Genus Lepraria Research Articles

Rethinking asexuality: the enigmatic case of functional sexual genes in Lepraria (Stereocaulaceae)

BackgroundThe ubiquity of sex across eukaryotes, given its high costs, strongly suggests it is evolutionarily advantageous. Asexual lineages can avoid, for example, the risks and energetic costs of recombination, but suffer short-term reductions in adaptive potential and long-term damage to genome integrity. Despite these costs, lichenized fungi have frequently evolved asexual reproduction, likely because it allows the retention of symbiotic algae across generations. The lichenized fungal genus Lepraria is thought to be exclusively asexual, while its sister genus Stereocaulon completes a sexual reproductive cycle. A comparison of sister sexual and asexual clades should shed light on the evolution of asexuality in lichens in general, as well as the apparent long-term maintenance of asexuality in Lepraria, specifically.ResultsIn this study, we assembled and annotated representative long-read genomes from the putatively asexual Lepraria genus and its sexual sister genus Stereocaulon, and added short-read assemblies from an additional 22 individuals across both genera. Comparative genomic analyses revealed that both genera were heterothallic, with intact mating-type loci of both idiomorphs present across each genus. Additionally, we identified and assessed 29 genes involved in meiosis and mitosis and 45 genes that contribute to formation of fungal sexual reproductive structures (ascomata). All genes were present and appeared functional in nearly all Lepraria, and we failed to identify a general pattern of relaxation of selection on these genes across the Lepraria lineage. Together, these results suggest that Lepraria may be capable of sexual reproduction, including mate recognition, meiosis, and production of ascomata.ConclusionsDespite apparent maintenance of machinery essential for fungal sex, over 200 years of careful observations by lichenologists have produced no evidence of canonical sexual reproduction in Lepraria. We suggest that Lepraria may have instead evolved a form of parasexual reproduction, perhaps by repurposing MAT and meiosis-specific genes. This may, in turn, allow these lichenized fungi to avoid long-term consequences of asexuality, while maintaining the benefit of an unbroken bond with their algal symbionts.

Contributions to the phylogeny of Lepraria (Stereocaulaceae) species from the Southern Hemisphere, including three new species

We utilized ITS and mtSSU sequence data to study the phylogenetic relationships of Lepraria samples collected in the Southern Hemisphere, including Australia, Chile, New Zealand and Antarctica. Morphological characters and the secondary chemistry of the specimens were also examined. Using a combination of morphological, chemical and molecular data, we identified nine lineages in our material. The lineages are: Lepraria toilenae, L. eburnea, L. nothofagi, L. straminea, L. caerulescens, L. finkii, and three previously undescribed clades that are here described as L. chileana, L. neozelandica and L. ulrikii. The first is described from Chile. The second occurs in New Zealand, and the third has an Australasian distribution, occurring in New Zealand, mainland Australia, and Tasmania. In addition, L. straminea is identified as an usnic acid-producing species of the genus Lepraria. Moreover, L. caerulescens is confirmed as a distinct species.

The lichen genus Lepraria Ach. (Stereocaulaceae, lichenized Ascomycota) in Romania

Introduction. The genus Lepraria includes diffuse or indefinitely delimited species, always sterile, Lendemer (1) naming it „the most unusual member of the sterile lichen crusts”. According to Tonsberg (2), the leprarioid state appeared as an adaptation to a substrate characterized by dry surfaces, in sites with high humidity and low illumination. The thallus is leprose with an entirely sorediate surface. The lack of fruiting bodies has made the lichens from this group among the least known and studied for a long time. The increase in the number of studies on sterile crustose lichens in recent period has led to an increase in the number of accepted species of the genus Lepraria. The information on the genus Lepraria is not uniformly distributed, the current checklist describes only two species, L. caesioalba and L. finkii in Romania. The recent appearance of several studies that indicate the presence in Romania of other species of the genus mentioned, created the motivation of this study. 
 Material and methods. This study is based on material from the Babes-Bolyai University (CL) herbaria in Cluj-Napoca, Romania and literature data. For 13 species, specimens have been examined.
 Results. The key for the species of genus Lepraria is proposed, adapted from Wirth (3). The species distribution maps in Romania are given.
 Conclusions. Fifteen Romanian species are revised, Lepraria eburnea, L. ecorticata, L. umbricola were reported from two locations, L. neglecta was found only in one location. Most widely distributed species in Romania seems to be L. finkii and L. membranacea.

Lichens genus Lepraria in Belarus: ecology and distribution of species

Sterile crustose lichens, i. e., those species that do not form fruiting bodies on the territory of Belarus, domestic scientists started to focus only at the beginning of the 21st century, despite the fact that already in the 60–70’s in the 20th century and methods for determining lichen substances in lichens were developed.Subjects of the study were herbarium specimens of lichenized fungi of the genus Lepraria in the amount of 68 herbarium bags from the collection of lichens MSK-L. As a result of the determination of secondary metabolites in the samples and the use of morphological features, it is established that the samples studied are represented by 9 species from the genus Lepraria: L. caesioalba, L. eburnea, L. elobata, L. finkii, L. incana, L. jackii, L., neglecta, L. rigidula и L. vouauxii. Lichen Lepraria caesioalba first time provides for the territory of the republic. The biotopes and substrate association of lichens with the genus Lepraria has been established. The qualitative composition of secondary metabolites of the studied samples is revealed. Among certain species, lichens L. incana and L. finkii are common on the territory of Belarus. The herbarium material on lichens of the genus Lepraria determined using TLC can be used in the preparation of the next volume of “Flora of lichens of Belarus”.

The lichen genera Lepraria (Stereocaulaceae) and Leprocaulon (Leprocaulaceae) in India

A taxonomic study of the genus Lepraria in India revealed one new species Lepraria indica R. Bajpai & Upreti and 14 new records (L. achariana, L. aurescens, L. caesiella, L.caesioalba, L. cupressicola, L. eburnea, L. ecorticata, L. elobata, L. friabilis, L. granulata, L. incana, L. isidiata, L. leuckertiana, L.lobata) together with two new records of Leprocaulon (L. adhaerens and L. textum) for the lichen flora of the country. An artificial key to all known species of Lepraria and Leprocaulon from India is also provided.

Distribution of Lichen Species of the Genus Lepraria in the Knyszyn Forest (Ne Poland) in Different Forest Plant Communities

Abstract The aim of the study was to evaluate the distribution of lichen species of the genus Lepraria in Knyszyn Forest (NE Poland) to different forest plant communities. Six species of Lepraria [L. eburnea J. R. Laundon, L. elobata Tønsberg, L. incana (L.) Ach., L. jackii Tønsberg, L. lobificans Nyl. and L. vouaxii (Hue) R. C. Harris] recorded from Knyszyn Forest. Lepraria eburnea is a new species for the studied area. The most common species were Lepraria incana and L. lobificans. Among the studied forest communities the richest in species (5 species of Lepraria) were oak-hornbeam forest (Tilio-Carpinetum), and the least species-rich (2 species) were maple-linden slope forest (Aceri-Tilietum), alder carr (Carici elongatae-Alnetum) and spruce forest (Sphagno girgensohnii-Piceetum). The richest lichen diversity in the Knyszyn Forest was found on deciduous trees such as Carpinus betulus L. and Quercus robur L. (4 species), Tilia cordata Mill. (3 spp.), and conifers such as Picea abies (L.) H. Karst. and Pinus sylvestris L. (3 spp.).

The genus Lepraria (lichen-forming fungi) in Hungary

The genus Lepraria was a neglected lichen group in Hungary for a long time. Its species were difficult to differentiate in the lack of fruit-bodies. Generally the entire thallus consists of soredia. Chemical characters were investigated by spot reactions only. However, international investigations of the last decades show fine morphological characters seen only by high magnification and resolution microscopic investigations. Furthermore lichen secondary metabolites analysed by thin-layer chromatography is a more advanced method for detecting these diagnostic characters. Application of the revised character set resulted in identification of 9 species in Hungary. These species are illustrated by micrographs, and some details of the analysis on lichen secondary metabolites are presented. So far about 350 specimens were analysed. Fresh collections from various areas within Hungary and the surrounding countries are still necessary to clear the exact distribution of the species in our region. The work is supported by the projects OTKA K81232 and NKFI K124341.

The genus Lepraria (Stereocaulaceae, lichenized Ascomycota) in Belarus

Based on an examination of 360 herbarium specimens of the genus Lepraria, this study deals with their morphology, secondary chemistry, habitat requirements and distribution in Belarus. Nine taxa have been accepted, of which L. ecorticata, L. finkii and L. rigidula are new to the country. L. incana appears to be the commonest species in the country (48% of the studied specimens).

A monograph of the crustose members of the genus Lepraria Ach. s. str. (Stereocaulaceae, Lichenized Ascomycetes) in North America north of Mexico

A monograph of the crustose members of the genus Lepraria Ach. s. str. (Stereocaulaceae, Lichenized Ascomycetes) in North America north of Mexico

Fungal farmers or algal escorts: lichen adaptation from the algal perspective

Domestication of algae by lichen-forming fungi describes the symbiotic relationship between the photosynthetic (green alga or cyanobacterium; photobiont) and fungal (mycobiont) partnership in lichen associations (Goward 1992). The algal domestication implies that the mycobiont cultivates the alga as a monoculture within its thallus, analogous to a farmer cultivating a food crop. However, the initial photobiont 'selection' by the mycobiont may be predetermined by the habitat rather than by the farmer. When the mycobiont selects a photobiont from the available photobionts within a habitat, the mycobiont may influence photobiont growth and reproduction (Ahmadjian & Jacobs 1981) only after the interaction has been initiated. The theory of ecological guilds (Rikkinen etal. 2002) proposes that habitat limits the variety of photobionts available to the fungal partner. While some studies provide evidence to support the theory of ecological guilds in cyanobacterial lichens (Rikkinen etal. 2002), other studies propose models to explain variation in symbiont combinations in green algal lichens (Ohmura etal. 2006; Piercey-Normore 2006; Yahr etal. 2006) hypothesizing the existence of such guilds. In this issue of Molecular Ecology, Peksa & Škaloud (2011) test the theory of ecological guilds and suggest a relationship between algal habitat requirements and lichen adaptation in green algal lichens of the genus Lepraria. The environmental parameters examined in this study, exposure to rainfall, altitude and substratum type, are integral to lichen biology. Lichens have a poikilohydric nature, relying on the availability of atmospheric moisture for metabolic processes. Having no known active mechanism to preserve metabolic thallus moisture in times of drought, one would expect a strong influence of the environment on symbiont adaptation to specific habitats. Adaptation to changes in substrata and its properties would be expected with the intimate contact between crustose lichens in the genus Lepraria. Altitude has been suggested to influence species distributions in a wide range of taxonomic groups. This is one of the first studies to illustrate an ecological guild, mainly for exposure to rainfall (ombrophiles and ombrophobes), with green algal lichens.

Notes on the lichen genus Lepraria from maritime (South Shetlands) and continental (Schirmacher and Bunger Oases) Antarctica

Material of the genus Lepraria from maritime and continental Antarctica collected in 1986–2007 was studied. Four species were distinguished, L. alpina, L. caerulescens, L.straminea and one putative new taxon provisionally called Lepraria sp. AO. L. caerulescens is tentatively resurrected from the synonyms of L. alpina for the chemotype with atranorin and angardianic/roccellic acid. Lepraria sp. AO is characterized by its granular thallus similar to other members of the L. neglecta group and the presence of two fatty acids, so far unidentified and not known from other members of the genus. Morphological and chemical diagnostic characters of all taxa, their distribution and ecological features are discussed. An updated key for identification of all Antarctic species is provided.

Species delimitation in the Lepraria isidiata-L. santosii group: a population study in the Mediterranean-Macaronesian region

AbstractA thorough chemical, molecular and morphological study has been carried out on a problematic group in the genus Lepraria characterized by lobed, granular thalli with a raised rim and a preference for mosses, rocks and mineral soils in exposed, xeric habitats. The material examined was collected in seven countries of the Mediterranean-Macaronesian region, from chalk, carbonate rocks and derived soils (A-thalli), and from siliceous rocks and derived soils (B-thalli). The results of a phylogenetic analysis based on 93 ITS sequences (29 of which newly obtained) support the identification and the segregation of two taxa at species level, provisionally identified as Lepraria isidiata s. lat., (most of the A-thalli), and L. santosii s. lat. (B-thalli plus the remaining A-thalli), as the observed genetic variability is quite high. Three chemotypes were detected in L. isidiata s. lat., and seven in L. santosii s. lat. The two taxa are morphologically well characterized: in L. isidiata s. lat. the thallus is thicker and the propagules larger than in L. santosii s. lat. The first stages of thallus development from single propagules are described in both species. Some critical remarks are made about the increasing use of the species rank for taxa of Lepraria, which are morphologically and genetically scarcely characterized.

Large genetic divergence of new, morphologically similar species of sterile lichens from Europe (Lepraria, Stereocaulaceae, Ascomycota): concordance of DNA sequence data with secondary metabolites.

Lichenized fungi of the genus Lepraria are known for their paucity of morphological characters. Species identification is therefore largely based on secondary chemistry. We investigated different chemotypes of the morphologically highly similar L. jackii species complex by internal transcribed spacer (ITS) sequencing. In phylogenetic analyses including all available Lepraria species, samples belonging to different chemotypes of the L. jackii agg. corresponded to four highly divergent clusters. While true L. jackii was genetically uniform, the other three clades represented previously unrecognized species. They originated from different major speciation events, and two of them were not closely related to any other species. Assessment of intraspecific genetic variability revealed four different patterns with respect to geographic scale. ITS sequences proved to be the most reliable and distinctive characters for species recognition in the Lepraria jackii complex and were in accordance with chemical and ecogeographic data. Frequent occurrence of long branches, relatively few resolved relationships despite high genetic variability, and the discovery and description of a considerable part of the Lepraria species within the last 10 years suggest that the genus is probably much larger than currently known. The diversification of this asexual group in the potential absence of recombination is discussed. © The Willi Hennig Society 2008.

Phylogenetic distribution and evolution of secondary metabolites in the lichenized fungal genus Lepraria (Lecanorales: Stereocaulaceae)

Molecular sequence data are used to explore the phylogenetic distribution of secondary metabolites and metabolite classes among species of Lepraria. All substance classes examined were phylogenetically widespread, except for � -orcinol meta-depsides and anthraquinones, which appeared rare and restricted to a single major clade. Benzyl esters were also found to be rare. Taxa producing each substance class examined were not monophyletic. The ability to regularly produce orcinol para- depsides, � -orcinol meta-depsides, � -orcinol depsidones, dibenzofurans, benzyl esters, terpenoids and anthraquinones appears to have been gained more than lost, while the ability to produce � -orcinol para-depsides and higher aliphatic acids has been lost more than gained. Our results suggest that chemical similarities may not necessarily indicate close phylogenetic relationships. Finally, ancestral state reconstruction at the base of genus Lepraria suggests that its ancestor produced � -orcinol para-depsides (atranorin) but did not produce orcinol para-depsides, � -orcinol meta- depsides, benzyl esters or anthraquinones.

Dissociation and horizontal transmission of codispersing lichen symbionts in the genus Lepraria (Lecanorales: Stereocaulaceae)

Lichenized fungi of the genus Lepraria lack ascomata and conidiomata, and symbionts codisperse by soredia. Here, it is determined whether algal symbionts associated with Lepraria are monophyletic, and whether fungal and algal phylogenies are congruent, both of which are indicative of a long-term, continuous association between symbionts. The internal transcribed spacer (ITS) and part of the actin type I locus were sequenced from algae associated with Lepraria, and the fungal ITS and mitochondrial small subunit (mtSSU) were sequenced from fungal symbionts. Phylogenetic analyses tested for monophyly of algal symbionts and congruence between algal and fungal phylogenies. Algae associated with Lepraria were not monophyletic, and identical algae associated with different Lepraria individuals and species. Algal and fungal phylogenies were not congruent, suggesting a lack of strict codiversification. This study suggests that associations between symbionts are not strictly maintained over evolutionary time. The ability to switch partners may provide benefits similar to genetic recombination, which may have helped this lineage persist.

Phylogenetic relationships of Stereocaulaceae based on simultaneous analysis of beta‐tubulin, GAPDH and SSU rDNA sequences

AbstractThe phylogenetic relationships of the lichenised ascomycete family Stereocaulaceae were investigated with partial beta‐tubulin, partial glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) and SSU rDNA sequence data. Due to the marked length variation in the SSU rDNA sequences, the analyses were performed with direct optimization. The combined analysis of the beta‐tubulin, GAPDH and SSU rDNA sequences as well as the separate analyses of beta‐tubulin and GAPDH data recognized the monophyletic group comprising Lepraria, Muhria and Stereocaulon. In the combined analysis Stereocaulon tornense appears as a basal taxon in the Stereocaulon clade, suggesting that the crustose growth form and the absence of cephalodia are primitive features within the genus. Muhria is nested in Stereocaulon and groups with the crustose S. cumulatum and S. leucophaeopsis. The genus Lepraria is monophyletic if Leproloma is included, but species that were represented by several specimens in our study, i.e., Lepraria jackii and Leproloma membranaceum, do not appear as monophyletic entities. The genus Pilophorus is included in Cladoniaceae. Combined analysis of the three datasets clearly led to an increase in support values compared to the separate analyses, showing high support for the monophyly of families Cladoniaceae and Stereocaulaceae and for the sistergroup relation for the two families. The relationships between higher groupings did not reach high support values probably due to the incongruencies among the three datasets.