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Patterns of Arabidopsis Gene Expression in Response to Ethylene and UV Radiation.  V. Lapin1, A.L. Paul2 and R.J. Ferl2 1University of Toronto, Trinity College, ON, Canada. 2University of Florida, Gainesville, FL.  Any future in prolonged human space travel will require a source of renewable food resources.  Plants have been shown to withstand various environmental stresses associated with spaceflight.  In this study Arabidopsis thaliana was used to examine the effects of select stresses related to spaceflight and possible planetary scenarios. Twelve day old plants were exposed to ethylene and to simulated Mars ground level UV radiation. Transgenic Arabidopsis engineered with GFP reporters driven by promoters from ChiB, FAD7, NR1 or GSH2 were used to evaluate tissue specific transgene expression with fluorescent microscopy. In addition, native gene expression was evaluated with quantitative RT-PCR (Taqman).  Two transcription factors (G-box factor 3--GBF3 and homeobox-leucine zipper protein--AthB12) and three genes associated with stress metabolism (ACC synthase, putative peroxidase--PPrx and cyclin-dependent protein kinase--Cdc2b) were evaluated. Ethylene stress resulted in the induction of the ChiB/GFP transgene, and exposing plants to simulated Martian surface UV showed pronounced GSH2/GFP expression in shoots and leaves with minor induction in roots.  In addition, UV treated plants were chosen for quantitative analysis and showed increased ACC synthase induction. This research was supported by the Spaceflight and Life Sciences Training Program (SLSTP).