


The world’s bread baskets are heating up, threatening the global food supply. Climate change has already shrunk yields for major crops like wheat and maize, and crop losses are likely to worsen in the coming decades.
But researchers are trying to avoid that future by helping plants deal with heat.
“There’s a lot of excitement in identifying why it is that some crops that are grown in the most extreme conditions are able to survive,” said Carl Bernacchi, a crop researcher at the University of Illinois Urbana-Champaign and the author of one of a trio of papers on crop modification that were published Thursday in the journal Science.
Farmers can help crops beat the heat with water-based cooling, but that method has limitations. Modifying crops, either through traditional crossbreeding, artificially sped-up mutation or direct genetic editing, offers control over how plants respond to heat.
Photosynthesis, the process through which plants get energy, grinds to a halt between 40 and 45 degrees Celsius, or 104 to 113 degrees Fahrenheit, temperatures that are becoming more common in many of the world’s agricultural regions.
“Photosynthesis really dictates the currency plants have to use,” Dr. Bernacchi said. “If photosynthesis falters, plants run out of energy and die.”
Dr. Bernacchi and his co-authors reviewed the potential of editing rubisco, the key enzyme that transforms carbon into sugar, and its partner, rubisco activase. In plants that grow in warm climates, rubisco activase seems to work better at helping rubisco function. Transferring that molecule from hot-climate plants to cool-climate plants can help cool-climate plants adapt to heat. Simply boosting its activity could help, too.