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Eventual protective action of calcium (Ca, 100 or 1000 μM) against cadmium (Cd, 10 or 100 μM) toxicity in common lichen Hypogymnia physodes after 24 h of exposure was studied. Total Cd reached 482 and 2801 μg/g DW in 10 and 100 μM Cd treatments while Ca content reached over 23 mg/g DW in 1000 μM Ca treatment. Ca suppressed Cd accumulation by 23 and 38% in total fraction and completely in absorbed fraction. Fluorescence microscopy of Cd and Ca ions revealed good correlation with quantitative data. Cd stimulated increase in ROS formation and lipid peroxidation as detected using fluorescent reagents and quantification of H2O2 while co-application of Ca suppressed these effects. Formation of nitric oxide was mainly affected by cadmium. Cd depleted amount of amino acids but proteins or phenols remained unaffected by Cd or Ca. On the contrary, sum of thiols, reduced glutathione and ascorbic acid were depleted by Cd but reversed mainly by higher Ca dose. Among organic acids, only Cd-induced depletion of citric acid content was reversed by Ca. Data indicate that ameliorative effect of Ca under Cd excess in lichens is comparable with effect in plants and metabolic responses in various life lineages are discussed.
A lichen body is formed most often from green alga cells trapped in a net of ascomycetous fungi and accompanied by endolichenic or parasitic fungi, other algae, and symbiotic or free-living bacteria. The lichen's microcosmos is inhabited by mites, insects, and other animals for which the lichen is a source of food or a place to live. Novel, four-segmented dsRNA viruses were detected in saxicolous Chrysothrixchlorina and Leprariaincana lichens. Comparison of encoded genome proteins revealed classification of the viruses to the genus Alphachrysovirus and a relationship to chrysoviruses from filamentous ascomycetous fungi. We propose the names Chrysothrix chrysovirus 1 (CcCV1) and Lepraria chrysovirus 1 (LiCV1) as acronyms for these viruses. Surprisingly, observation of Chrysothrixchlorina hybridization with fluorescent-labelled virus probe by confocal microscope revealed that the CcCV1 virus is not present in the lichen body-forming fungus but in accompanying endolichenic Penicilliumcitreosulfuratum fungus. These are the first descriptions of mycoviruses from a lichen environment.
- MeSH
- dvouvláknová RNA MeSH
- fylogeneze MeSH
- genom virový MeSH
- genomika metody MeSH
- lišejníky virologie MeSH
- mykoviry klasifikace fyziologie MeSH
- RNA-viry MeSH
- sekvence aminokyselin MeSH
- symbióza * MeSH
- virové proteiny chemie genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Identifying factors that influence species interactions is central to research in symbiotic systems. While lichens represent iconic models of symbiosis and play important roles in understanding the biology of symbiotic interactions, patterns of interactions in lichen symbionts and mechanisms governing these relationships are not well characterized. This is due, in part to the fact that current taxonomic approaches for recognizing diversity in lichen symbionts commonly fail to accurately reflect actual species diversity. In this study, we employed DNA-based approaches to circumscribed candidate species-level lineages in rock-posy lichen symbionts (mycobiont=Rhizoplaca s. lat. species; photobiont=Trebouxia species). Our results revealed a high degree of cryptic diversity in both the myco- and photobionts in these lichens. Using the candidate species circumscribed here, we investigated the specificity of the symbionts toward their partners and inferred the relative importance of various factors influencing symbiont interactions. Distinct mycobiont species complexes, ecozones, and biomes are significantly correlated with the occurrence of photobiont OTUs, indicating that complex interactions among mycobiont lineages, ecogeography, and microhabitat determine interactions between photobionts and their mycobionts in lichen symbiosis. One-to-one specificity between mycobiont and photobiont species was not found, with the exception of R. maheui that associated with a single Trebouxia OTU that was not found with other Rhizoplaca s. lat. species. We estimated the most recent common ancestor of the core Rhizoplaca group at c. 62.5Ma, similar in age to the diverse parmelioid core group in the well-studied family Parmeliaceae. However, in contrast to Parmeliaceae, species in Rhizoplaca were found to associate with a narrow range of photobionts. Our study provides important perspectives into species diversity and interactions in iconic lichen symbiotic systems and establishes a valuable framework for continuing research into rock-posy lichens.
Ecological preferences, partner compatibility, or partner availability are known to be important factors shaping obligate and intimate lichen symbioses. We considered a complex of Cladonia species, traditionally differentiated by the extent of sexual reproduction and the type of vegetative propagules, to assess if the reproductive and dispersal strategies affect mycobiont-photobiont association patterns. In total 85 lichen thalli from 72 European localities were studied, two genetic markers for both Cladonia mycobionts and Asterochloris photobionts were analyzed. Variance partitioning analysis by multiple regression on distance matrices was performed to describe and partition variance in photobiont genetic diversity. Asexually reproducing Cladonia in our study were found to be strongly specific to their photobionts, associating with only two closely related Asterochloris species. In contrast, sexually reproducing lichens associated with seven unrelated Asterochloris lineages, thus being photobiont generalists. The reproductive mode had the largest explanatory power, explaining 44% of the total photobiont variability. Reproductive and dispersal strategies are the key factors shaping photobiont diversity in this group of Cladonia lichens. A strict photobiont specialisation observed in two studied species may steer both evolutionary flexibility and responses to ecological changes of these organisms, and considerably limit their distribution ranges.
- MeSH
- Ascomycota klasifikace MeSH
- biodiverzita * MeSH
- Chlorophyta klasifikace genetika MeSH
- fylogeneze MeSH
- lišejníky klasifikace genetika MeSH
- rozmnožování MeSH
- šíření semen fyziologie MeSH
- symbióza * MeSH
- zeměpis MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
Lichens survive harsh weather of Antarctica as well as of other hostile environments worldwide. Therefore, this investigation is important to understand the evolution of life on Earth in relation to their stress tolerance strategy. We have used chlorophyll a fluorescence (ChlF) and Raman spectroscopy, respectively, to monitor the activation/deactivation of photosynthesis and carotenoids in three diverse Antarctic lichens, Dermatocarpon polyphyllizum (DP), Umbilicaria antarctica (UA), and Leptogium puberulum (LP). These lichens, post 4 h or 24 h of hydration, showed differences in their ChlF transients and values of major ChlF parameters, e.g., in the maximum quantum efficiency of PSII photochemistry (Fv/Fm), and yields of fluorescence and heat dissipation (Φf,d), of effective quantum efficiency of PSII photochemistry (ΦPSII) and of non-photochemical quenching (Φnpq), which may be due to quantitative and/or qualitative differences in the composition of their photobionts. For understanding the kinetics of hydration-induced activation of photosynthesis, we screened ΦPSII of these lichens and reported its non-linear stimulation on a minute time scale; half of the activation time (t1/2) was fastest ~4.05 ± 0.29 min for DP, which was followed by 5.46 ± 0.18 min for UA, and 13.95 ± 1.24 min for LP. Upon drying of fully activated lichen thallus, there was a slow decay, in hours, of relative water content (RWC) as well as of Fv/Fm. Raman spectral signatures were different for lichens having algal (in DP and UA) and cyanobacteria (in LP) photobionts, and there was a significant shift in ν1(C=C) Raman band of carotenoids post 24 h hydration as compared to their value at a dry state or post 4 h of hydration; this shift was decreased, when drying, in DP and LP but not in UA. We conclude that hydration nonlinearly activated photosynthetic apparatus/reactions of these lichens in minute time range but there was a de-novo synthesis of chlorophylls as well as of carotenoids post 24 h. Their dehydration-induced deactivation, however, was comparatively slow, in hours range, and there seemed a degradation of synthesized chlorophylls and carotenoids post dryness. We conclude that in extremophilic lichens, their photosynthetic partners, in particular, possess a complex survival and photoprotective strategy to be successful in the extreme terrestrial environments in Antarctica.
- MeSH
- Ascomycota MeSH
- chlorofyl a MeSH
- chlorofyl MeSH
- fluorescence MeSH
- fotosyntéza MeSH
- karotenoidy metabolismus MeSH
- lišejníky * metabolismus MeSH
- Ramanova spektroskopie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Antarktida MeSH
The distribution patterns of symbiotic algae are thought to be conferred mainly by their hosts, however, they may originate in algal environmental requirements as well. In lichens, predominantly terrestrial associations of fungi with algae or cyanobacteria, the ecological preferences of photobionts have not been directly studied so far. Here, we examine the putative environmental requirements in lichenized alga Asterochloris, and search for the existence of ecological guilds in Asterochloris-associating lichens. Therefore, the presence of phylogenetic signal in several environmental traits was tested. Phylogenetic analysis based on the concatenated set of internal transcribed spacer rDNA and actin type I intron sequences from photobionts associated with lichens of the genera Lepraria and Stereocaulon (Stereocaulaceae, Ascomycota) revealed 13 moderately to well-resolved clades. Photobionts from particular algal clades were found to be associated with taxonomically different, but ecologically similar lichens. The rain and sun exposure were the most significant environmental factor, clearly distinguishing the Asterochloris lineages. The photobionts from ombrophobic and ombrophilic lichens were clustered in completely distinct clades. Moreover, two photobiont taxa were obviously differentiated based on their substrate and climatic preferences. Our study, thus reveals that the photobiont, generally the subsidiary member of the symbiotic lichen association, could exhibit clear preferences for environmental factors. These algal preferences may limit the ecological niches available to lichens and lead to the existence of specific lichen guilds.
- MeSH
- aktiny genetika MeSH
- Chlorophyta genetika fyziologie MeSH
- DNA primery genetika MeSH
- ekosystém MeSH
- fylogeneze MeSH
- lišejníky mikrobiologie MeSH
- mezerníky ribozomální DNA genetika MeSH
- molekulární sekvence - údaje MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- sekvenční seřazení MeSH
- životní prostředí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Evropa MeSH
- Kalifornie MeSH
