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Highlights • Temporal changes in metal concentrations of Xanthoria parietina thalli were examined. • A pronounced upward trend in Pb concentration over time was observed. • Vegetative parts of the thallus and apothecia differ in element accumulation levels. • Definition of part of thallus designated for elemental analysis is highly desirable. • Certain anatomical characteristics are correlated with concentrations of trace metals. Abstract Certain lichens are widely used in air pollution biomonitoring because the contents of various elements in their thalli accurately reflect the chemical composition of the air. Temporal changes in selected concentrations of trace metals in vegetative and generative parts of Xanthoria parietina thalli exposed to urban-related pollution were analysed and the relationship between anatomical organisation and element accumulation identified. The lichen material included thalli relocated to an urban area of Cracow (southern Poland) along with their host trees, which had previously been cultivated at a site characterised by a lower level of air pollution. The thalli were sampled immediately and 1, 3, 6, and 12 months after planting trees. Concentrations of Zn, Pb, Cd, Cu, Ni, and Cr, as measured by means of flame atomic absorption spectrometry (FAAS), and various anatomical characteristics were determined in vegetative thalli and the corresponding apothecia. Accumulation of Pb over time demonstrated a pronounced upward trend; calculated exposed-to-control (EC) ratios indicate 'severe accumulation' of this element. Diverse levels of accumulation in different parts of thalli – higher, in the cases of Pb, Cd, Cu, Ni, Cr, and lower, in the case of Zn, in vegetative parts compared to apothecia – were observed. Thus sampling uniformity is highly desirable in air biomonitoring studies, along with a determination of which part of the thallus is to be designated for elemental analysis. The results also showed that certain anatomical characteristics are correlated with concentrations of metal elements in the thallus. [ABSTRACT FROM AUTHOR]

This study compared bioaccumulation as well as physiological (content of ergosterol as marker of fungal vitality and photosynthetic efficiency as marker of algal vitality) and ultrastructural effects of glyphosate in the lichen Xanthoria parietina , with the herbicide being provided either by soaking or spraying of the samples. The results showed that bioaccumulation of glyphosate is fast and proportional to the dose supplied, and is independent on the way it is supplied. Toxic effects resulting from glyphosate uptake by both soaking and spraying were evident at physiological and ultrastructural level, both in the algal and fungal partner, with negative effects being generally dose- and time-dependent. Since our results showed that the concentration of glyphosate bioaccumulated in X. parietina remains stable (at least up to 90 days), a perspective is open for using lichens in biomonitoring of atmospheric pollution by glyphosate as a side effect of the application of this herbicide. [ABSTRACT FROM AUTHOR]

Arthonia parietinaria is described as new to science. Host of the type and at the same time the only confirmed host species is the foliose macrolichen Xanthoria parietina . Sequence data of nucLSU rRNA genes reveal a close relationship to Arthonia molendoi . A. parietinaria is recorded for many countries in Europe, western Asia, and northern Africa. [ABSTRACT FROM AUTHOR]

Secondary metabolites of lichens can be involved in production of chelates with heavy metals. We hypothesized that parietin plays important role in protection of photobiont cells in Xanthoria parietina from an excess of cadmium ions. Two types of X. parietina lichen thalli, natural with presence of secondary metabolite parietin (p+) as well as without parietin (p−) were exposed to different doses of cadmium (up to 300 μmol g −1 dw). Based on determination of the total and intracellular Cd-accumulation, ergosterol and thiobarbituric acid reactive substances (TBARS) content did not show statistically significant differences in the response of both types of thalli (p+ and p−). However, a stronger toxic effect of the highest Cd-dose on photosynthetic pigment content and chlorophyll a fluorescence was observed in the parietin-depleted thalli. The protective role of parietin against Cd excess was better supported and concluded from the differences observed in the production of non-protein thiol compounds (cysteine, glutathione and phytochelatins) involved in Cd detoxification. In the p+ thalli Cys content was stable but GSH content slightly decreased in the studied Cd range, while in the p− thalli these compounds were completely absent at high Cd doses. At Cd doses higher than 37.5 μmol Cd g −1 dw, toxic to both types of X. parietina thalli, Cys and GSH contents were significantly higher in p+ than in p− thalli. Also, the photobiont partner in the p+ thalli was better protected of the metal exposition, and able to produce phytochelatins (PCs) over the whole range of metal, while in the p− thalli the production was completely inhibited at 75 μmol Cd g −1 dw and higher concentrations, together with the inhibition of cysteine (Cys) and reduced glutathione (GSH) production. The obtained results indicate that the parietin layer is a natural barrier decreasing Cd access to algal cells in X. parietina . Comparison of PCs production appeared to be the most sensitive marker for estimation of Cd availability to photobiont in the symbiotic system. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) empirical critical levels for Europe were re-evaluated in 2009, based mainly on the ecological responses of lichen communities without acknowledging the physiological differences between oligotrophic and nitrophytic species. Here, we compare a nitrogen sensitive lichen (Evernia prunastri) with a nitrogen tolerant one (Xanthoria parietina), focussing on their physiological response (Fv/Fm) to short-term NH3 exposure and their frequency of occurrence along an NH3 field gradient. Both frequency and Fv/Fm of E. prunastri decreased abruptly above 3 μg m−3 NH3 suggesting direct adverse effects of NH3 on its photosynthetic performance. By contrast, X. parietina increased its frequency with NH3, despite showing decreased capacity of photosystem II above 50 μg m−3 NH3, suggesting that the ecological success of X. parietina at ammonia-rich sites might be related to indirect effects of increased nitrogen (NH3) availability. These results highlight the need to establish NH3 critical levels based on oligotrophic lichen species. [Copyright &y& Elsevier]

Highlights: [•] Effects of external Spd on the lichen Xanthoria parietina under Al stress were investigated. [•] Increased GR activity and psbA mRNA transcript levels were observed in the X. parietina thalli. [•] Application of Spd could mitigate aluminium-induced oxidative damage on lichen X. parietina. [Copyright &y& Elsevier]

Abstract: Airborne metal deposition in the major urban and the industrial districts of Kocaeli was monitored using Xanthoria parietina lichen specimen as a biomonitoring organism. Lichen samples were analyzed for Al, As, Co, Cd, Cu, Fe, Hg, Mn, Ni, Pb, Ti, Tl, V and Zn contents to determine the relationship between the potential pollutant sources in the region and the degree of airborne metal deposition. Results showed that airborne metal deposition in the Kocaeli province was widespread and environmental alteration was serious near the industrial facilities. Mean metal concentrations of lichen samples in the industrial district (Dilovası) of Kocaeli were two to seven folds higher than those in the urban districts of Kocaeli: Mn (7), Pb–Cd–Zn (6), Fe–Ni–Cu (3) and Al–Co–Ti–Hg–As–V (2). Environmental alteration in Dilovası region was severe in terms of all metals analyzed. Cluster analysis showed that metal industry (iron–steel, aluminum, zinc) in Dilovası, fossil fuel combustion processes related to the industry and power plant and heavy traffic contributed significantly to the metal emission in Dilovası region. Airborne metal deposition in the urban districts of Kocaeli was high especially around the coal-fired cement plant in Hereke and petroleum refinery in Körfez. Fossil fuel combustion and traffic emission were among the important sources of airborne metals in the urban–suburban districts. [Copyright &y& Elsevier]

Abstract: Atmospheric mercury (Hg) deposition around a mercury cell chlor-alkali plant located near Grenoble, south-east France, was assessed using Hg concentrations in lichens and soils. Hg content in the epiphytic Xanthoria parietina lichen ranged from ∼0.07 to ∼2.51μgg−1, and concentrations decreased with increasing distance to the plant, with a contamination radius of ∼2km. Soil Hg concentration profiles were consistent with an atmospheric origin, with higher concentrations in the upper part of the profiles. Concentration of Hg in lichens and top soils (0–10cm depth) as a function of the distance to the chlor-alkali plant exhibited highly similar variations. Using a simple first-order deposition model, mean Hg fallouts for the whole history of chlor-alkali plant are estimated to ∼36gHgday−1 in this area, compatible with values reported for reactive gaseous mercury (RGM) emissions of similar industrial plants. Using literature data on RGM to total Hg emission ratio, we estimate that the plant emitted ∼650kgHgyear−1. Two kilometres away from the plant, Hg content in top soils falls to values of (0.13±0.07)μgg−1 Hg, which is the local anthropogenic geochemical background level, but higher than unperturbed geochemical background found at the bottom of soil profiles (below 40cm depth) estimated to (0.04±0.01)μgg−1 Hg. The present study evidences that lichens are a pertinent proxy for soil Hg contamination around chlor-alkali plants. They are attractive biomonitoring tools since sampling and preparations protocols for lichens are less time consuming than those used for soils. [Copyright &y& Elsevier]

Abstract: The sensitivity of three foliose lichen species to urban environments with different air pollution loads and climatic conditions was tested using chlorophyll a fluorescence (Chl a F) PAM measurements. Transplants of Xanthoria parietina (L.) Th. Fr., Flavoparmelia caperata (L.) Hale and Parmotrema perlatum (Huds.) M. Choisy collected in a pristine site of the Classic Karst (Trieste, NE Italy) were exposed for 12 weeks (August–December 2008) at that site (control, A), and in two urban sites with heavy traffic in Trieste (B) and Udine (C). Concentrations of the main gaseous pollutants were monitored by passive samplers in A (NO2, O3), and by pollution monitoring stations in B and C (NOX, NO2, SO2, O3). In the laboratory, Kautsky curves were induced under standardized conditions at species-specific PPFD values before exposure, after 6 weeks and at the end of the exposure. Significant decrease in F v/F m was only observed in P. perlatum transplants exposed in B, possibly as a consequence of the dry conditions of that site. Non-photochemical quenching (NPQ) was negatively affected in all three species, although with different intensity, in both urban sites, but more intensively in C than in B. Chl a F data shows clearly that (i) the decrease of NPQ was modulated by time exposure to NOX as well as by NOX concentration, and (ii) the species response to pollutants was related to species ecology: X. parietina, which is more nitro- and xerophytic than the other two species, tolerated better the transplant environmental conditions, confirming recent floristic observations carried out in several urban areas of Central Europe. [Copyright &y& Elsevier]

Abstract: Effects of methyl jasmonate (MeJA), salicylic acid (SA) or 2-aminoindane-2-phosphonic acid (AIP) pre-treatments on the sensitivity of Xanthoria parietina exposed to UV-A were studied. UV decreased chlorophylls and stimulated increase in hydrogen peroxide and superoxide level. Accumulation of soluble phenols and flavonoids increased in response to UV treatment. Metabolic modulators had negligible impact on these UV-induced changes. Within free amino acids, AIP (−UV variant) and SA and MeJA (+UV variants) altered their accumulation. AIP had no effect on the amount of phenylalanine. Benzoic and cinnamic acids were elevated by UV and mainly MeJA influenced their accumulations. Among lichen specific metabolites, vulpinic acid and ergosterol increased while usnic acid and atranorin decreased after exposure to UV; accumulation of parietin was not affected. Applied modulators showed a different effect on these lichen metabolites but biosynthetic pathway-specific trend of alteration was visible. Overall, MeJA showed the most pronounced effect among studied parameters. Accumulation of selected phenolics in response to UV-A seems to be an important feature of Xanthoria tolerance. Present finding in the context of phenolic metabolism in non-vascular plants and with respect to limited data about effect of studied modulators on non-vascular plants are discussed. [Copyright &y& Elsevier]

Abstract: The aim of this study was to test in a short term laboratory experiment the accumulation and physiological effects of As in the epiphytic lichen Xanthoria parietina. Arsenic content in treated samples increased progressively with increasing concentration in treatment solutions. Treatment of X. parietina thalli with 0.1, 1, 10ppm As solutions caused significant decrease of viability, measured as intensity of respiratory activity, and damages to cell membranes, assessed by increase of electric conductivity of rinsing water and lipid peroxidation products. Soluble proteins content decreased and H2O2 content increased already at the lowest As concentration tested (0.01ppm). Photosynthetic efficiency, measured in terms of FV /FM ratio, decreased significantly only at the highest As concentration (10ppm). It was concluded that As exposure causes physiological stress both on the mycobiont and the photobiont and that cell membrane damage, expressed in terms of electric conductivity of rinsing water, is the parameter most affected by As treatment. [ABSTRACT FROM AUTHOR]

Total nitrogen in transplanted and in situ lichen thalli of Xanthoria parietina were related to ambient ammonia air concentrations measured with passive ALPHA (Adapted Low-cost Passive High Absorption) diffusion samplers in Denmark. Transplants and ALPHA samplers were exposed four months in a transect on heathland close to a pig farm. Monthly mean ammonia concentrations declined exponentially approaching background levels after 300m. Nitrogen content of the lichen transplants tended to decline with distance, though only a few stations were significantly different from each other. Where ammonia concentrations were high, maximum content of nitrogen was reached after one month of exposure. Conversely, at sites with background concentrations, it took several months to reach a statistically significant uptake. The correlation between ammonia concentration in the air and in situ X. parietina was significant. [Copyright &y& Elsevier]

Abstract: This study aimed to assess biomass growth as a response variable in lichens during short-term laboratory experiments. To do this, we studied the influence of UV-B and temperature on lichen performance including the synthesis of solar radiation screening cortical compounds. The pioneer lichen Xanthoria aureola from exposed sea cliffs and the old forest lichen Lobaria pulmonaria were cultivated for 15 days in the laboratory in a factorial experiments with temperature (12 and 21°C) and UV-B (0, 0.1, 0.3 and 1.0Wm−2) as treatments. Prior to the experiment, the cortical pigment parietin was non-destructively extracted from X. aureola, whereas the sampled shade-adapted thalli of L. pulmonaria lacked cortical melanic compounds. Therefore both lichens were deficient in cortical sun-screening compounds when the UV-B exposure started. At 12°C, the relative growth rate was 7.2±0.6 and 3.0±0.8mgg−1 day−1 in L. pulmonaria and X. aureola, respectively, reduced to 1.8±0.5 and −2.6±0.9mgg−1 day−1, at 21°C. These figures showed that lichen growth is a useful response variable in short-term laboratory experiments. Growth was not influenced by UV-B alone in these pigment-deficient transplants, suggesting that UV-B had little adverse effects on either of the lichen bionts. The cortical sun screens (parietin and melanic compounds) were synthesized in the presence of UV-B, and increased statistically significantly with increasing UV-B at both cultivation temperatures. However, in X. aureola the synthesis was highest at the lowest temperature (12°C). At 12°C, changes in chlorophylls, F v/F m and NPQ during cultivation were consistent with a substantial level of acclimation to the growth chamber conditions for both species, whereas strong reductions in photosynthetic pigments, F v/F m and Ф II at 21°C indicated serious damage and chlorophyll degradation at high temperature. In conclusion, lichen growth and the synthesis of protective compounds are highly responsive lichen processes in short-term experiments. [Copyright &y& Elsevier]

Abstract: The results of a study aimed at investigating the effects of boron excess on a set of ecophysiological parameters in the lichen Xanthoria parietina, to set up a monitoring system to trace early biological effects of boron pollution in geothermal areas, are reported. To this purpose, lichen thalli have been incubated for 24h in solutions at boron concentrations of 0.1, 1, 10 and 100ppm, which were within the range in bulk deposition and geothermal fluids. The results showed a general trend of decreasing sample viability and increasing cell membrane damage and membrane lipid peroxidation under increasing boron concentrations, while photosynthetic efficiency, chlorophyll degradation and the contents of H2O2 and water-soluble proteins were not affected. It was argued that the fungal partner, that represents the large majority of the lichen biomass, is more sensitive to boron excess than the algal partner. [Copyright &y& Elsevier]

Abstract: We characterize the transcript of a polyketide synthase gene (PKS) from the cultured mycobiont of Xanthoria elegans (XePKS1) using SMART-rapid amplification of cDNA ends (RACE) cDNA synthesis. Sequence analysis of the cloned cDNA reveals an open reading frame of 2144 amino acid residues. It contains features of a non-reducing fungal type I PKS with an N-terminal starter unit: acyl carrier protein (ACP) transacetylase domain, ketosynthase, acyltransferase, two acyl carrier protein domains, and a thioesterase domain. XePKS1 was the only paralogue detected in the cDNA and the genomic DNA of the cultured X. elegans mycobiont by using a degenerate PCR approach targeted at the conserved regions of non-reducing type I PKS genes. The hypothetical protein is phylogenetically related to genes that are basal to a clade of dihydroxynaphthalene synthases (non-reducing clade II) and anthraquinone type synthases of non-lichenized fungi (non-reducing clade I). According to hplc and tlc analyses, the cultured mycobiont exclusively produced anthraquinones and its precursors. Therefore, we discuss whether the characterized paralogue is involved in anthraquinone production, which raises the possibility of a paraphyletic origin of lichen anthraquinone biosynthesis. The cDNA of XePKS1 was the first full-length coding sequence of a lichen PKS to be published. This proves SMART RACE to be a suitable tool for obtaining full-length coding sequences of genes from environmental samples and organisms, which are hardly amenable to standard molecular approaches or genomic sequencing. [Copyright &y& Elsevier]

Abstract: The Teloschistaceae is a widespread family with considerable morphological and ecological heterogeneity across genera and species groups. In order to provide a comprehensive molecular phylogeny for this family, phylogenetic analyses were carried out on sequences from the nuclear ribosomal ITS region obtained from 114 individuals that represent virtually all main lineages of Teloschistaceae. Our study confirmed the polyphyly of Caloplaca, Fulgensia and Xanthoria, and revealed that Teloschistes is probably non-monophyletic. We also confirm here that species traditionally included in Caloplaca subgenus Gasparrinia do not form a monophyletic entity. Caloplaca aurantia, C. carphinea and C. saxicola s. str. groups were recovered as monophyletic. The subgenera Caloplaca and Pyrenodesmia were also polyphyletic. In the subgenus Caloplaca, the traditionally recognized C. cerina group was recovered as monophyletic. Because this study is based solely on ITS, to maximize taxon sampling, the inclusion of phylogenetic signal from ambiguously aligned regions in MP (recoded INAASE and arc characters) resulted in the most highly supported phylogenetic reconstruction, compared with Bayesian inference restricted to alignable sites. [Copyright &y& Elsevier]

The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation. [Copyright &y& Elsevier]

The results of long-term biomonitoring of nine elements (Cd, Cr, Ni, Pb, V, Cu, Zn, Fe and Al) with the epiphytic lichen Xanthoria parietina over a seven year time span are reported. A total of 51 sampling stations were monitored in two surveys, obtaining information about heavy metal concentrations in a large area characterized by a high impact of industrial and urban sources of air pollution. The results showed that the approach adopted is indeed a reliable tool to assess environmental alteration, pinpointing not only the trends of the nine elements analysed but also their reciprocal correlations. As a consequence it was possible to characterize changes in air pollution composition and the common origin and behavior of several groups of elements. [Copyright &y& Elsevier]

Effects of high ammonia emissions and nitrogen deposition were investigated on lichens around a pig stockfarm (ca. 7,000 animals) in central Italy. Four sites were selected along a transect at 200, 400, 1000 and 2500m from the stockfarm, the diversity of epiphytic lichens was measured and transplanted thalli of Xanthoria parietina and Flavoparmelia caperata exposed, together with passive NH3 (diffusion tubes) samplers. Ammonia dramatically decreased from the centre of the stockfarm to the sampled sites, where it was correlated with bark pH. Total lichen diversity was not associated with either NH3 concentrations or bark pH, but the diversity of strictly nitrophytic species was highly correlated with both parameters. Physconia grisea was the best indicator species for NH3 pollution. Total N accumulated in X. Parietina and F. Caperata was correlated with NH3 concentrations. [Copyright &y& Elsevier]

Abstract: HPLC analyses of Xanthoria elegans cultivated on different media and either aposymbiontically or with its photobiont revealed that the carbon source and the presence of the algal partner have an impact on the secondary metabolism of the mycobiont. The aposymbiotically (without photobiont) grown mycobiont contained up to 70% more of the main compounds in its thallus than in resynthesis stage. Although this is speculative, the induction of the polyketide pathway may be a feedback mechanism to the absence of the photobiont. All cultures produce a variety of substances which were not detectable in the voucher specimen. Besides physcion (the major substance), we were able to identify emodin as well as physcion-bisanthrone, teloschistin monoacetate and derivatives. A strong inducible effect on the production of physcion, physcion-bisanthrone and on their precursors and derivatives was found for mannitol. By contrast, supplementation of ribitol had negligible effects, if any, on polyketide quantities although it is the main carbon source for the mycobiont in free-living lichens with Trebouxia photobiont. [Copyright &y& Elsevier]

This study aims to clarify taxonomic relationships within the current concept of Xanthoria parietina in northern Europe. For comparison, X. calcicola was also included in the study. Morphological as well as molecular data were utilized. Morphology indicated the presence of three species, Xanthoria parietina, X. calcicola, and X. aureola, the latter of which is resurrected here from synonymy. The most important separating characters involve colour and thickness of the thallus, lobe width, morphology of laminar structures, and the texture of the upper surface. X. aureola, as recognized here, mostly occurs on seashore rocks. Part of the IGS region as well as the complete ITS were sequenced in 70 individual thalli representing ten geographical regions in Europe. In total, 19 different IGS haplotypes and 20 different ITS haplotypes were present in the data set. Owing to indications of possible recombination between the IGS and the ITS, the two data sets were analyzed separately. Haplotype networks were estimated, both of which indicate that X. parietina is distinct from X. aureola and X. calcicola. In our sample, the two latter do not share haplotypes, but are only separated by a few mutational steps. [ABSTRACT FROM AUTHOR]

Genetic variability among sterile cultured single ascospore isolates of Xanthoria parietina, X. calcicola, X. ectaneoides, X. capensis, X. polycarpa and X. resendei was investigated with RAPD-PCR. If available five out of eight ascospores per ascus were analysed. In some samples multispore and mycelial isolates from ascomata were included in the analysis. Ascospore germination rates and phenotypic features such as growth rate, pigmentation and secondary metabolites were uniform in X. parietina sporelings of the same ascus, but varied among the progeny of meiosis in all other species. Phenotypic features correlated with genetic variability. X. parietina revealed polymorphisms among specimens from different worldwide locations. In contrast nine out of ten sets of sibling spores were genetically uniform, with only 2% polymorphism in the remaining set, indicating that X. parietina might be homothallic. X. calcicola, X. ectaneoides, X. capensis, X. polycarpa and X. resendei revealed 9–66% polymorphic loci and therefore are considered heterothallic. [ABSTRACT FROM AUTHOR]

Seven highly-coloured lichen species belonging to the genera Caloplaca, Candelariella, Aspicilia and Xanthoria from ecclesiastical buildings in northern Spain have been analysed non-destructively by FT-Raman spectroscopy. The vibrational band assignments in the spectra of the specimens, which were still attached to their limestone or sandstone substrata, were accomplished with the assistance of the chemical compositions obtained from wet chemical extraction methods. β-Carotene was found in all specimens as the major pigment, and the characteristic spectral signatures of calcium oxalate monohydrate (whewellite) and dihydrate (weddelite) could be identified; chemical signatures were found for these materials even in lichen thalli growing the non-calcareous substrata, indicating, probably, that the calcium was provided here from wind-or-rain-borne sources. The Raman spectral biomarkers found in the lichens broadly agreed with the chemical extraction profiles as expected, but the present study indicates that some form of non-destructive taxonomic identification based on Raman spectroscopy was possible. [Copyright &y& Elsevier]

A molecular phylogenetic analysis of rDNA was performed for seven Caloplaca, seven Xanthoria, one Fulgensia and five outgroup species. Phylogenetic hypotheses are constructed based on nuclear small and large subunit rDNA, separately and in combination. Three strongly supported major monophyletic groups were revealed within the Teloschistaceae. One group represents the Xanthoria fallax-group. The second group includes three subgroups: (1) X. parietina and X. elegans; (2) basal placodioid Caloplaca species followed by speciations leading to X. polycarpa and X. candelaria; and (3) a mixture of placodioid and endolithic Caloplaca species. The third main monophyletic group represents a heterogeneous assemblage of Caloplaca and Fulgensia species with a drastically different metabolite content. We report here that the two genera Caloplaca and Xanthoria, as well as the subgenus Gasparrinia, are all polyphyletic. The taxonomic significance of thallus morphology in Teloschistaceae and the current delimitation of the genus Xanthoria is discussed in light of these results. [ABSTRACT FROM AUTHOR]

A method for visualization of fungal nuclear structures using the DNA specific fluorochrome SYTOX Green and confocal laser scanning microscopy is presented. The staining procedure detects nuclei in different cell types with high contrast. Furthermore, the method permits generation of high-resolution confocal image stacks using optimised scanning conditions. This approach significantly improved visualization of stained fungal nuclear structures. The technique was applied to some lichenized fungi, but can also be used to study similar detail in non-lichenized fungi. In certain cases, incompletely separated chromosome-like structures, heterochromatic material as well as weakly stained nucleolar regions can be seen. In Xanthoria parietina, variation in the nuclear division was observed in developing ascospores. Delayed division after the formation of endospore thickening resulted in the exchange of nuclear material through a narrow isthmus. [ABSTRACT FROM AUTHOR]