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Význam rostlinných proteinů z podrodiny ABCB pro transport auxinu
Kubeš, Martin ; Zažímalová, Eva (advisor) ; Hejátko, Jan (referee) ; Reinöhl, Vilém (referee)
Polar auxin transport provides essential directional and positional information for many developmental processes in plants. At the cellular level, it is realized by both passive diffusion and the active transport through the membrane proteins - AUX1/LAXes, PINs and ABCBs. The aim of this thesis was to characterize the role of ABCB1, ABCB4 and ABCB19 proteins in polar auxin transport using transformed tobacco BY-2 cell lines. It was shown that the plasma membrane (PM) localization of the ABCB1, 4 and 19 is not polar. The ABCB4 was also more stable on PM after the treatment with auxin influx inhibitors; making use of ABCB4-cell line helped to uncover new characteristics of markers of endocytosis - the FM- dyes. The induction of ABCB19 has led to a decrease in 3 H-NAA accumulation with characteristic auxin starvation phenotype, similar to PIN7 overexpressing cell line, that could be rescued in case of PIN7 cell line by application of the auxin efflux inhibitor NPA; however, the accumulation of auxin in ABCB19-overexpressing cell line was less sensitive to NPA and the rescue of the auxin starvation phenotype was ineffective. Importantly, unique property of the ABCB4 was demonstrated: It displayed dual, auxin-concentration-dependent auxin transport activity in Arabidopsis roots, tobacco BY-2 and yeast cells. The...
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Rodina auxinových přenašečů PIN: funkční a evoluční pohled
Skůpa, Petr ; Zažímalová, Eva (advisor) ; Hejátko, Jan (referee) ; Opatrný, Zdeněk (referee)
Growth and development of plant body is dependent on correct and effective integration of information about current deployment of its body parts, as well as on perception and transduction of inputs from environment. Multiple developmental processes within plant body are determined by specific and tightly controlled distribution of molecule with unique signaling mission within plant development - auxin. Spatial distribution of auxin is co-determined by plethora of tightly controlled processes, and the polar auxin transport plays unique role among them. PIN proteins are the plant-specific family of secondary transporters driving movement of auxin across membranes. With their frequent asymmetrical localization within cells, specific expression patterns in developing tissues and their reactiveness to external cues they secure unique, dynamic and asymmetric distribution of auxin within the plant body. This dissertation thesis is focused on characterization of the role different PIN proteins play in determining cellular auxin homeostasis and consequent formation of auxin gradients. Controlled overexpression of PIN proteins in tobacco cells showed, that PIN4 and to some extent also PIN6, function as the direct auxin efflux carriers. In the cellular auxin transport they play the role analogous to other...
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Rodina auxinových přenašečů PIN: funkční a evoluční pohled
Skůpa, Petr ; Zažímalová, Eva (advisor) ; Hejátko, Jan (referee) ; Opatrný, Zdeněk (referee)
Growth and development of plant body is dependent on correct and effective integration of information about current deployment of its body parts, as well as on perception and transduction of inputs from environment. Multiple developmental processes within plant body are determined by specific and tightly controlled distribution of molecule with unique signaling mission within plant development - auxin. Spatial distribution of auxin is co-determined by plethora of tightly controlled processes, and the polar auxin transport plays unique role among them. PIN proteins are the plant-specific family of secondary transporters driving movement of auxin across membranes. With their frequent asymmetrical localization within cells, specific expression patterns in developing tissues and their reactiveness to external cues they secure unique, dynamic and asymmetric distribution of auxin within the plant body. This dissertation thesis is focused on characterization of the role different PIN proteins play in determining cellular auxin homeostasis and consequent formation of auxin gradients. Controlled overexpression of PIN proteins in tobacco cells showed, that PIN4 and to some extent also PIN6, function as the direct auxin efflux carriers. In the cellular auxin transport they play the role analogous to other...
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Význam rostlinných proteinů z podrodiny ABCB pro transport auxinu
Kubeš, Martin ; Zažímalová, Eva (advisor) ; Hejátko, Jan (referee) ; Reinöhl, Vilém (referee)
Polar auxin transport provides essential directional and positional information for many developmental processes in plants. At the cellular level, it is realized by both passive diffusion and the active transport through the membrane proteins - AUX1/LAXes, PINs and ABCBs. The aim of this thesis was to characterize the role of ABCB1, ABCB4 and ABCB19 proteins in polar auxin transport using transformed tobacco BY-2 cell lines. It was shown that the plasma membrane (PM) localization of the ABCB1, 4 and 19 is not polar. The ABCB4 was also more stable on PM after the treatment with auxin influx inhibitors; making use of ABCB4-cell line helped to uncover new characteristics of markers of endocytosis - the FM- dyes. The induction of ABCB19 has led to a decrease in 3 H-NAA accumulation with characteristic auxin starvation phenotype, similar to PIN7 overexpressing cell line, that could be rescued in case of PIN7 cell line by application of the auxin efflux inhibitor NPA; however, the accumulation of auxin in ABCB19-overexpressing cell line was less sensitive to NPA and the rescue of the auxin starvation phenotype was ineffective. Importantly, unique property of the ABCB4 was demonstrated: It displayed dual, auxin-concentration-dependent auxin transport activity in Arabidopsis roots, tobacco BY-2 and yeast cells. The...
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Auxin Transport in Arabidopsis thaliana: From the whole plant to suspension cultured cells
Seifertová, Daniela ; Zažímalová, Eva (advisor) ; Opatrný, Zdeněk (referee) ; Hejátko, Jan (referee)
in English Plants with their sessile life-style are exposed to many stimuli from environment. They have developed mechanisms how to coordinate their growth and development, which allows them to survive sometimes in very difficult conditions. Plant hormones are one of the most important regulators of this signal transduction. Auxins, as the oldest known group of plant hormones, play important role in many physiological processes in plants. To allow perceiving the information in every single cell, auxin molecule is transported by cell-to-cell manner. Auxin molecules enter the cell by passive diffusion or by active uptake by auxin influx carriers. To reach the next cell, they are transported actively out of the cell by auxin efflux carriers. Athough active auxin transport has been studied for almost four decades, past two decades contributed to the identification and characterization of particular auxin carriers remarkably. This thesis contributes to the knowledge on the auxin efflux and influx carriers and their involvement in the processes occurring from a single cell level to the level of a whole plant. Firstly, it brings detailed description of auxin transport characteristics in Arabidopsis thaliana cell suspension cells (Ath cells). Secondly, it shows that the overproduction of PIN1 auxin efflux...
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