Heidi Lie Andersen

The Limitations of Ancestral State Reconstruction and the Evolution of the Ascus in the Lecanorales (Lichenized Ascomycota)

Ancestral state reconstructions of morphological or ecological traits on molecular phylogenies are becoming increasingly frequent. They rely on constancy of character state change rates over trees, a correlation between neutral genetic change and phenotypic change, as well as on adequate likelihood models and (for Bayesian methods) prior distributions. This investigation explored the outcomes of a variety of methods for reconstructing discrete ancestral state in the ascus apex of the Lecanorales, a group containing the majority of lichen-forming ascomycetes. Evolution of this character complex has been highly controversial in lichen systematics for more than two decades. The phylogeny was estimated using Bayesian Markov chain Monte Carlo inference on DNA sequence alignments of three genes (small subunit of the mitochondrial rDNA, large subunit of the nuclear rDNA, and largest subunit of RNA polymerase II). We designed a novel method for assessing the suitable number of discrete gamma categories, which relies on the effect on phylogeny estimates rather than on likelihoods. Ancestral state reconstructions were performed using maximum parsimony and maximum likelihood on a posterior tree sample as well as two fully Bayesian methods. Resulting reconstructions were often strikingly different depending on the method used; different methods often assign high confidence to different states at a given node. The two fully Bayesian methods disagree about the most probable reconstruction in about half of the nodes, even when similar likelihood models and similar priors are used. We suggest that similar studies should use several methods, awaiting an improved understanding of the statistical properties of the methods. A Lecanora-type ascus may have been ancestral in the Lecanorales. State transformations counts, obtained using stochastic mapping, indicate that the number of state changes is 12 to 24, which is considerably greater than the minimum three changes needed to explain the four observed ascus apex types. Apparently, the ascus in the Lecanorales is far more apt to change than has been recognized. Phylogeny corresponds well with morphology, although it partly contradicts currently used delimitations of the Crocyniaceae, Haematommataceae, Lecanoraceae, Megalariaceae, Mycoblastaceae, Pilocarpaceae, Psoraceae, Ramalinaceae, Scoliciosporaceae, and Squamarinaceae.

Molecular Evidence of Apatococcus, including A. fuscideae sp. nov., as Photobiont in the Genus Fuscidea

The knowledge of the taxonomy and classification of algae (including lichenized) has recently increased rapidly, but there are still many gaps. We aimed to 1) identify the Fuscidea photobionts by locating their taxonomic positions in the green algal classification, and 2) to resolve their interspecific relationships. The lichenized algae were examined based on morphological observations of axenic isolates as well as molecular studies of 18S and ITS nrDNA sequences. Analysis of the secondary structure of the ITS2 operon complemented these investigations. We found that the Fuscidea photobionts were placed within the Trebouxiophyceae, related to Apatococcus lobatus (Chodat) J.B.Petersen. Phylogenetic analyses revealed one clade nesting free-living and lichenized Apatococcus F.Brand which comprised six different lineages in the ITS phylogeny. The lichenized alga associated with the investigated Fuscidea species, except for F. lightfootii (Sm.) Coppins & James, represents a hitherto unknown lineage within Apatococcus. Fuscidea lightfootii was lichenized with a separate lineage within Apatococcus, together with free-living members, which were already known from Genbank sequences. All retrieved groups within Apatococcus were rather different in their ITS sequences, thus most likely corresponding to different species. The most common photobiont of Fuscidea species, Apatococcus fuscideae A.Beck & Zahradn., was described as new to science.

Growing with dinosaurs: natural products from the Cretaceous relict Metasequoia glyptostroboides Hu & Cheng—a molecular reservoir from the ancient world with potential in modern medicine

After the sensational rediscovery of living exemplars of the Cretaceous relict Metasequoia glyptostroboides—a tree previously known exclusively from fossils from various locations in the northern hemisphere, there has been an increasing interest in discovery of novel natural products from this unique plant source. This article includes the first complete compilation of natural products reported from M. glyptostroboides during the entire period in which the tree has been investigated (1954–2014) with main focus on the compounds specific to this plant source. Studies on the biological activity of pure compounds and extracts derived from M. glyptostroboides are reviewed for the first time. The unique potential of M. glyptostroboides as a source of bioactive constituents is founded on the fact that the tree seems to have survived unchanged since the Cretaceous era. Since then, its molecular defense system has resisted the attacks of millions of generations of pathogens. In line with this, some recent landmarks in Metasequoia paleobotany are covered. Initial spectral analysis of recently discovered intact 53 million year old wood and amber of Metasequoia strongly indicate that the tree has remained unchanged for millions of years at the molecular level.

Non-Polar Natural Products from Bromelia laciniosa, Neoglaziovia variegata and Encholirium spectabile (Bromeliaceae)

Extensive regional droughts are already a major problem on all inhabited continents and severe regional droughts are expected to become an increasing and extended problem in the future. Consequently, extended use of available drought resistant food plants should be encouraged. Bromelia laciniosa, Neoglaziovia variegata and Encholirium spectabile are excellent candidates in that respect because they are established drought resistant edible plants from the semi-arid Caatinga region. From a food safety perspective, increased utilization of these plants would necessitate detailed knowledge about their chemical constituents. However, their chemical compositions have previously not been determined. For the first time, the non-polar constituents of B. laciniosa, N. variegata and E. spectabile have been identified. This is the first thorough report on natural products from N. variegata, E. spectabile, and B. laciniosa. Altogether, 20 non-polar natural products were characterized. The identifications were based on hyphenated gas chromatography-high resolution mass spectrometry (GC-HRMS) and supported by 1D and 2D Nuclear Magnetic Resonance (NMR) plant metabolomics.

The taxonomy of the lichen Fuscidea cyathoides (Fuscideaceae, Umbilicariomycetidae, Ascomycota) in Europe

Based on morphometric and molecular methods, the taxonomy of the infraspecific taxa of Fuscidea cyathoides (Ach.) V. Wirth & Vězda, var. corticola (Fr.) Kalb and var. sorediata (H. Magn.) Poelt, has been assessed. No formal taxonomic recognition should be attributed to the morphological and ecological variation. Accordingly, var. corticola and var. sorediata are synonymized with F . cyathoides var. cyathoides . New synonyms at the specific level are Fuscidea fagicola (Zschacke) Hafellner & Turk and F . stiriaca (A. Massal.) Hafellner.