As climate change makes growing seasons less predictable, scientists dig into a novel approach to boosting crop resilience

Epigenetic modification of plants shows promise for enhancing food security — but we still have a lot to learn

5 min readJun 18, 2020


Photo courtesy of Sally Mackenzie

By Allison Gacad for Ensia | @ensiamedia | @allisongacad

Sally Mackenzie spent her childhood summers walking through the vast fields of bright, red, ripe tomato crops: They grow best in the heat of her home state of California. Yet recent seasons prove it can get too hot for a tomato.

“It just sits there, puts out these little green knobs, and won’t do anything with them, because it just can’t handle the heat,” says Mackenzie, now a professor of biology and plant science at Penn State University in University Park.

Growing vegetables has never been easy, but climate change is ramping up the risk. “Fresh market agriculture is a nail-biting proposition,” says Mackenzie, whose father was a West Coast produce distributor. “One rain at the wrong time can wipe out a tomato crop, and that’s hundreds of thousands of dollars.”

Increasingly unpredictable growing seasons are a threat to income and livelihoods not only in California, where rising temperatures coupled with scarce precipitation have taken a nearly US$3 billion toll on the state’s agricultural industry, but also around the world. Now Mackenzie is working to do something about that. As producers and scientists search for ways to make crops more resilient in the face of such challenges, she sees promising potential in tapping into plants’ natural ability to rapidly turn select genes on and off in response to stress.

Best of Both Worlds

Traditionally, plant breeders have used selective breeding to create high-yielding varieties that can thrive under different growing conditions. However, there’s often a trade-off between breeding for yield potential and yield stability, says Nathan Springer, a geneticist who studies maize at the University of Minnesota. It’s possible to breed a plant that’s very drought tolerant, he says. But in a year where there isn’t any drought, this breed of plant may “only yield half as much.”




Ensia is a solutions-focused nonprofit media outlet reporting on our changing planet.