Book of Abstracts (PDF) - International Mycological Association

IMC7 Tuesday August 13th Lectures
pieces. Because many isolates do not sporulate and
therefore cannot be identified, researchers have turned to
molecular tools: RFLP and sequence analysis. We have
mapped the fine-scale distribution of the fungi cultured
from roots and found that in most cases the same fungus
did not grow out of adjacent 2mm root segments. However,
not all ericoid or epacrid root endophytic fungi are
culturable. We have found two different communities of
fungi when isolating and cultivating versus cloning PCRamplified
DNA from the same roots. We have also
accessed the 200+ sequences in GenBank of ericoid and
epacrid mycorrhizal fungi and root endophytes from a
number of research groups and carried out phylogenetic
analyses. These analyses indicate there are only 7 ericoid
mycorrhizal fungi or fungal groups in the parts of 3
continents that have been studied thus far. These same 7
fungi can also be found in the roots of a single plant on a
site on northern Vancouver Island, British Columbia.
180 - Ascomycetous mycorrhizae from prescribed burn
in ponderosa pine forest from Northwest, USA
K.E. Fujimura 1* , J.E. Smith 2 , T.R. Horton 3 , N.S. Weber 4 &
J.W. Spatafora 5
1 University of Northern British Columbia, 3333 University
Way, Prince George, BC V2N 4Z9, Canada. - 2 2USDA
Forest Service, Pacific Northwest Research Station,
Forestry Sciences Laboratory, 3200 Jefferson Way,
Corvallis, OR 97331, U.S.A. - 3 SUNY, 1 Forestry Dr.,
Syracuse, NY 13210, U.S.A. - 4 Oregon State University,
Richardson Hall, Corvallis, OR 97331, U.S.A. - 5 Oregon
State University, Dept. of Botany, Corvallis, OR 97331,
U.S.A. - E-mail: fujimurk@unbc.ca
Post-fire Pezizales include members that fruit as early as
two weeks and others as late as two years after a fire.
Despite frequent occurrence, little is known about their
ecological function. Ponderosa pine forests have a natural
fire regime that includes low intensity fires at a 15 to 30
year return interval. Our objective is to determine if
members of the post-fire Pezizales associated with
ponderosa pine forests are mycorrhizal, which may aid in
re-generation of these forests. Because fungi are patchily
distributed over the landscape, and the location of
associated mycorrhizal root tips difficult to determine, we
collected soil cores directly beneath Pezizalean sporocarps
from three sites that had been burned to mimic the natural
fire regime. Root tips from the soil cores were sorted into
morphological groups. Restriction fragment length
polymorphism (RFLP) patterns were obtained for each
morphological group to compare to RFLP patterns of
collected sporocarps. Twenty three patterns were found but
did not match any of the five genera and ten species of
Pezizalean sporocarps collected. Sequence analysis using
the small ITS region of the nrDNA was done for
comparison with Ascomycetous sequences, representing
both mycorrhizal and reputed non mycorrhizal species.
Matches were found with Geopora spp. and Wilcoxina spp.
58
Book of Abstracts
181 - Mycorrhiza-associated sterile fungi in a
Mediterranean environment: systematic heterogeneity
versus ecological convergence?
M. Girlanda * , S. Ghignone & A.M. Luppi
Dipartimento Biologia Vegetale dell'Università and IPP-
CNR, V.le Mattioli 25, 10125 Torino, Italy. - E-mail:
mariangela.girlanda@unito.it
Mediterranean ecosystems, featuring high plant diversity
and co-dominance, offer an interesting scenario for the
study of root-endophytic dark sterile mycelia (DSM) in
different hosts. Investigation of ectomycorrhizal Pinus
halepensis and endomycorrhizal Rosmarinus officinalis
plants in Italy indicated that neighboring healthy
individuals of these two hosts harbor several DSM
morphotypes. Sequence analyses of nuclear ITS and 18S
rDNA regions of the dominant morphotypes allowed their
identification as a unique spectrum of DSM, being quite
diverse and distinct from those so far described in other
host plants investigated. Recognition of systematic
affinities was possible with varying degrees of resolution
for the different morphotypes, ranging from species-level
identification to placement within Ascomycete subclasses.
Association of these fungi with both hosts spanned at least
eleven years; they thus appear to be true root colonizers
coexisting with the accredited mycorrhizal symbionts. In
spite of their taxonomic diversity, such DSM displayed
some morphophysiological convergence justifying their
recognition as an ecological group. One morphotype was
identified as Rhizopycnis vagum D.F. Farr, a recently
described fungus so far known as a root pathogen of crop
plants. Studies of population genetics of this fungus and
pathogenicity assays are unraveling the actual range of its
ecological plasticity.
182 - Mutualistic colonization of roots by endophytic
fungi
B. Schulz 1* , A.-K. Römmert 1 , U. Dammann-Tugend 1 , M.
Götz 2 , T. Lange 3 , M. Oros-Sichler 2 & C. Boyle 1
1
Institut für Mikrobiologie, Technische Universität
Braunschweig, Spielmannstr. 7, D-38106 Braunschweig,
Germany. - 2 Biologische Bundesanstalt, Messeweg, D-
38104 Braunschweig, Germany. -
3 Institut für
Pflanzenbiologie, Technische Universität Braunschweig,
Mendolssohnstrasse, 38106 Braunschweig, Germany. - Email:
b.schulz@tu-bs.de
Fungal colonization of plant roots is often mutualistic, a
well known example being that of mycorrhiza, but also
interactions of dark septate endophytes (DSE) and the
mycorrhizal-like basidiomycete Piriformaspora indica
with roots of their hosts may counteract the negative effects
of stress or improve growth of the host. We compared
endophytic colonizations of the roots with those of aboveground
plant organs. Endophytic infections of Fusarium
spp. in the shoots of bean and barley were asymptomatic,