As Climate Change Makes Growing Seasons Less Predictable, Scientists Dig Into A Novel Approach to Boosting Crop Resilience
(Ensia) 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.
…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.”
Both Mackenzie and Springer are interested in the role that epigenetic mechanisms — the biological processes that activate and deactivate genes — may play in this dynamic balance between yield potential and yield stability. If breeders could enhance plants’ ability to flip the switch as environmental conditions change, it could make it possible to (for instance) activate physiological changes that enhance drought tolerance only when needed, avoiding the ding on productivity.
…Mackenzie’s “trick” is to use RNA interference to silence a gene called MSH1, which is found in the plant cell’s plastid — a compartment that has the ability to sense stress. She and her colleagues discovered that when they suppress MSH1 in a parent plant, epigenetic regulation kicks in, and gene expression is altered in a way that allows it to better respond to stress.
Advantages of this approach discussed in the remaining article include a faster result than that of using standard breeding methods. Also, no DNA foreign to the plant is used, so a lengthy approval process through the U.S. Department of Agriculture is avoided.
Casava is another crop to which they are looking to apply this technique.