Poster: Heavy metals & phytoremediation

Abs # 55: Studies of TNT toxicity to plants using Arabidopsis as a model system

Presenter:	Moon, Hangsik , hmoon00@iastate.edu
Authors	Moon, Hangsik  (A)   Xiang, Chengbin  (A)   Murali, Subramanian  (B)   Sarah, Rollo  (B)   Jacqueline, Shanks V. (B)   David, Oliver J. (A)
Affiliations:	(A): Iowa State University, Department of Genetics, Development and Cell Biology (B): Department of Chemical Engineering

Energetic materials such as TNT and RDX are significant sources of groundwater and surface soil contamination at the sites of manufacturing, training, and testing. TNT, the most widely studied of all energetic materials, can be transformed to non-toxic forms by a variety of plant species and the basic transformation processes are known. However, no plant genes or enzymes have been identified that are involved in the detoxification of TNT. To understand the mechanisms of TNT toxicity to plants, we used a reverse genetics approach using Arabidopsis as a model system. Activation-tagged Arabidopsis mutant lines were generated by transforming with the binary vector pSKI015 which harbors BAR gene for selection and 4X CaMV 35S enhancers in its T-DNA segment. To isolate mutants that are resistant to TNT, approximately 300,000 mutant seeds were plated on half-strength MS medium containing TNT and 10 mutant lines showed germination rates significantly better than wild-type. When cultured in a liquid medium containing TNT, some of the mutants showed rates of TNT disappearance from the medium faster than the wild-type did. TAIL-PCR was performed to identify the genomic sequences flanking the T-DNA insertions from the mutant lines. The number of insertions identified by the TAIL-PCR differed among the mutants ranging from one to three. Further molecular and genetic analyses of those flanking sequences will result in identification of the genes that are responsible for detoxification of TNT.