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Function of the Tetratrico-peptide Thioredoxin-Like (TTL) gene family in root system development
Xin, Pengfei ; Soukup, Aleš (advisor) ; Vaňková, Radomíra (referee) ; Ovečka, Miroslav (referee)
The root system performs fundamental plant functions such as uptake of nutrients and water, anchoring in the substrate, and interacting with the rhizosphere abiotic and biotic interactions, playing an important role in meeting the food security needs of today's world. Lateral roots (LR) are essential components of the plant root system. We have identified the TETRATRICOPEPTIDE-REPEAT THIOREDOXIN- LIKE 3 (TTL3) gene as being related to LR emergence and later development. Loss-of-function of TTL3 results in a reduced number of emerging LRs due to delayed development of lateral root primordia (LRP). In the Arabidopsis TTL gene family, except for TTL2 which was specifically involved in male gametophyte development, the expressions of the other three TTLs (TTL1, TTL3 and TTL4) were all related to root growth and development. The temporal and spatial distribution of TTL3 expression was consistent with its role in LR growth preceding and following LRP emergence. In the subcellular localization of TTL1, TTL2 and TTL3, all were shown to be associated with microtubules during the transient transformation of tobacco leaves, and TTL3 was confirmed to interact with microtubules. TTL3 was also associated with the endomembrane system and was known to be interacting with the brassinosteroid (BR) signaling pathway....
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The role of gene AHL20 in initiation and development of lateral roots.
Svobodová, Barbora ; Soukup, Aleš (advisor) ; Růžička, Kamil (referee)
Members of the AHL (AT-hook motif nuclear-localized) gene family have been found in all sequenced plant land species, hence a link between divergence of AHL genes and colonization of terrestrial environments by plants is assumed. One of the adaptations of plants to the terrestrial environment was the development of a root system. Currently there is only a few information about the possible function of AHL genes in root system establishment and development. A typical characteristic of AHL genes is the presence of an AT-hook motif and a highly conserved PPC domain. Many studies have confirmed the involvement of AHL genes in a wide range of plant processes. They are potentially strong regulators of transcription at different levels. They function as transcription factors, interact with other transcription factors through the PPC domain, and are capable of chromatin remodeling through histone modifications. We selected candidate genes based on publicly available transcriptomic data: AHL18, AHL19, AHL20, AHL21, AHL22, AHL23, AHL27, and AHL28 with predicted function in root formation and development. The first aim of this thesis was to investigate possible involvement of AHL genes in lateral root development. For AHL19, AHL20, AHL21, AHL23, AHL27, and AHL28, we examined transcription rates at the root...
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Experimental cultivation systems in root system research
Střelec, Petr ; Soukup, Aleš (advisor) ; Lhotáková, Zuzana (referee)
The growing awareness of plant root importance has contributed to the continuous development of cultivation methods that facilitate more efficient and effective root research. Due to their sessile nature, plants rely extensively on roots for water and ion absorption (Meister et al., 2014). As a result, plant roots must adjust to an array of unfavorable conditions such as salinity, drought, and high temperatures. To better understand root response and promote agricultural development, researchers simulate various stressors in controlled conditions. More recently developed transparent soils and soilless cultures aim to overcome the limitations of traditional soil cultivation, which include imprecise variable control, heterogeneous conditions, and destructive root sampling (Gregory et al., 2009). When planning an experiment, it is crucial to select an appropriate cultivation method to ensure success. The aim of this thesis is to provide a comprehensive overview of the benefits and limitations of commonly used cultivations techniques in plant stress research. Transparent soil reliably mimics the mechanical properties of soil whilst allowing for easy root access and use of numerous visualization techniques. On the other hand, it still maintains the need for a larger cultivation area just like soil. The...
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Adaptations of orchid roots to epiphytism
Ungrová, Anna ; Ponert, Jan (advisor) ; Soukup, Aleš (referee)
The evolutionary success of orchids is to a large extent driven by the ability to colonize epiphytic habitats. This ability is based on a number of adaptations at different levels, and the adaptive features of aerial roots can play a key role because the roots are practically the only organ providing water and nutrient uptake. The main aim of this work is to review available information about roots of epiphytic orchids (Orchidaceae), especially their adaptations to the epiphytic way of life. The roots of epiphytes must deal with a periodic lack of water and nutrients, often in conjunction with high irradiation. The roots of epiphytic orchids adapt to these conditions on many levels. Rhizodermis forms a velamen capable to retain water and nutrients and protecting roots against environmental conditions including UV radiation. Root cortex contains chloroplasts, which can perform photosynthesis at least in some orchid species. Exodermis is well differentiated with thick secondary cell walls and acts as a selective barrier for the transport of substances with the use of passage and aeration cells. The function of some adaptive structures is still unclear, for example, tilosomes could regulate transpiration. Epiphytism evolved multiple times in orchids, and some root adaptations therefore originated...
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Closer analysis of gene trap line MGT180 and its candidate genes
Šnajdrová, Tereza ; Soukup, Aleš (advisor) ; Klíma, Petr (referee)
Root branching allows plants to explore rhizosphere, to gain efficiently water, mineral nutrients or enter in various biotic interactions. Initiation of lateral root formation is localized to pericycle cells, flanking the xylem poles of diarch vascular bundle in Arabidopsis thaliana. Right in these pericycle cells, there is the expression pattern of the gene trap line MGT180. In this theseis , I have provided the evidence that the expression pattern of MGT180 is related with AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED18 (AHL18; At3g60870). AHL18 belongs to a gene family of 29 transcriptional factors of Arabidopsis. AHL18 has not been functionally characterized yet, the analysis of singlemutant ahl18 and some others revealed no significant phenotype. However, one of doublemutants, E15, showed a significant phenotype. This phenotype was evident mainly in the aboveground part of plants, and was not corresponding to any phenotype of AHL mutation described so far. There is a known redundancy among some AHL genes, confirmed by crossing of ahl18 and ahl28 leading to E15 plant. Translation phusion AHL18-mRUBY and AHL22-mRUBY under native promotors should reveal, where these two related proteins act, and if they fiction in autonomous manner or not. Key words Arabidopsis thaliana, lateral root, AHL, pericycle
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Stress induced morphogenic response in plant root system
Otradovcová, Michala ; Soukup, Aleš (advisor) ; Vaňková, Radomíra (referee)
The root system architecture adjustment is one of the possible plant reactions to stress effects of environmental conditions. The shape of root system is jointly formed by the root apical meristem activity, the rate of elongation of root cells and by the degree of formation, developement and organization of secondary and adventitious roots. This paper aims to describe basic mechanisms of the root system developement and outline the morphological and regulatory changes occuring during development while being affected by selected stress factors.
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Lateral root and their origin
Nováková, Hana ; Soukup, Aleš (advisor) ; Sekereš, Juraj (referee)
The origin of lateral roots is one of the determinants of the structure of the overall architecture of the root system of plants. Individual plant species differs in point of initiation of lateral roots in the longitudinal and transverse plane of the parent root. This paper briefly summarizes the findings relating to the establishment and development of lateral roots in the model of plant Arabidopsis thaliana and on the sample of several species of ferns and monocots and dicots of literature outlines the variability that manifests itself especially during initiation of lateral roots. The ferns initiation site located in the endodermis of the parent root, for other species to form the lateral root primordium of pericycle cells that are found in a certain position in relation to vascular elements in the central cylinder of the parent root. Another highly variable factor in the development of lateral root initiation site is the distance from the root apical meristem, which is related to the place of the auxin signal competent cells and also the rate of growth and progress of cells from the parent root apical meristem. Powered by TCPDF (www.tcpdf.org)
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Mechanisms of epidermal cells polarization in plants.
Vojtíková, Zdeňka ; Žárský, Viktor (advisor) ; Soukup, Aleš (referee)
Plant epidermal cells form contact area of the plant, they protect it from impacts of surrounding environment and they mediate the communication with its neighbourhood. In the epidermis there are evenly distributed several cell types with quite specialized morphology (pavement cells, trichomes and guard cells) due to the polarization mechanisms. The cytoskeleton and signal molecules of ROP GTPase family promote the polarized growth. Thanks to polarized growth the cells reach their shapes. The cytoskeleton responds to the signal by expanding the cell, helps with targeting of the secretion to the sites of active growth and mediates polarized formation of the cell wall. On the upper side of the epidermis the cuticle and layer of epicuticular waxex is secreted. The secretion of cuticular components is baso-apicaly polarized. This work summarizes the mechanisms of the polarization in plant epidermal cells discoverd untill now.
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