Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
1036 - Evaluating colonization of ECM fungi at Quercus
petraea seeds, seminal roots and at the roots of
greenhouse seedlings
A. Silberstein 1* , S. Kotter 2 , J. Wöllecke 1 , B.
Münzenberger 3 & R.F. Hüttl 1
1
Brandenburg University of Technology Cottbus, Chair of
Soil Protection and Recultivation, Universitätsplatz 3-4,
03044 Cottbus, Germany. - 2 Tinplant Biotechnics and
Plant Propagation Inc., Magdeburger Str. 33, 39164 Klein
Wanzleben, Germany. -
3 Center for Agricultural
Landscape and Land Use Research (ZALF) e.V., Institute
of Primary Production and Microbial Ecology,
Eberswalder Str. 84, 15374 Müncheberg, Germany. - Email:
silber@tu-cottbus.de
In order to recultivate postmining landscapes, to diversify
existing coniferous forests and to re-afforest uneconomic
agricultural areas millions of young oak tree plants
(Quercus spec.) are needed. But we are faced with many
problems when cultivating the young oak plants. This is,
above all, true as regards the germinating process of the
acorns, as their seminal roots are often infected by
pathogenic fungi. The plant raising enterprises are,
therefore, facing huge costs. The project is accomplished
with the Tinplant company that is specialized in the raising
of containerized greenhouse seedlings of Q. petraea and
aims at evolving and testing simple and economical
methods of mycorrhization of oaks. To utilize the positive
effects of ECM fungi at a very early stage of plant
development, the hyphae should be established at the
stored or germinating seeds already. Plant raising
enterprises could look forward to better results during the
seed storage and germinating stages, as compared to
existing procedures. Recultivating companies could expect
a lower plant mortality rate after oak tree afforestation, by
making use of ectomycorrhizal fungi, suitable to the
respective location.
1037 - Population structure and pathogenicity of
Fusarium oxysporum isolated from soil and root
necrosis of pea
K. Skovgaard 1* , L. Bødker 2 & S. Rosendahl 1
1
Department of Mycology, University of Copenhagen,
Oester Farimagsgade 2D, 1353 Copenhagen K, Denmark.
2
- Danish Institute of Agricultural
Sciences, Research
Centre Flakkebjerg, Dept. of Crop Protection, 4200
Slagelse, Denmark. - E-mail: kerstins@bot.ku.dk
Forty-nine strains of Fusarium oxysporum were isolated
from five different sample locations within two
neighbouring pea fields. Of these, thirty-nine strains were
isolated from soil and ten from pea plants showing
symptoms of root rot. Twenty-eight of the isolates were
tested for pathogenicity towards pea. Based on percentage
discoloration of the roots and the stem base the isolates
were divided into three groups. Seven strains were
pathogenic, fourteen strains were weakly pathogenic, and
seven strains were non-pathogenic towards pea. To assess
the genetic relatedness of all forty-nine strains, gene
genealogies were constructed from aligned DNA sequences
from part of translation elongation factor, nitrate reductase,
beta tubulin, and mitochondrial small subunit rDNA.
Maximum parsimony analysis of the combined dataset
yielded a single most-parsimonious tree containing three
strongly supported clades which may represent cryptic
species. No correlation was observed between the
multigene phylogeny and pathogenicity toward pea, strain
geographic origin and substrate (soil or plant) from which
the strains were isolated. Strains of F. oxysporum that were
either non-pathogenic, weakly pathogenic or pathogenic
sometimes shared the same multilocus genotype. These
results suggest that strains pathgenic and putatively nonpathogenic
to pea are very closely related genetically.
1038 - Increased below-ground diversity of
ectomycorrhizal fungi after removal of litter and humus
determined from fungal hyphae in bulk soil
E. Smit 1 , C. Veenman 1 & J. Baar 2*
1 National Institute of Public Health and the Environment,
Microbiological Laboratory for Health Protection, P.O.
Box 1, 3720 BA Bilthoven, The Netherlands. - 2 Applied
Plant Research, Wageningen University and Research
Center, P.O. Box 6042, 5960 AA Horst, The Netherlands. -
E-mail: j.baar@ppo.dlo.nl
Ectomycorrhizal fungi have declined in coniferous stands
in The Netherlands over the last decades due to nitrogen
deposition originating from air pollution. The effects of
restoration practices on the ectomycorrhizal communities
in nitrogen-enriched Pinus sylvestris (Scots pine) stands in
The Netherlands were studied by Baar (1995). Litter and
humus were removed to reduce nitrogen availability in the
soils. This resulted in increased diversity of
ectomycorrhizal fungi within three years. However, all data
were obtained by counting sporocaps. The effects of litter
and humus removal on the below-ground ectomycorrhizal
communities remained unknown. In the present study the
composition of the below-ground ectomycorrhizal
communities in a P. sylvestris stand in The Netherlands
was determined five years after litter and humus removal.
Fungal DNA was extracted directly from soil samples and
PCR was applied with basidiomycete-specific ITS primers.
Samples were analyzed by DGGE to visualize diversity. To
assess species composition, ITS regions of the amplified
fragments were cloned and sequenced. Sequences were
compared with known sequences and were analyzed
phylogenetically. The analyses showed that the diversity of
the ectomycorrhizal fungi below ground in the treated plots
was higher than in the untreated plots. Rhizopogon luteolus
was the most abundant species after litter and humus
removal, while Lactarius and Russula species were the
most common species in the untreated plots.
Book of Abstracts 313