The movements of heavy metals in plant systems, their uptake, distribution, usage in active centers of enzymes or as structural components, in short the heavy metal homeostasis, is far from being completely understood. New components can be identified by the analysis of heavy metal tolerance since genes and proteins involved in the metal tolerance are often also part of the basal metal uptake, redistribution or storage systems. In this work, such components were to be found by exploiting the natural variation of heavy metal tolerance within the species thale cress (Arabidopsis thaliana). Zinc and Cadmium tolerant ecotypes were compared to less tolerant ones and candidate genes were identified, that could have an impact on the Zn and Cd tolerance. Evidence was collected which shows that the gene At1G23040 might be responsible for the higher Zn tolerance in the ecotype Cvi-0. A third ecotype, the newly discovered Mwg-3, was assessed for a potential adaptation to its natural habitat which features an acidic, highly manganese available soil. An adaptational change is a mutation which becomes fixed in the genotype of a population because it leads to a higher fitness of the individual in the habitat it is occurring in. To investigate the higher manganese tolerance of Mwg-3 molecularly the genome of the ecotype was sequenced. By implementing protocols to identify SNPs linked to the Mn tolerance genomic regions containing candidate genes will soon be identified. With the goal in mind to also study effects of lead on plant growth and physiological processes, a new medium was developed to enable lead treatment of plants. Thus experimental challenges which had prevented reliable investigations into lead-stress on plants could be circumvented. Employing the new medium, the involvement of phytochelatins in the chelation and detoxification of lead ions could be shown for the first time.
|School:||Universitaet Bayreuth (Germany)|
|Source:||DAI-C 81/1(E), Dissertation Abstracts International|
|Subjects:||Plant sciences, Biogeochemistry|
|Keywords:||Heavy metal uptake|
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