How does a tomato plant decide if it's warm enough to bear fruit? What causes basil to bolt and rush to produce flowers when the weather gets hot? Do we really understand how plants sense temperature? For decades, researchers searched for a single "thermosensor"-a biological thermometer buried deep in the plant's molecular machinery. But a new theory is flipping that idea on its head.
A growing number of studies suggest that plants don't have one master sensor, according to Avilash Singh Yadav, postdoctoral associate with Adrienne Roeder, professor at the Weill Institute for Cell and Molecular Biology, and the Cornell College of Agriculture and Life Sciences School of Integrative Plant Science, Plant Biology Section. "What we realize is that temperature sensing in plants is dispersed randomly across a whole network of molecules," Singh Yadav said. "It's more like a weather radar than a thermostat."
Singh Yadav and the team refined the new model based on years of existing evidence. The researchers' insights challenge and refine some assumptions in plant biology and argue that thermal sensing is not the job of a single protein or gene.
"Simply put, plants don't have a nervous system, and they don't sense temperature using dedicated sensors like animals do," he said.
In a review article in Science, the researchers illustrate how plants use many temperature-sensitive components scattered randomly across signaling pathways, including proteins that change shape, RNA that melts, and DNA strands that pack loosely or tightly together, depending on temperature.
"Temperature touches everything in a plant," said Singh Yadav, who authored the article with his Ph.D. advisor Sureshkumar Balasubramanian, professor at School of Biological Sciences, Monash University in Australia, Alok Krishna Sinha, National Institute of Plant Genome Research, India, and Sridevi Sureshkumar, School of Biological Sciences, Monash University. "It affects how genes are turned on and off, how cells grow, and how organs form."
Temperature by Chance and by Design
Avilash Singh Yadav studies how plant temperature sensors trigger flowering and fruit production at Cornell's Weill Institute of Cell and Molecular Biology.
As Singh Yadav and his colleagues looked closer, they realized that there wasn't a single temperature-sensitive component, there were many. Some controlled light sensing. Others affected hormone signaling. A few regulated the plant's internal clock.
"It was like trying to find the lead violinist in an orchestra," Singh Yadav said, "only to realize there isn't one-it's the whole ensemble playing in sync."
The team's model, which they call "dispersed thermal sensing," suggests that heat-responsive proteins are spread across signaling systems. Some proteins change shape in the heat. Others form or dissolve tiny droplets inside cells, a process called liquid-liquid phase separation. Still others interact with RNA or DNA differently depending on the temperature. Together, these changes ripple through the plant's internal systems, producing visible responses: leaves droop, roots stretch, flowers bloom. The researchers highlight the idea that temperature sensing at the whole plant level is essentially a characteristic, or an emergent property, of randomly disbursed temperature-sensitive components.
This randomness may sound chaotic, but it gives plants a kind of resilience and robustness, "just like the way our universe works," Singh Yadav said. If one pathway fails, another can still carry the message. It's biological redundancy-and in an unpredictable climate, that's a good thing, according to Singh Yadav. Temperature cues are woven into pre-existing signaling pathways through the natural temperature sensitivity of various biomolecules and biophysical processes.
Why It Matters
The real-world implications for a greater understanding of plant temperature sensing are vast, including within agriculture, Singh Yadav said. "If we want crops that can handle unpredictable temperature fluctuations, we can't just edit one gene," he said. "We need to think about networks, systems-about how whole plants respond."
With a better understanding of dispersed sensing, scientists could design crops that adapt more flexibly, by targeting multiple components simultaneously. A plant with multiple thermal sensing pathways might grow normally even if one of those pathways is knocked out by stress. Or researchers could "tune" a plant's network to favor survival traits, like deeper roots or increased yield under heat, Singh Yadav said.
This approach is already underway. At the Weill Institute, where Singh Yadav is now a postdoctoral fellow, researchers are studying how interactions among cells and cellular components lead to robust organ growth even under variable environmental conditions. They're especially interested in how cells decide to divide or stretch-decisions that shape a leaf or a stem.
His work was supported by Weill Institute's 2023 Sam and Nancy Fleming Research Fellowship. "I couldn't have done this without the support of the Weill Institute, the Roeder lab and the Fleming Research Fellowship," he said. Now, as he balances research alongside teaching and mentoring students, Singh Yadav finds comfort in watching both people and plants grow. "There's something therapeutic about seeing things take root."
Henry C. Smith is the communications specialist for Biological Systems at Cornell Research and Innovation.
