Theses and Dissertations - UTB/UTPA
SfMTP1 and SpMTP1 Cloning and Expression in Saccharomyces Cerevisiae: Potential for The Genetic Engineering of Arabidopsis Thaliana
Date of Award
Master of Science (MS)
Dr. Michael Persans
Dr. Matthew Terry
Dr. Frank Dirrigl
To evaluate metal tolerance conferred by the overexpression of Metal Tolerance Protein 1 (MTP1) in transgenic non-accumulator plants such as Arabidopsis thaliana, a model system was developed in Saccharomyces cerevisiae containing either SfMTP1 cDNA, from the metal tolerant plant Streptanthus farnsworthianus, or SpMTP1 cDNA, from the hyperaccumulator Streptanthus polygaloides. Nonquantitative RT-PCR showed constitutive expression of MTP1 in both plant species. Alignment of SfMTP1 and SpMTP1 protein sequences shows a gap in SpMTP1 in a variable histidine region known to affect metal transport. Disk assays revealed SfMTP1 cDNA imparted greater Ni tolerance to yeast than SpMTP1 cDNA; however, SpMTP1 showed higher Cd tolerance than SfMTP1. No significant difference was found with Co; but both cDNAs made yeast slightly more Zn sensitive. MTP1 histidine-rich regions control metal transport mechanisms, but differences in these regions may be responsible for higher tolerance of specific metals between different Streptanthus species.
University of Texas-Pan American
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