Circadian Regulation of Auxin Signal Transduction

University Of California-Davis, Davis CA

Investigators

Abstract

Every organism on earth must cope with a constantly changing environment. Animals can deal with environmental stress by moving away from it; however, this is not an option for plants, which are literally rooted in place. Plants have therefore developed sophisticated ways to regulate their physiology and development both in response to their specific growth environment and in anticipation of changes that occur each day due to the earth's rotation on its axis. An unexpected connection has been found between the circadian clock, which regulates many aspects of plant physiology in a time-of-day specific manner, and the plant hormone auxin, which controls many spatial aspects of plant growth and development. A surprising finding is that the circadian clock controls at least some plant responses to the hormone auxin: plants respond differently to auxin when it is administered at different times of day. In the current project, the connection between the circadian clock and auxin responses will be investigated using genetic, genomic, and advanced imaging techniques. This research will help determine 1) whether aspects of auxin responses such as directional growth are also under clock regulation, 2) in which plant organs clock regulation of auxin responses occurs, and 3) the molecular basis of clock regulation of auxin responses. Fundamental insights into how two important regulatory pathways, the circadian clock and auxin signaling, interact with each other are expected. This information will be of great interest to scientists studying both normal plant development and plant responses to environmental stresses, with possible future applications in optimizing growth of crop plant species in variable environments. In addition, the work outlined in this proposal will provide valuable hands-on training for students at the high school, college, graduate, and post-graduate levels. Furthermore, research findings will be presented to high school students, teachers and undergraduates in an effort to promote the understanding and support of science by the general public.