The research team found that the offspring of this parent plant inherit memory of this “stress”: They, too, had altered gene expression, even without the artificial stress. Tomatoes treated in this way grew better and were more resilient to the heat of Florida field conditions — with up to a 35% boost in yield compared with an heirloom tomato variety.

Mackenzie sees value in this approach to boosting resilience because of the speed at which it can take place. Standard breeding methods could take 10 years to achieve a similar result, she says. In contrast, using an epigenetics approach, “I’m doing this in a year’s time,” she says.

Not only that, but because this final product contains no detectable foreign DNA, Mackenzie doesn’t need to go through a lengthy process of regulation by the U.S. Department of Agriculture that other crop breeding technologies such as genome editing or genome modification may require for commercial use.

Nathan Springer studies the epigenetic regulation of traits in maize, an important food crop around the world. Photo courtesy of Nathan Springer

Springer notes that it’s difficult to determine the extent to which these results can be attributed to epigenetics, however. “It’s hard to confirm that,” he says. “[Mackenzie’s] lab is working really hard on understanding the mechanisms.”

Testing the Technology

The success in tomato has motivated Mackenzie to try a similar approach in other crops, including soybean, sorghum, alfalfa and strawberry. But she says company partnerships are needed to test the technology in different seasons, environments and countries.

Springer says that seed companies may hesitate to engage in epigenetic breeding because a gene turned off through epigenetics could suddenly turn on again, compromising their commitment to sell a uniform product.  If a crop grown from seeds produced by epigenetically modified plants has more variability than expected, he says, “you have a problem.” Mackenzie maintains, however, that the epigenetic changes she sees remain consistent over several generations of plants.

Other researchers are also testing epigenetic approaches. A trial in cassava, a staple crop for hundreds of millions of people in tropical countries, proved challenging.

Cassava, a staple in many tropical countries, is among the crops in which epigenetic modification shows promise for improving yields. Photo © | pailoolom

“Cassava is a very long-term crop — the breeding cycle of cassava is about eight years,” says Paul Chavarriaga, lead scientist of the Advanced Breeding Platform at the International Center for Tropical Agriculture in Cali, Colombia, who collaborated with Mackenzie on cassava trials. Early results were promising, but funding ran out before the study could be completed.

Enhance, Not Supplant

Mackenzie emphasizes that manipulating epigenetics is not a silver bullet: It cannot supplant breeding, but rather, enhances it.

“It’s not that you just create these varieties and then you walk away,” she says. As with all epigenetic phenomena, after a few generations the plant will eventually return to its nonstressed state. “No epigenetic phenomenon will hold forever, and nor should it,” she says.

Mackenzie says epigenetic breeding is important to pursue, given the rapid impacts of a changing climate on the agricultural industry.

“Given that we’ve got to accelerate our progress as quickly as we can with as many crops as possible, we need breakthroughs,” she says. “There are no simple, rapid, traditional plant breeding solutions. You really have to think outside the box.”

Editor’s note: Allison Gacad wrote this story as a participant in the Ensia Mentor Program. The mentor for the project was Virginia Gewin. Nathan Springer, who is quoted in this story, is affiliated with Ensia’s publisher, the Institute on the Environment.