Notes on the circumscription of the lichens Lecanora leprosa and L. sulphurescens (Lecanoraceae, lichenised Ascomycotina)

Lecanora leprosa and L. sulphurescens are two commonly misidentified pantropical lichens. A detailed circumscription is presented to help overcome such difficulties. Both species contain a chemosyndrome of chlorodepsidones based on gangaleoidin. The new depsidone chlorolecideoidin (methyl 2,4,9-trichloro-3,8-dihydroxy-1,6-dimethyl-11-oxo-11H-dibenzo[b,e][1,4]-dioxepin- 7-carboxylate) has been shown to be a minor component of both species.Lecanora leprosa und L. sulphurescens sind zwei häufig fehlbestimmte pantropische Flechten. Eine ausführliche Beschreibung der beiden Arten wird vorgelegt. Beide Arten enthalten ein auf Gangaleoidin basierendes Chemosyndrom von Chlordepsidonen. Das neue Depsidon Chlorlecideoidin (Methyl 2,4,9-Trichlor-3,8-dihydroxy-1,6-dimethyl-11-oxo-11Hdibenzo[ b,e][1,4]-dioxepin-7-carboxylat) wird beschrieben. Es kommt in beiden Arten als Nebeninhaltsstoff vor

Diversity of Lecidea (Lecideaceae, Ascomycota) species revealed by molecular data and morphological characters

The diversity of lichens, especially crustose species, in continental Antarctica is still poorly known. To overcome difficulties with the morphology based species delimitations in these groups, we employed molecular data (nuclear ITS and mitochondrial SSU rDNA sequences) to test species boundaries within the genus Lecidea. Sampling was done along a north–south transect at five different areas in the Ross Sea region (Cape Hallett, Botany Bay to Mount Suess, Taylor Valley, Darwin Area and Mount Kyffin). A total of 153 specimens were collected from 13 localities. Phylogenetic analyses also include specimens from other regions in Antarctica and non-Antarctic areas. Maximum parsimony, maximum likelihood and Bayesian analyses agreed in placing the samples from continental Antarctica into four major groups. Based on this phylogenetic estimate, we restudied the micromorphology and secondary chemistry of these four clades to evaluate the use of these characters as phylogenetic discriminators. These clades are identified as the following species Lecidea cancriformis, L. andersonii as well as the new species L. polypycnidophora Ruprecht & Türk sp. nov. and another previously unnamed clade of uncertain status, referred to as Lecidea sp. (L. UCR1)

Evolution of lichens

Peer reviewe

Cryptic species in lichen-forming fungi

This contribution provides a synopsis of the presentations and discussions during the SIG session on cryptic speciation in lichen-forming fungi held during IMC9. In several cases, a re-examination of morphology against the background of molecular phylogenetic evidence revealed, sometimes subtle, morphological and/or chemical characters, supporting the distinction of particular clades at species level. However, there are also examples of cryptic species in which no morphological characters could be identified to distinguish between lineages. Several cases were presented in which distinct lineages are correlated with biogeographical patterns. When and how to name cryptic species was debated, and the use of terms such as “complex” or “aggregate” commended where the taxa formed part of a single lineage

Ancient Horizontal Gene Transfer from Bacteria Enhances Biosynthetic Capabilities of Fungi

Polyketides are natural products with a wide range of biological functions and pharmaceutical applications. Discovery and utilization of polyketides can be facilitated by understanding the evolutionary processes that gave rise to the biosynthetic machinery and the natural product potential of extant organisms. Gene duplication and subfunctionalization, as well as horizontal gene transfer are proposed mechanisms in the evolution of biosynthetic gene clusters. To explain the amount of homology in some polyketide synthases in unrelated organisms such as bacteria and fungi, interkingdom horizontal gene transfer has been evoked as the most likely evolutionary scenario. However, the origin of the genes and the direction of the transfer remained elusive.We used comparative phylogenetics to infer the ancestor of a group of polyketide synthase genes involved in antibiotic and mycotoxin production. We aligned keto synthase domain sequences of all available fungal 6-methylsalicylic acid (6-MSA)-type PKSs and their closest bacterial relatives. To assess the role of symbiotic fungi in the evolution of this gene we generated 24 6-MSA synthase sequence tags from lichen-forming fungi. Our results support an ancient horizontal gene transfer event from an actinobacterial source into ascomycete fungi, followed by gene duplication.Given that actinobacteria are unrivaled producers of biologically active compounds, such as antibiotics, it appears particularly promising to study biosynthetic genes of actinobacterial origin in fungi. The large number of 6-MSA-type PKS sequences found in lichen-forming fungi leads us hypothesize that the evolution of typical lichen compounds, such as orsellinic acid derivatives, was facilitated by the gain of this bacterial polyketide synthase

Unravelling the phylogenetic relationships of lichenised fungi in Dothideomyceta

We present a revised phylogeny of lichenised Dothideomyceta (Arthoniomycetes and Dothideomycetes) based on a combined data set of nuclear large subunit (nuLSU) and mitochondrial small subunit (mtSSU) rDNA data. Dothideomyceta is supported as monophyletic with monophyletic classes Arthoniomycetes and Dothideomycetes; the latter, however, lacking support in this study. The phylogeny of lichenised Arthoniomycetes supports the current division into three families: Chrysothrichaceae (Chrysothrix), Arthoniaceae (Arthonia s. l., Cryptothecia, Herpothallon), and Roccellaceae (Chiodecton, Combea, Dendrographa, Dichosporidium, Enterographa, Erythrodecton, Lecanactis, Opegrapha, Roccella, Roccellographa, Schismatomma, Simonyella). The widespread and common Arthonia caesia is strongly supported as a (non-pigmented) member of Chrysothrix. Monoblastiaceae, Strigulaceae, and Trypetheliaceae are recovered as unrelated, monophyletic clades within Dothideomycetes. Also, the genera Arthopyrenia (Arthopyreniaceae) and Cystocoleus and Racodium (Capnodiales) are confirmed as Dothideomycetes but unrelated to each other. Mycomicrothelia is shown to be unrelated to Arthopyrenia s.str., but is supported as a monophyletic clade sister to Trypetheliaceae, which is supported by hamathecium characters. The generic concept in several groups is in need of revision, as indicated by non-monophyly of genera, such as Arthonia, Astrothelium, Cryptothecia, Cryptothelium, Enterographa, Opegrapha, and Trypethelium in our analyses

Diversidad de especies de Xanthoparmelia (Parmeliaceae) en la vegetación de matorrales xerofíticos mexicanos, evidenciada por datos moleculares, morfológicos y químicos

The genus Xanthoparmelia is the largest genus of lichen- forming fungi with about 800 species worldwide. Xanthoparmelia is also common in the deserts of central Mexico, but only a few molecular studies exist on its species’ diversity in this region. In this study, we sampled 38 Xanthoparmelia species from around the world including species from the xerophytic scrubs of central Mexico to assess the diversity using an integrative approach. Molecular phylogenetic analyses were performed using a combination of the ITS, mtSSU and nuLSU genetic markers. We evaluated our phylogenetic results in a context of traditional morphological and chemical characters. The combined evidence of molecular, morphological, and chemical data identified a total of 18 Xanthoparmelia species-level lineages occurring in central Mexico. However, numerous traditionally circumscribed species did not form monophyletic groups in the molecular phylogenetic reconstructions. This conflict indicates that taxonomy and species delimitation in the genus Xanthoparmelia requires revision and emphasizes the importance of molecular evidence for more robust species delimitations in this genus.Xanthoparmelia es el género más grande de hongos liquenizados, con alrededor de 800 especies en todo el mundo. Xanthoparmelia es común en los desiertos del centro de México, pero existen pocos estudios moleculares sobre la diversidad de especies en esta región. En este estudio, muestreamos 38 especies de Xanthoparmelia de diferentes partes del mundo, incluidas especies de los matorrales xerófilos del centro de México, para evaluar la diversidad usando una aproximación integrativa. Los análisis filogenéticos moleculares se realizaron combinando los marcadores genéticos ITS, mtSSU y nuLSU. Además, evaluamos nuestros resultados filogenéticos en un contexto de caracteres morfológicos y químicos usados en la taxonomía tradicional. Teniendo en cuenta las evidencias obtenidas a partir de caracteres moleculares, morfológicos y químicos se identificaron un total de 18 linajes de Xanthoparmelia con categoría de especie que aparecen en el centro de México. Sin embargo, muchas especies tradicionalmente circunscritas no formaron grupos monofiléticos. Este conflicto indica que la taxonomía y delimitación de especies en el género Xanthoparmelia requiere revisión y enfatiza la importancia de los datos moleculares para una delimitación más robusta de especies en este género

Species recognition and phylogeny of Thelotrema species in Australia (Ostropales, Ascomycota)

Species circumscriptions based on morphological data are difficult in crustose lichens with limited characters as they often show remarkable variability. An example is the genus Thelotrema s.str., a speciose genus of mostly tropical lichens. Morphological studies on Australian Thelotrema spp. were accompanied by a phylogenetic analysis of mt SSU rDNA sequence data of 19 species, including 25 newly obtained sequences. We performed maximum parsimony and Bayesian phylogenetic analyses of 50 samples, representing 25 species. Our results indicate that more species need to be accepted in Thelotrema than previously thought. Subtle morphological differences were found to be associated with independent lineages in the phylogenetic trees. Furthermore, monophyly of Thelotrema s.str. is strongly supported. On the basis of the corroboration of morphological evidence by molecular data, the new species Thelotrema capetribulense Mangold, T. crespoae Mangold, Lumbsch & Elix, T. oleosum Mangold, and T. pseudosubtile Mangold are described. The new combinations Chapsa phlyctidioides (Müll.Arg.) Mangold and Thelotrema defossum (Müll.Arg.) Mangold are proposed

Contrasting patterns of climatic niche divergence in Trebouxia—A alade of lichen-forming algae.

Lichen associations are overwhelmingly supported by carbon produced by photosynthetic algal symbionts. These algae have diversified to occupy nearly all climates and continents; however, we have a limited understanding of how their climatic niches have evolved through time. Here we extend previous work and ask whether phylogenetic signal in, and the evolution of, climatic niche, varies across climatic variables, phylogenetic scales, and among algal lineages in Trebouxia—the most common genus of lichen-forming algae. Our analyses reveal heterogeneous levels of phylogenetic signal across variables, and that contrasting models of evolution underlie the evolution of climatic niche divergence. Together these analyses demonstrate the variable processes responsible for shaping climatic tolerance in Trebouxia, and provide a framework within which to better understand potential responses to climate change associated perturbations. Such predictions reveal a disturbing trend in which the pace at which modern climate change is proceeding will vastly exceed the rate at which Trebouxia climatic niches have previously evolved