March 2008 - Mycological Society of America

Everhart, Sydney E.*, Keller, Harold W. and Ely, Joseph S. Department
of Biology, University of Central Missouri, Warrensburg, MO
64093, USA. everhart@ucmo.edu. Quantitative analysis of bark
characteristics and epiphyte cover on distribution patterns of corticolous
myxomycetes (true slime molds) in the tree canopy. Corticolous
myxomycetes form plasmodia and fruiting bodies on the bark of
living trees and vines. Bark was sampled from 30 trees and 30
grapevines along a vertical transect up to 15 m, to examine the relationship
between bark characteristics (pH, water absorption, and thickness),
epiphyte cover, geographic location, and myxomycete species.
Moist chamber culture technique was used to induce myxomycete
fruiting and bark pH was measured after 24 hours using an Orion 610
pH flat probe. Plates were scanned for presence of myxomycetes after
4, 16, and 32 days, and percent cover data was collected in a stratified
random design on day 32. Different species of trees and grapevines had
significantly different bark characteristics, however, the only tree
which had a significant difference in the vertical variation of any bark
characteristic was P. occidentalis. Accordingly, P. occidentalis also
had a significant decrease in richness of myxomycete species with increasing
height in the canopy. Non-metric multi-dimensional scaling
and multi-response permutation procedure were performed; distinct
species assemblages correspond to each tree and grapevine species and
were differentiated by pH, DBH, and elevation. Financially supported
by NSF Award DEB-0343447, National Geographic Research and Exploration
Award-7272-02, and Discover Life in America Awards
2001-26 and 2002-17. Poster
Exeter, Ronald L. 1 and Norvell, Lorelei L. 2 * 1 USDI Bureau of Land
Management, 1717 Fabry Road SE, Salem, OR 97306-1720, USA,
2 Pacific Northwest Mycology Service, Portland, OR 97229-1309.
USA. llnorvell@pnw-ms.com. Ramarias of Pacific Northwest. The
colorful coral fungi are among the loveliest denizens of the vast temperate
rainforests of western North America. The US government’s
Northwest Forest Plan targeted 28 rare or uncommon taxa of Ramaria
(Basidiomycota, Gomphales) as worthy of survey and management
within the range of the endangered northern spotted owl. Examination
of both type and recent collections and reference to classic papers by
Marr & Stuntz, Petersen, and others led to the development of a single
key identifying all species in the region and the discovery of a new
species, Ramaria rasilisporoides. A recent 157-page USDI-BLM publication,
Ramaria of the Pacific Northwestern United States (Exeter,
Norvell & Cazares, 2006), treats all four subgenera: Lentoramaria,
Echinoramaria, Ramaria, and Laeticolora. The lavishly illustrated
monograph contains 193 color photos and covers all 90 of the region’s
known species and varieties. Each one- to two-page taxonomic treatment
presents synonyms, field descriptions, summary technical descriptions
from hard-to-find publications, ecological and distributional
data, diagnostic characters, additional comments, and references.
Known phylogenetic relationships, taxonomic characters, tables, a new
glossary, complete bibliography, and previously published microscopic
keys are also provided. Poster
Fedorova, Natalie 1 , McDonagh, Andrew 2 , Yu, Yan 1 , Armstrong-
James, Darius 2 , Haynes, Ken 2 , Bignell, Elaine 2 and Nierman, William
C. 1 * 1 J. Craig Venter Institute, Rockville, MD, USA, 2 Department of
Molecular Microbiology and Infection, Imperial College London, London
SW7 2AZ, UK. wnierman@jcvi.org. Transcriptome analysis of
Aspergillus fumigatus during early stage mammalian lung infection.
Aspergillus fumigatus is a particularly virulent fungus whose
spores infect human hosts having compromised immunity. Its success
as a pathogen is unique among close phylogenetic relatives and thought
to depend upon concerted control over multiple functions including nutrient
acquisition, metabolic plasticity and immunotoxin production. A.
fumigatus virulence, and that of other opportunistic fungal pathogens,
has escaped definition at the molecular level promoting scepticism regarding
the existence of ‘true’ virulence factors in such species. Newly
published genomes for several fungal pathogens and emerging evidence
for epigenetic control of fungal virulence mechanisms support
the view that hierarchical co-ordination of multiple processes may un-
16 Inoculum 59(2), March 2008
derpin fungal pathogenicity. Comparative genomics analysis has raised
suspicions that niche adaptation genes may reside in lineage-specific
regions of the Aspergillus genomes. To assess transcriptional co-ordination
during host niche-adaptation we have characterised A. fumigatus
gene expression during initiation of mammalian infection, using laboratory
cultured germlings as a comparator. We show that during the
early phase of infection A. fumigatus co-ordinately regulates expression
of gene clusters encoding biosynthesis of gliotoxin, iron siderophore,
and five other putative secondary metabolites. In addition our analyses
identify multiple clusters of physically linked, co-regulated genes,
which are likely to share a concerted function, which cannot be predicted
from genomic analyses alone. The analysis demonstrated a
genome-wide transcriptional reprogramming favoring subtelomeric
and lineage-specific genes. Taken together these observations reveal a
pattern of co-ordinated gene regulation thus far undiscovered from in
vitro analyses, and provides the first transcriptional snapshot of a fungal
genome during initiation of mammalian infection. Symposium
Presentation
Ferreira, Renato B. 1 , Inácio, Carlos A. 2 and Dianese, José C. 21 Centro
Universitário de Brasília, UNICEUB, Asa Norte, Brasília, DF, Brazil,
2 Dep. de Fitopatologia, Universidade de Brasília, 70910-900, Brasília,
DF, Brazil. jcarmine@unb.br. New Ascomycota on petioles of Mauritia
flexuosa (Palmae) from Central Brazil. Mauritia flexuosa (Burití)
is a palm tree found endemically on swampy areas (“veredas”) of
the cerrado. In 2006 leaf samples were collected from the State of
Goiás in Central Brazil. Two new Ascomycota were detected on leaf
petioles and are now described, as follows: 1. a new xylariaceous ascomycete,
forming lesions that are darkened and irregular; ascomata 50
– 213 × 105 - 300 µm, black, partially erumpent, irregular in shape with
a convoluted internal lining, and 26 – 13 µm thick black outer wall; paraphyses:
1 µm diam., hyaline, septate, branched; asci: 30 - 50 × 7 - 15
µm, cylindrical, unitunicate, 7-8 ascospores, J+; ascospores: 11 – 17 ×
5 - 10 µm, ellipsoidal, guttulate when young becoming light-brown to
brown, uniseriate, aseptate, with mucilaginous sheath and a clear germ
slit. 2. a new Saccardiaceae (Dothideomycetidae) forming colonies 8-
21 mm diam., dark, circular, confluent; greyish, containing dark ascomata;
ascomata 75 – 103 × 225 - 475 µm, superficial, black, circular,
discoid, non-ostiolate; upper wall 13 – 24 µm; paraphyses: 40 – 60 × 1
– 2 µm diam., hyaline, filiform, simple; asci: 20 – 45 × 16 - 34 µm, globose
to ovoid, bitunicate; ascospores: 17 – 30 × 8 - 14 µm, hyaline, ellipsoidal,
6 - 8 transversal septa and rare longitudinal septa, covered by
a mucilaginous sheath. Poster
Ferrer, A. 1 *, Sarmiento, C. 2 and Shearer, C.A. 1 1 Plant Biology, University
of Illinois, 505 S. Goodwin Ave., Urbana, Il 61801, USA, 2 Universidad
de Los Andes, Bogota, Colombia. aferrer@life.uiuc.edu. Distribution
of ascomycete diversity in Costa Rican freshwater
habitats. Diversity patterns of freshwater ascomycetes in the tropics
are undescribed. As part of an ongoing study of the distribution of
freshwater ascomycetes along latitudinal gradients, we undertook a
comparative survey of three lowland sites and one lower montane site
in Costa Rica. Submerged wood was collected from streams at La
Selva, Barra del Colorado and Las Cruces National Park and from
lentic habitats in Caño Negro. At each site, 30 samples of submerged,
partially decomposed woody debris were collected. Wood samples
were incubated in moist chambers and examined periodically for fruiting
body production. Species richness was higher than that reported
from temperate areas and included new species discovered at each site.
No one genus or family dominated any site. We recorded very few
species that were shared between sites indicating high alpha and beta
diversity in this fungal community. Numerous species collected from
Costa Rica also have been reported from similar habitats in the paleotropics,
suggesting a global distribution for some tropical freshwater
species. Our results highlight the importance of sampling multiple sites
to capture freshwater fungal diversity, and indicate that many freshwater
taxa remain to be discovered. Poster
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