March 2008 - Mycological Society of America

However, these genes show numerous variants within a single fungal
isolate. The mitochondrial large subunit rDNA (mtLSU) has been
shown to be homogeneous within isolates of Glomus, but the sequence
data were limited to G. intraradices and G. proliferum. By using previously-designed
and new specific primers, we obtained mtLSU sequences
from other taxa of the Glomeromycota. Although clearly
showing a phylogenetic relationship, partial mtLSU sequences of
Scutellospora verrucosa differ from Glomus in their intron content and
are distinct in their exon sequence. Additional mtLSU sequences from
the Gigasporaceae and other families are investigated. Using these data,
the variable regions might help in distinguishing genotypes and the
more conserved regions will be used to elucidate the phylogeny of the
Glomeromycota. Poster
Thompson, Lisa*, Goldmann, Lauren, Wright, Angela and Weir, Alex.
Department of Environmental & Forest Biology, SUNY College of Environmental
Science & Forestry, 241 Illick Hall, 1 Forestry Drive,
Syracuse, NY 13210, USA. lithomps@syr.edu. Laboulbeniales from
Costa Rica. There has been much recent interest in documenting the
mycota of Costa Rica, with particular emphasis on the macrofungi, and
lichenized and non-lichenized ascomycetes associated with wood. The
diversity of fungi associated with insects, however, has received little
attention to date. As one of the focal collection areas for our NSF-PEET
Grant investigating the phylogeny of Laboulbeniales, we have unveiled
a surprising richness of Laboulbeniales taxa within this region. To date
only limited sampling has taken place in Puentarenas Province and at
Monteverde, yet, more than 50 species of Laboulbeniales have been
recorded. This represents a significant addition to the approximately 20
known species recorded by Thaxter, and more recently by the late R.K.
Benjamin. Of the 50 newly recorded taxa approximately half are
thought to represent undescribed species. We are continuing to examine
our collections and are confident that much more remains to be discovered
about the Laboulbeniales of this region. Poster
Toledo-Hernandez, Carlos, Zuluaga-Montero, Anabella, Rodriguez,
Jose A. and Bayman, Paul.* Departamento de Biologia, Universidad de
Puerto Rico - Rio Piedras, PO Box 23360, San Juan PR 00931. pbayman@uprrp.edu.
Variation in fungal communities of sea fans (Gorgonia
ventalina). Diseases are threatening many species of corals in the
Caribbean. One of the best-known diseases of corals is aspergillosis of
sea fans, caused by Aspergillus sydowii. However, the source of inoculum
and the mycoflora of healthy sea fans are largely unknown; it is not
clear if the presence of the pathogen is sufficient to cause aspergillosis
or how the microbial community changes when a colony becomes diseased.
We isolated fungi from sea fans (Gorgonia ventalina) with aspergillosis,
healthy sea fans and sea water in Puerto Rico from 2003-
2007. Fungi were identified by sequencing the nuclear ribosomal ITS
region. Different methods of isolation of fungi were compared. For A.
flavus, one of the most common species, aflatoxin production in vitro
was determined by HPLC. We found variation in fungal communities
of sea fans at several different levels: differences between healthy and
infected tissues, differences between sea fans and seawater, differences
between sampling dates, differences in fungi isolated from different
sizes of tissue pieces, and differences in aflatoxin production among
isolates. In many cases these differences were significant. This variability
complicates efforts to understand the disease, and suggests that
several opportunistic pathogens may be responsible. Poster
Trail, Frances 1, 2 * and Hallen, Heather E. 11 Department of Plant Biology
and 2 Department of Plant Pathology, Michigan State University, East
Lansing, MI 48824-1312, USA. trail@msu.edu. Identification of genes
involved in sexual development in Gibberella zeae (anamorph
Fusarium graminearum) by expression analysis. We have used
Affymetrix GeneChips to track differences in transcript abundance during
a sexual development time course, from vegetative hyphae (control)
to mature perithecia with asci and multiseptate ascospores. For approximately
ten percent of the genes, transcripts were present during one of
the five sexual development stages, yet were absent from vegetative hyphae
and several other vegetative growth conditions. While this distri-
40 Inoculum 59(2), March 2008
bution does not prove that the genes corresponding to these probesets
are unique to sexual development (some genes may be expressed in vegetative
growth conditions not yet studied), it does provide a distinct
group of genes associated with development on which to focus further
studies. At 72 hours following induction of sexual development, the
timepoint at which transcripts for meiotic processes and ascus and ascospore
differentiation are likely to be first detected, the highest number
of uniquely-expressed genes is present. This is the first whole-genome
analysis of expression during sexual development in a filamentous ascomycete.
Symposium Presentation
Trail, F. 1,2 *, Hallen, H. E. 1 and Cavinder, B. 31 Department of Plant Biology,
2 Department of Plant Pathology, and 3 Genetics Program, Michigan
State University, East Lansing, MI, USA. trail@msu.edu. Update
on the genetics and physiology of the mechanism of forcible ascospore
discharge. With an acceleration of 8,500,000 m s -2 within the
ascus, the ascospores of Gibberella zeae (anamorph Fusarium graminearum)
hold the biological record (Trail et al., 2005). However, the
minute size of the spores compared to most other far-flung propagules
goes hand in hand with prodigious acceleration, and there do not appear
to be any unusual structures driving the spore release. We have begun
structural and genetic dissection of the ascus to determine the components
that drive its unusual function. We will present an update of the
genetic and physiological components we have identified that contribute
directly to spore release. Poster
Trusty, Paul* and Cripps, Cathy L. Plant Sciences and Plant Pathology,
Montana State University, Bozeman, MT 59717, USA.
pauletrusty@yahoo.com. Ectomycorrhizal fungi of whitebark pine
seedlings on burned and adjacent unburned forests in regard to
restoration strategies. Whitebark pine (Pinus albicaulis) is a keystone
species in the Northern Rocky Mountains critical to watersheds and
maintenance of wildlife diversity at high elevations. Blister rust, mountain
pine beetles, and fire suppression have compounded the decline of
whitebark pine forests throughout its range. Serious efforts are underway
to restore these forests using natural and prescribed fires as a management
tool to eliminate competitors and stimulate whitebark pine
seedling regeneration. An important restoration component is post-fire
plantings of rust resistant whitebark pine seedlings. This study is evaluating
the mycorrhizal colonization of rust resistant nursery seedlings
in the Fridley Burn, (Gallatin County, MT) in comparison to those regenerating
naturally in the burn and on adjacent unburned forest. Morphotyping
and ITS analysis of ectomycorrhizal roots revealed that 1) all
seedlings were colonized with fungi, 2) the severe burn reduced diversity
and caused a shift in fungi (burned: Pseudotomentella, Amphinema,
Wilcoxina, Thelephoroids: unburned: Piloderma, Cenococcum,
Rhizopogon spp; both: Rhizopogon), and 3) exotic nursery fungi persist
after 5 years. This study will help determine if appropriate mycorrhizal
fungi are available on severe burns for effective mycorrhization of
whitebark pine seedlings planted after a severe fire for restoration purposes.
Poster
Tuggle, Alicia A., Melhart, Christy A., Slay, Michael E. and Stephenson,
Steven L.* Department of Biological Sciences, University of
Arkansas, Fayetteville, AR 72701, USA. slsteph@uark.edu. Cave
crickets as vectors for dictyostelids in caves. A study was carried out
to determine if dictyostelid cellular slime molds (dictyostelids), which
are known to occur in cave habitats, were associated with a species of
cave cricket (Ceuthophilus gracilipes) in Pigeon Roost Cave in Benton
County, Arkansas. Cave crickets were captured alive and rinsed in a
water/wetting agent solution in a small sterile plastic tube. The rinsed,
live crickets were then placed in a container to collect any fecal matter
they might deposit. The tubes with the water/wetting agent solution as
well as the fecal matter left in the container were plated out on hay-infusion
agar and these plates examined for colonies of dictyostelids.
Four species of dictyostelids were recovered from the rinse wash and/or
the fecal matter, which suggests that the cave crickets can serve as vectors
to transport dictyostelid spores within the cave habitat. Since the
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