Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
and identified from temperate soils of varying altitudes of
North India. The isolation of Chaetomium senegalense
belonging to Ascomycetes, Myceliophthora fergusii and
Synnmukerjiomyces thermophile belonging to mitosporic
fungi are reported for the first time from India. The later
species is a new synnematous hyphomycetous fungus.
Detailed studies on importance value index (IVI) and
numerical values for population number were conducted.
Soil pH, moisture and altitude of their habitat were recored.
In the present work, an attempt was also made to evaluate
the thermostable enzymes especially, amylase, cellulase,
lipase and xylanase employing Chaetomium thermophile,
Thermomyces lanuginosus, Malbranchea sulfurea and
Torula thermophila species. In the course of present
investigation, it was further realised that the exploration of
the biodiversity of thermophilic fungi has immense
potential for the future.
1135 - Gene expression in a whitish truffle during the
phase transition from mycelium to fruitbodies
I. Lacourt 1 , S. Duplessis 2 , S. Abba' 1 , F. Martin 2 & P.
Bonfante 1*
1 Dipartimento di Biologia Vegetale - Università di Torino
and Istituto per la Protezione delle Piante del CNR-sezione
di Torino, V.le Mattioli, 25 - 10125, Torino, Italy. - 2 UMR
INRA/UHP, Centre de Recherches de Nancy, 54280
Champenoux, France. - E-mail: p.bonfante@csmt.to.cnr.it
The transition from vegetative mycelium to the fruit body
in truffles requires differentiation processes which lead to
edible ascomata consisting of different cell and tissue
types. The identification of genes differentially expressed
during these developmental processes can contribute
greatly to a better understanding of truffle morphogenesis.
A cDNA library was constructed from vegetative
mycelium RNAs of the white truffle Tuber borchii and 214
cDNAs were sequenced. Up to 58% of the ESTs were
coding for known genes. The majority of the identified
sequences represented 'housekeeping' proteins, i.e.,
proteins involved in gene/protein expression, cell wall
formation, primary and secondary metabolism and
components of signaling pathways. We screened 171
arrayed cDNAs by using cDNA probes constructed from
mRNAs of vegetative mycelium and ascomata to identify
fruit body-regulated genes. Comparisons of signals from
vegetative mycelium and fruit body, bearing 15% or 70%
mature spores, revealed significant differences in the
expression levels for up to 33% of the investigated genes.
The expression level of six highly regulated genes was
confirmed by RNA blot analysis. Expression of glutamine
synthetase, 5-aminolevulinic acid synthetase, isocitrate
lyase, thioredoxin, glucan 1,3-ß-glucosidase and UDPglucurosyl
transferase were highly up-regulated suggesting
that amino acid biosynthesis, glyoxylate cycle pathway and
cell wall synthesis are strikingly altered during
morphogenesis.
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Book of Abstracts
1136 - Methyl radical derived from non-enzymatic
coordinated-copper system and its potential relation to
the selective delignification by white-rot fungi
P. Lamaipis 1* , K. Fackler 2 , T. Watanabe 3 , F. Pohleven 4 , M.
Sentjurc 5 & K. Messner 2
1
Fermentation and Biochemical Engineering Laboratory,
National Center for Genetic Engineering and
2
Biotechnology, Bangkok, Thailand. - Institute for
Biochemical Technology and Microbiology, University of
Technology Vienna, Vienna, Austria. - 3 Wood Research
Institute, Kyoto University, Kyoto, Japan. - 4 Biotechnology
Faculty, Department of Wood Science and Technology,
University of Ljubljana, Ljubljana, Slovenia. - 5 Jozef Stefan
Institute, Ljubljana, Slovenia. - E-mail:
plamaipis@biotec.or.th
White-rot fungi are able to degrade lignin more or less
selectively. A non-enzymatic catalytic system consisting of
a Cu-coordinating compound and hydroperoxides was
proposed to play a role in the selective delignification of
wood. White-rot fungi produce hydroperoxide containing a
pyridine nucleus. Cu is present in wood. Hydroperoxide
could be either obtained from lipid contained in resin or
derived by fungi. Due to this hypothesis the radicals
produced oxidatively by coordinated-Cu system could be
the compound mediating the depolymerization of lignin.
EPR measurement is the method of choice to elucidate the
radicals produced from organic peroxides by coordinated
transition metals. Methyl-, hydroxyl-, methoxyl-, and acyl
radicals were generated and trapped with DEPMPO. The
strongest signal was found for the methyl radical when Cu
was coordinated with 4-AP. In uncoordinated reactions as
well as when Fe or Mn was used, the hydroxyl radical was
predominated. When these systems were applied on wood
sections, fast delignification without major visual damage
of the cellulose part of wood cell wall was only found with
the coordinated Cu system. Faster delignification occurred
on hardwood than softwood. These correlated to the
preference of white-rot fungi on native lignin. Therefore,
we propose that the methyl radical formation from
coordinated-Cu and organic peroxide is the key step
leading to selective delignification in native wood probably
involve in selective delignify fungi.
1137 - Genome characterization of the ectomycorrhizal
fungus Paxillus involutus
A. Le Quéré, T. Johansson, D. Wright, P. Samson, B.
Söderström * & A. Tunlid
Department of Microbial Ecology, Ecology Building, Lund
University, Sölvegatan, 37 SE-223 62 Lund, Sweden. - Email:
bengt.soderstrom@mbioekol.lu.se
The basidiomycete Paxillus involutus is forming
ectomycorrhizal (ECM) symbiosis with a broad range of
forest trees. Reassociation kinetics and genomic
reconstruction analyses on nuclear DNA indicated that P.
involutus has a haploid genome size of 21.5 Mb including
11% of repetitive DNA. Analyses of a 33-kb genomic