The study, published this week, appears in the online edition of the Proceedings of the National Academy of Sciences.
"Having two clocks with different sensitivities to light and to temperature is a better way to ensure that both signals of environmental input are fully understood by the plant," says C. Robertson McClung, professor of biological sciences and an author on the paper. "The plant can then process the data and make decisions about flowering, which is a very critical decision. Arabidopsis flowers in response to the lengthening days of spring, but if it were to flower too soon and there is a nasty frost, the blossoms will die. Early spring is cool, so it makes sense for a plant to clue in to more than one environmental signal."
The researchers, which included McClung, Todd Michael, a former graduate student who is now a postdoctoral fellow at the Salk Institute in San Diego, and Patrice Salom, a graduate student, followed rhythms in two kinds of genes one kind that encodes for photosynthesis and another not involved in photosynthesis. The genes in this study are both found in the mesophyll, the spongy inner layer of tissue in leaves.
To measure gene expression, McClung and his students manipulated the clock-controlled genes they were studying and put them in control of luciferase, the enzyme that makes fireflies glow, and then introduced that new gene into Arabidopsis. Each plant in the study had only one altered, light-making gene. When that gene was stimulated, light production was captured by a very sensitive camera. McClung and his team used t
Contact: Sue Knapp