Book of Abstracts (PDF) - International Mycological Association

IMC7 Monday August 12th Lectures
1 - Character evolution in the Lasiosphaeriaceae sensu
lato
A.N. Miller 1* & S.M. Huhndorf 2
1 University of Illinois at Chicago, Dept. of Biological
Sciences, Chicago, IL 60607-7060, U.S.A. - 2 The Field
Museum of Natural History, Dept. of Botany, Chicago, IL
60605-2496, U.S.A. - E-mail: amiller@fmnh.org
There are a limited number of phylogenetically informative
morphological characters for delimiting taxa above the
species level in many pyrenomycetes, mostly due to their
small stature and simplistic form. Ascospore morphology
has been used extensively throughout the filamentous
ascomycetes for distinguishing families and genera and
many genera in the Lasiosphaeriaceae have been
segregated using ascospore morphology. However, other
morphological characters, such as ascomatal wall
characters, have been suggested, but not tested, for
delimiting genera in this family. For example, several
genera possess unique bombardioid walls in which the
middle wall layer is gelatinized and several species of
Lasiosphaeria and Cercophora possess identical threelayered
walls in which the outer layer is composed of
hyphal strands. To test the utility of these morphological
characters for predicting evolutionary relationships,
sequences of the 28S nuclear ribosomal large-subunit
(LSU) gene were generated for taxa within the
Lasiosphaeriaceae and selected outgroups. Sequences from
two nuclear protein-coding genes, B-tubulin and RPB2,
were also generated to corroborate the LSU data.
Maximum parsimony and Bayesian analyses of separate
and combined data sets suggest that ascospore characters
are extremely homoplastic and not useful for delimiting
genera in the Lasiosphaeriaceae. Ascomatal wall characters
are, however, sometimes phylogenetically informative and
could be used for segregating taxa.
2 - Developing phylogenies for integrating mitotic fungi
in the Hypocreales and Diaporthales
A.Y. Rossman * , L.A. Castlebury & D.F. Farr
Systematic Botany & Mycology Laboratory, USDA-ARS,
Beltsville, MD 20705, U.S.A. - E-mail: amy@nt.arsgrin.gov
Recent comprehensive studies of the Hypocreales and
Diaporthales using both morphological and molecular
characters present the opportunity to integrate the mitotic
fungi and to evaluate character evolution of both
teleomorphic and anamorphic states. The majority of plantassociated
fungi are mitotic species without any known
sexual state and limited morphology. Using molecular
sequence data it is possible to integrate the mitotic fungi
into the Hypocreales and Diaporthales and to demonstrate
that a vast number of mitotic fungi are derived from within
these sexual state lineages. In the Hypocreales, the mitotic
fungi tend to be hyphomycetous with the exception of the
Clavicipitaceae while in the Diaporthales they are primarily
coelomycetous. Despite considerable effort, some mitotic
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Book of Abstracts
species cannot be closely linked with sexual states or even
families and thus appear to represent divergent lineages.
The character evolution within the Hypocreales and
Diaporthales appear similar with fruiting bodies ranging
from solitary perithecia to compound stromata, often
characteristic of specific families. Ascospore morphology
is also characteristic of specific families although
exceptions exist in each family. Biologically the
Diaporthales appear to be confined to plant substrata often
as virulent plant pathogens in temperate regions while the
Hypocreales fill much broader niches attacking insects and
other fungi as well as plant substrata with their greatest
diversity in tropical regions.
3 - Remembering and dismembering Stilbella: A
classical hyphomycete genus
K.A. Seifert
Eastern Cereal and Oilseed Research Centre, Agriculture
& Agri-Food Canada, 960 Carling Ave., Ottawa, Ontario
K1A 0C6, Canada. - E-mail: seifertk@em.agr.ca
The 275 described taxa of Stilbum and Stilbella were
reduced to 45 species in seven genera in my 1985
monograph. Cladistic analysis of LSU rDNA sequences
provides new insight into the phylogeny and taxonomy of
these fungi. Stilbella-like anamorphs occur in four families
of Hypocreales (Bionectriaceae, Hypocreaceae,
Nectriaceae, Clavicipitaceae), in the Phyllachorales,
Microascales and Leotiales. The type, S. fimetaria, is
related to the cleistothecial Emericellopsis
(Bionectriaceae). Previous delimitations of Tubercularia
(teleomorphs: Nectria ss, Nectriaceae), Gliocladium
(teleomorphs: Sphaerostilbella, Hypocreaceae),
Rhizostilbella (teleomorph: Corallomycetella, Nectriaceae)
and Polycephalomyces (teleomorphs: Byssostilbe,
Clavicipitaceae) are supported by LSU data. The recently
described Gracilistilbella (teleomorphs: Stilbocrea), is a
monophyletic group within the Bionectriaceae. Volutella
(teleomorphs Cosmospora, Nectriaceae), previously
restricted to setose sporodochial species, is emended to
include synnematous species. Stilbella annulata is related
to the Phyllachorales. The phylogenetic distribution of
these anamorphs suggests that synnemata are either
plesiomorphic in the Hypocreales and sporadically
expressed, or that they have arisen repeatedly. A strictly
redefined Stilbella includes only two species, but implies
recognition of many monotypic genera. This once large
form taxon is a useful metaphor for patterns in anamorph
taxonomy revealed by molecular data.
4 - Ecology and evolution in the Onygenales: an
overview based on molecular and morphological
characters
W.A. Untereiner
Brandon University, 270-18th Street, Brandon Manitoba
R7A 6A9, Canada. - E-mail: untereiner@brandonu.ca