more resilient future.
So next time you think of transformation, you might still picture a butterfly emerging from its chrysalis, but maybe also a peanut plant sprouting in a greenhouse, carrying inside it a tiny but powerful piece of scientific innovation.
