Circadian Rhythms Play Key Role in Plant Adaptation to Cold

Just as monarch butterflies depend on circadian cues to begin their annual migration, so do plants to survive freezing temperatures. All living things – humans, animals, plants, microbes – are influenced by circadian rhythms, which are physical, mental and behavioral changes that follow a 24-hour cycle. In the April 6, 2011 online edition of PNAS, Dr. Michael Thomashow, University Distinguished Professor of molecular genetics, along with MSU colleagues Dr. Malia Dong and Dr. Eva Farré, has identified that the circadian clock provides key input required for plants to attain maximum freezing tolerance. “The integration of cold-signaling pathways with the circadian clock may have been an important evolutionary event that has contributed to plant adaptation to cold environments,” Dr. Thomashow said. Dr. Thomashow, who is an elected member of the National Academy of Sciences for his contributions to the field of plant biology, has focused his research on the identification of stress response pathways involved in freezing and drought tolerance. Stresses, including extreme temperatures and water deficit, are major factors that limit the geographical locations where food and potential bioenergy crops can be grown. His research led to the identification of the C-repeat binding factor, or CBF response pathway, a stress pathway that can be found in many different plants and plays a major role in freezing and drought tolerance. Reducing abiotic stresses, such as extremes in temperature and drought, can help expand where crops can be grown and increase yields on an annual basis, Dr. Thomashow said.