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There is something in the air: Diversity of lichen symbionts in the aeroplankton
Veselá, Veronika ; Škaloud, Pavel (advisor) ; Vančurová, Lucie (referee)
Lichens that reproduce primarily sexually rely on the presence of their symbionts in the environment. A new lichen cannot develop without direct contact between the filaments of the germinating spore and a compatible symbiotic alga. However, the results of earlier studies do not provide solid evidence for photobiont presence on lichen-colonized substrates. The objective of this thesis was to assess various environmental types (air, bark, soil, stone, and artificial substrates) as potential sources of symbiotic algae. To achieve in-depth understanding of the diversity of green algae at a long-studied Central Bohemian study-site, Illumina MiSeq metabarcoding of the ITS2 rDNA region was combined with traditional sequencing of lichen algal ITS rDNA and morphological observations. The methods used revealed 283 species-level lineages and 1313 OTUs, many of which belonged to unknown species or higher taxonomic categories. All photobiont species associating solely with sexual lichens at the site could also be found in the vicinity of lichen thalli. As a result, both the substrates and the air, where these symbiotic algae occurred as well, may act as photobiont sources. In contrast, many symbionts that associate only with asexual lichen species, were never found at the site outside of lichen thalli....
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Photobiont plurality in lichen thalli
Dědková, Kamila ; Steinová, Jana (advisor) ; Vančurová, Lucie (referee)
Photobiont plurality refers to the presence of multiple photobionts within a single lichen thallus. This phenomenon was described at the end of the last century but has received deeper attention in the last decade. The available literature on this topic is limited. This bachelor thesis summarizes all the important findings published on plurality to date. The most common photobionts coexisting in a thallus are algae of the genus Trebouxia, but other algae and cyanobacteria more or less phylogenetically related may also coexist together. Thallus with multiple photobionts is formed either at the beginning by the association of hyphae with several photobionts at once (horizontal transport) or by the acquisition of additional photobionts during life (vertical transport). The most important factors affecting the cooccurrence of multiple photobionts in a single thallus are probably the specificity and selectivity of mycobionts and local environmental conditions. The plurality of photobionts has been found in more than fifty lichen species. Many important findings have been described in a model lichen Ramalina farinacea. Its coexisting photobionts differ in responses to several environmental, mostly stress conditions, suggesting that the presence of multiple photobionts in a thallus may provide an...
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Let's meet in the littoral: Diversity of symbiosis in the Verrucariaceae lichens
Schmidtová, Jana ; Škaloud, Pavel (advisor) ; Peksa, Ondřej (referee)
Lichens are organisms formed by several symbiotic partners, most importantly a fungus (mycobiont) and an alga or cyanobacteria (photobiont). Although most lichens are terrestrial, some can be found also in aquatic environments. Black crustose lichens from the family Verrucariaceae (Verrucariales, Eurotiomycetes, Ascomycota) were able to adapt to this environment very well and often dominate in the seashore near fluctuating water level. The ability of these lichens to inhabit various environments is associated with their unusually wide range of photobionts. However, this symbiont is not known to most of them. This work investigates the diversity of lichens of the family Verrucariaceae in the littoral zone of the Baltic and the North Sea coasts, the relationships between symbionts and the connection between lichen diversity and the salinity gradient. Using metabarcoding, the diversity of free-living algae in the vicinity of the studied lichens is determined and the symbiotic algae are compared with the photobionts found in the lichens. Mycobionts and photobionts were identified using ITS and 18S rDNA. A total of nine lineages of mycobionts and photobionts were found. The most common lichen turned out to be the species Hydropunctaria maura with its photobiont Pseudendoclonium submarinum. For several...
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Functional traits and functional diversity in lichens
Kolenská, Lucie ; Malíček, Jiří (advisor) ; Vondrák, Jan (referee)
Functional traits are a discussed topic across disciplines and articles with lichens are published as well. Traits are the attributes that define the organism from morphological features through anatomy to the physiology of the individual, including interaction in environmental and environmental influences. The most frequently studied functional trait of lichens is the type of thallus. Another commonly studied trait is the type of photobiont, where the presence of algae Trentepohlia is negatively affected by frost and because of this its number decreases with increasing altitude. Another functional trait of lichens which is studied is reproduction, and also secondary metabolites, which protect lichens, for example, against UV light or herbivores. Functional traits together form functional diversity, which is another way how to measure diversity on a planet where the most diverse ecosystem is not always the one with the highest number of species. Functional diversity indices then can reveal unique communities that should be protected. However, neither the definitions nor the calculation of functional diversity are exatly specified, we use different indices. The Rao index of quadratic entropy is most often used for lichens. Keywords indices, lichenized fungi, mycobiont, photobiont, thallus
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Photobiont dynamics of Stereocaulon lichens
Vančurová, Lucie ; Škaloud, Pavel (advisor) ; Bérešová, Anna (referee) ; Dal Grande, Francesco (referee)
7 Abstract Lichens are an iconic example of symbiosis. They are widespread throughout the world. In some ecosystems, lichens are dominant autotrophs, sometimes one of the few living organisms capable of surviving local conditions. They grow on a variety of substrata, including artificial surfaces. Great diversity of their life strategies is related to the diversity of symbiotic partners forming the lichen thalli, which remains largely unresearched. Lichens as sessile organisms often have to face a changing environment or adapt to conditions at new localities where their propagules can spread. We have chosen the widespread genus Stereocaulon as a model system for studying symbiotic relationships in lichens and the connection of this relationships with environmental conditions. The main goals of this thesis were (1) to uncover the diversity of phycobionts (i.e., green algal photobionts) associated with Stereocaulon within the whole genus and particular species-level lineages; (2) to identify environmental factors affecting the distribution of phycobionts and their relationships with mycobionts on a global and local scale; and (3) to inspect the possibility of sharing phycobiont pool with other lichens and soil. For this purpose, we used phylogenetic analyses (ITS rDNA, 18S rDNA, rbcL, and actin type I gene),...
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The efect of environmental variables on diversity of lichen photobionts
Červenková, Tereza ; Škaloud, Pavel (advisor) ; Peksa, Ondřej (referee)
Lichens represent a synergistic combination of at least two organisms, a heterotrophic fungus and a photosynthetic alga or a cyanobacterium. This association has resulted in a symbiotic organism, which is well tolerant to environmental influences. In fact, symbiotic relationship provides mutual benefit for both organisms. It is generally well known that the fungal partners of lichens are far less sensitive to environmental conditions, such as the temperature, altitude, rainfall or the type and composition of the substrate, in comparison to their algal partners. Therefore, lichen forming fungi have much wider ecological valences than the photobionts interacting with them. Indeed, most of the photosyntetic genera and species are adapted only to certain environmental conditions. For this reason, the symbiotic algae and cyanobacteria probably play a major role during the initial lichen formation on the site. This thesis focuses on the adaptability of photoautotrophic symbionts of lichens, coccoid green algae and cyanobacteria, to environmental conditions. Ecological diversification of photobionts has a direct impact on their genetic differentiation and thus to differentiate lichen species themselves. Unfortunately, in many studies the authors mostly dealt with the diversity of macroscopic symbiotic...
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Diversity of green algae identified as lichen photobionts
Vaiglová, Zuzana ; Škaloud, Pavel (advisor) ; Štifterová, Anna (referee)
This thesis is focused on green algae, which have been recorded as lichen photobionts. The thesis consists of description of genera from the green algal from classes Ulvophyceae, Trebouxiophyceae and Chlorophyceae. I focused on phylogenetics position of genera, I define their morphology and I summarize their participation in lichen symbiotic relationships. I compare evidences based on the traditional morphological methods and modern molecular data. The following genera can be stated to uncertainly represent lichen photobionts: Trentepohlia, Cephaleuros, Phycopeltis and Dilabifilum from the class Ulvophyceae, and Dictyochloropsis, Chloroidium, Elliptochloris, Coccomyxa, Diplosphaera, Auxenochlorella, Myrmecia, Asterochloris, Trebouxia, Coccobotrys and Leptosira from the class Trebouxiophyceae. The genera Chlorella and Stichococcus are morphologically poorly defined, but they are commonly reported as lichen photobionts. Prasiola associates with the mycobiont, but the identity of their partnership is not certainly defined. The lichen symbiosis of genera Parachloroidium, Pseudochlorella and Gloeocystis has not been confirmed by molecular methods, so far. Key words photobiont, lichen, green algae, Chlorophyta, diversity, phylogeny, Trebouxiophyceae
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Comparing the diversity of free-living and symbiotic algae in lichen symbioses
Veselá, Veronika ; Škaloud, Pavel (advisor) ; Vančurová, Lucie (referee)
This work discusses the diversity of free-living lichen photobionts belonging to the class Trebouxiophyceae (Chlorophyta). The introduction summarises the change in perspective on the possibility of existence of free-living photobionts. The main part of this work contains a list of lichen photobiont genera with their description and taxonomical classification. In addition, I summarize published records and of these organisms in studies focusing on diversity of aerophytic and soil algae. The work also contains a list of known lichen photobionts species of the class Trebouxiophyceae. Keywords: Trebouxiophyceae, Trebouxia, green algae, photobiont, lichen, diversity
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Diversity of symbiotic partners within the lichen family Verrucariaceae
Schmidtová, Jana ; Škaloud, Pavel (advisor) ; Steinová, Jana (referee)
This thesis summarizes the current knowledge of photobionts of the lichen family Verrucariaceae. It classifies the free-living photobionts systematically, mentions their main morphological features, distribution, and ecology, and notices their participation in the symbiosis. Subsequently, it also describes and characterizes the fungal component of mycobionts, their phylogenetic position, the main morphological features, distribution, and the most common habitats. Finally, it studies the influence of the environment, mycobiont, and other factors in the occurrence of particular photobionts in lichens. Keywords: Verrucariaceae, photobiont, mycobiont, lichen, diversity, symbiosis, characterization
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Dynamics of a lichen symbiosis
Vaiglová, Zuzana ; Škaloud, Pavel (advisor) ; Vondrák, Jan (referee)
The symbiotic relationships often represent not only the permanent cohabitation of two organisms, but they can evolve and change over time. Many papers published so far focused on the the specificity of lichens, characterising both highly specific species and those that can establish a symbiosis with many algal genotypes. In this second case we can imagine the possibility of a photobiont exchange during the life of lichen - the dynamics of lichen symbiosis. In this thesis I compared the occurence and diversity of photobionts within the thalli of lichens growing on the disturbed localities and on the the localities without the disturbance. These two types of localities were similar to species richness of photobionts, but the disturbed localities dominated by the number of photobiont genera. These localities also reached a higher value of phylogenetic diversity. Conversely, non-phylogenetic analysis revealed the higher level of photobiont diversity on non-disturbed localities, where the core of diversity was formed by different lineages of Trebouxia. I have also found the lichens, which cooperate with different algae on disturbed and non-disturbed localities. The photobiont distribution presented in this paper shows the possibility of photobiont exchange during the community succesion. The...
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