The offspring of experimentally grafted tomato plants were, on average, 35 percent more productive than their parents -- as well as more vigorous and resilient. Photo by Penn State
Oct. 22 (UPI) -- Scientists have discovered a new plant grafting technique that yields more robust and vigorous progeny.
The research team, including scientists from Penn State, the University of Florida and a small Nebraskan startup company, detailed their breakthrough Thursday in the journal Nature Communications.
Before grafting, scientists manipulated the expression of a gene called MSH1 in a group of plants. In effect, researchers implanted a "stress memory," triggering an epigenetic response.
"When a plant experiences a stress such as drought or prolonged extreme heat, it has the ability to adjust quickly to its environment to become phenotypically 'plastic' -- or flexible," study co-author Sally Mackenzie, professor of plant science at Penn State University, said in a news release. "And, it turns out, it 'remembers.'"
When researchers grafted the stressed plants onto an unmodified scion, or above-ground shoot, the resulting progeny proved more productive and resilient than their parent plants.
Because the process doesn't involve the introduction of new genetic material, researchers estimate their grafting method could help growers avoid the controversy and legal restrictions associated with genetically modified food.
"Although we did this with tomato, it can be done with any plant," she said. "We think that this study represents a major breakthrough in showing the potential of epigenetic breeding for crops. And later, it will have major implications for trees and forests in the face of climate change."
Building on earlier research, scientists used the MSH1 gene pathway to alter the tomato plant's expression of a variety of genes associated with resiliency.
When researchers grafted the epigenetically-modified rootstock with a novel above-ground shoot, they found the "remembered" traits were transmitted from the roots to the top of the hybrid plant. The new grafted plant produced seeds that yielded more productive and resilient offspring.
During the experiment, large storms dropped seven inches of rain on their test fields in short order. The heavy rains and flooded fields wiped out many plants in other test plots, but most of the grafted plants survived.
Researchers found the enhanced survivability of the grafted plant's offspring persisted for at least five generations.
"Everything we're doing, any plant breeder in agriculture can do, and now we've shown on a large scale that it has agricultural value," said Mackenzie. "It's ready to go -- a breeder could read about this and implement the system to improve his or her variety."