Time's Ticking: Plant's Biological Clock Depends on Temperature

A plant's biological clock - the one that modulates the speed of circadian (daily) rhythms - depends on temperature, and scientists have discovered a key genetic factor that drives this pattern. With global warming raising temperatures and creating extreme climate environments, this kind of discovery could be crucial for the survival of plant species.

Transcription factors, or genetic switches, drive gene expression in plants based on external stresses - such as light, rain, soil quality, or even animals grazing on them. Researchers at the University of Southern California (USC) found one in particular, called FBH1, reacts to temperature by tweaking the rhythm here and there as needed while in keeping it on a consistent track.

"Temperature helps keep the hands of the biological clock in the right place," corresponding author Steve A. Kay explained in a statement. "Now we know more about how that works."

Kay and his team conducted their research on Arabidopsis, a flowering member of the mustard family that is used as a model organism by scientists because of its high seed production, short life cycle, and the fact that now all of its genome has been sequenced.

By understanding the underlying mechanism of how a plant's biological clock works in time with FBH1, scientists can breed plants that are better able to deal with stressful environments. And in a world where plants are stressed by numerous factors, like rising temperatures from global warming, and farmers attempt to feed an increasing population amid urban development of arable land, this kind of discovery could be crucial for various plant species.

"Global climate change suggests that it's going to get warmer and since plants cannot run away from the heat, they're going to have to adapt to a changing environment. This study suggests one mechanism for us to understand how this interaction works," lead author Dawn Nagel said.

Plants have on average six times as many transcription factors than animals. That's because unlike animals, they cannot simply get up and walk away to escape the heat. They have evolved to deal with stressors that surround them in their environment. This study's findings could be one way to help plants adapt to global warming, something they might not be able to survive on their own.

The findings were published in the journal Proceedings of the National Academy of Science.