Proposal Number IOS-0746756
In plants, light is commonly recognized as the driving force of photosynthesis. However, light has another important role as an environmental signal, informing the state of the plant's immediate surroundings. Plants maintain a set of sensitive sensors that monitor ambient light, adjusting plant form and function to best meet the prevailing conditions. In this way plants continually adapt to the changing environment, ranging from changes in gene expression to large-scale re-orientation of leaves and stems. These various responses develop in response to different light qualities, mainly red and blue light. However, green light has historically been shown to have minor effects that contribute to this process. Over the past several years research has demonstrated several specific effects of green illumination that are contrary to those affected by red or blue light. This project seeks to complement and expand ongoing efforts in photomorphogenesis (light mediated plant development) by further characterizing green light responses in the model plant, Arabidopsis thaliana. Preliminary data show an effect on chloroplast response to red or far-red light, the rate of flowering, stem elongation, shade avoidance symptoms and a suite of other visible changes. The activities herein carefully characterize these physiological processes to great resolution, pinpointing the timing and context of green light contributions to plant growth. A photobiological component attempts to describe the specific light qualities that define the light sensor, helping to guide candidate gene studies. Finally a genetic approach analyzes the potential mechanisms that transduce the green light signal. These activities will guide discovery of green light sensing components and aid the characterization of an additional system that controls plant growth and development. These experimental objectives are complemented by an ambitious graduate student driven outreach component that brings the principles of photomorphogenesis to the K-12 classroom. Selected classrooms will receive an LED-based light system, along with seeds and mutants to characterize for light responses. The data will be reported to www.respondingtotherainbow.com, a website housing the information and data relative to this project.
