ELF3 Regulation of Circadian Rhythm and Flowering in Arabidipsis

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Meeks-Wagner9808208The Early Flowering 3(ELF3) gene has been cloned from Arabidopsis thaliana and has been found to lack any similarity to genes in the available databases. Results to date suggest that ELF3 functions as a novel key regulator of the circadian oscillator, as well as a regulator of inflorescence and floral meristem identity genes. The hypothesis that the ELF3 gene product regulates photoperiodism by functioning as a component of a photosensory pathway that controls the activity of circadian clocks will be tested. The role of ELF3 in regulating the genetic pathways that control floral initiation and flower meristem development will also be investigated. The specific aims are: 1) To characterize the spatial and temporal regulation of ELF3 transcription and translation 2) To create and characterize -developmentally and for circadian responses- various transgenic lines that overexpress or ectopically express ELF3 by using the endogenous ELF3 regulatory sequences, and constitutive, tissue specific, inducible promoter systems 3) To define the genetic pathways related to ELF3 gene function that regulate floral initiation and meristem identity in Arabidopsis 4) To identify gene products that interact with ELF3 to facilitate proper circadian response and flowering and to identify genes regulated by ELF3 function which may be downstream genes or genes that are autoregulated components of the circadian clock.The long-term goal of this research is to understand the molecular mechanisms that regulate plant developmental responses to changes in daylength. Responses such as floral initiation are likely to be controlled by photosensory pathways that also impinge upon the function of the circadian clocks of plants. A molecular genetic approach to understanding the photoperiodic control of flowering in Arabidopsis will be taken, focused upon the ELF3 gene, isolated and characterized in this laboratory. Previous results suggest the possibility that ELF3 represents a link between photosensory input pathways to the circadian oscillator and developmental responses in higher plants. The development of a framework for the genetic and molecular basis of photomorphogensis and floral initiation in the model plant will make it possible to better engineer desirable modifications in commerically important plants.