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Study of the interaction of proteins involved in the exocytosis in the plant defense against pathogens
Ortmannová, Jitka ; Pečenková, Tamara (advisor) ; Burketová, Lenka (referee)
Plant cells are mostly immobile, therefore it is crucial for them to distinguish a direction of the signals coming into the cell and on the other hand they have to precisely target their own signals. To achieve this communication, plant cells use endomembrane system and secretory vesicles, which are recruited to the specific membrane domains. This ability is important for the plant defense against pathogenic microorganisms and it even forms a part of the innate plant immunity. Two complexes, the exocyst and SNARE, play a prominent role in the process of polarized secretion. In this work, we focused on a possible interaction between these two complexes in preinvasive defense and particularly, we studied the exocyst subunit EXO70B2 and SNARE protein SYP121. We obtained double mutant plants of EXO70B2 and SYP121 by utilizing the reverse genetics approach. These mutant plants did not show any obvious phenotype under standard conditions in comparison with Wt plants. However, we observed marked defects of secretory pathway in double mutant exo70B2/syp121 after infection by pathogenic fungi Blumeria graminis f. sp. hordei. Using histochemical staining, we described problems with the deposition of defensive papilla and secretion of haustorial encasement. We prove that these defects are not connected with...
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Role of the exocyst complex in stomata dynamics
Drs, Matěj ; Pečenková, Tamara (advisor) ; Fendrych, Matyáš (referee)
The exchange of gases between the plant and the environment is mediated by guard cells, which, by changing their volume, regulate the size of the stomatal pore where the exchange takes place. Unique properties of stomata are given by a specifically designed cell wall, allowing asymmetric cell expansion. During the opening of stomata, there is a large increase in turgor pressure, accompanied by the uptake of considerable amount of water. For this reason, it is necessary to quickly change the inner surface of the guard cell. This process is ensured by the dynamic movement of the membranes inside the cell. During these processes, the vesicles are removed from the plasma membrane and reintegrated back during stomatal closure. One of the important regulators of the polarized transport of vesicles within the cell is a multiprotein complex exocyst. Due to the multiplication of exocyst subunits, the exocyst complex functions in plants are extensively diversified and involved in many cellular processes. In this thesis the effect of mutation in subunits exo70B1, exo70B2 and its combination exo70B1/exo70B2, on stomatal dynamics is studied. Both of these mutations affect the opening of the stomata during increased light intensity. The mutation of exo70B1 is in this case affected in greater manner. These...
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Study of the interaction of proteins involved in the exocytosis in the plant defense against pathogens
Ortmannová, Jitka ; Pečenková, Tamara (advisor) ; Burketová, Lenka (referee)
Plant cells are mostly immobile, therefore it is crucial for them to distinguish a direction of the signals coming into the cell and on the other hand they have to precisely target their own signals. To achieve this communication, plant cells use endomembrane system and secretory vesicles, which are recruited to the specific membrane domains. This ability is important for the plant defense against pathogenic microorganisms and it even forms a part of the innate plant immunity. Two complexes, the exocyst and SNARE, play a prominent role in the process of polarized secretion. In this work, we focused on a possible interaction between these two complexes in preinvasive defense and particularly, we studied the exocyst subunit EXO70B2 and SNARE protein SYP121. We obtained double mutant plants of EXO70B2 and SYP121 by utilizing the reverse genetics approach. These mutant plants did not show any obvious phenotype under standard conditions in comparison with Wt plants. However, we observed marked defects of secretory pathway in double mutant exo70B2/syp121 after infection by pathogenic fungi Blumeria graminis f. sp. hordei. Using histochemical staining, we described problems with the deposition of defensive papilla and secretion of haustorial encasement. We prove that these defects are not connected with...
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