| The production of flowers is the end result of a complex network of signaling pathways. Plants use internal cues to ensure that flowering occurs at an appropriate developmental state. Upon becoming reproductively competent, plants rely on environmental signals to ensure that flower and seed production occur during the optimal season. Daylength or photoperiod serves as an excellent indicator of season, and plants have evolved mechanisms to sense the relative changes in the length of day and night. The daylength response is the result of interplay between daily fluctuations in light quantity and an endogenous timekeeper. The endogenous timekeeper, known as the circadian clock, is composed of a feedback loop. The ELF4 gene is an essential component of this feedback loop as loss of this gene results in severe impairment of the clock. Plants lacking ELF4 are early flowering under non-inductive photoperiods and display elongated hypocotyls and petioles. The ELF4 protein sequence does not reveal a clear biochemical function. We took several approaches to help characterize the function of this protein. We also used the elf4 mutant as a tool to isolate additional genes involved in the regulation of flowering time. |
