Book of Abstracts (PDF) - International Mycological Association

IMC7 Friday August 16th Lectures
artificial inoculation and were identified as A. laevigatum.
Isolates from the basidiocarps and the mycangia of
horntails had similar ITS and peroxidase A sequences. The
wood of all inoculated trees showed discoloration, with no
difference in shape and pattern of discoloration among the
two isolates from the basidiocarps of A. laevigatum and
two from the mycangia of horntails. The inoculated fungi
were reisolated from the areas of discoloration in the
inoculated trees. This is the first report on wood
discoloration of hinoki and sugi caused by the horntails and
A. laevigatum.
430 - Relationships amongst the fungal symbionts of
Siricid woodwasps and their spread in the Southern
Hemisphere
B. Slippers 1* , T.A. Coutinho 1 , B.D. Wingfield 2 & M.J.
Wingfield 1
1
Forestry and Agricultural Biotechnology Institute (FABI),
Dept of Microbiology and Plant Pathology, University of
2
Pretoria, Pretoria, South Africa. - Forestry and
Agricultural Biotechnology Insititute (FABI), Dept of
Genetics, University of Pretoria, Pretoria, South Africa. -
E-mail: bernard.slippers@fabi.up.ac.za
The Basidiomycetes genus Amylostereum is best known for
its symbiosis with siricid wood wasps. In this study, the
phylogenetic relationships between Amylostereum spp. and
other Basidiomycetes were investigated, using sequence
data of the nuc-IGS and mt-SSU rDNA regions. A.
areolatum was more distantly related to the three other
species of Amylostereum, than they were to each other. A.
ferreum and A. laevigatum were the most closely related
species. These data support hypotheses relating to the
mating behaviour and ecology of Amylostereum spp.
Furthermore, contrary to previous suggestions, the
Amylostereum spp. were more closely related to
Echinodontium tinctorium (Echinodontiaceae) than to the
Stereaceae. Apart from phylogenetic studies, vegetative
compatibility and PCR-RFLP analyses were also used to
study the spread of the introduced S. noctilio-A. areolatum
complex in the Southern Hemisphere. Isolates of A.
areolatum from South Africa and South America were
found to represent a single VCG. PCR-RFLP profiles from
nuc-IGS region showed that all isolates from the Southern
Hemisphere shared the same profile, which differed from
that of other populations. This genetically uniform
population of A. areolatum has emerged from its obligate
relationship with S. noctilio, which disperses only asexual
fungal propagules. These results suggest a single or limited
introduction of the A. areolatum-S. noctilio into the
Southern Hemisphere.
431 - Interspecific combative interactions - an overview
L. Boddy * & D.P. Donnelly
Cardiff School of Biosciences, Cardiff University, PO Box
915, Cardiff CF10 3TL, U.K. - E-mail:
boddyl@cardiff.ac.uk
Competition by fungi for nutrients in dead organic
resources is effectively brought about by competition for
space. Such competition can be divided into primary
resource capture (obtaining uncolonized resources) and
secondary resource capture (combat to obtain resources
already colonized by other fungi). Combat occurs not only
in organic resources but also when mycelia grow out of the
resource, e.g.into soil, in search of new resources.
Combative mechanisms include antagonism at a distance,
mycoparasitism, hyphal interference and gross mycelial
contact. Outcome of interactions can be deadlock, where
neither species gains territory from the other, or
replacement, where one mycelium partially or completely
wrests territory from the other. A hierarchy of combative
abitlity can be discerned amongst fungi that inhabit a
particular resource, but within this hierarchy there is
intransitivity and outcomes can vary depending on abioic
variables and the presence of other organisms. Interactions
can dramatically alter mycelial function even when the
outcome is deadlock. The review will be illustrated largely
with examples of wood decay fungi and of wood decay
fungi interacting with ectomycorrhizal mycelium.
432 - Interactions among wood-inhabiting fungi:
implications for fungal succession and biocontrol
J. Stenlid * , L. Holmer & A. Iakovlev
Dept Forest Mycology and Pathology, Swedish University
of Agricultural Sciences, Box 7026, S- 750 07 Uppsala,
Sweden. - E-mail: Jan.Stenlid@mykopat.slu.se
Interactions among wood inhabiting fungi are important for
succession and have also implications for biocontrol. Early
establishment secures resources for the mycelium while
late arrival to a substrate necessitates strategies for entering
an already established decay community. Mycelial
parasitism and replacement in wood has proven to be one
important driving force in succession in wood.
Replacement involves developmental changes in the
mycelia and can often be facilitated by production of
antimicrobial secondary substances. Other key factors for
succession include differences in ability to handle
recalcitrant compounds, differences in growth rate,
differences in responses to gaseous regime and water
potential etc. We will describe experiments indicating both
species specific and general replacement patterns,
metabolite production, and gene expression during
interaction between various wood inhabiting fungi. Special
reference will be given to the possibilities to find
biocontrol against economically important root rot fungi
such as Heterobasidion annosum.
Book of Abstracts 133