Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
A. gallica was stochastic where target woody food bases
were placed laterally with respect to the colonized source;
however rhizomorph foraging was significantly directed
when the target woody food base was placed above or
below the source. Presence of con-specific neighbor genets
altered the allocation of rhizomorph length and the number
of foraging tips without affecting fractal dimension for
both A. gallica and A. mellea. Similarly, neighboring
genets of different species did not influence the fractal
dimension of A. gallica or A. mellea rhizomorph systems.
Thus, Armillaria rhizomorph system pattern is influenced
in abundance and physical location in the landscape by
adjacent genets of the same or different species, while the
inherent foraging pattern remains unresponsive to such
influences.
1007 - Micro-evolution in the ectomycorrhizal fungus
Suillus luteus
L.A.H. Muller, K. Adriaensen, J. Vangronsveld & J.V.
Colpaert *
Limburgs Universitair centrum, Laboratory of
Environmental Biology, Universitaire Campus, 3590
Diepenbeek, Belgium. - E-mail: jan.colpaert@luc.ac.be
Previous research has shown that populations of the
ectomycorrhizal fungus Suillus luteus found in areas
polluted with high levels of heavy metals (Zn, Cd) have
acquired adaptive tolerance to elevated levels of these
metals. Furthermore, these populations showed a reduced
genetic variability, as measured by ISSR markers,
compared to control populations from unpolluted sites. In
this study we aim to analyse the microevolution of
populations of Suillus luteus in areas polluted with heavy
metals. Therefore, the genetic structure of these
populations, as well as the structure of populations from
unpolluted areas, the amount of gene flow between these
populations and the occurrence of bottlenecks will be
described using microsatellite and AFLP markers. In a later
stage, mtDNA markers will also be used, after having
resolved the inheritance mode of the mitochondria in S.
luteus. After identification of genes related with the heavy
metal tolerance, natural selection will be investigated on a
molecular level using these genes and the selectively
neutral molecular markers.
1008 - Genetic diversity within French populations of
Tuber melanosporum Vittad.
C. Murat 1* , P. Luis 2 , J. Diez 2 , C. Delaruelle 2 , C. Dupré 3 , G.
Chevalier 3 & F. Martin 2
1 University of Torino, Viale Mattioli, 25, 10125 Torino,
Italy. - 2 UMR 'Interaction Tree-Microorganisms' INRA of
Nancy, 54280 Champenoux, France. - 3 INRA Unity of
Mycology, Crouelle, 63039 Clermont-Ferrand cedex 2,
France. - E-mail: claude.murat@unito.it
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Book of Abstracts
Truffles are ectomycorrhizal ascomycetes and edible fungi
of economic value. They have been the focus of numerous
studies of genetic diversity. Certain species show a high
genetic diversity (e.g. Tuber uncinatum), whereas others
have low polymorphism (e.g. T. melanosporum). T.
melanosporum was regarded as a clonal species without
any geographic genetic structure. We have analyzed the
genetic diversity of T. melanosporum populations from
different geographic regions in France by looking for
polymorphic loci. We have used RAPD (Random
Amplified Polymorphism DNA) profiles, genomic
sequences previously identified as SCAR (Sequence
Characterized Amplified Random) and sequences from the
internal transcribed spacers (ITS) of nrDNA. The RAPD
phenotypic analysis and the sequence analysis of genomic
tags have confirmed the genetic homogeneity of this
species. RAPD phenotypes can not be correlated to their
origin region. However, we have found some polymorphic
populations and, according to the Shannon's index, isolates
from 'Bourgogne' were the most variable. Sequencing of
the ITS allowed us to identify four haplotypes (I, II, III and
IV) in 47 ascocarps. Haplotypes I and II were the most
frequent and they were found in every populations except
for haplotype I in 'Lorraine'. On the other hand, haplotypes
III and IV were more scarce and restricted to particular
French regions (e.g. Haplotype IV was found only in
'Lorraine') suggesting a genetic structure in T.
melanosporum.
1009 - Ceratocystis wilt of Acacia mearnsii in Uganda
G. Nakabonge * , I. Barnes, J. Roux & M.J. Wingfield
Forestry and Agricultural Biotechnology Institute (FABI),
University of Pretoria, 0002, Pretoria, South Africa. - Email:
grace.nakabonge@fabi.up.ac.za.
Ceratocystis wilt caused by C. albofundus is a severe
disease of Acacia mearnsii, in Africa. In a recent survey,
this disease was found on wounded A. mearnsii in South
Western Uganda. Diseased trees showed extensive
discoloration of the wood, dieback, gummosis, wilting and
death. Previous studies of the gene diversity of a South
African population using CAT5 marker and 8 microsatellite
markers revealed a high gene diversity. The high gene
diversity and presence of C. albofundus on native Protea
species has led to a hypothesis that it is native to South
Africa. The aim of this study was to determine the gene
diversity of a Ugandan population and compare it to that of
the South African population. 36 isolates, were obtained
from A. mearnsii trees in South Western Uganda. Eight
microsatellite primers pairs previously designed for C.
fimbriata were used to amplify the microsatellite rich
regions of the genome. Analysis of the microsatellite data
revealed 7 loci to be polymorphic. Nei's gene diversity (H)
showed that the South African population is slightly more
diverse than the Ugandan population with a value of
0.4320 compared to 0.4082. Results further revealed that
very few alleles are shared, with little gene flow between
the two populations. The high gene diversity in both
populations strongly suggests that C. albofundus is native
to the African continent and not necessarily only to South
Africa, as previously suggested.