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Gewählte Doctoral Thesis:

Doctoral Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 172. UB BOKU obvsg

Data Source: ZID Abstracts
Heavy metals are the most abundant soil contaminants. Phytoextraction consists in the use of metal accumulating plants to remove metals from contaminated soils. This slow process can be improved by using bacterial inoculants. Microbacteriaceae species have often been associated to heavy metal contaminated environments and to the phenomenon of metal mobilization. The main goals of this thesis consisted in the phylogenetic, functional and comparative genomic analysis of selected Microbacteriaceae to determine their taxonomic position and to identify secondary metabolite gene clusters possibly involved in metal mobilization and genes related to metal homeostasis. The first part of this work was focused on the characterization as a new species of an isolate belonging to the Agromyces genus. Its genome was subjected to whole genome sequencing resulting in the complete genomic sequence which was used for genomic comparison with related organisms. In the second part of this study, Microbacterium spp. from heavy metal contaminated and non-contaminated sites were selected for phylogenetic analysis and genome-mining for the identification of secondary metabolite gene clusters. The genome-mining analysis of the Agromyces strain and the different Microbacterium spp. revealed the presence of a wide range of secondary metabolite gene clusters: terpenoids, type III polyketide synthases, non-ribosomal peptide synthetases, desferrioxamines, resorcinol, bacteriocins, ectoine, butyrolactone and ribosomally synthesized post-translationally modified peptides. These clusters showed only moderate homology to the ones present in related organisms. In vitro tests confirmed the ability of the analyzed Microbacteriaceae spp. to survive in the presence of metals and to increase their mobility through the secretion of specific metabolites. However, the inoculation of B. napus and N. caerulescens plants with selected strains caused only a slight increase of the iron concentrations in the shoots

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