Book of Abstracts (PDF) - International Mycological Association

IMC7 Monday August 12th Lectures
studied the diversity and phylogenetic affinities of
symbiotic root-associated ascomycetes of the Helotiales
based on ITS1-5.8S-ITS2 (ITS) nrDNA sequences.
Mycobionts were obtained from roots of ericoid plants and
grasses and from Piceirhiza bicolorata ectomycorrhizas
(pbECM) on conifers and hardwoods, predominantly in
burnt and metal-polluted habitats. The mycobionts were
sequenced through the ITS and compared to sequences of
known helotialean taxa. We recognised 132 fungal ITSsequences
with affinity to the Helotiales, of which 75% (54
different ITS-genotypes) grouped within the
Hymenoscyphus ericae aggregate including Phialophora
finlandia. This aggregate showed stronger affinity to
members of the Hyaloscyphaceae and Dermateaceae than
to Hymenoscyphus fructigenus (genus-type species;
Helotiaceae). The H. ericae aggregate may be referable to a
generic unit, and includes a diverse group of closely related
± darkly pigmented root-associated ascomycetes where the
borders between intra- and interspecific ITS-sequence
variation as well as different types of root-symbioses
remain unclear.
62 - How little we know about the inoperculates in
China
W.-y. Zhuang
Institute of Microbiology, Chinese Academy of Sciences,
P.O. Box 2714, Beijing 100080, China. - E-mail:
zhuangwy@sun.im.ac.cn
Three stages can be recognized in studies of inoperculate
discomycetes in China. Saccardo's taxonomic treatments
were applied by the early mycologists at the very
beginning, the influence of Seaver's works constituted the
second stage, and treatments by Nannfeldt and Korf were
much involved after the 1950's. Revisionary work by Korf
plus several other recent workers towards the natural
classification system is accepted currently. Known species
of the inoperculates in China increased from 67 in the
1930's and 1940's, 81 in 1963 by Prof. S. C. Teng and 140
in 1979 by Prof. F. L. Tai, and up to 424 in 103 genera at
the end of 2001 in the third stage. Significant progress has
been made through the efforts of mycologists from
different institutions dealing with species diversity of the
group in the past two decades and the known species
increased dramatically. Examples revealing the species
richness of the Hyaloscyphaceae and a number of genera in
other families were provided. Gross morphology, detailed
anatomic structures, and molecular data should be
combined properly in order to discover the phylogenetic
relationships among genera or families aiming at the
establishment of correct species concepts and a reasonable
taxonomic system for inoperculate discomycetes. We seem
to be far from that goal.
63 - Will ascus characters give meaning to future
reclassifications of non-lichenized inoperculate
discomycetes?
G.J.M. Verkley
Centraalbureau voor Schimmelcultures, P.O.Box 85167,
NL-3508 AD, Utrecht, The Netherlands. - E-mail:
verkley@cbs.knaw.nl
Most families of the inoperculate discomycetes are still
regarded as heterogeneous. Many genera are also still
poorly delimited, although in recent years progress has
been made by integrating molecular and phenotypic
approaches in some monographic studies. With molecular
tools we can rapidly trace the informative morphological
characters. Although there is still an enormous amount of
work to be done, we should also take action at suprageneric
level, using a similar approach. It is clear that the
inoperculate discomycetes are not monophyletic, and major
reclassification is imperative, but this calls for robust multigene
datasets, combined with congruent morphological
character complexes that provide enough synapomorphies.
Familiar characters such as excipular anatomy and
gelatinous substances may fail at this point. Ultrastructural
studies of selected taxa e.g., in the Helotiaceae and
Hyaloscyphaceae, have shown that the ascus apical
apparatus constitutes a promising set of microanatomical
features and should be explored further. Although some
fundamental differences in apical structures are only
resolved by transmission electron microscopy, it is
certainly feasible to screen larger groups of taxa using light
microscopy. I will attempt to correlate morphological and
molecular data currently available, however fragmentary
they may be. Obviously, more data should be gathered
before extensive conclusions can be drawn.
64 - Progress and challenge: Helotiales in the new
millenium
B.M. Spooner
Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE,
U.K. - E-mail: b.spooner@rbgkew.org.uk
After 70 years of progress, radical changes to the
classification of inoperculates proposed by Nannfeldt have
been few. Such changes are mainly recent, based on
powerful tools such as DNA and ultrastructural analyses.
They include demolition of the traditional Leotiaceae and
Sclerotiniaceae, now regrouped into 5 families and, more
extreme, the ousting of Orbilia as representative of a whole
new class. In contrast, molecular study of Hyaloscyphaceae
indicates surprising coherence of seemingly disparate taxa.
But there remain conflicts in results and uncertainty about
the placement of many taxa. Problems include an acute
lack of data on the species involved. Two-thirds of these
may remain undescribed, and only a handful have yet been
sampled for modern analyses. Small subunit RNA
sequences, for example, are known for less than 50 genera,
Book of Abstracts 21