The Lichen Genus (Lobariaceae, Peltigerales) in East African Montane Ecosystems.

The lichen flora of Africa is still poorly known. In many parts of the tropics, recent studies utilizing DNA methods have revealed extraordinary diversity among various groups of lichenized fungi, including the genus . In this study, East African species and their ecology are reviewed using the genetic barcoding marker nuITS and morphological characters.

Woodpeckers can act as dispersal vectors for fungi, plants, and microorganisms.

Bird-mediated dispersal is presumed to be important in the dissemination of many different types of organisms, but concrete evidence remains scarce. This is especially true for biota producing microscopic propagules. Tree-dwelling birds, such as woodpeckers, would seem to represent ideal dispersal vectors for organisms growing on standing tree trunks such as epiphytic lichens and fungi.

Complex Interaction Networks Among Cyanolichens of a Tropical Biodiversity Hotspot.

Interactions within lichen communities include, in addition to close mutualistic associations between the main partners of specific lichen symbioses, also more elusive relationships between members of a wider symbiotic community. Here, we analyze association patterns of cyanolichen symbionts in the tropical montane forests of Taita Hills, southern Kenya, which is part of the Eastern Afromontane biodiversity hotspot. The cyanolichen specimens analyzed represent 74 mycobiont taxa within the order Peltigerales (Ascomycota), associating with 115 different variants of the photobionts genus (Cyanobacteria).

Diversity of (Collemataceae, Ascomycota) in East African Montane Ecosystems.

Tropical mountains and especially their forests are hot spots of biodiversity threatened by human population pressure and climate change. The diversity of lichens in tropical Africa is especially poorly known. Here we use the mtSSU and nuITS molecular markers together with morphology and ecology to assess (Peltigerales, Ascomycota) diversity in the tropical mountains of Taita Hills and Mt.

Crustose lichens with lichenicolous fungi from Paleogene amber.

Lichens, symbiotic consortia of lichen-forming fungi and their photosynthetic partners have long had an extremely poor fossil record. However, recently over 150 new lichens were identified from European Paleogene amber and here we analyse crustose lichens from the new material. Three fossil lichens belong to the extant genus Ochrolechia (Ochrolechiaceae, Lecanoromycetes) and one fossil has conidiomata similar to those produced by modern fungi of the order Arthoniales (Arthoniomycetes).

Diversity and ecological adaptations in Palaeogene lichens.

Lichens are highly specialized symbioses between heterotrophic fungi and photoautotrophic green algae or cyanobacteria. The mycobionts of many lichens produce morphologically complex thalli to house their photobionts. Lichens play important roles in ecosystems and have been used as indicators of environmental change.

Evolution of the tRNALeu (UAA) Intron and Congruence of Genetic Markers in Lichen-Symbiotic Nostoc.

The group I intron interrupting the tRNALeu UAA gene (trnL) is present in most cyanobacterial genomes as well as in the plastids of many eukaryotic algae and all green plants. In lichen symbiotic Nostoc, the P6b stem-loop of trnL intron always involves one of two different repeat motifs, either Class I or Class II, both with unresolved evolutionary histories. Here we attempt to resolve the complex evolution of the two different trnL P6b region types.

Alectorioid Morphologies in Paleogene Lichens: New Evidence and Re-Evaluation of the Fossil Alectoria succini Mägdefrau.

One of the most important issues in molecular dating studies concerns the incorporation of reliable fossil taxa into the phylogenies reconstructed from DNA sequence variation in extant taxa. Lichens are symbiotic associations between fungi and algae and/or cyanobacteria. Several lichen fossils have been used as minimum age constraints in recent studies concerning the diversification of the Ascomycota.

The genetic basis for O-acetylation of the microcystin toxin in cyanobacteria.

Microcystins are a family of cyclic peptide toxins produced by cyanobacteria. They are responsible for the toxicosis and death of wild and domestic animals throughout the world. They display extensive variation in amino acid composition and functional group chemistry.

Convergent evolution of [D-Leucine(1)] microcystin-LR in taxonomically disparate cyanobacteria.

Background: Many important toxins and antibiotics are produced by non-ribosomal biosynthetic pathways. Microcystins are a chemically diverse family of potent peptide toxins and the end-products of a hybrid NRPS and PKS secondary metabolic pathway. They are produced by a variety of cyanobacteria and are responsible for the poisoning of humans as well as the deaths of wild and domestic animals around the world.

Geographic mosaic of symbiont selectivity in a genus of epiphytic cyanolichens.

In symbiotic systems, patterns of symbiont diversity and selectivity are crucial for the understanding of fundamental ecological processes such as dispersal and establishment. The lichen genus Nephroma (Peltigerales, Ascomycota) has a nearly cosmopolitan distribution and is thus an attractive model for the study of symbiotic interactions over a wide range of spatial scales. In this study, we analyze the genetic diversity of Nephroma mycobionts and their associated Nostoc photobionts within a global framework.

Cyanobacteria produce a high variety of hepatotoxic peptides in lichen symbiosis.

Lichens are symbiotic associations between fungi and photosynthetic algae or cyanobacteria. Microcystins are potent toxins that are responsible for the poisoning of both humans and animals. These toxins are mainly associated with aquatic cyanobacterial blooms, but here we show that the cyanobacterial symbionts of terrestrial lichens from all over the world commonly produce microcystins.

Reconstruction of structural evolution in the trnL intron P6b loop of symbiotic Nostoc (Cyanobacteria).

In this study we reconstruct the structural evolution of the hyper-variable P6b region of the group I trnLeu intron in a monophyletic group of lichen-symbiotic Nostoc strains and establish it as a useful marker in the phylogenetic analysis of these organisms. The studied cyanobacteria occur as photosynthetic and/or nitrogen-fixing symbionts in lichen species of the diverse Nephroma guild. Phylogenetic analyses and secondary structure reconstructions are used to improve the understanding of the replication mechanisms in the P6b stem-loop and to explain the observed distribution patterns of indels.

Microcystin production in the tripartite cyanolichen Peltigera leucophlebia.

We show that the cyanobacterial symbionts of a tripartite cyanolichen can produce hepatotoxic microcystins in situ. Microcystins were detected with high-performance liquid chromatography mass spectrometry both from cephalodia of the tripartite cyanolichen Peltigera leucophlebia and from a symbiotic Nostoc strain isolated from the same lichen specimen. Genetic identities of symbiotic Nostoc strains were studied by amplifying and sequencing the 16S rRNA gene.