Book of Abstracts (PDF) - International Mycological Association

IMC7 Friday August 16th Lectures
higher level classification may require 20-50 gene
sequences.
410 - Lecanoromycetes
G. Rambold
Lehrstuhl für Pflanzensystematik, Universität Bayreuth,
Universitätsstrasse 30 - NW 1, D-95447, Bayreuth,
Germany.
In the current Myconet classification, lichenized
discomycetes are mainly placed in the two classes
Arthoniomycetes and Lecanoromycetes with 6 orders,
about 64 families, 72 Arthoniomycetes and 494
Lecanoromycetes genera. The class Arthoniomycetes with
one order is represented by nearly 400 known species, the
class Lecanoromycetes might well comprize ca. 6.300
species. Following the Myconet classification, the order
Lecanorales s. str. is segregated into four suborders,
whereas some other units formerly treated at suborder rank,
have been (re-)assigned the status of orders. In the last
years there were main activities in molecular phylogenetic
research concerning both classes. From 2930 (partial) 18S
rDNA sequences actually existing for Pezizomycotina, ca.
1,6% refer to Arthoniomycetes and ca. 10% to
Lecanoromycetes. For Arthoniomycetes additional 78 ITS
sequences (ca. 1.2%) have been published aside from a
negligible number of 26S and mitochondrial sequence data.
For Lecanoromycetes, nearly 900 ITS sequences, 250
sequences of 26S and a small number of mitochondrial
sequence data are available in GenBank. To estimate the
support of existing classifications of the two ascomycete
classes by published molecular data, topologies of 18Strees
of 20 publications are evaluated and compared with
phylogenies calculated from 600 high quality sequences of
1600 bp minimum length. Supplementary information from
ITS- and LSU-based phylogenies is respected in the
considerations.
411 - Chaetothyriomycetes and Dothideomycetes
H.T. Lumbsch
Fachbereich 9/Botanik, Universität Essen,
Universitätsstraße 5 D-45117 Essen, Germany.
Major results of recent studies, mainly based on molecular
methods, concerning the phylogeny of these two classes of
ascolocularous fungi are presented and discussed. This
includes the inclusion of lichenized fungi (e.g.
Verrucariales) in the Chaetothyriomycetes and their
relationships to other ascomycetes. Recent studies on the
Dothideomycetes mainly dealed with the subdivision of
this large class of fungi into natural lineages. Results and
prospects for further is discussed using some examples.
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Book of Abstracts
412 - Eurotiomycetes
R.S. Currah
Department of Botany, University of Alberta, b414
Biological Sciences Centre Edmonton, Alberta T6G 2E9,
Canada.
The morphological signature of the Eurotiomycetes
embodies fungi that generally produce spherical,
evanescent, eight-spored asci within more or less globose
ascomata. Ascospores are minute, single-celled and hyaline
or very pale in colour. DNA sequence analyses underline
the convergent nature of this signature and have been the
basis of arguments to align taxa with the typical
eurotiomycete signature with other classes (e.g.,
Cryptendoxyla, Myxotrichum). Similarly, DNA analyses
have been used to align taxa with quite anomalous
morphology within the Eurotiomycetes (e.g.,
Pseudotulostoma). Understanding the nature of the
ecological pressures creating these morphological variants
will help us rationalize the taxonomic journeys of taxa
among the classes of the Ascomycota.
413 - Leotiomycetes
H.-O. Baral 1 & R. Galán 2*
1 Blaihofstr. 42, D-72074 Tuebingen, Germany. -
2 Department of Plant Biology, University of Alcalá 28871
Alcalá de Henares, Madrid, Spain.
Molecular sequence data have suggested a more or less
severe rearrangement of some genera or species within the
Helotiales, or even their removal from the order to which
they have previously been placed according to
morphological characters. Whether these modern results
can be accepted in every case remains to be seen.
Morphological studies are based on a high number of
species and specimens, while molecular studies often still
concern only one or a few species per genus. Some
morphologies are so complex in structure that a
polyphyletic origin advocated by molecular data in some
cases seems quite impossible to imagine. Furthermore,
identification of species is still problematic in the
Ascomycetes, considering the fact that a large number of
taxa still remains to be described, followingly erroneous
specific or even generic names may have been attached to
specimens from which molecular data derive. Nobody has
control over correct determination when using data from
GenBank. The potential of descriptive light-microscopical
morphology is far from being fully exhausted. This
especially concerns the various characters of the living
fungus (vital taxonomy) which offer a huge amount of
stable information on both generic and specific levels, but
also concerns exact studies of apical apparatus, croziers
etc. Such carefully gained morphological results often
coincide with those of the sequence data, especially if a
combination of characters is used for the generic concepts.