March 2008 - Mycological Society of America

some ectomycorrhizal mushroom species. Truffles, the hypogeous ascocarps
of the ectomycorrhizal genus Tuber, are currently cultivated in
orchards to offset declining wild production. Truffle cultivation begins
by germinating host seeds, inoculating the host seedlings with truffle
spores, growing the seedlings in greenhouses until the mycorrhizal relationship
is well established, and then outplanting the seedlings. Little
is known in the USA about the effect of native ectomycorrhizal species
on colonization of host trees by the European Burgundy truffle fungus
(Tuber aestivum). Here we identify the fungal community composition
in the greenhouse in three types of potting media, and then track fungal
community composition for two years after outplanting. We found that
the infection rates of fungal species commonly present in the greenhouse
decline to low levels in the field. We also found that after two
years of field growth, both Tuber aestivum colonization levels and native
ectomycorhizal species richness and abundance increased, indicating
that native species, in the short term, do not displace the introduced
Tuber spp. Contributed Presentation
Raja, H.A.*, Ferrer, A. and Shearer, C.A. Department of Plant Biology,
University of Illinois at Urbana-Champaign, Urbana, IL 61801,
USA. raja@uiuc.edu. The latitudinal, habitat, and substrate distribution
of freshwater ascomycetes. Freshwater ascomycetes play an
important ecological role in aquatic ecosystems as decomposers of organic
matter. Despite evidence of their ecological role, there is a lack
of knowledge of freshwater ascomycete identities, phylogenetic relationships,
geographical distributions and species richness patterns. To
address these issues, we are surveying freshwater ascomycetes using a
latitudinal approach by collecting submerged herbaceous and woody
debris in freshwater habitats through North and Central America to answer
the following questions: 1) Do community composition and
species richness differ along latitudinal gradients from the subarctic to
tropical areas? 2) Do species richness and composition differ between
lentic and lotic habitats? 3) Are species substrate specialists or generalists?
Research to date reveals; 1) Species composition is quite different
among subarctic, temperate and tropical latitudes, but we found high
species overlap at temperate and tropical latitudes between the eastern
and western hemisphere; 2) Some geographically broadly distributed
species occur in both lentic and lotic habitat types, but more species
occur only in one or the other habitat; 3) More species occur on wood,
while fewer species are found on herbaceous material; species occurring
on wood were also observed on herbaceous substrates, while those
colonizing herbaceous substrates were seldom recorded on wood. Contributed
Presentation
Raja, H.A. 1 *, Miller, A.N. 2 and Shearer, C.A. 1 1 Department of Plant
Biology, University of Illinois at Urbana-Champaign, Urbana, IL
61801, USA, 2 Illinois Natural History Survey, Center for Biodiversity,
1816 Oak Street, Champaign, IL 61820, USA. raja@uiuc.edu.
Aquapoterium pinicola gen. et sp. nov. from freshwater habitats in
Florida. During investigations of freshwater ascomycetes along the
Florida peninsula, a very small, hyaline discomycete fungus was found
on submerged pine needles from lotic and lentic habitats. Based on
morphological characteristics and 28S large subunit nuclear ribosomal
sequence data, the new genus is placed in the Helotiales (Leotiomycetes).
The characteristic features of this new fungus are white to
cream colored, minute apothecium, stipitate or sessile, appearing goblet
like; cylindric-clavate, slightly cymbiform asci; hyaline smoothwalled,
1-celled, guttulate, short clavate-cylindric ascospores surrounded
by an irregular mucilaginous sheath; subhymenium, ectal
excipulum, medullary excipulum of the apothecium simple and composed
of textura oblita type of tissue. The fungus differs from other
closely related species in the Helotiales such as Aquadiscula and Hymenoscyphus
in having a relatively simple excipulum made up of only
one type of tissue. Aquapoterium pinicola, a new genus and species,
will be described and illustrated. Poster
Redecker, Dirk 1 *, Raab, Philipp 1 , Oehl, Fritz 1 , Camacho, Francisco J. 2
and Courtecuisse, Regis. 3 1 Botanical Institute, University of Basel,
Switzerland, 2 Dept. of Environmental Science, University of Califor-
34 Inoculum 59(2), March 2008
nia, Riverside, USA, 3 Dept. of Botany, University of Lille, France.
dirk.redecker@unibas.ch. Phylogeny of a novel clade of sporocarpforming
species of glomeromycotan fungi. Since the early times of
taxonomy of arbuscular mycorrhizal fungi (Glomeromycota) the focus
has shifted from sporocarpic species to species forming spores singly.
For many of the sporocarpic species described in the 1970’s and earlier,
no molecular data have been available and their phylogenetic position
thus has remained unclear. We obtained nuclear-encoded ribosomal
DNA sequences from specimens of glomeromycotan sporocarps
from tropical islands that were assigned to the morphospecies Glomus
fulvum, Glomus pulvinatum and the newly-described species Glomus
megalocarpum. Molecular phylogenetic analyses placed all species analyzed
as a monophyletic sister group to the Diversispora spurca/Glomus
versiforme clade (Glomus group C) within the Diversisporales.
The phylogenetic divergence from other known species suggests
that this clade may constitute a new genus. The consequences of these
findings for taxon definition within the Diversisporales and the possible
adaptation of these taxa to islands will be discussed. Contributed
Presentation
Redhead, S.* Neatby Bldg., ECORC, CEF, Agriculture & Agri-Food
Canada, Ottawa, Ontario, Canada, K1A 0C6. redheads@agr.gc.ca.
Naming pleomorphic fungi – the debate on how to deal with Article
59 of the International Code of Botanical Nomenclature. Fungi
are the only living organisms that are legitimately permitted by any
Code of Nomenclature to bear multiple Latin scientific binomial
names. This convention is rooted in the historical treatment of fungal
names before their life-cycles were fully understood. It has been allowed
to continue because it is still extremely difficult to precisely
match morphological forms with others expressed by the same holomorph,
and, at the generic level, to recognize as congeneric taxa that
may not resemble each other morphologically. The advent of phylogenetic
analyses of fungi using DNA-DNA sequence comparison independent
of phenetic morphological comparisons has re-opened the
door on the methodology for describing and naming fungi with multiple
morphologies. Molecular based phylogenies now allow mycologists
to directly compare and confidently place morphologically dissimilar
taxa leading to the recognition of or confirming previous
suspicions of conspecificity or other close relationships. However, with
over 250 years of historical names, agreed upon rules for naming and
describing different morphological forms (anamorphs, teleomorphs),
and a lack of consensus or alternatives, mycologist face the dilemma of
trying to standardize the naming of fungi in line with other sciences,
without creating chaos. The issue is so divisive amongst mycologists
that it served as the lightning rod for debate at the 8th International Mycological
Congress (IMC8) on whether to abandon completely the International
Code of Botanical Nomenclature (ICBN). Previous discussions
at IMC7 resulted in proposals to change ICBN Art. 59, which
deals with names for pleomorphic fungi, published by David
Hawksworth. Changes were made to ICBN Art. 59 at the 17th International
Botanical Congress, based upon these suggestions, and epitypification
of anamorph names by teleomorphs is now permitted. However,
this action has not yet been tested and several published
recommendations were sent to a Special Committee assigned to draw
up recommendations for the next IBC. This Committee is now examining
all of Art. 59 as well as the outstanding previously published proposals.
Symposium Presentation
Rehner, Stephen A. 1 * and Meyling, Nicolai. 21 Insect Biocontrol Laboratory,
USDA-ARS, Beltsville, MD 20705, USA, 2 Department of Ecology,
The Royal Veterinary and Agricultural University, Frederiksberg,
Denmark. Stephen.Rehner@ars.usda.gov. Local phylogenetic and
population genetic diversity of the entomopathogen Beauveria in
adjacent agricultural and non-agricultural habitats. The hierarchical
genetic diversity of Beauveria in a tilled agricultural field and an adjacent
naturally vegetated hedgerow in Denmark was determined. Beauveria
isolates originated from soil, phylloplanes and latent-infected in-
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