Integrating Environmental Variables in Plant Circadian and Photoperiodic Timing.

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Plants evolved in response to advantageous and deleterious environmental variables, such as light, temperature, moisture and the threat of pests. To counteract daily stresses, and to maximize energy storage during the day, plants developed complex regulatory circuits that can predict daily (circadian) and seasonal (photoperiodic) rhythms, thus providing an evolutionary advantage and improved organism fitness. As such, plant circadian rhythms control all facets of plant growth and development, including flowering times, photosynthesis, latitudinal species distribution, and resistance to drought, cold and pests. It is estimated that greater than one third of all plant genes are under circadian control and that proper day-length measurements are imperative to the maintenance of plant growth, reproduction and crop yields. How these circadian clocks measure and adapt to a wide array of environmental signals is poorly understood. This is particularly the case for adaptation to daily and seasonal variations in the quality and quantity of environmental light. The current proposal aims to use a multidisciplinary approach to model how plants sense and adapt to changes in the intensity of blue-light in a given environment. Aside from gaining fundamental understanding of the chemical processes that govern plant photobiology, the project is likely to provide new avenues to improve crop yields and biomass production for renewable energy, and develop novel varieties of plants that are more drought and pest resistant. The project will provide unique training opportunities for undergraduate students and outreach to local science teachers and K-12 students.How Light-Oxygen-Voltage proteins integrate environmental cues is poorly understood. The proposed research leverages recent discoveries of new signaling mechanisms that delineate adaptive responses to environmental stimuli. The concerted chemical, biophysical and synthetic biology approach will provide quantitative understanding of adaptive responses in complex signaling networks. The primary technical objectives are three fold. 1) A combination of chemical kinetics and predictive mathematical models will be developed to gain a systems level understanding of Light-Oxygen-Voltage protein function in seasonal and daily clocks. A direct result of these efforts will be a detailed understanding of how multiple chemical inputs to Light-Oxygen-Voltage protein function dictate signal transduction and optogenetic tool development. 2) The project will use the new understanding of Light-Oxygen-Voltage protein signaling networks to design synthetic gene circuits in mammalian cells, and thus enable the testing of the understanding of the network in the absence of extraneous plant proteins that may affect signal transduction. 3) The ultimate goal is to combine this understanding to guide the construction of new Arabidopsis thaliana strains that exhibit altered circadian function and plant flowering periods to demonstrate how Light-Oxygen-Voltage protein chemistry is essential for triggering systems-level adaptive changes in a plant system.