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Use of biochemical methods in the study of plant metabolism with emphasis on the defense system
Bělonožníková, Kateřina ; Ryšlavá, Helena (advisor) ; Luhová, Lenka (referee) ; Plchová, Helena (referee)
As sessile organisms, plants cannot avoid being exposed to various biotic and abiotic stress factors. To defend themselves plants have developed complex and sophisticated defense mechanisms. In agriculture, pesticides are used for plant protection, but they can have undesirable side effects, and therefore attention is being paid to biological control agents. One such agent is Pythium oligandrum, a soil oomycete that has a positive effect on plants at several levels. On the one hand, it secretes elicitins, which stimulate defensive responses and prepare the plant for possible infection (i.e., priming effect), and on the other hand, it produces tryptamine, a precursor of auxin, thus supporting the plant's growth. Furthermore, P. oligandrum directly acts as pathogen mycoparasite or evokes antibiosis, or competition for nutrients and space with other microorganisms. The key research topic of this thesis was the analysis of the biochemical properties of eleven Pythium strains and their impact on plant metabolism. Our results showed that even closely related P. oligandrum strains significantly differ in the content of compounds secreted into the medium, including proteins, amino acids, tryptamine, and hydrolytic enzymes capable of degrading cell walls (endo-β-1,3-glucanase, chitinase, and cellulase),...
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Use of biochemical methods in the study of plant metabolism with emphasis on the defense system
Bělonožníková, Kateřina
As sessile organisms, plants cannot avoid being exposed to various biotic and abiotic stress factors. To defend themselves plants have developed complex and sophisticated defense mechanisms. In agriculture, pesticides are used for plant protection, but they can have undesirable side effects, and therefore attention is being paid to biological control agents. One such agent is Pythium oligandrum, a soil oomycete that has a positive effect on plants at several levels. On the one hand, it secretes elicitins, which stimulate defensive responses and prepare the plant for possible infection (i.e., priming effect), and on the other hand, it produces tryptamine, a precursor of auxin, thus supporting the plant's growth. Furthermore, P. oligandrum directly acts as pathogen mycoparasite or evokes antibiosis, or competition for nutrients and space with other microorganisms. The key research topic of this thesis was the analysis of the biochemical properties of eleven Pythium strains and their impact on plant metabolism. Our results showed that even closely related P. oligandrum strains significantly differ in the content of compounds secreted into the medium, including proteins, amino acids, tryptamine, and hydrolytic enzymes capable of degrading cell walls (endo-β-1,3-glucanase, chitinase, and cellulase),...
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The effect of rape seed treatment with oomycete Pythium oligandrum on plant metabolism
Vaverová, Kateřina ; Ryšlavá, Helena (advisor) ; Müller, Karel (referee)
Lot of attention is paid to biological control agents of plant pathogens as it will reduce the amount of pesticides used in agriculture. Pythium oligandrum oomycete is already used commercially in the form of watering and spraying. In this work the properties of other isolates were characterized, and the metabolic changes were studied in plants of oilseed rape (Brassica napus subsp. Oleifera), whose seeds were treated with preparates based on Pythium oligandrum. In the first part of the thesis the properties of compounds secreted by isolates of Pythium oligandrum were tested. The amount of phenolic substances and the activity of endoglycosidase endo-β-1,3-glucanase, cellulase, chitinase as well as proteases were measured to assess the ability of oomycete Pythium oligandrum mycoparasitically protect the plant. Substances, especially oligandrin, which during interaction with the plant are responsible for "priming", have been observed, enabling the plant to respond rapidly to pathogen infection through systemic plant resistance. Differences between individual isolates also manifested themselves in electrophoretic separation in the protein representation. In the second part of the work, the effect of rapeseed seed treatment with isolates of Pythium oligandrum on plant metabolism was monitored. While...
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