Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Poster: Brassicas, Arabidopsis
            

TRANSCRIPTOME RESPONSES IN ARABIDOPSIS THALIANA ROOTS EXPOSED TO TNT DETECTED USING SAGE

¹ Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA

² Daniel B. Warnell School of Forest Resources, University of Georgia, Athens, GA 30602, USA

³ National Exposure Research Laboratory, Ecosystems Research Division, U.S. Environmental Protection Agency, Athens, GA 30605, USA

Serial Analysis of Gene Expression (SAGE) was used to identify Arabidopsis thaliana. genes that respond to trinitrotoluene (TNT) exposure. Knowledge of the genes and pathways involved in resistance and/or degradation of TNT by plants should help increase the success of future phytoremediation strategies directed at TNT and other xenobiotics. Using A. thaliana root tissue grown in sterile liquid medium, two SAGE libraries (TNT-exposed and control) were constructed. Sequencing of the TNT-exposure library to a level of 32,203 tags identified 12,005 unique tags of which 162 appeared more than 20 times. While similar numbers were seen in the control library, 60% of the unique tags (7,635 out of 12,719) were not seen in the TNT-exposure library, indicating that specific changes in transcription had occurred. The tag most highly induced by TNT (27-fold greater than in control tissues) represented a glutathione S-transferase transcript. In addition, a large number of cytochrome P450 transcripts and an ABC transporter transcript were strongly induced in the root tissues treated with TNT. This evidence strongly supports the multiphase-phase model of xenobiotic metabolism that has been proposed for plants (1-3). These analyses also revealed an oxidative stress response as indicated by the induction of monodehydroascorbate reductase, dehydroascorbate reductase, and L-ascorbate peroxidase transcripts. This work marks the first SAGE study completed in Arabidopsis. This work was supported by a USEPA NNEMS Graduate Fellowship to D.R.E.