University of Mississippi researchers are studying how plants respond to heat at the molecular level, an important consideration for farmers, businesses and policymakers as global temperatures rise.
In a study published in Nature Communications , Ole Miss researchers investigated the internal structures plants rely on to adjust how they grow and survive in warm temperatures.
"Plants are the foundation of our food system, but unlike animals, they cannot relocate to escape high-temperature conditions," said Haibo Xiong, a postdoctoral researcher in the Department of Biology and co-author of the study. "As global temperatures continue to rise, understanding how plants respond to warmer conditions is essential for ensuring stable crop production and food security.
"If we understand how plants sense and adapt to elevated temperatures, we can better predict these changes and develop strategies to maintain crop productivity in a changing climate."
The National Oceanic and Atmospheric Administration charted 2024 as the warmest year on record since data collection began in 1850, and 2025 as the third-warmest. As temperatures continue to increase, biologists need to understand how plants respond to temperature to make them more heat-resistant.
Yongjian Qiu, associate professor of biology, along with Xiong and three graduate research assistants in biology, Abhishesh Bajracharya, Ranjeeta Odari and Anupa Wasti, spent five years examining how plants adapt in warmer settings.
Plants respond in multiple ways to increasing temperatures, such as elongating their stems, flowering early and tilting their leaves toward the sky to funnel away heat.
"From the agricultural perspective, for cereal crops and vegetables, you may or may not like this response," Qiu said. "Is stem elongation a good thing for farmers? Maybe not, because if there's strong wind or rain, it's very easy for a longer stem to fall down.
"But let's say, for vegetables, we know a warm-temperature response is bigger leaves. If you're growing leafy vegetables, maybe that's a good thing."
All those changes may hinge on PIF4, a protein that acts like a control switch for plant growth responses triggered by warmer temperatures, Qiu said.
"The reason we say PIF4 is important is because if you get rid of PIF4, the mutant (plants) cannot respond to temperature," he said. "Just get rid of PIF4, and you see a dramatic defect in response."
PIF4 is a transcription factor , meaning it can turn genes on or off by binding to DNA and recruiting other molecules that control gene activity.
"It's like a production line where PIF4 recruits workers and says, 'Come here and start building RNA,'" Qiu said. "If we disrupt DNA binding or disrupt the recruitment of the enzyme, this protein should not be functional. It would be as though the workers would not come.
"The surprising thing is we mutated PIF4, got rid of the DNA binding feature or the recruitment feature, put it back into the mutant plants, and it worked. The mutant plants were still able to respond to temperature."
This result means that PIF4 functions less like a middle manager and more like a boss delegating tasks to other molecules, Qiu said. If it cannot bind to DNA itself, it outsources the job.
"This finding shows that plant systems are highly adaptable at the molecular level," Xiong said. "Even when some key functions of PIF4, such as DNA binding or gene activation, are disrupted, the plant can still maintain its growth response to warm temperatures.
"This is because other partner proteins can compensate and carry out similar roles."
The research found that what makes PIF4 special is its ability to "team up" with other proteins and delegate tasks, Xiong said. That finding could inform future efforts to make heat-resistant crops.
"Instead of focusing only on individual genes or specific biochemical activities, it may be more effective to prioritize proteins that act as organizers, or those that bring together multiple partners to control growth," he said. "Targeting these types of proteins could help streamline the identification of key regulators, as they sit at central points in the network.
"This may ultimately make it easier to develop crops that maintain stable growth under warmer conditions."
