March 2008 - Mycological Society of America

lineages of land plants and (2) biogeographic provinces ranging from
the arctic to the tropics, I will explore the degree to which a large-scale,
single-locus (bar-code) data set based on the nuclear ribosomal internal
transcribed spacer (ITS) can further our understanding of fungal diversity
and ecology. Specifically, I will (1) address patterns of geographical
distributions, taxonomic makeup, host specificity, and diversity of
endophytic fungi using a data set of over 6000 ITS sequences from cultures
and environmental samples; (2) explore empirical approaches for
delimiting meaningful taxonomic units from ITS data alone; (3) highlight
a variety of limitations imposed by the single-locus and ITS-specific
approach, and demonstrate that such issues vary in intensity
among clades of Ascomycota and among different geographic sites; (4)
discuss the degree to which ITS data are congruent and incongruent
with inferences based on multi-locus datasets; and (5) describe several
new methods for visualizing ITS data in spatial and phylogenetic contexts,
with the goal of critically evaluating the biological realism and inferential
strength of the bar-code approach for studies of highly diverse
fungi. Symposium Presentation
Atkinson, Toni J. 1 *, Orlovich, David, A. 2 and Miller, Andrew N. 11 Section
for Biodiversity, Illinois Natural History Survey, 1816 S. Oak St.,
Champaign, IL 61820, USA, 2 Department of Botany, University of
Otago, P.O. Box 56, Dunedin 9054, New Zealand.
toni@botany.otago.ac.nz. From the Land of the Long White Cloud
to the Great Smoky Mountains: New Zealand and Appalachian diversity
among woody decay pyrenomycetes. The New Zealand archipelago,
a temperate, oceanic island group 1600 km south-east of
Australia, forms the largest landmass in the south Pacific. Island biotas
are usually considered ‘depauperate’ when compared with those of
continents. New Zealand does have fewer plant and animal taxa than a
continent, but its biota has long been noted for its uniqueness. Recent
research among woody decay pyrenomycetes in New Zealand, while
finding a high level of endemism, nonetheless shows that families, genera,
and frequently morphological species are shared with the continental
northern hemisphere. From knowledge to date, we will discuss
the striking morphological and molecular similarities and differences
between New Zealand and Appalachian members of the Lasiosphaeriaceae,
Chaetosphaeriaceae, and Helminthosphaeriaceae. Contributed
Presentation
Avis, Peter G.*, Leacock, Patrick and Mueller, Greg M. Department of
Botany, The Field Museum of Natural History, 1400 South Lake Shore
Drive, Chicago IL 60605, USA. pavis@fieldmuseum.org. Scale dependent
responses of ectomycorrhizal fungal communities to simulated
nitrogen deposition in oak forests of the Chicago region. Nitrogen
deposition can dramatically impact the diversity and species
composition of ectomycorrhizal communities, but it is uncertain at
what level of added nitrogen or at what spatial scale these responses
occur in temperate deciduous ecosystems. We tested the impact of projected
realistic increases in nitrogen deposition levels in the Chicago region
by measuring the response of ectomycorrhizal fungi to nitrogen
fertilization at two oak dominated forests. We systematically surveyed
ectomycorrhizal sporocarps in treatment and control plots from 2003-
2006, but did not detect any significant differences in either abundance
or species richness of ectomycorrhizal mushrooms. Belowground, we
measured ectomycorrhizal fungi colonizing roots by morphological
and molecular methods including terminal restriction length fragment
length polymorphisms and sequencing. We detected significant differences
between treatment and controls in species richness and composition
at the scale of the treatment plots but not at the scale of the soil core
or individual roots. Such responses indicate that realistic future increases
of nitrogen deposition could impact ectomycorrhizal communities,
especially at larger spatial scales. Contributed Presentation
Baucom, Deana*, Romero, Marie and Creamer, Rebecca. New Mexico
State University, Las Cruces, NM 88003, USA. dbaucom@nmsu.edu.
Morphological and genetic characterization of
new fungal endophytes of locoweed found in six western states.
Toxic locoweeds (Astragalus and Oxytropis spp.) found throughout the
6 Inoculum 59(2), March 2008
western USA are accountable for significant losses to grazing animals.
Fungal endophytes of locoweed are responsible for production of the
toxic alkaloid swainsonine and have been shown to cause symptoms of
locoweed toxicity outside of the plant environment. Fungal endophytes
of locoweed have been characterized previously from only a few of the
many species of Astragalus and Oxytropis. To further expand our understanding
of this endophytic fungus, we examined culture morphology
and genetics of fungi isolated from nine locoweed species collected
from six states. Although all isolates were typically slow growing in
culture, as indicative of the locoweed fungal endophyte, we found
novel morphological characteristics that were not seen in the previously
limited examination of locoweed species. Genetic differences were
also observed in nucleic acid sequences of the ITS (internal transcribed
spacer) and gpd (glyceraldehyde phosphate dehydrogenase) regions of
the different isolates. The morphological and genetic differences we
found illustrate the diversity of the fungal endophyte and allow us to
distinguish between isolates collected from a number of different locoweed
species. Poster
Beard, Charles E. Department of Entomology, Soils, and Plant Sciences,
Clemson University, Clemson, SC 29634, USA.
cbrd@clemson.edu. Trichospore shapes of the trichomycete fungus
Harpella melusinae. The trichomycete fungus Harpella melusinae is a
common symbiote in the midgut of larval black flies. The variation and
wide distribution of Harpella melusinae probably represents the existence
of a species complex, but limited morphological characters are
available for discriminating possible cryptic species. The asexual
spores (trichospores) of the fungus vary from coiled to straight. Straight
and coiled or curved trichospores have not been found on the same thallus.
Straight-spored thalli might represent a species or genotype distinct
from coiled- or curved-spore thalli. We are testing the heritability of
spore shape by allowing horizontal transmission of the fungus from
field-collected larvae to lab-reared trichomycete-free larvae. The
straight spore shape (from Simulium innoxium) carries over to the new
host (Simulium vittatum). Coiled spores are more difficult to collect and
horizontal transmission is less successful, suggesting that the lab-reared
larvae are less competent hosts for the coiled spores from field-collected
larvae (Simulium tuberosum grp.), or that the coiled spores are less
infective in this study. Spore shape might be related to other parameters
such as host physiology. We also demonstrate that horizontal transmission
between host species occurs. Contributed Presentation
Bechara, Mark A. 1 *, Heinemann, Paul 1 , Walker, Paul N. 1 and Romaine,
C. Peter. 21 Department of Agricultural and Biological Engineering, 249
Agriculture Engineering Building, The Pennsylvania State University,
University Park, PA 16802, USA, 2 Department of Plant Pathology, 211
Buckhout Laboratory, The Pennsylvania State University, University
Park, PA 16802, USA. mab568@psu.edu. The development of noncomposted
grain-based substrates for mushroom production. Two
different systems for Agaricus bisporus (button mushroom) production
are proposed as alternatives to the traditional environmentally problematic
mushroom production system that relies on composting of plant and
animal organic matter. Each system involves processing grains into suitable
mushroom substrates. The first system proposes the use of commercial
grain spawn, the vehicle typically used to inoculate traditional
substrates, supplemented with high protein delayed-release supplements.
In this system, grain spawn producers supply mushroom producers the
entire substrate for mushroom production. The second system consists of
producing mushrooms on sterilized grains supplemented with oilseeds.
In this system, an aseptic processing system would be located on-site at
the mushroom production facility to sterilize grain substrates. For the second
system, mushroom producers would need to get their inoculum from
grain spawn producers to inoculate the sterilized substrates. The highest
yield of mushrooms for the commercial grain spawn substrate supplemented
with delayed-release supplements was 13.7 kg/m 2 , whereas yield
from substrates composed of cereal grains and oilseeds was 16.9 kg/m 2 .
A discussion about the advantages and disadvantages of each alternative
mushroom production system will be addressed. Poster
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