Gitta Langer

Bio: Gitta Langer is an academic researcher from University of Kassel. The author has contributed to research in topics: Biology & Mycovirus. The author has an hindex of 6, co-authored 13 publications receiving 2711 citations. Previous affiliations of Gitta Langer include University of Tübingen.

Reconstructing the early evolution of Fungi using a six-gene phylogeny

Abstract: The ancestors of fungi are believed to be simple aquatic forms with flagellated spores, similar to members of the extant phylum Chytridiomycota (chytrids). Current classifications assume that chytrids form an early-diverging clade within the kingdom Fungi and imply a single loss of the spore flagellum, leading to the diversification of terrestrial fungi. Here we develop phylogenetic hypotheses for Fungi using data from six gene regions and nearly 200 species. Our results indicate that there may have been at least four independent losses of the flagellum in the kingdom Fungi. These losses of swimming spores coincided with the evolution of new mechanisms of spore dispersal, such as aerial dispersal in mycelial groups and polar tube eversion in the microsporidia (unicellular forms that lack mitochondria). The enigmatic microsporidia seem to be derived from an endoparasitic chytrid ancestor similar to Rozella allomycis, on the earliest diverging branch of the fungal phylogenetic tree.

The phylogenetic distribution of resupinate forms across the major clades of mushroom-forming fungi (Homobasidiomycetes)

Abstract: Phylogenetic relationships of resupinate Homobasidiomycetes (Corticiaceae s. lat. and others) were studied using ribosomal DNA (rDNA) sequences from a broad sample of resupinate and nonresupinate taxa. Two datasets were analysed using parsimony, a 'core' dataset of 142 species, each of which is represented by four rDNA regions (mitochondrial and nuclear large and small subunits), and a 'full' dataset of 656 species, most of which were represented only by nuclear large subunit rDNA sequences. Both datasets were analysed using traditional heuristic methods with bootstrapping, and the full dataset was also analysed with the Parsimony Ratchet, using equal character weights and six-parameter weighted parsimony. Analyses of both datasets supported monophyly of the eight major clades of Homobasidiomycetes recognised by Hibbett and Thorn, as well as independent lineages corresponding to the Gloeophyllum clade, corticioid clade and Jaapia argillacea. Analyses of the full dataset resolved two additional groups, the athelioid clade and trechisporoid clade (the latter may be nested in the polyporoid clade). Thus, there are at least 12 independent clades of Homobasidiomycetes. Higher- level relationships among the major clades are not resolved with confidence. Nevertheless, the euagarics clade, bolete clade, athelioid clade and Jaapia argillacea are consistently resolved as a monophyletic group, whereas the cantharelloid clade, gomphoid-phalloid clade and hymenochaetoid clade are placed at the base of the Homobasidiomycetes, which is consistent with the preponderance of imperforate parenthesomes in those groups. Resupinate forms occur in each of the

Evolution of gilled mushrooms and puffballs inferred from ribosomal DNA sequences

Abstract: Homobasidiomycete fungi display many complex fruiting body morphologies, including mushrooms and puffballs, but their anatomical simplicity has confounded efforts to understand the evolution of these forms. We per- formed a comprehensive phylogenetic analysis of homobasi- diomycetes, using sequences from nuclear and mitochondrial ribosomal DNA, with an emphasis on understanding evolu- tionary relationships of gilled mushrooms and puffballs. Parsimony-based optimization of character states on our phylogenetic trees suggested that strikingly similar gilled mushrooms evolved at least six times, from morphologically diverse precursors. Approximately 87% of gilled mushrooms are in a single lineage, which we call the ''euagarics.'' Recently discovered 90 million-year-old fossil mushrooms are probably euagarics, suggesting that (i) the origin of this clade must have occurred no later than the mid-Cretaceous and (ii) the gilled mushroom morphology has been maintained in certain lin- eages for tens of millions of years. Puffballs and other forms with enclosed spore-bearing structures (Gasteromycetes) evolved at least four times. Derivation of Gasteromycetes from forms with exposed spore-bearing structures (Hymenomyce- tes) is correlated with repeated loss of forcible spore discharge (ballistospory). Diverse fruiting body forms and spore dis- persal mechanisms have evolved among Gasteromycetes. Nev- ertheless, it appears that Hymenomycetes have never been secondarily derived from Gasteromycetes, which suggests that the loss of ballistospory has constrained evolution in these lineages.

The cantharelloid clade: dealing with incongruent gene trees and phylogenetic reconstruction methods

Abstract: We reassessed the circumscription of the cantharelloid clade and identified monophyletic groups by using nLSU, nSSU, mtSSU and RPB2 sequence data. Results agreed with earlier studies that placed the genera Cantharellus, Craterellus, Hydnum, Clavulina, Membranomyces, Multiclavula, Sistotrema, Botryobasidium and the family Ceratobasidiaceae in that clade. Phylogenetic analyses support monophyly of all genera except Sistotrema, which was highly polyphyletic. Strongly supported monophyletic groups were: (i) Cantharellus-Craterellus, Hydnum, and the Sistotrema confluens group; (ii) Clavulina-Membranomyces and the S. brinkmannii-oblongisporum group, with Multiclavula being possibly sister of that clade; (iii) the Sistotrema eximum-octosporum group; (iv) Sistotrema adnatum and S. coronilla. Positions of Sistotrema raduloides and S. athelioides were unresolved, as were basal relationships. Botryobasidium was well supported as the sister taxon of all the above taxa, while Ceratobasidiaceae was the most basal lineage. The relationship between Tulasnella and members of the cantharelloid clade will require further scrutiny, although there is cumulative evidence that they are probably sister groups. The rates of molecular evolution of both the large and small nuclear ribosomal RNA genes (nuc-rDNA) are much higher in Cantharellus, Craterellus and Tulasnella than in the other cantharelloid taxa, and analyses of nuc-rDNA sequences strongly placed Tulasnella close to Cantharellus-Craterellus. In contrast analyses with RPB2 and mtSSU sequences placed Tulasnella at the base of the cantharelloid clade. Our attempt to reconstruct a "supertree" from tree topologies resulting from separate analyses that avoided phylogenetic reconstruction problems associated with missing data and/or unalignable sequences proved unsuccessful.

Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for Fungi

Abstract: Six DNA regions were evaluated as potential DNA barcodes for Fungi, the second largest kingdom of eukaryotic life, by a multinational, multilaboratory consortium. The region of the mitochondrial cytochrome c oxidase subunit 1 used as the animal barcode was excluded as a potential marker, because it is difficult to amplify in fungi, often includes large introns, and can be insufficiently variable. Three subunits from the nuclear ribosomal RNA cistron were compared together with regions of three representative protein-coding genes (largest subunit of RNA polymerase II, second largest subunit of RNA polymerase II, and minichromosome maintenance protein). Although the protein-coding gene regions often had a higher percent of correct identification compared with ribosomal markers, low PCR amplification and sequencing success eliminated them as candidates for a universal fungal barcode. Among the regions of the ribosomal cistron, the internal transcribed spacer (ITS) region has the highest probability of successful identification for the broadest range of fungi, with the most clearly defined barcode gap between inter- and intraspecific variation. The nuclear ribosomal large subunit, a popular phylogenetic marker in certain groups, had superior species resolution in some taxonomic groups, such as the early diverging lineages and the ascomycete yeasts, but was otherwise slightly inferior to the ITS. The nuclear ribosomal small subunit has poor species-level resolution in fungi. ITS will be formally proposed for adoption as the primary fungal barcode marker to the Consortium for the Barcode of Life, with the possibility that supplementary barcodes may be developed for particular narrowly circumscribed taxonomic groups.

The skin microbiome

Abstract: The skin is the human body's largest organ, colonized by a diverse milieu of microorganisms, most of which are harmless or even beneficial to their host. Colonization is driven by the ecology of the skin surface, which is highly variable depending on topographical location, endogenous host factors and exogenous environmental factors. The cutaneous innate and adaptive immune responses can modulate the skin microbiota, but the microbiota also functions in educating the immune system. The development of molecular methods to identify microorganisms has led to an emerging view of the resident skin bacteria as highly diverse and variable. An enhanced understanding of the skin microbiome is necessary to gain insight into microbial involvement in human skin disorders and to enable novel promicrobial and antimicrobial therapeutic approaches for their treatment.

Fungal endophytes: diversity and functional roles.

Abstract: Summary 1 Summary All plants in natural ecosystems appear to be symbiotic with fungal endophytes. This highly diverse group of fungi can have profound impacts on plant communities through increasing fitness by conferring abiotic and biotic stress tolerance, increasing biomass and decreasing water consumption, or decreasing fitness by altering resource allocation. Despite more than 100 yr of research resulting in thousands of journal articles, the ecological significance of these fungi remains poorly characterized. Historically, two endophytic groups (clavicipitaceous (C) and nonclavicipitaceous (NC)) have been discriminated based on phylogeny and life history traits. Here, we show that NC-endophytes represent three distinct functional groups based on host colonization and transmission, in planta biodiversity and fitness benefits conferred to hosts. Using this framework, we contrast the life histories, interactions with hosts and potential roles in plant ecophysiology of C- and NC-endophytes, and highlight several key questions for future work in endophyte biology.

Reconstructing the early evolution of Fungi using a six-gene phylogeny

Abstract: The ancestors of fungi are believed to be simple aquatic forms with flagellated spores, similar to members of the extant phylum Chytridiomycota (chytrids). Current classifications assume that chytrids form an early-diverging clade within the kingdom Fungi and imply a single loss of the spore flagellum, leading to the diversification of terrestrial fungi. Here we develop phylogenetic hypotheses for Fungi using data from six gene regions and nearly 200 species. Our results indicate that there may have been at least four independent losses of the flagellum in the kingdom Fungi. These losses of swimming spores coincided with the evolution of new mechanisms of spore dispersal, such as aerial dispersal in mycelial groups and polar tube eversion in the microsporidia (unicellular forms that lack mitochondria). The enigmatic microsporidia seem to be derived from an endoparasitic chytrid ancestor similar to Rozella allomycis, on the earliest diverging branch of the fungal phylogenetic tree.