National Repository of Grey Literature 61 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Environmental drivers of microbial community composition in a temperate forest
Martinović, Tijana ; Baldrian, Petr (advisor) ; Vašutová, Martina (referee) ; Kopecký, Jan (referee)
Recently, much attention has been focused on the importance of forests to the global carbon cycle. Microorganisms are a critical component of the carbon cycle in forests, participating in important ecosystem processes and degrading various carbon compounds, from simple to highly recalcitrant compounds. However, most studies in this regard have focused on fungi. Only in recent years has it become known that bacteria are also capable of degrading complex plant polymers in soil, and that their contribution to the carbon cycle may be as important as that of fungi. Furthermore, our knowledge of the temporal dynamics of both fungal and bacterial communities is limited, as well as their response to different environmental drivers. The main objective of this dissertation was to fill these knowledge gaps by (1) quantifying the rate of temporal turnover of fungal and bacterial communities in soils of temperate forests, (2) describing the factors that shape fungal communities in spruce and beech stands during their long-term development (stand age), (3) assessing the contribution of fungi and bacteria to the utilisation of different carbon sources in forest soils, and finally (4) describing the development of bacterial communities in response to clearcutting of a spruce stand. The study of microbes...
The use of molecular markers for the study of the impact of global change on fungal communities
Faltysová, Julie ; Baldrian, Petr (advisor) ; Koukol, Ondřej (referee)
Fungi are an essential part of life on Earth. Besides their main role in decomposition of organic matter, they belong among key symbiotic organisms and they take part in providing a range of ecosystem processes important for humankind such as primary production and with that related food availability or soil water regulation. For the study of fungal distribution, we often use a method called DNA metabarcoding which combines the use of specific molecular markers, most commonly universal fungal ITS, and high-throughput sequencing. The importance of the method has been rising in the current time of changing environment and it has helped us observe changes in fungal communities due to global change. It seems that primarily various climatic factors such as warming, changes in rainfall patterns and nitrogen deposition have strongly influenced community and fungal guilds composition. Consequently, these changes may potentially have an impact on ecosystem functioning so that their overall balance can be in threat. Key words: molecular markers, DNA metabarcoding, fungal community, warming, climate change, nitrogen deposition
Fungi associated with tree roots
Charvátová, Markéta ; Baldrian, Petr (advisor) ; Gryndler, Milan (referee)
In contrast to the bulk soil environment, plant roots represent a habitat with higher nutrient availability due to the supply of photosynthesis-derived C-containing compounds. The roots thus support the life of various microorganisms that use such compounds, but the root-associated microbes in the same time may face a limitation in N and P availability. Unlike bacteria, many filamentous fungi are able to transport these compounds from soil and their mycelia thus typically extend into this environment. Ectomycorrhizal fungi are a typical example of this nutrition strategy. Tree roots produce exudates, that differ in thein composition for each species and they can also differ among individuals. It causes a high diversity of root-associated fungi. Soil is also inhabited by parasitic and saprotrophic fungi. Composition and activity of microbial communisies in the rhizosphere differ from the bulk soil. This work points at the differences of the rhizosphere and builk soil, the importance mycorrhizal fungi and it presents an overview of fungal species that have been found on the roots of spruce - Picea abies. Key words: fungi, mycorrhiza, soil, rhizosphere, Picea abies
Ecology of yeasts in forest soils
Mašínová, Tereza ; Baldrian, Petr (advisor) ; Marečková, Markéta (referee) ; Kolařík, Miroslav (referee)
Microbial communities inhabiting upper soil horizons represent an important component of forest ecosystems. However, despite the evidence that yeasts represent an integral part of topsoil fungal communities, their role in forest ecosystems received so far little attention. The aims of my PhD thesis were to describe yeast communities in soil and litter of a temperate forest using high- throughput sequencing of environmental DNA, identify dominant yeast species and to explore how the composition of yeast communities reflects the biotic and abiotic factors of the environment. I also aimed to isolate yeasts from forest topsoil, describe novel yeast taxa abundant according to the environmental DNA survey and screen representative isolates for the traits relevant to their involvement in organic matter transformation. I have demonstrated that in forest topsoil, yeasts represent a substantial proportion of fungal communities with higher relative abundance in soil than in litter. In litter, yeast communities differ significantly among beech, oak and spruce-dominated stands. Drivers of community assembly are probably more complex in soils and comprise the effects of soil chemistry and vegetation. Even though there are similarities in the response of the communities of yeasts and filamentous fungi to...
Molecular biology and ecology of microbial decomposition of plant-derived biopolymers in forest ecosystems
Žifčáková, Lucia ; Baldrian, Petr (advisor) ; Uhlík, Ondřej (referee) ; Bárta, Jiří (referee)
The abilities of fungi and bacteria to degrade simple and complex carbon compounds derived from different sources, such as root exudates, litter, soil organic matter or fungal mycelium were studied in this dissertation. Knowledge of functional traits, especially degradation abilities of fungi and bacteria, are important for deciphering the black box of microbial functioning in topsoil and thus aiding in modeling and predicting future directions of microbial communities development in face of global changes. Among fungal cultures form culture collection representing strains with different taxonomy and ecophysiology, the ecophysiology of fungi was more important in manifestation of functional traits than taxonomy. Among bacterial isolates from the litter and soil of spruce forest, Acidobacteria were confirmed to express multiple decomposition enzymes in high rates in vitro and were also abundant and active degraders in acidic spruce forest soil. The expression of degradation capacities of both bacteria and fungi were further studied in situ in spruce forest topsoil, that represents an important environment due to the ubiquity of coniferous forests on the Northern hemisphere. There is an obvious gap of knowledge, when comes to our understanding of seasonal effect on microbial functioning, and this is...
Cellulolytic fungi and their diversity on plant litter
Gálová, Diana ; Baldrian, Petr (advisor) ; Kolařík, Miroslav (referee)
Litter decomposition requires the presence of corresponding degradative enzymes, produced mainly by fungi. Forest soils show considerable spatial heterogeneity of distribution of these enzymes at diferent scales. Moreover, enzyme pruduction varies during the year, usually accompanied by the change in fungal community composition. In this work I examined if this spatial heterogeneity can be seen even at a scale of an individual leaf and whether the fungal community differs among enzyme activity hotspots and inactive parts of the leaves. Another goal was isolation of celulytic fungi from cellulose litterbags incubated on forest floor using particle filtration and dilution-to-extinction method. In a broadleaved forest dominated by oak leaves at different stages of decay were collected: senescent leaves on twigs, and leaves after 2, 10 and 22 months of decomposition. Ten leaves per season were taken for analysis of cellobiohydrolase activity over the leaf surface. Leaves were attachmed onto melted agarose plate and leaf surface was covered with low melting point agarose containing fluorescently labelled substrate. For each leaf a map of enzyme activity was created and area with the high and low enzyme activity was identified. From both sites a square of approx. 1 cm2 was cut out, DNA was extracted and fungal...
Ecophysiology of microscopic fungus Pseudogymnoascus destructans
Homutová, Karolína ; Kubátová, Alena (advisor) ; Baldrian, Petr (referee)
A microscopic fungus Pseudogymnoascus destructans (Ascomycota: Pseudeurotiaceae) causes illness known as white-nose syndrome (WNS) causing death of bats during hibernation. The illness occurs in the North America and in Europe. The fungus is characteristic by asymmetrically curved conidia, by slow growth and growth at low temperatures (below 20 řC). The aim of this study is to clarify properties responsible for unique ecelogy of Pseudogymnoascus destructans by comparison with ecological related or unrelated pathogenic or nonpathogenic fungi. This part includes study of tolerance to physiological stresses and recognition of spectrum of utilizating nutrients (compounds of carbon, nitrogen, phosphorus, sulphur and nutrient supplements). Testing to physiological stresses should help to estimate a potentiality of fungus to spread out of caves. The last aim is to develop a selective isolation medium for P. destructans. Influence of several types of physiological stress (e.g. UVA, UVA with UVB, 25 řC, 30 řC, 37 řC and dryness) was investigated with fluorescent stain propidium iodide (PI) by flow cytometry. The spores of Pseudogymnoascus destructans and three fungi from underground spaces were not viable after 3 weeks at 37 řC. Other stresses did not cause a decreasing of viability or some stresses caused...
Structure and function of microbial communities of montane spruce forest
Štursová, Martina ; Baldrian, Petr (advisor) ; Uhlík, Ondřej (referee) ; Slaninová Kyselková, Martina (referee)
Structure and function of soil microbial communities in montane spruce forest Martina Štursová Abstract Coniferous forests are spatially heterogeneous environments and represent an important ecosystem that acts as carbon sink under current climate storing large amounts of carbon in standing biomass or as soil organic matter. The formation of organic matter via decomposition of dead biomass and transformation of rhizodeposited organic compounds is primarily mediated by microbial community of forest topsoil. Despite growing insight into the composition of these soil communities, little is known about the microbes actually responsible for those transformation processes, about the drivers shaping these communities or their response to increasing numbers of severe disturbances. Studies presented in this thesis contribute to filling the information. The studies were carried out in unmanaged spruce forests in the highest elevations of Bohemian Forest, in both, the undisturbed areas as well as those affected by bark beetle outbreaks at different time periods. Combination of methods including culturing of fungi, enzymatic activity measurements or high throughput sequencing were used to describe the microbial communities, their distribution in space and time, and factors involved in shaping these communities in those...
Fungi associated with decomposing wood in temperate forests
Štercová, Lucie ; Baldrian, Petr (advisor) ; Zikánová, Blanka (referee)
Wood decaying fungi are an essential part of all forest ecosystems. On their functioning depends a number of other organisms which use substances produced during decay of wood. Enzymes that degrade wood represent indispensable tool for fungi in converting structural compounds of wood to water and carbon dioxide. That makes them an essential part of the carbon cycle in nature. The dynamic of fungal communities on decaying wood is determined by a range of abiotic and biotic factors. The variability of microclimatic conditions, differences in the wood humidity and a gaseous mode are identifying stress factors which define the presence of species adapted to those conditions. An important factor, with which we can partially predict community composition, is the degree of decomposition of wood and the history of a species on the substrate. Another indicator, which may partly explain the composition of the community is a way of dying of a tree and a type of decaying substrate. Often, the development of a community follows from the primary colonizers, with high tolerance to unfavorable conditions, through the secondary colonizers, which have the ability to obtain the substrate over primary colonizers, but require more stable microclimatic conditions, to late colonizers, who are adapted to stress factors as...

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