by Hua Lu and Linda Wiratan: Biologists are taking a close look at how precisely calibrated timekeepers in organisms influence plant-pathogen interactions…
At dusk, the leaves of the tamarind tree close, waiting for another dawn. Androsthenes, a ship captain serving under Alexander the Great, made the first written account of these leaf movements in the fourth century B.C.
It took centuries longer to discover that he was describing the effects of the circadian clock. This internal time-sensing mechanism allows many living organisms to keep track of time and coordinate their behaviors along 24-hour cycles. It follows the regular day/night and seasonal cycles of Earth’s daily rotation. Circadian research has advanced so far that the 2017 Nobel Prize in physiology or medicine was awarded for the groundbreaking work that elucidated the molecular basis underlying circadian rhythms.
Biologists like us are studying the circadian clocks in plants for insights into how they affect the health and well-being of all life on Earth. As researchers continue to untangle more about how these clocks work – including how they influence interactions between hosts and their invading pathogens and pests – new forms of specially timed precision medicine could be on the horizon.
Our hidden pacemaker
Organisms from all three domains of life possess an amazing diversity of circadian rhythms. Seemingly simple Cyanobacteria alternate photosynthetic activity between day and night. The fungus Neurospora crassa produces spores every morning just before dawn. Migratory monarch butterflies use a delicate sun compass in their annual migration. Almost every aspect of human activity is influenced by the circadian clock – you can easily see this in yourself if you fly across time zones or engage in shift work.