Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/19/2004
Publication Date: 7/24/2004
Citation: Klein, M., Kochian, L.V. 2004. In planta characterization of zinc tolerance genes from thlaspi caerulescens. American Society of Plant Biologists Annual Meeting. p. 98. Interpretive Summary:
Technical Abstract: We are studying the zinc tolerance mechanisms used by Thlaspi caerulescens, a heavy metal hyperaccumulating plant species that accumulates up to 30,000 ppm zinc in the above ground biomass without exhibiting toxicity symptoms. Previous work has shown that altered regulation of micronutrient uptake, transport and sequestration plays a key role in the hyperaccumulation phenotype. This makes T. caerulescens an excellent model system to study mechanisms of micronutrient homeostasis and extreme metal tolerance. Additionally, as a member of the Brassicaceae, the rich genomic resources of Arabidopsis thaliana are readily accessible for comparative studies. While previous research has shown increased uptake and transport of zinc from the roots to foliar tissue in T. caerulescens relative to non-accumulating species, the mechanism of sequestration and tolerance of these elevated metal concentrations within the plant are still under investigation. We are examining the molecular basis for zinc tolerance in T. caerulescens through a functional complementation screen in yeast. From the genes identified in the screen, we have narrowed our focus to four putative zinc tolerance genes including a 14-3-3 protein, a putative protein kinase, a vesicle related protein and a putative DNA binding protein. Overexpression and T-DNA knockout lines of the closest Arabidopsis homologs in Arabidopsis were screened for their ability to affect zinc tolerance relative to wild type plants. This research is supported by NSF Integrative Plant Biology Grant #IBN-0129844.