Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme II: SYSTEMATICS, PHYLOGENY AND EVOLUTION Posters
Lentinus lindquistii (Sing.) Lechner & Alberto (=Pleurotus
lindquistii Singer) is known only from its type locality in
Argentina. Lentinus lindquistii has been separated from L.
tigrinus s. s. based on non-inflated generative hyphae and
other slight morphological differences (i.e. spore size). We
employed tester strains of L. lindquistii and singlebasidiospore
isolates (SBIs) of L. tigrinus (Bull.: Fr.) from
10 widely scattered geographic locations to ascertain
congruence of morphological, biological, and genetical
species concepts. SBIs of L. tigrinus were obtained from
fresh material collected in the field and basidiomata
produced in vitro. SBIs from each collection were paired
with those of all other collections (n = 4 or 8) to ascertain
sexual intercompatibility. Results showed complete
compatibility among collections, indicating that all
collections represented the same biological species. Our
data demonstrate the morphological variability of two 'taxa'
in the L. tigrinus complex. Sequence analysis of the ITS1-
5.8S-ITS2 nrDNA suggests that widely scattered
geographical populations of the L. tigrinus complex are
genetically divergent. Although these populations have
been separated long enough to allow sequence evolution,
they are still capable of compatible mating.
671 - Ascocarp impalement: a novel mechanism of
dispersal in cleistothecial ascomycetes
M.D. Greif * & R.S. Currah
Department of Biological Sciences, University of Alberta,
CW-405, Edmonton T6G 2E9, Canada. - E-mail:
mattgreif@hotmail.com
Ascomycetes have evolved a variety of mechanisms to
ensure the dispersal of their meiospores by animals. Some
of these include the production of sticky spores (e.g.
Ophiostomatales) or even the development of the ascocarp
directly on the body of an arthropod (e.g. Laboulbeniales),
both ensuring that propagules are transferred economically
from one suitable habitat to another. Here, we report a
novel mechanism that has developed independently in two
ascomycete lineages, the Leotiomycetes and the
Eurotiomycetes. In representatives of these classes, namely
Myxotrichum and Auxarthron respectively, the ascocarp is
a cage-like cleistothecium with an internal mass of minute,
pale coloured ascospores borne within a lattice of rigid
thick walled hyphae. By exposing mature ascocarps of
these two fungi to active Dipterans (Sarcophagidae and
Calliphoridae) for 24 hours we demonstrated that this type
of ascocarp is picked up through an impalement event in
which the arthropod hairs pass between the spaces of the
cleistothecial lattice, glancing or piercing the ascospore
mass and affixing the entire ascocarp to the body of the
vector. We suggest that this impalement mechanism is the
driving force behind the convergence in ascocarp form in
these cleistothecial fungi.
672 - Cryphonectria cubensis resides in a genus outside
Cryphonectria
M.V. Gryzenhout 1* , H. Myburg 2 , M.J. Wingfield 1 & B.D.
Wingfield 2
1 Department of Microbiology and Plant Pathology,
Forestry & Agricultural Biotechnology Institute (FABI),
University of Pretoria, Pretoria, 0002, South Africa. -
2 Department of Genetics, Forestry & Agricultural
Biotechnology Institute (FABI), University of Pretoria,
Pretoria, 0002, South Africa. - E-mail:
Marieka.Gryzenhout@fabi.up.ac.za
Cryphonectria cubensis is a serious pathogen of Eucalyptus
spp., clove (Syzigium aromaticum) and Tibouchina spp. in
the tropics and sub-tropics. In previous studies, sequence
data from the ITS1/ITS2 regions of the ribosomal DNA
operon, and LSU and SSU DNA, suggested that C.
cubensis does not group together with other Cryphonectria
spp. The aim of the present study was to pursue this
question further and to determine an appropriate generic
placement for C. cubensis. An expanded collection of
Cryphonectria and Endothia spp. was included and we
produced additional sequences for the ITS1/ITS2 regions
and the beta--tubulin genes. Herbarium specimens,
including type collections, of C. cubensis and other species
of Cryphonectria were also examined in detail. DNA
sequences revealed that a world-wide collection of C.
cubensis isolates, grouped separately from Cryphonectria
and Endothia species in a strongly resolved clade. The
anamorph of C. cubensis is blackened, pycnidium-like and
superficial, and the teleomorph has black perithecial necks
extending beyond the stromatal surface. This is in contrast
to Cryphonectria that has orange stromata with semiimmersed
anamorphs and orange perithecial necks.
Morphological characteristics support DNA-based
analyses, showing that C. cubensis should reside in a genus
separate from Cryphonectria. In contrast to previous views,
anamorph morphology and colour appear to be more
taxonomically informative than teleomorph structure and
ascospores.
673 - Reconsideration of the conspecificity of Endothia
eugeniae and Cryphonectria cubensis
M.V. Gryzenhout 1* , H. Myburg 2 , M.J. Wingfield 1 & B.D.
Wingfield 2
1 Department of Microbiology and Plant Pathology,
Forestry & Agricultural Biotechnology Institute (FABI),
University of Pretoria, Pretoria, 0002, South Africa. -
2 Department of Genetics, Forestry & Agricultural
Biotechnology Institute (FABI), University of Pretoria,
Pretoria, 0002, South Africa. - E-mail:
Marieka.Gryzenhout@fabi.up.ac.za
Endothia eugeniae, a canker pathogen of clove (Syzigium
aromaticum), was synonymised with the Eucalyptus canker
pathogen Cryphonectria cubensis. This synonymy emerged
Book of Abstracts 203