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The role of trehalose in mycorrhizal associations
Šoch, Jan ; Ponert, Jan (advisor) ; Hála, Michal (referee)
Mycorrhizal symbiosis is a widely spread phenomenon in nature. A translocation of nutrients occurs between symbionts with disaccharide trehalose playing a key role in the process. However, this saccharide fulfils many important roles in metabolism of fungi and plants. Fungi use trehalose mainly as storage and transport saccharide. On the other hand, trehalose occurs in extremely low amounts in plants where it acts as a signal molecule. Thus it is likely that the saccharide could be used by the fungus to manipulate plant metabolism on a physical interface between symbionts. Trehalose has a similar function in many parasitic interactions. In most cases of mycorrhizal associations trehalose synthesis creates a carbon sink in mycelium which leads to saccharide transfer from the host plant to the fungus. Completely different situation occurs in the types of mycorrhizal symbiosis, where saccharides are translocated from a fungus to a plant. Some plants can utilize trehalose effectively as a sole source of energy. Consequently, the question raises - could such plants gain fungal trehalose on purpose as a source of energy and carbon? This review aims to assess and discuss the mentioned possibilities considering available literature. Key words: mycorrhiza, orchids, parazitism, saccharides, sink, symbiosis,...
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Utilization of trehalose in orchids: evolution of trehalase genes
Šoch, Jan ; Ponert, Jan (advisor) ; Hála, Michal (referee)
All orchid species studied so far have been shown to participate in orchideoid mycorrhizal symbiosis. Morover, this symbiosis is absolutely vital component of their life cycle. Exchange of nutrients occurs between symbionts where the fungi provides the orchid with energy and carbon supply at least in its early developmental stages. This study focuses on the possible role of trehalose in this transfer. In vitro experiments have showed in five species from three different subfamilies of Orchidaceae family that they can utilize trehalose comparably with sucrose and glucose. Thus, the ability of trehalose utilization seems to be conserved among orchids. Trehalase enzyme activity was localized histochemically in orchid mycorrhizas. The activity strongly colocalized with colonized tissue supporting a hypothesis that trehalose transfer occurs in this site and is mediated by trehalase. Using bioinformatic methods, trehalase gene duplications were identified in many taxons of Embryophyta including three orchid species. Interestingly, highest number of trehalase gene copies was identified in genome of orchid Dactylorhiza majalis. Trehalose utilization, high trehalase activity in mycorrhizas and trehalase gene duplications in some orchids together indicate that trehalose transfer in orchid myccorhizas...
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The role of trehalose in mycorrhizal associations
Šoch, Jan ; Ponert, Jan (advisor) ; Hála, Michal (referee)
Mycorrhizal symbiosis is a widely spread phenomenon in nature. A translocation of nutrients occurs between symbionts with disaccharide trehalose playing a key role in the process. However, this saccharide fulfils many important roles in metabolism of fungi and plants. Fungi use trehalose mainly as storage and transport saccharide. On the other hand, trehalose occurs in extremely low amounts in plants where it acts as a signal molecule. Thus it is likely that the saccharide could be used by the fungus to manipulate plant metabolism on a physical interface between symbionts. Trehalose has a similar function in many parasitic interactions. In most cases of mycorrhizal associations trehalose synthesis creates a carbon sink in mycelium which leads to saccharide transfer from the host plant to the fungus. Completely different situation occurs in the types of mycorrhizal symbiosis, where saccharides are translocated from a fungus to a plant. Some plants can utilize trehalose effectively as a sole source of energy. Consequently, the question raises - could such plants gain fungal trehalose on purpose as a source of energy and carbon? This review aims to assess and discuss the mentioned possibilities considering available literature. Key words: mycorrhiza, orchids, parazitism, saccharides, sink, symbiosis,...
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