Minisymposium 28: Biotechnology

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Abs # M2804: Development of a Plant Sentinel for terrorist agents and environmental pollutants using computationally designed receptors with synthetic and hybrid signal transduction

Presenter:	Medford, June I.       Contact Presenter
Authors	Medford, June I. (A)   Kevin, Morey J. (A)   Antunes, Mauricio S. (A)   Tewari-Singh, Neera  (A)   Smith, James J. (B)   Hellinga, Homme W. (A)
Affiliations:	(A): Department of Biology, Colorado State University, Fort Collins, CO 80523-1878 USA (B): Department of Biochemistry, Nanaline H. Duke, Box 3711, Duke University Medical Center, Durham, NC 27710

Plants have elegant mechanisms to sense and respond to their environment, suggesting that they can be adapted to make inexpensive and widely used biological sentinels for substances of interest. For a plant sentinel, a sensing system and reporting system are needed. We developed a sensing system that uses computationally designed receptors and linked the input via histidine kinase signal transduction systems. To provide proper input, we developed two independent signaling systems: one system is based on forming hybrid signaling proteins between plant and bacteria components and one based on a synthetic signal transduction system. Both systems function well and link perception of a specific ligand to activate gene expression in Arabidopsis plants. Because the system is modular and the receptors are designed in a computer our system will allow plants to detect substances such as explosives, nerve gas, environmental pollutants, heavy metals, etc. In addition, our advances in signal transduction are being applied to discern how cytokinin signaling works in plant development as well as elaboration of endogenous signaling systems in plants. We also developed an output system for a plant sentinel using a synthetic degreening circuit. With this readout system, chlorophyll becomes a reporter useful for remote detection and detection in large areas. Upon degreening circuit induction, changes are rapidly detected (<2hours) and a phenotype readily recognizable by the public results (white plants). Plants regreen upon removal of the inducer, so that the degreening circuit provides the first reset capacity in a reporter gene. Our work provides a system so that changes in large areas such as cities, shopping centers and transportation hubs can be remotely monitored.