A project undertaken at the University of Melbourne, and supervised by Michael Haydon
The rotation of the Earth and its orbit around the sun generates dramatic daily and seasonal environmental cycles. These present significant challenges to all life, but this is especially true for plants. Because plants are immobile, they are exposed to extreme daily and seasonal fluctuations in temperature. Furthermore, plants depend on daylight to generate their own sugars from photosynthesis and support their growth. This means they must adjust their metabolism between the day and night to survive. Like most organisms, plants have evolved a circadian clock in order to predict and adapt to these environmental cycles. This is a biological time-keeper that uses environmental cues to adjust rhythms of growth and physiology accordingly to the time of day using a finely-controlled gene network.
A luciferase gene from firefly is used as a reporter for circadian clock gene expression in Arabidopsis seedlings
We have recently discovered a new mechanism that plants use to adjust their circadian rhythm according to sugar availability. We propose that this enables plants to measure metabolic state in the evening and manage energy use through the night. This project will investigate how particular metabolic signals are sensed in plant cells and used to control the activity of genes that affect circadian rhythms and growth. Successful outcomes from the project will have significant impact in addressing long-standing questions about how plant cells sense metabolic status and adjust to fluctuating environments. This information would have implications for improving crop performance in a changing climate.
A 24-hour time-series of Arabidopsis seedlings stained for superoxide (blue), a rhythmic metabolite signal that affects circadian gene expression