|
|
Regulation of phosphate uptake by strigolactones
Balín, Michal ; Vaňková, Radomíra (advisor) ; Tylová, Edita (referee)
This Bachelor thesis is focused on the reactions of plants to low levels of available phosphorus, which is essential element for plant nutrition. In the context of plant stress, plant hormones strigolactones play very important role. Strigolactones influence growth and development of the whole plant. Biosynthesis of strigolactones increases under phosphate deficiency. This thesis consists of three parts. The first part is concentrated on phosphorus, its compounds and its availability in the environment. The second part is mainly dedicated to phosphate stress - its sensing by plants, their adaptations to stress and local as well as long distance signalling. Attention is also paid to phytohormones, namely auxins, cytokinins, gibberellins, ethylene, abscisic acid and other signal molecules, like sucrose, the phosphate molecule itself and microRNAs. The third part is focused mainly on the structure, biosynthesis, signal transduction and the mode of action of strigolactones during phosphate stress. Keywords: phosphate, deficiency, strigolactone, phytohormones, stress
|
|
|
Searching for mechanisms and functions of microtubular interactions with other plant cell structures
Krtková, Jana ; Schwarzerová, Kateřina (advisor) ; Vaňková, Radomíra (referee) ; Ovečka, Miroslav (referee)
Microtubular cytoskeleton is involved in many processes in plant cells, including cell division, growth and development. Other proteins enable its functions by modulation of its dynamics and organization and by mediation of functional and structural interaction with other cell structures. Identification of the mediating proteins and the functions of these interactions under specific conditions were the main aims of the thesis. Membrane proteins interacting with microtubules were identified using biochemical methods. Surprisingly, the identified proteins co-sedimenting with microtubules were not members of the "classical" microtubule associated proteins (MAPs). There were enzymes, chaperones and plant specific proteins among them. For further studies, the identified microtubule-associated heat-shock protein 90 (Hsp90_MT) was chosen. Recombinant Hsp90_MT binds directly to microtubules and tubulin dimers in vitro. The ATP-binding pocket is not responsible for this association. In BY-2, Hsp90_MT co-localizes with phragmoplast and cortical microtubules and is involved in microtubule recovery after their depolymerization during cold treatment. In plants, Hsp90 is involved in cell cycle progression, its inhibition causes cell-cycle arrest in G1 phase. Based on literature search for animal proteins...
|
|
|
Regulation of cytokinin metabolism in tobacco plants and chloroplasts
Havlová, Marie ; Vaňková, Radomíra (advisor) ; Ryšlavá, Helena (referee) ; Malá, Jana (referee)
Cytokinins (CKs) are one of the most important group of phytohormones influencing many processes throughout the whole plant. As many processes are regulated both by the light and phytohormones, the first part of this work has been focused on evaluation of diurnal rhytmicity in levels of cytokinins and other cooperating hormones like auxin (indol-3-acetic acid, IAA), abscisic acid (ABA) and polyamines (PA). The changes in activity of selected enzymes participating in metabolism of the above mentioned phytohormones were followed as well. Diurnal variation of phytohormones was tested in tobacco leaves (Nicotiana tabacum L. cv. Wisconsin 38) grown under a 16/8 h (light/dark) period. The main peak of the physiologically active forms of CKs, found after the middle of the light period, coincided well with the maximum of IAA and PA levels and with activity of the corresponding enzymes. The achieved data indicate that metabolism of CKs, IAA and PAs is tightly regulated by the circadian clock. The other part of the study has been focused on changes in the contents of CKs, IAA and ABA in transgenic tobacco plants with altered cytokinin metabolism, achieved via the over-expression of particular enzymes participating in CK metabolism (biosynthesis, degradation and reversible conjugation). As CKs are known to be...
|
|
|
Study of cytokinin role in abiotic stress response
Dobrá, Jana ; Vaňková, Radomíra (advisor) ; Ryšlavá, Helena (referee) ; Brzobohatý, Břetislav (referee)
Plants had to evolve, due to their sessile growth habit, a complex system of defence against adverse environmental conditions. Plant abiotic stress responses are regulated by plant hormones, especially by cytokinins (CKs) and abscisic acid (ABA). In order to evaluate the effect of enhanced stress tolerance on the dynamics of hormones (CKs, auxin and ABA) as well as polyamine levels during the drought and/or heat stress (HS) progression, response of tobacco plants with enhanced level of osmolyte proline was compared with the corresponding wild-type. HS (40řC) caused a transient increase in bioactive CK content, accompanied by decrease of ABA, which indicated stimulation of transpiration, important mechanism to cool down the leaf temperature at the early phase of HS. Simultaneously, a transient increase in spermidine and spermine levels was found, more profound in proline-over-producing transformant. The activities of particular polyamine metabolic enzymes correlated well with their content. Drought stress resulted in the establishment of a gradient of bioactive CKs in favour of the upper leaves, crucial for their preferential protection. Application of HS at the end of drought period strongly enhanced the stress severity, mainly due to additional water loss caused by enhanced transpiration....
|
|
|
Isoflavonsynthasa: přítomnost a aktivita v bobovitých a nebobovitých rostlinách
Pičmanová, Martina ; Honys, David (advisor) ; Vaňková, Radomíra (referee)
Isoflavone synthase (IFS; CYP93C) plays a key role in the biosynthesis of the plant secondary metabolites, isoflavonoids. These phenolic compounds, which are well-known for their multiple biological effects, are produced mostly in leguminous plants (family Fabaceae). However, at least 225 of them have also been described in 59 other families, without any knowledge of orthologues to hitherto known IFS genes from legumes (with the single exception of sugar beet - Beta vulgaris, from the family Chenopodiaceae). In view of these facts, this masters thesis has focused on two main objectives: (1) to identify isoflavone synthase genes in selected leguminous and non-leguminous plants exploiting the PCR strategy with degenerate and non-degenerate primers, and (2) to find a system for the verification of the correct function of these genes. Our methodology for the identification of IFS orthologues was successfully demonstrated in the case of two examined legumes - Phaseolus vulgaris L. and Pachyrhizus tuberosus (Lam.) Spreng, in the genomic DNA of which the complete IFS sequences have been newly identified. To design a procedure for ascertaining the correct function of these genes and others once they have been completely described, a pilot study with IFS from Pisum sativum L. (CYP93C18; GenBank number...
|
|
|
Effect of drought on the metabolism of tobacco plants
Miedzińska, Lucia ; Ryšlavá, Helena (advisor) ; Vaňková, Radomíra (referee)
EEffffeecctt ooff ddrroouugghhtt oonn tthhee mmeettaabboolliissmm ooff ttaabbaaccccoo ppllaannttss (Nicotiana tabacum L.) Diploma thesis - abstract Lucia Miedzińska, Bc. Work Supervisor: Doc. RNDr. Helena Ryšlavá, CSc. Consultant: RNDr. Veronika Doubnerová, PhD. Drought stress is one of the most frequent form of plant stress, which occurs not only under condition of limited water availability, but also under reduced ability to accept water by roots, for example in salted or cold soils. In this thesis the changes in enzyme activities of: NADP-malic enzyme (EC 1.1.1.40; NADP-ME), phosphoenolpyruvate carboxylase (EC 4.1.1.31; PEPC) and pyruvate, phosphate dikinase (EC 2.7.9.1; PPDK) in tobacco plants (Nicotiana tabacum L., cv. W38) after drought were investigated. Enzyme activities in tobacco leaves were significantly increased during 11 days of stress, PEPC 2-fold, PPDK 3,3- fold and NADP-ME 4-fold compared to control plants. The regulation of NADP-ME and PEPC activities were studied on transcriptional level - by the real-time PCR method and on translational level - immunochemically. The expression of NADP-ME protein and transcription of mRNA for chloroplast NADP-ME isoform were increased, but mRNA for cytosolic isoform was not affected. The protein expression of PEPC was slightly increased, transcription of...
|
|
|
Production of strawberries in organic system of growing
Pištěková, I. ; Boček, S. ; Vaňková, Radomíra ; Drahošová, H. ; Odstrčilová, L. ; Salaš, P. ; Sasková, H.
A technology of growing strawberries in organic farming systems is presented in the methodology. The methodology is aimed at selecting the most suitable varieties of strawberry, previous crop influence, the influence of supplementary plant products and biofungicides on the yield of single varieties. It contains evaluation of health condition and fruiting characteristics of varieties. Yield potential of varieties and resistance to diseases were found in the most suitable varieties and technological processes for organic cultivation of strawberries were selected. The methodology for practice is a comprehensive guide for growing strawberries in organic production systems.
|
|
|
Evaluation of the possible role of cytokinin O-glucosylation in response of tobacco plants to drought stress
Nováková, Marie ; Dobrev, Petre ; Motyka, Václav ; Gaudinová, Alena ; Malbeck, Jiří ; Pospíšilová, Jana ; Martin, R. C. ; Mok, D. W. S. ; Mok, M. C. ; Vaňková, Radomíra
|
|
| |
|
| |
guest ::
RSS feed.