Plant circadian rhythms have been extensively studied in laboratory settings where environmental factors such as light and temperature can be controlled. However, less is known about how these biological timing mechanisms operate in nature, where conditions are more unpredictable. A collaborative study between researchers from the UK and Japan aimed to bridge this gap by conducting field experiments to observe how plants integrate clock signals with environmental cues under fluctuating conditions. The team, consisting of scientists from the John Innes Centre, Kyoto University, and The Sainsbury Laboratory, produced statistical models based on their field studies that could help predict how plants, including major crops, might respond to future temperatures.
The research team’s previous study had identified a genetic pathway controlled by the biological clock that protects photosynthesizing plants from cell damage in bright cold conditions. In their present study, published in the Proceedings of the National Academy of Sciences (PNAS), they set out to identify this mechanism in nature using Arabidopsis halleri plants in a rural Japanese field site. By monitoring gene expression changes over 24-hour cycles in response to varying light and temperature, the researchers were able to track how the plants responded to their natural environment. They also manipulated temperatures around the plants to recreate the conditions observed in their laboratory study.
Despite challenges such as working in the dark with green filters over their head torches to avoid influencing the plants, the team successfully collected data on gene expression patterns in response to environmental signals. They observed that the wild populations of plants exhibited the same sensitivity to cold and bright dawn conditions seen in laboratory experiments. This information enabled them to develop statistical models that accurately predicted gene expression activity controlled by the circadian clock in response to environmental signals in natural settings. This approach could potentially help breed plants that are better adapted to future climate conditions.
The study’s joint first author, Dr. Haruki Nishio from Shiga University, highlighted the effectiveness of Bayesian time-series modeling in disentangling complex signal integration in natural environments. The team’s ability to model a whole circadian clock signaling pathway in plants growing outdoors was a significant achievement that could have implications for predicting plant responses to environmental changes. By applying their statistical models to functions of plant physiology such as photosynthesis and temperature adaptation, the researchers hope to further understand how circadian-regulated processes are aligned with fluctuating environmental conditions.
Dr. Dora Cano-Ramirez, a circadian clock researcher and joint first author, emphasized the importance of understanding how circadian-regulated processes translate to field conditions. By modeling the plant circadian signaling pathway and its integration with environmental signals, researchers could gain valuable insights into plant responses in an increasingly unpredictable climate. The study, titled “Circadian and environmental signal integration in a natural population of Arabidopsis,” provides a foundation for future research on plant physiology and adaptation to changing environmental conditions.