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University of Cape Town (2014)

Metabolomics of desiccation tolerance in Xerophyta humilis

Dace, Halford

Titre : Metabolomics of desiccation tolerance in Xerophyta humilis

Auteur : Dace, Halford

Université de soutenance : University of Cape Town.

Grade : Master of Science 2014

Resurrection plants are unique in the ability to survive near complete water loss in vegetative tissues without loss of viability. In order to do so, they employ multifaceted strategies which include structural adaptations, antioxidant and photoprotective mechanisms, and the accumulation of proteins and metabolites that stabilise macromolecules. A full understanding of the phenomenon of vegetative desiccation tolerance will require a systems view of these adaptations at the levels of the genome, the control of gene expression, and the control of metabolic pathways. This dissertation reports a high-throughput metabolomic analysis of the changes that occur in vegetative tissues of resurrection plant Xerophyta humilis during dehydration. A combination of chromatography, mass spectrometry and nuclear magnetic resonance revealed numerous primary and secondary metabolites in the plant. Multivariate statistics identified a subset of metabolites that were significantly up- or down-regulated in response to water deficit stress. These metabolites both confirmed existing observations about the metabolic response of X. humilis to drying and revealed compounds not previously known to be associated with this response. Desiccation-associated metabolites were mapped onto known biochemical pathways, to generate hypotheses concerning possible regulatory schemes in the stress response, inviting deeper investigation in future.


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