Climate change disrupts plant immune systems. Can they be restarted?

Much of this work has been done on the hardy Arabidopsis – ‘the laboratory rat of plants,” nor does He place it. There are several things that make it the perfect test subject. One is that the humble weed’s genome is relatively short, part of the reason it was the first plant to be fully sequenced. Another is the unique way its code can be modified. For most plants, the process is painful. New genetic material is introduced into a petri dish carried by bacteria that penetrate the plant’s cells. Once this happens, these modified cells must be cultured and become new roots and stems. But Arabidopsis offers a shortcut. Biologists need only dip the plant’s flowers into a solution full of gene-carrying bacteria, and the messages will be carried straight to the seeds, which can simply be planted. In the painstakingly slow field of botany, this happens at warp speed.

Still, it took years to figure out what all those SA-producing genes were doing in perfect greenhouse conditions. Only then can the He team begin to interfere with the environment to check what went wrong. Their mission: to find the gene (or genes) that control whatever step holds down SA production when it gets hot. It took 10 years to find the answer. They modified gene by gene, infecting plants and observing the effects. But no matter what they did, the plants still withered from disease. “You wouldn’t believe how many failed experiments we’ve had,” he says. Main waters, such as foreign laboratory identification of heat-sensitive genes that affect flowering and growth ended in crushing disappointment. Generations of students have supported the project. “My job is basically to be their cheerleader,” he says.

In the end, the lab found a winner. Gen. was calling CBP60g, and appeared to act as a “master switch” for a number of the steps involved in the formation of SA. The process of taking these genetic instructions and producing a protein was stymied by an intermediate molecular step. The key was to get around it. The researchers could do this, they found, by introducing a new section of code—a “promoter” taken from a virus—that would force the plant to transcribe CBP60g and restoration of the SA assembly line. There was another obvious benefit: The change also seemed to help restore less-understood disease-resistance genes that had been suppressed by the heat.

His team has since begun testing the gene modifications on food crops such as canola, a close cousin of Arabidopsis. Aside from the genetic similarities, this plant is a good one to work with, he says, because it grows in cool climates, where the plant is more likely to be affected by rising temperatures. So far, the team has been able to reactivate the immune response in the lab, but they need to do field tests. Other potential candidates include wheat, soybeans and potatoes.

Given the ubiquity of the SA pathway, it’s not surprising that He’s genetic correction would work widely in many plants, says Mark Nishimura, a plant immunity expert at Colorado State University who was not involved in the research. But this is only one of many climate-sensitive immune pathways that biologists need to explore. And there are variables other than heat waves that will affect plant immunity, he points out, such as increased humidity or prolonged heat that lasts throughout the growing season. “It might not be the perfect solution for every plant, but it gives you a general idea of ​​what’s going wrong and how you can fix it,” he says. He sees this as a victory for using basic science to decipher plant genes.

But for any of this to work, consumers will have to accept more genetic manipulation of their food. The alternative, Nishimura says, is more crop loss and more pesticides to prevent it. “As climate change accelerates, we will be under pressure to learn things in the lab and move them to the field more quickly,” he says. “I don’t see how we’re going to do that without more acceptance of genetically modified plants.”

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